47 CFR 87.145 - Acceptability of transmitters for licensing.

Code of Federal Regulations, 2011 CFR

2011-10-01

... square error which assumes zero error for the received ground earth station signal and includes the AES transmit/receive frequency reference error and the AES automatic frequency control residual errors.) The...

Prototype Environmental Assessment of the impacts of siting and construction of an SPS ground receiving station

NASA Technical Reports Server (NTRS)

Hill, J.

1980-01-01

A prototype assessment of the environmental impacts of siting and constructing a Satellite Power System (SPS) Ground Receiving Station (GRS) is reported. The objectives of the study were: (1) to develop an assessment of the nonmicrowave related impacts of the reference system SPS GRS on the natural environment; (2) to assess the impacts of GRS construction and operations in the context of actual baseline data for a site in the California desert; and (3) to identify critical GRS characteristics or parameters that are most significant in terms of the natural environment.

End-to-End Data System Architecture for the Space Station Biological Research Project

NASA Technical Reports Server (NTRS)

Mian, Arshad; Scimemi, Sam; Adeni, Kaiser; Picinich, Lou; Ramos, Rubin (Technical Monitor)

1998-01-01

The Space Station Biological Research Project (SSBRP) Is developing hardware referred to as the "facility" for providing life sciences research capability on the International Space Station. This hardware includes several biological specimen habitats, habitat holding racks, a centrifuge and a glovebox. An SSBRP end to end data system architecture has been developed to allow command and control of the facility from the ground, either with crew assistance or autonomously. The data system will be capable of handling commands, sensor data, and video from multiple cameras. The data will traverse through several onboard and ground networks and processing entities including the SSBRP and Space Station onboard and ground data systems. A large number of onboard and ground (,entities of the data system are being developed by the Space Station Program, other NASA centers and the International Partners. The SSBRP part of the system which includes the habitats, holding racks, and the ground operations center, User Operations Facility (UOF) will be developed by a multitude of geographically distributed development organizations. The SSBRP has the responsibility to define the end to end data and communications systems to make the interfaces manageable and verifiable with multiple contractors with widely varying development constraints and schedules. This paper provides an overview of the SSBRP end-to-end data system. Specifically, it describes the hardware, software and functional interactions of individual systems, and interface requirements among various entities of the end-to-end system.

Korea Geodetic VLBI Station, Sejong

NASA Technical Reports Server (NTRS)

Donghyun, Baek; Sangoh, Yi; Hongjong, Oh; Sangchul, Han

2013-01-01

The Sejong VLBI station officially joined the IVS as a new Network Station in 2012. This report summarizes the activities of the Sejong station during 2012. The following are the activities at the station: 1) VLBI test observations were carried out with the Tsukuba 34-m antenna of the GSI in Japan. As a result, the Sejong antenna needs to improve its efficiency, which is currently in progress, 2) A survey to connect the VLBI reference point to GNSS and ground marks was conducted, and 3) To see the indirect effects of RFI (Radio Frequency Interference) at this place, we checked the omni-direction (AZ 0? to 360?, EL fixed at 7?) for RFI influence.

Space Station Biological Research Project: Reference Experiment Book

NASA Technical Reports Server (NTRS)

Johnson, Catherine (Editor); Wade, Charles (Editor)

1996-01-01

The Space Station Biological Research Project (SSBRP), which is the combined efforts of the Centrifuge Facility (CF) and the Gravitational Biology Facility (GBF), is responsible for the development of life sciences hardware to be used on the International Space Station to support cell, developmental, and plant biology research. The SSBRP Reference Experiment Book was developed to use as a tool for guiding this development effort. The reference experiments characterize the research interests of the international scientific community and serve to identify the hardware capabilities and support equipment needed to support such research. The reference experiments also serve as a tool for understanding the operational aspects of conducting research on board the Space Station. This material was generated by the science community by way of their responses to reference experiment solicitation packages sent to them by SSBRP scientists. The solicitation process was executed in two phases. The first phase was completed in February of 1992 and the second phase completed in November of 1995. Representing these phases, the document is subdivided into a Section 1 and a Section 2. The reference experiments contained in this document are only representative microgravity experiments. They are not intended to define actual flight experiments. Ground and flight experiments will be selected through the formal NASA Research Announcement (NRA) and Announcement of Opportunity (AO) experiment solicitation, review, and selection process.

Design Document for Differential GPS Ground Reference Station Pseudorange Correction Generation Algorithm

DOT National Transportation Integrated Search

1986-12-01

The algorithms described in this report determine the differential corrections to be broadcast to users of the Global Positioning System (GPS) who require higher accuracy navigation or position information than the 30 to 100 meters that GPS normally ...

Comparison of System Identification Techniques for the Hydraulic Manipulator Test Bed (HMTB)

NASA Technical Reports Server (NTRS)

Morris, A. Terry

1996-01-01

In this thesis linear, dynamic, multivariable state-space models for three joints of the ground-based Hydraulic Manipulator Test Bed (HMTB) are identified. HMTB, housed at the NASA Langley Research Center, is a ground-based version of the Dexterous Orbital Servicing System (DOSS), a representative space station manipulator. The dynamic models of the HMTB manipulator will first be estimated by applying nonparametric identification methods to determine each joint's response characteristics using various input excitations. These excitations include sum of sinusoids, pseudorandom binary sequences (PRBS), bipolar ramping pulses, and chirp input signals. Next, two different parametric system identification techniques will be applied to identify the best dynamical description of the joints. The manipulator is localized about a representative space station orbital replacement unit (ORU) task allowing the use of linear system identification methods. Comparisons, observations, and results of both parametric system identification techniques are discussed. The thesis concludes by proposing a model reference control system to aid in astronaut ground tests. This approach would allow the identified models to mimic on-orbit dynamic characteristics of the actual flight manipulator thus providing astronauts with realistic on-orbit responses to perform space station tasks in a ground-based environment.

Validation of the SMOS-MIRAS Soil Moisture Product (SML2UDP) in the Pampean Region of Argentina

NASA Astrophysics Data System (ADS)

Niclòs, Raquel; Rivas, Raúl; Sánchez, Juan Manuel; García-Santos, Vicente; Doña, Carolina; Valor, Enric; Holzman, Mauro; Bayala, Martín Ignacio; Carmona, Facundo; Ocampo, Dora; Soldano, Alvaro; Thibeault, Marc

2014-05-01

A validation campaign was carried out to evaluate the SMOS-MIRAS Soil Moisture (SM) SML2UDP product (v5.51) in the Pampean Region of Argentina on February 2013. The study area was selected because it is a vast area of flatlands containing quite homogeneous rainfed croplands, with prevalence of soybean crops, considered SMOS nominal land uses (i.e., crops with vegetation heights not exceeding 1 to 2 m by opposition to trees). Transects of ground SM measurements were collected by Delta-T ThetaProbe ML2x SM probes within four ISEA-4H9 DGG SMOS nodes. The SM data obtained by each probe transect in each parcel were checked by collecting soil samples in the same parcels at the same time and measuring their masses. The gravimetric method was used to obtain reference values. An uncertainty of ± 0.03 m3m-3 was obtained for the ML2x probes. Additionally, they were calibrated in the laboratory for different SMs by saturating and drying a specific and representative variety of soil samples collected from the experimental parcels (loam, clay loam and silt loam samples). This calibration showed again accurate operations for the ML2x probes, which even attain uncertainties of ±0.01 m3m-3, in agreement with the manufacturer. The comparison of the SM transect data collected during the campaign with the SMOS-MIRAS SML2UDP product values showed a negative bias between concurrent SMOS data and ground SM measurements, which means a slight SMOS-MIRAS underestimation, and a standard deviation of ± 0.06 m3m-3. The validation sites were selected taking as reference the locations of permanent SM stations property of the Argentinean Comisión Nacional de Actividades Espaciales (CONAE, National Commission of Space Activities), Instituto Nacional de Tecnología Agropecuaria (INTA, National Institute of Farming Technology) and Instituto de Hidrología de Llanuras (IHLLA, Plain Hydrology Institute). During the campaign several transects were carried out in the parcels where permanent SM stations were located, mainly in those within one of the nodes (with 5 stations inside). The objective was to evaluate the station SM data reliability at the SMOS spatial resolution with the aim of using station data series as reference for SMOS-MIRAS SM product validations. A linear correlation was obtained between the ground SM values and the SM station data within the node, with a coefficient of determination of 0.98 and a fitting error of ± 0.010 m3m-3. Therefore, the station data adjusted to obtain node representative values are being evaluated as reference data to extend the validation of SMOS-retrieved data beyond the campaign results.

NRT Atmospheric Water Vapour Retrieval on the Area of Poland at IGG WUELS AC

NASA Astrophysics Data System (ADS)

Kaplon, Jan; Bosy, Jaroslaw; Sierny, Jan; Hadas, Tomasz; Rohm, Witold; Wilgan, Karina; Ryczywolski, Marcin; Oruba, Artur; Kroszczynski, Krzysztof

2013-04-01

Global Navigation Satellite Systems (GNSS) are designed for positioning, navigation and amongst other possible applications it can also be used to derive information about the state of the atmosphere. Continuous observations from GNSS receivers provide an excellent tool for studying the neutral atmosphere, currently in near real-time. The Near Real-Time (NRT) neutral atmosphere and water vapour distribution models are currently obtained with high resolution from Ground Base Augmentation Systems (GBAS), where reference stations are equipped with GNSS and meteorological sensors. The Poland territory is covered by dense network of GNSS stations in the frame of GBAS system called ASG-EUPOS (www.asgeupos.pl). This system was established in year 2008 by the Head Office of Geodesy and Cartography in the frame of the EUPOS project (www.eupos.org) for providing positioning services. The GNSS data are available from 130 reference stations located in Poland and neighbour countries. The ground meteorological observations in the area of Poland and neighbour countries are available from ASG-EUPOS stations included in EUREF Permanent Network (EPN) stations, airports meteorological stations (METAR messages stations), and stations managed by national Institute of Meteorology and Water Management (SYNOP messages stations). Institute of Geodesy and Geoinformatics (IGG) of Wroclaw University of Environmental and Life Sciences had created permanent NRT service of ZTD (Zenith Total Delay) estimation for the area of Poland from GPS observations called IGGHZG. The first part of the paper presents the methodology of NRT GNSS data processing for ASG-EUPOS stations for ZTD estimation and its comparison to the results coming from EPN ACs and Military University of Technology in Warsaw AC (MUT AC). Second part covers the procedure of IWV (atmospheric Integrated Water Vapour content) estimation at IGG from IGGHZG product and ZHD (Zenith Hydrostatic Delay) derived from Saastamoinen formula (1972) and meteorological observations from ASG-EUPOS stations, SYNOP (synoptic stations network) and METAR (airport meteorological stations). Paper presents comparison of IWV with the results from NWP (Numerical Weather Prediction) models HIRLAM (via EGVAPII - http://egvap.dmi.dk) and COAMPS (via MUT AC) as well.

Geocenter variations derived from a combined processing of LEO- and ground-based GPS observations

NASA Astrophysics Data System (ADS)

Männel, Benjamin; Rothacher, Markus

2017-08-01

GNSS observations provided by the global tracking network of the International GNSS Service (IGS, Dow et al. in J Geod 83(3):191-198, 2009) play an important role in the realization of a unique terrestrial reference frame that is accurate enough to allow a detailed monitoring of the Earth's system. Combining these ground-based data with GPS observations tracked by high-quality dual-frequency receivers on-board low earth orbiters (LEOs) is a promising way to further improve the realization of the terrestrial reference frame and the estimation of geocenter coordinates, GPS satellite orbits and Earth rotation parameters. To assess the scope of the improvement on the geocenter coordinates, we processed a network of 53 globally distributed and stable IGS stations together with four LEOs (GRACE-A, GRACE-B, OSTM/Jason-2 and GOCE) over a time interval of 3 years (2010-2012). To ensure fully consistent solutions, the zero-difference phase observations of the ground stations and LEOs were processed in a common least-squares adjustment, estimating all the relevant parameters such as GPS and LEO orbits, station coordinates, Earth rotation parameters and geocenter motion. We present the significant impact of the individual LEO and a combination of all four LEOs on the geocenter coordinates. The formal errors are reduced by around 20% due to the inclusion of one LEO into the ground-only solution, while in a solution with four LEOs LEO-specific characteristics are significantly reduced. We compare the derived geocenter coordinates w.r.t. LAGEOS results and external solutions based on GPS and SLR data. We found good agreement in the amplitudes of all components; however, the phases in x- and z-direction do not agree well.

Localizing Ground Penetrating RADAR: A Step Towards Robust Autonomous Ground Vehicle Localization

DTIC Science & Technology

2015-05-27

truth reference unit is coupled with a local base station that allows local 2cm accuracy location measurements. The RT3003 uses a MEMS -based IMU and...of different electromagnetic properties; for example the interface between soil and pipes , roots, or rocks. However, it is not these discrete...depth is determined by soil losses caused by Joule heating and dipole losses. High conductivity soils, such as those with high moisture and salinity

Habitability design elements for a space station

NASA Technical Reports Server (NTRS)

Dalton, M. C.

1983-01-01

Habitability in space refers to the components, characteristics, conditions, and design parameters that go beyond but include the basic life sustaining requirements. Elements of habitability covered include internal environment, architecture, mobility and restraint, food, clothing, personal hygiene, housekeeping, communications, and crew activities. All elements are interrelated and need to be treated as an overall discipline. Designing for a space station is similar to designing on earth but with 'space rules' instead of ground rules. It is concluded that some habitability problems require behavioral science solutions.

First opportunity to synchronize the ILRS network thanks to T2L2 on Jason-2

NASA Astrophysics Data System (ADS)

Exertier, Pierre; Belli, Alexandre; Courde, Clément; Vernotte, François

2016-07-01

The Time Transfer by Laser Link (T2L2, on-board the oceanographic satellite Jason-2 at 1335 km) experiment allows us to synchronize remote clocks of Satellite Laser Ranging (SLR) stations throughout the whole ILRS (International Laser Ranging Service) network. We have developed a time transfer processing dedicated to non Common View (CV) cases, i.e. time transfer between stations from the Americas, Asia, Europe and Oceania. The main difficulty is to take into account the complex behaviour of the on-board Ultra Stable Oscillator (USO) over more than 1,500 s and up to a few thousands seconds. By integrating a recently published model describing the frequency responses of the USO to physical effects, as temperature and radiations, we show that it is possible to propagate the phase (time) of the on-board clock for an orbital revolution (1 rev = 6,700 s) or two with an error of a few nanoseconds (ns). Scheme of stages of this process is presented. The non CV time transfer process is applied in order to synchronize a plurality of remote stations involved in the T2L2/Jason-2 tracking by laser. The ground-to-space time transfers which we have processed over recent years (from 2013 to 2015) are all contributing to the development of a synthetic on-board time scale. The resulting ground-to-ground time transfers, computed between remote clocks of SLR stations, show differences of 250-300 ns up to a few microseconds ± 3-4 ns. The T2L2 space experiment is thus the first opportunity to estimate, quasi-instantaneously and to the ns level, time differences between clocks of the SLR stations which form one of the basis of the International Terrestrial Reference Frame (ITRF). This result would help the laser ranging community (time & frequency metrology of stations, analysis centres, and applications to the precise orbit and positioning) to achieve the GGOS (Global Geodetic Observing System) requirements in terms of accuracy and long-term stability of geodetic references.

Intrasite motions and monument instabilities at Medicina ITRF co-location site

NASA Astrophysics Data System (ADS)

Sarti, Pierguido; Abbondanza, Claudio; Legrand, Juliette; Bruyninx, Carine; Vittuari, Luca; Ray, Jim

2013-03-01

We process the total-station surveys performed at the ITRF co-location site Medicina (Northern Italy) over the decade (2001-2010) with the purpose of determining the extent of local intrasite motions and relating them to local geophysical processes, the geological setting and the design of the ground pillars. In addition, continuous observations acquired by two co-located GPS stations (MEDI and MSEL separated by ≈27 m) are analysed and their relative motion is cross-checked with the total-station results. The local ground control network extends over a small area (<100 × 100 m) but the results demonstrate significant anisotropic deformations with rates up to 1.6 mm a-1, primarily horizontal, a value comparable to intraplate tectonic deformations. The results derived from GPS and total-station observations are consistent and point to the presence of horizontal intrasite motions over very short distances possibly associated with varying environmental conditions in a very unfavourable local geological setting and unsuitable monument design, these latter being crucial aspects of the realization and maintenance of global permanent geodetic networks and the global terrestrial reference frame.

Peak ground motion predictions with empirical site factors using Taiwan Strong Motion Network recordings

NASA Astrophysics Data System (ADS)

Chung, Jen-Kuang

2013-09-01

A stochastic method called the random vibration theory (Boore, 1983) has been used to estimate the peak ground motions caused by shallow moderate-to-large earthquakes in the Taiwan area. Adopting Brune's ω-square source spectrum, attenuation models for PGA and PGV were derived from path-dependent parameters which were empirically modeled from about one thousand accelerograms recorded at reference sites mostly located in a mountain area and which have been recognized as rock sites without soil amplification. Consequently, the predicted horizontal peak ground motions at the reference sites, are generally comparable to these observed. A total number of 11,915 accelerograms recorded from 735 free-field stations of the Taiwan Strong Motion Network (TSMN) were used to estimate the site factors by taking the motions from the predictive models as references. Results from soil sites reveal site amplification factors of approximately 2.0 ~ 3.5 for PGA and about 1.3 ~ 2.6 for PGV. Finally, as a result of amplitude corrections with those empirical site factors, about 75% of analyzed earthquakes are well constrained in ground motion predictions, having average misfits ranging from 0.30 to 0.50. In addition, two simple indices, R 0.57 and R 0.38, are proposed in this study to evaluate the validity of intensity map prediction for public information reports. The average percentages of qualified stations for peak acceleration residuals less than R 0.57 and R 0.38 can reach 75% and 54%, respectively, for most earthquakes. Such a performance would be good enough to produce a faithful intensity map for a moderate scenario event in the Taiwan region.

Tracking and data relay satellite system configuration and tradeoff study. Volume 3: TDRSS configuration and data summary, part 1

NASA Technical Reports Server (NTRS)

1972-01-01

A reference handbook of configuration data and design information is presented. It treats the overall system definition, operations and control, and telecommunication service system including link budgets. A brief description of the user transceiver and ground station is presented. A final section includes a summary description of the TDR spacecraft and all the subsystems. The data presented are largely in tabular form for easy reference.

Observational study: microgravity testing of a phase-change reference on the International Space Station

PubMed Central

Topham, T Shane; Bingham, Gail E; Latvakoski, Harri; Podolski, Igor; Sychev, Vladimir S; Burdakin, Andre

2015-01-01

Background: Orbital sensors to monitor global climate change during the next decade require low-drift rates for onboard thermometry, which is currently unattainable without on-orbit recalibration. Phase-change materials (PCMs), such as those that make up the ITS-90 standard, are seen as the most reliable references on the ground and could be good candidates for orbital recalibration. Space Dynamics Lab (SDL) has been developing miniaturized phase-change references capable of deployment on an orbital blackbody for nearly a decade. Aims: Improvement of orbital temperature measurements for long duration earth observing and remote sensing. Methods: To determine whether and how microgravity will affect the phase transitions, SDL conducted experiments with ITS-90 standard material (gallium, Ga) on the International Space Station (ISS) and compared the phase-change temperature with earth-based measurements. The miniature on-orbit thermal reference (MOTR) experiment launched to the ISS in November 2013 on Soyuz TMA-11M with the Expedition 38 crew and returned to Kazakhstan in March 2014 on the Soyuz TMA-10 spacecraft. Results: MOTR tested melts and freezes of Ga using repeated 6-h cycles. Melt cycles obtained on the ground before and after launch were compared with those obtained on the ISS. Conclusions: To within a few mK uncertainty, no significant difference between the melt temperature of Ga at 1 g and in microgravity was observed. PMID:28725713

Observational study: microgravity testing of a phase-change reference on the International Space Station.

PubMed

Topham, T Shane; Bingham, Gail E; Latvakoski, Harri; Podolski, Igor; Sychev, Vladimir S; Burdakin, Andre

2015-01-01

Orbital sensors to monitor global climate change during the next decade require low-drift rates for onboard thermometry, which is currently unattainable without on-orbit recalibration. Phase-change materials (PCMs), such as those that make up the ITS-90 standard, are seen as the most reliable references on the ground and could be good candidates for orbital recalibration. Space Dynamics Lab (SDL) has been developing miniaturized phase-change references capable of deployment on an orbital blackbody for nearly a decade. Improvement of orbital temperature measurements for long duration earth observing and remote sensing. To determine whether and how microgravity will affect the phase transitions, SDL conducted experiments with ITS-90 standard material (gallium, Ga) on the International Space Station (ISS) and compared the phase-change temperature with earth-based measurements. The miniature on-orbit thermal reference (MOTR) experiment launched to the ISS in November 2013 on Soyuz TMA-11M with the Expedition 38 crew and returned to Kazakhstan in March 2014 on the Soyuz TMA-10 spacecraft. MOTR tested melts and freezes of Ga using repeated 6-h cycles. Melt cycles obtained on the ground before and after launch were compared with those obtained on the ISS. To within a few mK uncertainty, no significant difference between the melt temperature of Ga at 1 g and in microgravity was observed.

Status of NGS CORS Network and Its Contribution to the GGOS Infrastructure

NASA Astrophysics Data System (ADS)

Choi, K. K.; Haw, D.; Sun, L.

2017-12-01

Recent advancement of Satellite Geodesy techniques can now contribute to the global frame realization needed to improve worldwide accuracies. These techniques rely on coordinates computed using continuously observed GPS data and corresponding satellite orbits. The GPS-based reference system continues to depend on the physical stability of a ground-based network of points as the primary foundation for these observations. NOAA's National Geodetic Survey (NGS) has been operating Continuously Operating Reference Stations (CORS) to provide direct access to the National Spatial Reference System (NSRS). By virtue of NGS' scientific reputation and leadership in national and international geospatial issues, NGS has determined to increase its participation in the maintenance of the U.S. component of the global GPS tracking network in order to realize a long-term stable national terrestrial reference frame. NGS can do so by leveraging its national leadership role coupled with NGS' scientific expertise, in designating and upgrading a subset of the current tracking network for this purpose. This subset of stations must have the highest operational standards to serve the dual functions: being the U.S. contribution to the international frame, along with providing the link to the national datum. These stations deserve special attention to ensure that the highest possible levels of quality and stability are maintained. To meet this need, NGS is working with the international scientific groups to add and designate these reference stations based on scientific merit such as: colocation with other geodetic techniques, geographic area, and monumentation stability.

The International DORIS Service contribution to the 2014 realization of the International Terrestrial Reference Frame

NASA Astrophysics Data System (ADS)

Moreaux, Guilhem; Lemoine, Frank G.; Capdeville, Hugues; Kuzin, Sergey; Otten, Michiel; Štěpánek, Petr; Willis, Pascal; Ferrage, Pascale

2016-12-01

In preparation of the 2014 realization of the International Terrestrial Reference Frame (ITRF2014), the International DORIS Service delivered to the International Earth Rotation and Reference Systems Service a set of 1140 weekly solution files including station coordinates and Earth orientation parameters, covering the time period from 1993.0 to 2015.0. The data come from eleven DORIS satellites: TOPEX/Poseidon, SPOT2, SPOT3, SPOT4, SPOT5, Envisat, Jason-1, Jason-2, Cryosat-2, Saral and HY-2A. In their processing, the six analysis centers which contributed to the DORIS combined solution used the latest time variable gravity models and estimated DORIS ground beacon frequency variations. Furthermore, all the analysis centers but one excepted included in their processing phase center variations for ground antennas. The main objective of this study is to present the combination process and to analyze the impact of the new modeling on the performance of the new combined solution. Comparisons with the IDS contribution to ITRF2008 show that (i) the application of the DORIS ground phase center variations in the data processing shifts the combined scale upward by nearly 7-11 mm and (ii) thanks to estimation of DORIS ground beacon frequency variations, the new combined solution no longer shows any scale discontinuity in early 2002 and does not present unexplained vertical discontinuities in any station position time series. However, analysis of the new series with respect to ITRF2008 exhibits a scale increase late 2011 which is not yet explained. A new DORIS Terrestrial Reference Frame was computed to evaluate the intrinsic quality of the new combined solution. That evaluation shows that the addition of data from the new missions equipped with the latest generation of DORIS receiver (Jason-2, Cryosat-2, HY-2A, Saral), results in an internal position consistency of 10 mm or better after mid-2008.

Geocenter Coordinates from a Combined Processing of LEO and Ground-based GPS Observations

NASA Astrophysics Data System (ADS)

Männel, Benjamin; Rothacher, Markus

2017-04-01

The GPS observations provided by the global IGS (International GNSS Service) tracking network play an important role for the realization of a unique terrestrial reference frame that is accurate enough to allow the monitoring of the Earth's system. Combining these ground-based data with GPS observations tracked by high-quality dual-frequency receivers on-board Low Earth Orbiters (LEO) might help to further improve the realization of the terrestrial reference frame and the estimation of the geocenter coordinates, GPS satellite orbits and Earth rotation parameters (ERP). To assess the scope of improvement, we processed a network of 50 globally distributed and stable IGS-stations together with four LEOs (GRACE-A, GRACE-B, OSTM/Jason-2 and GOCE) over a time interval of three years (2010-2012). To ensure fully consistent solutions the zero-difference phase observations of the ground stations and LEOs were processed in a common least-square adjustment, estimating GPS orbits, LEO orbits, station coordinates, ERPs, site-specific tropospheric delays, satellite and receiver clocks and ambiguities. We present the significant impact of the individual LEOs and a combination of all four LEOs on geocenter coordinates derived by using a translational approach (also called network shift approach). In addition, we present geocenter coordinates derived from the same set of GPS observations by using a unified approach. This approach combines the translational and the degree-one approach by estimating translations and surface deformations simultaneously. Based on comparisons against each other and against geocenter time series derived by other techniques the effect of the selected approach is assessed.

Investigation on earthquake ground motions observed along a north-south survey line in the Kumamoto Plain, during the aftershocks of 2016 Kumamoto earthquake

NASA Astrophysics Data System (ADS)

Tsuno, S.; Korenaga, M.; Okamoto, K.; Chimoto, K.; Yamanaka, H.; Yamada, N.; Matsushima, T.

2017-12-01

To evaluate local site effects in the Kumamoto Plain, we installed 15 temporary seismic stations along the north-south survey line, after the 2016 Kumamoto earthquake foreshock (Mj 6.4). In this report, to investigate earthquake ground motions observed along the north-south survey line, we estimated site amplification factors from weak ground motion data and estimated S-wave velocity structures by array microtremor observations at temporary seismic stations. We installed 15 temporary seismic stations at an interval of 300m to 2.5km along the north-south survey line. We estimated site amplification factors, with a station at Mt. Kinbo as a reference. Site amplification factors at the middle part and the southern part along the survey line, located in the alluvial lowland, were dominated in the frequency of 1-2Hz. On the other hand, site amplification factors at the northern part along the survey line were dominated in the frequency of 2-5Hz. It suggests that the ground profiles near the surface are complicate along this north-south survey line in the Kumamoto Plain. Therefore, we performed array microtremor observations at the temporary seismic stations, to estimate S-wave velocity structures along the north-south survey line. We obtained phase velocities of Rayleigh waves by the SPAC method and estimated S-wave velocity structures by applying the Genetic Algorism to those phase velocity. The low velocity layer with a thickness of around 15m was deposited on the surface at sites located in the alluvial lowland. Finally, we compared the distribution of PGAs observed along the north-south survey line to AVs30 estimated by S-wave velocity structures. As a result, PGAs along the survey line were strongly concerned by AVs30. We concluded that earthquake ground motions in the frequency of more than 1Hz observed in this north-south survey line were excited by the low velocity layer near the surface.

Magnetotellurics with long distance remote reference to reject DC railway noise

NASA Astrophysics Data System (ADS)

Hanstein, T.; Jiang, J.; Strack, K.; Ritter, O.

2014-12-01

Some parts of railway network in Europe is electrified by DC current. The return current in the ground is varying in space, time and power when the train is moving. Since the train traffic is active 24 hours, there is no quite time. The train signal is dominating for periods longer than 1 s and is a near field source. The transfer function of the magnetotelluric sounding (MT) is influenced by this near field source, the phase is going to zero and amplitude increase with slope 1 for longer periods. Since this dominating noise is present all day robust magnetotelluric processing technique to identify and remove outliers are not applicable and sufficient. The remote reference technique has successfully been applied for magnetotelluric soundings Combining an disturbed local MT data set with the data of the remote station, which is recording simultaneously the horizontal magnetic fields, can improve the data quality. Finding a good remote station during field survey is difficult and expensive. There is a permanent MT remote reference station in Germany. The set up and maintance is done by the GFZ - Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences. The location is near Wittstock and has good signal-to-noise-ratio with low cutural noise, the ground is almost lD and recording since May 2010. The electric and magnetic field is continously recorded with 250 Hz sampling and induction coils. The magnetic field is also recorded with fluxgate magnetometers and 5 Hz sampling. The distance to the local MT site is about 600 km.

The impact of military activities on the concentration of mercury in soils of military training grounds and marine sediments.

PubMed

Gębka, Karolina; Bełdowski, Jacek; Bełdowska, Magdalena

2016-11-01

Military activities have been conducted on land and at sea. Both during conflicts and in peace time, some regions served as a military training ground which included firing positions and bunkers. Mercury fulminate has been used in ammunition primers and detonators. Certain amount of ammunition was dumped into the Baltic Sea after the Second World War. Because of corroded containers, mercury can be released into the marine environment. The soil and sediment samples were taken from military training grounds, southern Baltic in 2014 and 2015. The concentration of mercury was determined by AMA-254 analyzer. Hg concentration was higher in the places of military activities, as compared to other areas. Ten times increased concentration of Hg was determined in soil sample collected in area of active gun range compared to the reference station. The significant higher concentration of mercury was detected in stations where chemical warfare agents were found.

IGS14/igs14.atx: a new Framework for the IGS Products

NASA Astrophysics Data System (ADS)

Rebischung, P.; Schmid, R.

2016-12-01

The International GNSS Service (IGS) is about to switch to a new reference frame (IGS14), based on the latest release of the International Terrestrial Reference Frame (ITRF2014), as the basis for its products. An updated set of satellite and ground antenna calibrations (igs14.atx) will become effective at the same time. IGS14 and igs14.atx will then replace the previous IGS08/igs08.atx framework in use since GPS week 1632 (17 April 2011) and in the second IGS reprocessing campaign (repro2). Despite the negligible scale difference between ITRF2008 and ITRF2014 (0.02 ppb), the radial components of all GPS and GLONASS satellite antenna phase center offsets (z-PCOs) had to be updated in igs14.atx, because of modeling changes recently introduced within the IGS that affect the scale of the IGS products. This was achieved by deriving and averaging time series of satellite z-PCO estimates, consistent with the ITRF2014 scale, from the daily repro2 and latest operational SINEX solutions of seven IGS Analysis Centers (ACs). Compared to igs08.atx, igs14.atx includes robot calibrations for 16 additional ground antenna types, so that the percentage of stations with absolute calibrations in the IGS network will reach 90% after the switch. 19 type-mean robot calibrations were also updated thanks to the availability of calibration results for additional antenna samples. IGS14 is basically an extract of well-suited reference frame stations (i.e., with long and stable position time series) from ITRF2014. However, to make the IGS14 station coordinates consistent with the new igs14.atx ground antenna calibrations, position offsets due to the switch from igs08.atx to igs14.atx were derived for all IGS14 stations affected by ground antenna calibration updates and applied to their ITRF2014 coordinates. This presentation will first detail the different steps of the elaboration of IGS14 and igs14.atx. The impact of the switch on GNSS-derived geodetic parameter time series will then be assessed by re-aligning the daily repro2 and latest operational IGS combined SINEX solutions to IGS14/igs14.atx. A particular focus will finally be given to the biases and trends present in the satellite z-PCO time series derived from the daily AC SINEX solutions, and to their interpretation in terms of scale and scale rate of the terrestrial frame.

Photovoltaic central station step and touch potential considerations in grounding system design

NASA Technical Reports Server (NTRS)

Engmann, G.

1983-01-01

The probability of hazardous step and touch potentials is an important consideration in central station grounding system design. Steam turbine generating station grounding system design is based on accepted industry practices and there is extensive in-service experience with these grounding systems. A photovoltaic (PV) central station is a relatively new concept and there is limited experience with PV station grounding systems. The operation and physical configuration of a PV central station is very different from a steam electric station. A PV station bears some similarity to a substation and the PV station step and touch potentials might be addressed as they are in substation design. However, the PV central station is a generating station and it is appropriate to examine the effect that the differences and similarities of the two types of generating stations have on step and touch potential considerations.

Suspected time errors along the satellite laser ranging network and impact on the reference frame

NASA Astrophysics Data System (ADS)

Belli, Alexandre; Exertier, Pierre; Lemoine, Frank; Zelensky, Nikita

2017-04-01

Systematic errors in the laser ranging technologies must be considered when considering the GGOS objective to maintain a network with an accuracy of 1 mm and a stability of 0.1 mm per year for the station ground coordinates in the ITRF. Range and Time biases are identified to be part of these systematic errors, for a major part, and are difficult to detect. Concerning the range bias, analysts and working groups estimate their values from LAGEOS-1 & 2 observations (c.f. Appleby et al. 2016). On the other hand, time errors are often neglected (they are presumed to be < 100 ns) and remain difficult to estimate (at this level), from using the observations of geodetic satellites passes and precise orbit determination (i.e. LAGEOS). The Time Transfer by Laser Link (T2L2) experiment on-board Jason-2 is a unique opportunity to determine, globally and independently, the synchronization of all laser stations. Because of the low altitude of Jason-2, we computed the time transfer in non-common view from the Grasse primary station to all other SLR stations. We used a method to synchronize the whole network which consists of the integration of an Ultra Stable Oscillator (USO) frequency model, in order to take care of the frequency instabilities caused by the space environment. The integration provides a model which becomes an "on-orbit" time realization which can be connected to each of the SLR stations by the ground to space laser link. We estimated time biases per station, with a repeatability of 3 - 4 ns, for 25 stations which observe T2L2 regularly. We investigated the effect on LAGEOS and Starlette orbits and we discuss the impact of time errors on the station coordinates. We show that the effects on the global POD are negligible (< 1 mm) but are at the level of 4 - 6 mm for the coordinates. We conclude and propose to introduce time errors in the future analyses (IDS and ILRS) that would lead to the computation of improved reference frame solutions.

Edge Detection Method Based on Neural Networks for COMS MI Images

NASA Astrophysics Data System (ADS)

Lee, Jin-Ho; Park, Eun-Bin; Woo, Sun-Hee

2016-12-01

Communication, Ocean And Meteorological Satellite (COMS) Meteorological Imager (MI) images are processed for radiometric and geometric correction from raw image data. When intermediate image data are matched and compared with reference landmark images in the geometrical correction process, various techniques for edge detection can be applied. It is essential to have a precise and correct edged image in this process, since its matching with the reference is directly related to the accuracy of the ground station output images. An edge detection method based on neural networks is applied for the ground processing of MI images for obtaining sharp edges in the correct positions. The simulation results are analyzed and characterized by comparing them with the results of conventional methods, such as Sobel and Canny filters.

Non-linear and plastic soil response from strong ground motion detected using the ambient seismic field

NASA Astrophysics Data System (ADS)

Viens, L.; Denolle, M.; Hirata, N.

2017-12-01

Strong ground motion can induce dynamic strains large enough for the shallow subsurface to respond non-linearly and cause permanent velocity changes during earthquakes. We investigate the behavior of the near-surface in the Tokyo metropolitan area during the 2011 Mw 9.0 Tohoku-Oki earthquake using continuous records from 234 seismometers of the Metropolitan Seismic Observation network (MeSO-net). This network, which was deployed in shallow 20-m depth boreholes, recorded horizontal accelerations up to 236 cm/s2 during the mainshock. For each MeSO-net station, we compute the near-surface response using the single-station cross-correlation technique between vertical and horizontal components, every 6 hours for 2.5 months around the main event. Comparing each near-surface response against the pre-event reference, we find seismic velocity drops up to 10% in the near-surface of the Tokyo metropolitan area during the mainshock. The amplitude of the coseismic velocity drop increases with increasing ground shaking and decreasing VS30, which is the S-wave velocity the first 30-m of the ground. Furthermore, the waveforms experience a loss of coherence that recovers exponentially over a time. This recovery rate also increases with the acceleration levels. While most of the velocity changes and waveform coherence recover within a few days, we also find permanent changes at stations that experienced liquefaction and the strongest ground motions. The ambient seismic field captures the coseismic velocity changes in the shallow structure and the following healing process, and may be used to detect permanent damage.

Harmonizing multiple methods for reconstructing historical potential and reference evapotranspiration

USGS Publications Warehouse

Belaineh, Getachew; Sumner, David; Carter, Edward; Clapp, David

2013-01-01

Potential evapotranspiration (PET) and reference evapotranspiration (RET) data are usually critical components of hydrologic analysis. Many different equations are available to estimate PET and RET. Most of these equations, such as the Priestley-Taylor and Penman- Monteith methods, rely on detailed meteorological data collected at ground-based weather stations. Few weather stations collect enough data to estimate PET or RET using one of the more complex evapotranspiration equations. Currently, satellite data integrated with ground meteorological data are used with one of these evapotranspiration equations to accurately estimate PET and RET. However, earlier than the last few decades, historical reconstructions of PET and RET needed for many hydrologic analyses are limited by the paucity of satellite data and of some types of ground data. Air temperature stands out as the most generally available meteorological ground data type over the last century. Temperature-based approaches used with readily available historical temperature data offer the potential for long period-of-record PET and RET historical reconstructions. A challenge is the inconsistency between the more accurate, but more data intensive, methods appropriate for more recent periods and the less accurate, but less data intensive, methods appropriate to the more distant past. In this study, multiple methods are harmonized in a seamless reconstruction of historical PET and RET by quantifying and eliminating the biases of the simple Hargreaves-Samani method relative to the more complex and accurate Priestley-Taylor and Penman-Monteith methods. This harmonization process is used to generate long-term, internally consistent, spatiotemporal databases of PET and RET.

47 CFR 22.815 - Construction period for general aviation ground stations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 2 2014-10-01 2014-10-01 false Construction period for general aviation ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.815 Construction period for general aviation ground stations. The construction period (see...

47 CFR 22.815 - Construction period for general aviation ground stations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 2 2012-10-01 2012-10-01 false Construction period for general aviation ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.815 Construction period for general aviation ground stations. The construction period (see...

47 CFR 22.815 - Construction period for general aviation ground stations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 2 2013-10-01 2013-10-01 false Construction period for general aviation ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.815 Construction period for general aviation ground stations. The construction period (see...

47 CFR 22.815 - Construction period for general aviation ground stations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Construction period for general aviation ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.815 Construction period for general aviation ground stations. The construction period (see...

47 CFR 22.815 - Construction period for general aviation ground stations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 2 2011-10-01 2011-10-01 false Construction period for general aviation ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.815 Construction period for general aviation ground stations. The construction period (see...

Enhanced Fair-Weather Electric Fields Soon After Sunrise

NASA Technical Reports Server (NTRS)

Marshall, T. C.; Rust, W. D.; Stolzenburg, M.; Roeder, W.; Krehbiel, P. R.

1999-01-01

The typical fair weather electric field at the ground is between -100 and -300 V/m. At the NASA Kennedy Space Center and US Air Force Cape Canaveral Air Station (KSC) the electric field at the ground sometimes reaches -400 to -1200 V/m within an hour or two after sunrise on days that otherwise seem to be fair weather. We refer to the enhanced negative electric fields as the "sunrise enhancement." To investigate the sunrise enhancement at KSC we measured the electric field (E) in the first few hundred meters above the ground before and during several sunrise enhancements. From these E soundings we can infer the presence of charge layers and determine their thickness and charge density.

Estimating seismic site response in Christchurch City (New Zealand) from dense low-cost aftershock arrays

USGS Publications Warehouse

Kaiser, Anna E.; Benites, Rafael A.; Chung, Angela I.; Haines, A. John; Cochran, Elizabeth S.; Fry, Bill

2011-01-01

The Mw 7.1 September 2010 Darfield earthquake, New Zealand, produced widespread damage and liquefaction ~40 km from the epicentre in Christchurch city. It was followed by the even more destructive Mw 6.2 February 2011 Christchurch aftershock directly beneath the city’s southern suburbs. Seismic data recorded during the two large events suggest that site effects contributed to the variations in ground motion observed throughout Christchurch city. We use densely-spaced aftershock recordings of the Darfield earthquake to investigate variations in local seismic site response within the Christchurch urban area. Following the Darfield main shock we deployed a temporary array of ~180 low-cost 14-bit MEMS accelerometers linked to the global Quake-Catcher Network (QCN). These instruments provided dense station coverage (spacing ~2 km) to complement existing New Zealand national network strong motion stations (GeoNet) within Christchurch city. Well-constrained standard spectral ratios were derived for GeoNet stations using a reference station on Miocene basalt rock in the south of the city. For noisier QCN stations, the method was adapted to find a maximum likelihood estimate of spectral ratio amplitude taking into account the variance of noise at the respective stations. Spectral ratios for QCN stations are similar to nearby GeoNet stations when the maximum likelihood method is used. Our study suggests dense low-cost accelerometer aftershock arrays can provide useful information on local-scale ground motion properties for use in microzonation. Preliminary results indicate higher amplifications north of the city centre and strong high-frequency amplification in the small, shallower basin of Heathcote Valley.

Solar power satellite cost estimate

NASA Technical Reports Server (NTRS)

Harron, R. J.; Wadle, R. C.

1981-01-01

The solar power configuration costed is the 5 GW silicon solar cell reference system. The subsystems identified by work breakdown structure elements to the lowest level for which cost information was generated. This breakdown divides into five sections: the satellite, construction, transportation, the ground receiving station and maintenance. For each work breakdown structure element, a definition, design description and cost estimate were included. An effort was made to include for each element a reference that more thoroughly describes the element and the method of costing used. All costs are in 1977 dollars.

ASPEC: Solar power satellite

NASA Technical Reports Server (NTRS)

1991-01-01

The solar power satellite (SPS) will provide a clean, reliable source of energy for large-scale consumption. The system will use satellites in geostationary orbits around the Earth to capture the Sun's energy. The intercepted sunlight will be converted to laser beam energy that can be transmitted to the Earth's surface. Ground systems on the Earth will convert the transmissions from space into electric power. The preliminary design for the SPS consists of one satellite in orbit around the Earth transmitting energy to a single ground station. The SPS design uses multilayer solar cell technology arranged on a 20 km squared planar array to intercept sunlight and convert it to an electric voltage. Power conditioning devices then send the electricity to a laser, which transmits the power to the surface of the Earth. A ground station will convert the beam into electricity. Typically, a single SPS will supply 5 GW of power to the ground station. Due to the large mass of the SPS, about 41 million kg, construction in space is needed in order to keep the structural mass low. The orbit configuration for this design is to operate a single satellite in geosynchronous orbit (GEO). The GEO allows the system to be positioned above a single receiving station and remain in sunlight 99 percent of the time. Construction will take place in low Earth orbit (LEO); array sections, 20 in total, will be sailed on solar wind out to the GEO location in 150 days. These individual transportation sections are referred to as solar sailing array panels (SSAP's). The primary truss elements used to support the array are composed of composite tubular members in a pentahedral arrangement. Smart segments consisting of passive and active damping devices will increase the control of dynamic SPS modes.

Payload specialist station study. Volume 3: Program study cost estimates. Part 1: Work breakdown structure

NASA Technical Reports Server (NTRS)

1976-01-01

The work breakdown structure (WBS) for the Payload Specialist Station (PSS) is presented. The WBS is divided into two elements--PSS contractor and mission unique requirements. In accordance with the study ground rules, it is assumed that a single contractor, hereafter referred to as PSS Contractor will perform the following: (1) provide C and D hardware (MFDS and elements of MMSE), except for GFE; (2) identify software requirements; (3) provide GSE and ground test software; and (4) perform systems engineering and integration in support of the Aft Flight Deck (AFD) C and D concept. The PSS Contractor WBS element encompasses a core or standardized PSS concept. Payload peculiar C and D requirements identified by users will originate as a part of the WBS element mission unique requirements; these requirements will be provided to the PSS Contractor for implementation.

MODEL-BASED HYDROACOUSTIC BLOCKAGE ASSESSMENT AND DEVELOPMENT OF AN EXPLOSIVE SOURCE DATABASE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matzel, E; Ramirez, A; Harben, P

2005-07-11

We are continuing the development of the Hydroacoustic Blockage Assessment Tool (HABAT) which is designed for use by analysts to predict which hydroacoustic monitoring stations can be used in discrimination analysis for any particular event. The research involves two approaches (1) model-based assessment of blockage, and (2) ground-truth data-based assessment of blockage. The tool presents the analyst with a map of the world, and plots raypath blockages from stations to sources. The analyst inputs source locations and blockage criteria, and the tool returns a list of blockage status from all source locations to all hydroacoustic stations. We are currently usingmore » the tool in an assessment of blockage criteria for simple direct-path arrivals. Hydroacoustic data, predominantly from earthquake sources, are read in and assessed for blockage at all available stations. Several measures are taken. First, can the event be observed at a station above background noise? Second, can we establish backazimuth from the station to the source. Third, how large is the decibel drop at one station relative to other stations. These observational results are then compared with model estimates to identify the best set of blockage criteria and used to create a set of blockage maps for each station. The model-based estimates are currently limited by the coarse bathymetry of existing databases and by the limitations inherent in the raytrace method. In collaboration with BBN Inc., the Hydroacoustic Coverage Assessment Model (HydroCAM) that generates the blockage files that serve as input to HABAT, is being extended to include high-resolution bathymetry databases in key areas that increase model-based blockage assessment reliability. An important aspect of this capability is to eventually include reflected T-phases where they reliably occur and to identify the associated reflectors. To assess how well any given hydroacoustic discriminant works in separating earthquake and in-water explosion populations it is necessary to have both a database of reference earthquake events and of reference in-water explosive events. Although reference earthquake events are readily available, explosive reference events are not. Consequently, building an in-water explosion reference database requires the compilation of events from many sources spanning a long period of time. We have developed a database of small implosive and explosive reference events from the 2003 Indian Ocean Cruise data. These events were recorded at some or all of the IMS Indian Ocean hydroacoustic stations: Diego Garcia, Cape Leeuwin, and Crozet Island. We have also reviewed many historical large in-water explosions and identified five that have adequate source information and can be positively associated to the hydrophone recordings. The five events are: Cannekin, Longshot, CHASE-3, CHASE-5, and IITRI-1. Of these, the first two are nuclear tests on land but near water. The latter three are in-water conventional explosive events with yields from ten to hundreds of tons TNT equivalent. The objective of this research is to enhance discrimination capabilities for events located in the world's oceans. Two research and development efforts are needed to achieve this: (1) improvement in discrimination algorithms and their joint statistical application to events, and (2) development of an automated and accurate blockage prediction capability that will identify all stations and phases (direct and reflected) from a given event that will have adequate signal to be used in a discrimination analysis. The strategy for improving blockage prediction in the world's oceans is to improve model-based prediction of blockage and to develop a ground-truth database of reference events to assess blockage. Currently, research is focused on the development of a blockage assessment software tool. The tool is envisioned to develop into a sophisticated and unifying package that optimally and automatically assesses both model and data based blockage predictions in all ocean basins, for all NDC stations, and accounting for reflected phases (Pulli et al., 2000). Currently, we have focused our efforts on the Diego Garcia, Cape Leeuwin and Crozet Island hydroacoustic stations in the Indian Ocean.« less

Accuracy and Precision in the Southern Hemisphere Additional Ozonesondes (SHADOZ) Dataset 1998-2000 in Light of the JOSIE-2000 Results

NASA Technical Reports Server (NTRS)

Witte, J. C.; Thompson, A. M.; Schmidlin, F. J.; Oltmans, S. J.; McPeters, R. D.; Smit, H. G. J.

2003-01-01

A network of 12 southern hemisphere tropical and subtropical stations in the Southern Hemisphere ADditional OZonesondes (SHADOZ) project has provided over 2000 profiles of stratospheric and tropospheric ozone since 1998. Balloon-borne electrochemical concentration cell (ECC) ozonesondes are used with standard radiosondes for pressure, temperature and relative humidity measurements. The archived data are available at:http: //croc.gsfc.nasa.gov/shadoz. In Thompson et al., accuracies and imprecisions in the SHADOZ 1998- 2000 dataset were examined using ground-based instruments and the TOMS total ozone measurement (version 7) as references. Small variations in ozonesonde technique introduced possible biases from station-to-station. SHADOZ total ozone column amounts are now compared to version 8 TOMS; discrepancies between the two datasets are reduced 2\\% on average. An evaluation of ozone variations among the stations is made using the results of a series of chamber simulations of ozone launches (JOSIE-2000, Juelich Ozonesonde Intercomparison Experiment) in which a standard reference ozone instrument was employed with the various sonde techniques used in SHADOZ. A number of variations in SHADOZ ozone data are explained when differences in solution strength, data processing and instrument type (manufacturer) are taken into account.

FAST at MACH 20: clinical ultrasound aboard the International Space Station.

PubMed

Sargsyan, Ashot E; Hamilton, Douglas R; Jones, Jeffrey A; Melton, Shannon; Whitson, Peggy A; Kirkpatrick, Andrew W; Martin, David; Dulchavsky, Scott A

2005-01-01

Focused assessment with sonography for trauma (FAST) examination has been proved accurate for diagnosing trauma when performed by nonradiologist physicians. Recent reports have suggested that nonphysicians also may be able to perform the FAST examination reliably. A multipurpose ultrasound system is installed on the International Space Station as a component of the Human Research Facility. Nonphysician crew members aboard the International Space Station receive modest training in hardware operation, sonographic techniques, and remotely guided scanning. This report documents the first FAST examination conducted in space, as part of the sustained effort to maintain the highest possible level of available medical care during long-duration space flight. An International Space Station crew member with minimal sonography training was remotely guided through a FAST examination by an ultrasound imaging expert from Mission Control Center using private real-time two-way audio and a private space-to-ground video downlink (7.5 frames/second). There was a 2-second satellite delay for both video and audio. To facilitate the real-time telemedical ultrasound examination, identical reference cards showing topologic reference points and hardware controls were available to both the crew member and the ground-based expert. A FAST examination, including four standard abdominal windows, was completed in approximately 5.5 minutes. Following commands from the Mission Control Center-based expert, the crew member acquired all target images without difficulty. The anatomic content and fidelity of the ultrasound video were excellent and would allow clinical decision making. It is possible to conduct a remotely guided FAST examination with excellent clinical results and speed, even with a significantly reduced video frame rate and a 2-second communication latency. A wider application of trauma ultrasound applications for remote medicine on earth appears to be possible and warranted.

Operations Nomenclature [Annexes

NASA Technical Reports Server (NTRS)

Shannon, Yvette Y.

2011-01-01

The purpose of Operations Nomenclature (OpNom) is to document methods for denoting all hardware and software and associated data referenced by operations products produced by the International Space Station (ISS) operations community. This includes Operations Data File (ODF) procedures, ground and onboard displays, mission rules, commands, messages and advisories, planning products, etc. This document applies to all agencies and individuals participating in or contributing to ISS mission operations. Mission operations include ground checkout, training, and simulations, as well as real-time activities. The document also applies to all operations documentation (paper or electronic media) and other products that refer to ISS-related equipment or activities.

[Studies on the growth and reproduction of bacterial communities on structural materials of the international space station].

PubMed

Rakova, N M; Svistunova, Iu V; Novikova, N D

2005-01-01

Probability of microbial growth and reproduction on the ISS interior and equipment materials varying in chemical composition was studied with the strains of Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus saprophyticus, Pseudomonas putida etc. sampled from the ISS environment. Controls were ground reference strains of same bacterial species. Based on our results, some of the microorganisms are able to survive and proliferate on structural materials; the ability was greater in space isolates as compared with their ground analogs. The greatest ability to grow and proliferate on materials was demonstrated by Bacillus subtilis.

Enhanced Positioning Algorithm of ARPS for Improving Accuracy and Expanding Service Coverage

PubMed Central

Lee, Kyuman; Baek, Hoki; Lim, Jaesung

2016-01-01

The airborne relay-based positioning system (ARPS), which employs the relaying of navigation signals, was proposed as an alternative positioning system. However, the ARPS has limitations, such as relatively large vertical error and service restrictions, because firstly, the user position is estimated based on airborne relays that are located in one direction, and secondly, the positioning is processed using only relayed navigation signals. In this paper, we propose an enhanced positioning algorithm to improve the performance of the ARPS. The main idea of the enhanced algorithm is the adaptable use of either virtual or direct measurements of reference stations in the calculation process based on the structural features of the ARPS. Unlike the existing two-step algorithm for airborne relay and user positioning, the enhanced algorithm is divided into two cases based on whether the required number of navigation signals for user positioning is met. In the first case, where the number of signals is greater than four, the user first estimates the positions of the airborne relays and its own initial position. Then, the user position is re-estimated by integrating a virtual measurement of a reference station that is calculated using the initial estimated user position and known reference positions. To prevent performance degradation, the re-estimation is performed after determining its requirement through comparing the expected position errors. If the navigation signals are insufficient, such as when the user is outside of airborne relay coverage, the user position is estimated by additionally using direct signal measurements of the reference stations in place of absent relayed signals. The simulation results demonstrate that a higher accuracy level can be achieved because the user position is estimated based on the measurements of airborne relays and a ground station. Furthermore, the service coverage is expanded by using direct measurements of reference stations for user positioning. PMID:27529252

Enhanced Positioning Algorithm of ARPS for Improving Accuracy and Expanding Service Coverage.

PubMed

Lee, Kyuman; Baek, Hoki; Lim, Jaesung

2016-08-12

The airborne relay-based positioning system (ARPS), which employs the relaying of navigation signals, was proposed as an alternative positioning system. However, the ARPS has limitations, such as relatively large vertical error and service restrictions, because firstly, the user position is estimated based on airborne relays that are located in one direction, and secondly, the positioning is processed using only relayed navigation signals. In this paper, we propose an enhanced positioning algorithm to improve the performance of the ARPS. The main idea of the enhanced algorithm is the adaptable use of either virtual or direct measurements of reference stations in the calculation process based on the structural features of the ARPS. Unlike the existing two-step algorithm for airborne relay and user positioning, the enhanced algorithm is divided into two cases based on whether the required number of navigation signals for user positioning is met. In the first case, where the number of signals is greater than four, the user first estimates the positions of the airborne relays and its own initial position. Then, the user position is re-estimated by integrating a virtual measurement of a reference station that is calculated using the initial estimated user position and known reference positions. To prevent performance degradation, the re-estimation is performed after determining its requirement through comparing the expected position errors. If the navigation signals are insufficient, such as when the user is outside of airborne relay coverage, the user position is estimated by additionally using direct signal measurements of the reference stations in place of absent relayed signals. The simulation results demonstrate that a higher accuracy level can be achieved because the user position is estimated based on the measurements of airborne relays and a ground station. Furthermore, the service coverage is expanded by using direct measurements of reference stations for user positioning.

A source model of the 2014 South Napa Earthquake by the EGF broad-band strong ground motion simulation

NASA Astrophysics Data System (ADS)

Iwata, T.; Asano, K.; Kubo, H.

2014-12-01

The source model of the 2014 South Napa earthquake (Mw6.0) is estimated using broad band strong ground motion simulation by the empirical Green's function method (Irikura, 1986, Irikura et al., 1997). We used the CESMD strong motion data. Aftershock ground motion records of Mw3.6 which occurred at 05:33 on 24th August (PDT), are used as an empirical Green's function. We refer to the finite source model by Dreger et al. (2014) for setting the geometry of the source fault plane and the rupture velocity. We assume a single rectangular strong motion generation area (e.g. Miyake et al., 2003; Asano and Iwata, 2012). The seismic moment ratio between the target and EGF events is fixed from the moment magnitudes. As only five station data are available for the aftershock records, the size of SMGA area, rupture starting point, and the rise time on the SMGA are determined by the trial and error.　Preliminary SMGA model is 6x6km2 and the rupture mainly propagates WNW and shallower directions. The SMGA size we obtained follows the empirical relationship of Mw and SMGA size for the inland crustal events (Irikura and Miyake, 2011). Waveform fittings are fairly well at the near source station NHC (Huichica creek) and 68150 (Napa Collage), where as the fitting is not good at the south-side stations, 68206 (Crockett - Carquinez Br. Geotech Array) and 68310 (Vallejo - Hwy 37/Napa River E Geo. Array). Particularly, we did not succeed in explaining the high PGA at the 68206 surface station. We will try to improve our SMGA model and will discuss the origin of the high PGA observed at that station.

Experimental approach for estimating seismic amplification effects at the top of a ridge and their implication on ground motion predictions: the case of Narni (Central Italy).

NASA Astrophysics Data System (ADS)

Lovati, Sara; Bakavoli, Mohammad; Massa, Marco; Ferretti, Gabriele; Pacor, Francesca; Paolucci, Roberto

2010-05-01

From March to September 2009 a dense velocimetric network was installed in correspondence of Narni, a little village in central Italy, built on the top of a massive limestone ridge. The network was planned with the aim to investigate possible local site effects due to the morphology of the ridge, characterized by slopes ranging from 22° to 35° and a maximum difference of quota between top and bottom of 230 m. Three stations were installed at the base of the hill and other 7 monitored the crest. A remarkable dataset was obtained, composed by about 700 earthquakes, the great amount of which occurred after the 06th April 2009, Mw 6.3, L'Aquila earthquake. Site amplifications related to the ridge morphological features were investigated through empirical techniques with and without reference site, computing Spectral Standard Ratio, SSR and Horizontal to Vertical spectral ratio, HVSR. Directional spectral analyses were also performed . The agreement between the results coming from HVSR and SSR techniques allows us to assess with reliability a clear amplification effect for frequencies ranging between 3 and 5 Hz for all stations installed on the crest: in particular, SSR results show an amplification level with respect to the reference station up to 4.5. The highest amplification level (almost double) were observed when the direction perpendicular to the main elongation of the ridge is taken into account. Finally, considering the L'Aquila events with Mw > 4.5 and merging the information coming from the reference and non-reference site techniques, it was possible to recognize further amplification effects, at frequency lower than 1 Hz, probably related not to the morphology of the area but to source and/or polarization effects. Bidimensional numerical simulations were then computed in order to compare the results coming from the experiment with those obtained through numerical modeling. A hybrid finite-boundary element method based on code named HYBRID has been used for modeling. The model has been excited by SV and P Ricker wavelet in order to extract transform functions. The medium assumed to have a linear elastic constitutive behavior. All calculations were performed in time domain using direct boundary element method. The amplification patterns both in time and frequency domain were derived and similarities and discrepancies between the results were discussed. At last, considering only local events (epicentral distance R <= 30 km), empirical ground motion predictive equations, calibrated for maximum horizontal peak ground acceleration, PGA, velocity, PGV, and acceleration response spectra (SA, 5% damping) up to 1s, were carried out with the only aim to estimate topographical corrective coefficients. The results show significant corrective term values (between 0.35 and 0.48 in logarithmic scale) for the spectral ordinates between 0.2 s and 0.3 s. These results, in agreement to those obtained from the spectral analyses, suggest that the introduction of a topographic site class in the calculation of predictive models might probably reduce the inter-station variability for stations installed in correspondence of topographic irregularities, often included in reference-rock classes.

General Loss Function Applied to Satellite Scheduling Optimization

DTIC Science & Technology

2014-09-01

radio frequency communication with ground stations. The demand for satellite images is vast, spanning the industries of meteorology, oceanography...oscillators with the common frequency : / 2h  . 58 THIS PAGE INTENTIONALLY LEFT BLANK 59 LIST OF REFERENCES Apollo Mapping. 2014. “High...WA 98345-7610 10. SPONSORING/MONITORING AGENCY REPORT NUMBER 11 . SUPPLEMENTARY NOTES The views expressed in this thesis are those of the author and

Helicopter precision approach capability using the Global Positioning System

NASA Technical Reports Server (NTRS)

Kaufmann, David N.

1992-01-01

The period between 1 July and 31 December, 1992, was spent developing a research plan as well as a navigation system document and flight test plan to investigate helicopter precision approach capability using the Global Positioning System (GPS). In addition, all hardware and software required for the research was acquired, developed, installed, and verified on both the test aircraft and the ground-based reference station.

Astrometry VLBI in Space (AVS

NASA Technical Reports Server (NTRS)

Altunin, V.; Alekseev, V.; Akim, E.; Eubanks, M.; Kingham, K.; Treuhaft, R.; Sukhanov, K.

1995-01-01

A proposed new space radio astronomy mission for astrometry is described. The Astrometry VLBI (very long baseline) in Space (AVS) nominal mission includes two identical spacecraft, each with a 4-m antenna sending data to a 70-m ground station. The goals of AVS are improving astrometry accuracy to the microarcsecond level and improving the accuracy of the transformation between the inertial radio and optical coordinate reference frames.

Ultra-Stable Oscillators for Probe Radio Science Investigations

NASA Technical Reports Server (NTRS)

Asmar, Sami

2012-01-01

An Ultra-Stable Oscillator (USO) is: A frequency reference, and A clock It is stable, small, and sensitive. It is a science and an art form. It is flown on spacecraft/probes. It]is utilized at ground stations alone or as a cleanup loop. It eliminates lock-up time on uplink for occultation egress & effect of media on uplink signal. It has enabled significant planetary science investigations.

The Impact of Satellites on Cable Communications.

ERIC Educational Resources Information Center

Chayes, Abram

Two recent developments in communications satellite technology may speed the coming of cable TV (CATV) networks. First, increases in satellite power are reducing the cost of ground stations. Second, a connection between one ground station, the satellite, and any other ground station is no longer necessarily fixed. Now one station can communicate…

Scaled Composites' Doug Shane examines the screen of his ground control station during tests in New Mexico. Shane used this configuration as the ground control station to remotely pilot the Proteus aircraft during a NASA sponsored series of tests.

NASA Image and Video Library

2002-03-13

Scaled Composites' Doug Shane examines the screen of his ground control station during tests in New Mexico. Shane used this configuration as the ground control station to remotely pilot the Proteus aircraft during a NASA sponsored series of tests.

Analyzing Forest Inventory Data from Geo-Located Photographs

NASA Astrophysics Data System (ADS)

Toivanen, Timo; Tergujeff, Renne; Andersson, Kaj; Molinier, Matthieu; Häme, Tuomas

2015-04-01

Forests are widely monitored using a variety of remote sensing data and techniques. Remote sensing offers benefits compared to traditional in-situ forest inventories made by experts. One of the main benefits is that the number of ground reference plots can be significantly reduced. Remote sensing of forests can provide reduced costs and time requirement compared to full forest inventories. The availability of ground reference data has been a bottleneck in remote sensing analysis over wide forested areas, as the acquisition of this data is an expensive and slow process. In this paper we present a tool for estimating forest inventory data from geo-located photographs. The tool can be used to estimate in-situ forest inventory data including estimated biomass, tree species, tree height and diameter. The collected in-situ forest measurements can be utilized as a ground reference material for spaceborne or airborne remote sensing data analysis. The GPS based location information with measured forest data makes it possible to introduce measurements easily as in-situ reference data. The central projection geometry of digital photographs allows the use of the relascope principle [1] to measure the basal area of stems per area unit, a variable very closely associated with tree biomass. Relascope is applied all over the world for forest inventory. Experiments with independent ground reference data have shown that in-situ data analysed from photographs can be utilised as reference data for satellite image analysis. The concept was validated by comparing mobile measurements with 54 independent ground reference plots from the Hyytiälä forest research station in Finland [2]. Citizen scientists could provide the manpower for analysing photographs from forests on a global level and support researchers working on tasks related to forests. This low-cost solution can also increase the coverage of forest management plans, particularly in regions where possibilities to invest on expensive planning work are limited. References [1] Bitterlich, W. (1984) The Relascope Idea: Relative Measurements in Forestry, Commonwealth Agricultural Bureaux, Farnham Royal, 1984. [2] Molinier, M., Hame, T., Toivanen, T., Andersson, K., Mutanen, T., Relasphone -- Mobile phone and interactive applications to collect ground reference biomass data for satellite image analysis, Geoscience and Remote Sensing Symposium (IGARSS), 2014 IEEE International, pp. 836-839, 13-18 July 2014, doi: 10.1109/IGARSS.2014.6946554

Facilities for animal research in space with special reference to Space Station Freedom

NASA Technical Reports Server (NTRS)

Bonting, Sjoerd L.; Kishiyama, Jenny S.; Arno, Roger D.

1990-01-01

The facilities being planned for animal research on Space Station Freedom are considered in the context of the development of animal habitats from early ballistic and orbital flights to long-term missions aimed at more detailed scientific studies of the effects of space conditions on the vertebrate organism. Animal habitats are becoming more elaborate, requiring systems for environmental control, waste management, physiological monitoring, as well as ancillary facilities such as a 1-G control centrifuge and a glovebox. Habitats in use or to be used in various types of manned and unmanned spacecraft, and particularly those planned for Space Station Freedom, are described. The characteristics of the habitats are compared with each other and with current standards for animal holding facilities on the ground.

System and method for transferring telemetry data between a ground station and a control center

NASA Technical Reports Server (NTRS)

Ray, Timothy J. (Inventor); Ly, Vuong T. (Inventor)

2012-01-01

Disclosed herein are systems, computer-implemented methods, and tangible computer-readable media for coordinating communications between a ground station, a control center, and a spacecraft. The method receives a call to a simple, unified application programmer interface implementing communications protocols related to outer space, when instruction relates to receiving a command at the control center for the ground station generate an abstract message by agreeing upon a format for each type of abstract message with the ground station and using a set of message definitions to configure the command in the agreed upon format, encode the abstract message to generate an encoded message, and transfer the encoded message to the ground station, and perform similar actions when the instruction relates to receiving a second command as a second encoded message at the ground station from the control center and when the determined instruction type relates to transmitting information to the control center.

Temperature trends and Urban Heat Island intensity mapping of the Las Vegas valley area

NASA Astrophysics Data System (ADS)

Black, Adam Leland

Modified urban climate regions that are warmer than rural areas at night are referred to as Urban Heat Islands or UHI. Islands of warmer air over a city can be 12 degrees Celsius greater than the surrounding cooler air. The exponential growth in Las Vegas for the last two decades provides an opportunity to detect gradual temperature changes influenced by an increasing presence of urban materials. This thesis compares ground based thermometric observations and satellite based remote sensing temperature observations to identify temperature trends and UHI areas caused by urban development. Analysis of temperature trends between 2000 and 2010 at ground weather stations has revealed a general cooling trend in the Las Vegas region. Results show that urban development accompanied by increased vegetation has a cooling effect in arid climates. Analysis of long term temperature trends at McCarran and Nellis weather stations show 2.4 K and 1.2 K rise in temperature over the last 60 years. The ground weather station temperature data is related to the land surface temperature images from the Landsat Thematic Mapper to estimate and evaluate urban heat island intensity for Las Vegas. Results show that spatial and temporal trends of temperature are related to the gradual change in urban landcover. UHI are mainly observed at the airport and in the industrial areas. This research provides useful insight into the temporal behavior of the Las Vegas area.

Low-Frequency Amplitudes Observed in a Set of the Strongest Recorded Ground Motions (Invited)

NASA Astrophysics Data System (ADS)

Anderson, J. G.; Koketsu, K.; Miyake, H.

2010-12-01

Anderson (2010) compiled a set of “exceptional” ground motion characterized by peak acceleration that exceeds 500 gal on at least one component or peak velocity that exceeds 50 cm/s on at least one component. With the addition of more recent data, there are now over 280 openly available records that meet these criteria. These data are examined to find to the empirical upper bound of observed pseudo-acceleration (PSA) response spectra and smoothed Fourier amplitude spectra. Statistics of amplitudes of PSA and of low-pass filtered acceleration and velocity have also been determined. Amplitudes recorded at the Kawaguchi-cho station (40 km) at 5-6 second period from the 1964 Niigata earthquake (Mw=8.3) are within ~20% of the current empirical limit of ground motions observed from all earthquakes in the data set including those from the near field. An even more impressive example is that amplitudes recorded at the SCT station (~300 km from the fault) with period of about 2 seconds, during the 1985 Michoacan, Mexico, earthquake (Mw=8.0), are about the same as the current empirical limit of ground motions observed from near field records. These examples support the idea that the hazard caused by long-period ground motions, amplified by basins and site conditions, is not sufficiently appreciated. Reference: Anderson, J. G. (2010), Bull. Seism. Soc. Am. 100, 1-36.

A Study on Empirical Site Response at Bodrum Peninsula, Turkey

NASA Astrophysics Data System (ADS)

Alcik, H. A.; Tanircan, G.

2016-12-01

The Bodrum Peninsula with a population of one million in summer season is one of the most populated touristic centers of the southwest coast of Turkey. The region is located at the eastern part of the Volcanic Arc and Hellenic Arc-Trench System at the Aegean Sea. It is also surrounded by several offshore Aegean Graben systems. All of those systems have capability of producing large magnitude (M7+) earthquakes. Such tectonic entities pose a great threat to settlements around the region. Enrichment in ground motion arrays is an indispensable tool to investigate ground motion characteristics as well as behavior of shallow site profiles at such seismically active urban regions. Hence, Boğaziçi University Kandilli Observatory and Earthquake Research Institute (KOERI) Earthquake Engineering Department deployed a strong motion network at the Peninsula in June 2015. Three out of five stations (B1, B2, B3) are on an Alluvium sediment. The rests are on Limestone (B4) and Volcanic rock (B5). Soil profiles of the sites are not currently available. The network recorded more than 100 earthquakes in the last year. In the present study 15 events with magnitudes (Ml) from 3.4-5.4 occurred within 170 km epicentral distances were selected for calculation. PGA variations among stations were compared. B2 and B3 stations show consistently greater PGA values than others. Fundamental resonant frequencies of the sites were estimated by the H/V technique and relative amplifications were calculated by the Standard Spectral Ratio (SSR) technique. Based on fundamental resonant frequencies, B5 station was selected as the reference station for calculation of SSR spectra.Examining the earthquake data it was found out that (1) Predominant frequencies change between 2.0 - 3.7 Hz for soft soils, where it is 6 Hz for the reference site. The lowest frequency was observed at site B2; (2) Relative amplifications are in the range of 3 to 8. Even though B1, B2 and B3 stations rest on similar geological units, B1 gives the lowest relative amplification. It has been known that the building housing B1 station has a pile foundation and station may not be representative of free field conditions. Structural behaviors could be one of the reasons of such effect; (3) Spectral shapes obtained from SSR are similar to those obtained from H/V.

LEO Download Capacity Analysis for a Network of Adaptive Array Ground Stations

NASA Technical Reports Server (NTRS)

Ingram, Mary Ann; Barott, William C.; Popovic, Zoya; Rondineau, Sebastien; Langley, John; Romanofsky, Robert; Lee, Richard Q.; Miranda, Felix; Steffes, Paul; Mandl, Dan

2005-01-01

To lower costs and reduce latency, a network of adaptive array ground stations, distributed across the United States, is considered for the downlink of a polar-orbiting low earth orbiting (LEO) satellite. Assuming the X-band 105 Mbps transmitter of NASA s Earth Observing 1 (EO-1) satellite with a simple line-of-sight propagation model, the average daily download capacity in bits for a network of adaptive array ground stations is compared to that of a single 11 m dish in Poker Flats, Alaska. Each adaptive array ground station is assumed to have multiple steerable antennas, either mechanically steered dishes or phased arrays that are mechanically steered in azimuth and electronically steered in elevation. Phased array technologies that are being developed for this application are the space-fed lens (SFL) and the reflectarray. Optimization of the different boresight directions of the phased arrays within a ground station is shown to significantly increase capacity; for example, this optimization quadruples the capacity for a ground station with eight SFLs. Several networks comprising only two to three ground stations are shown to meet or exceed the capacity of the big dish, Cutting the data rate by half, which saves modem costs and increases the coverage area of each ground station, is shown to increase the average daily capacity of the network for some configurations.

Localized damage caused by topographic amplification during the 2010 M7.0 Haiti earthquake

USGS Publications Warehouse

Hough, S.E.; Altidor, J.R.; Anglade, D.; Given, D.; Janvier, M.G.; Maharrey, J.Z.; Meremonte, M.; Mildor, B.S.-L.; Prepetit, C.; Yong, A.

2010-01-01

Local geological conditions, including both near-surface sedimentary layers and topographic features, are known to significantly influence ground motions caused by earthquakes. Microzonation maps use local geological conditions to characterize seismic hazard, but commonly incorporate the effect of only sedimentary layers. Microzonation does not take into account local topography, because significant topographic amplification is assumed to be rare. Here we show that, although the extent of structural damage in the 2010 Haiti earthquake was primarily due to poor construction, topographic amplification contributed significantly to damage in the district of Petionville, south of central Port-au-Prince. A large number of substantial, relatively well-built structures situated along a foothill ridge in this district sustained serious damage or collapse. Using recordings of aftershocks, we calculate the ground motion response at two seismic stations along the topographic ridge and at two stations in the adjacent valley. Ground motions on the ridge are amplified relative to both sites in the valley and a hard-rock reference site, and thus cannot be explained by sediment-induced amplification. Instead, the amplitude and predominant frequencies of ground motion indicate the amplification of seismic waves by a narrow, steep ridge. We suggest that microzonation maps can potentially be significantly improved by incorporation of topographic effects. ?? 2010 Macmillan Publishers Limited. All rights reserved.

Solar power satellite system definition study. Volume 3: Reference system description, phase 1

NASA Technical Reports Server (NTRS)

1979-01-01

An analysis of the solar power satellite system is presented. The satellite solar energy conversion and microwave power transmission systems are discussed including the structure, power distribution, thermal control, and energy storage. Space construction and support systems are described including the work support facilities and construction equipment. An assessment of the space transportation system for the satellite and the ground receiving station is presented.

Landsat's international partners

USGS Publications Warehouse

Byrnes, Raymond A.

2012-01-01

Since the launch of the first Landsat satellite 40 years ago, International Cooperators (ICs) have formed a key strategic alliance with the U.S. Geological Survey (USGS) to not only engage in Landsat data downlink services but also to enable a foundation for scientific and technical collaboration. The map below shows the locations of all ground stations operated by the United States and IC ground station network for the direct downlink and distribution of Landsat 5 (L5) and Landsat 7 (L7) image data. The circles show the approximate area over which each station has the capability for direct reception of Landsat data. The red circles show the components of the L5 ground station network, the green circles show components of the L7 station network, and the dashed circles show stations with dual (L5 and L7) status. The yellow circles show L5 short-term ("campaign") stations that contribute to the USGS Landsat archive. Ground stations in South Dakota and Australia currently serve as the primary data capture facilities for the USGS Landsat Ground Network (LGN). The Landsat Ground Station (LGS) is located at the USGS Earth Resources Observation and Science (EROS) Center in Sioux Falls, South Dakota. The Alice Springs (ASN) ground station is located at the Geoscience Australia facility in Alice Springs, Australia. These sites receive the image data, via X-band Radio Frequency (RF) link, and the spacecraft housekeeping data, via S-band RF link. LGS also provides tracking services and a command link to the spacecrafts.

Tethered Vehicle Control and Tracking System

NASA Technical Reports Server (NTRS)

North, David D. (Inventor); Aull, Mark J. (Inventor)

2017-01-01

A kite system includes a kite and a ground station. The ground station includes a sensor that can be utilized to determine an angular position and velocity of the kite relative to the ground station. A controller utilizes a fuzzy logic control system to autonomously fly the kite. The system may include a ground station having powered winding units that generate power as the lines to the kite are unreeled. The control system may be configured to fly the kite in a crosswind trajectory to increase line tension for power generation. The sensors for determining the position of the kite are preferably ground-based.

Tethered Vehicle Control and Tracking System

NASA Technical Reports Server (NTRS)

North, David D. (Inventor); Aull, Mark J. (Inventor)

2014-01-01

A kite system includes a kite and a ground station. The ground station includes a sensor that can be utilized to determine an angular position and velocity of the kite relative to the ground station. A controller utilizes a fuzzy logic control system to autonomously fly the kite. The system may include a ground station having powered winding units that generate power as the lines to the kite are unreeled. The control system may be configured to fly the kite in a crosswind trajectory to increase line tension for power generation. The sensors for determining the position of the kite are preferably ground-based.

Performance of the PARCS Testbed Cesium Fountain Frequency Standard

NASA Technical Reports Server (NTRS)

Enzer, Daphna G.; Klipstein, William M.

2004-01-01

A cesium fountain frequency standard has been developed as a ground testbed for the PARCS (Primary Atomic Reference Clock in Space) experiment, an experiment intended to fly on the International Space Station. We report on the performance of the fountain and describe some of the implementations motivated in large part by flight considerations, but of relevance for ground fountains. In particular, we report on a new technique for delivering cooling and trapping laser beams to the atom collection region, in which a given beam is recirculated three times effectively providing much more optical power than traditional configurations. Allan deviations down to 10 have been achieved with this method.

Datum maintenance of the main Egyptian geodetic control networks by utilizing Precise Point Positioning "PPP" technique

NASA Astrophysics Data System (ADS)

Rabah, Mostafa; Elmewafey, Mahmoud; Farahan, Magda H.

2016-06-01

A geodetic control network is the wire-frame or the skeleton on which continuous and consistent mapping, Geographic Information Systems (GIS), and surveys are based. Traditionally, geodetic control points are established as permanent physical monuments placed in the ground and precisely marked, located, and documented. With the development of satellite surveying methods and their availability and high degree of accuracy, a geodetic control network could be established by using GNSS and referred to an international terrestrial reference frame used as a three-dimensional geocentric reference system for a country. Based on this concept, in 1992, the Egypt Survey Authority (ESA) established two networks, namely High Accuracy Reference Network (HARN) and the National Agricultural Cadastral Network (NACN). To transfer the International Terrestrial Reference Frame to the HARN, the HARN was connected with four IGS stations. The processing results were 1:10,000,000 (Order A) for HARN and 1:1,000,000 (Order B) for NACN relative network accuracy standard between stations defined in ITRF1994 Epoch1996. Since 1996, ESA did not perform any updating or maintaining works for these networks. To see how non-performing maintenance degrading the values of the HARN and NACN, the available HARN and NACN stations in the Nile Delta were observed. The Processing of the tested part was done by CSRS-PPP Service based on utilizing Precise Point Positioning "PPP" and Trimble Business Center "TBC". The study shows the feasibility of Precise Point Positioning in updating the absolute positioning of the HARN network and its role in updating the reference frame (ITRF). The study also confirmed the necessity of the absent role of datum maintenance of Egypt networks.

Benefits Derived From Laser Ranging Measurements for Orbit Determination of the GPS Satellite Orbit

NASA Technical Reports Server (NTRS)

Welch, Bryan W.

2007-01-01

While navigation systems for the determination of the orbit of the Global Position System (GPS) have proven to be very effective, the current research is examining methods to lower the error in the GPS satellite ephemerides below their current level. Two GPS satellites that are currently in orbit carry retro-reflectors onboard. One notion to reduce the error in the satellite ephemerides is to utilize the retro-reflectors via laser ranging measurements taken from multiple Earth ground stations. Analysis has been performed to determine the level of reduction in the semi-major axis covariance of the GPS satellites, when laser ranging measurements are supplemented to the radiometric station keeping, which the satellites undergo. Six ground tracking systems are studied to estimate the performance of the satellite. The first system is the baseline current system approach which provides pseudo-range and integrated Doppler measurements from six ground stations. The remaining five ground tracking systems utilize all measurements from the current system and laser ranging measurements from the additional ground stations utilized within those systems. Station locations for the additional ground sites were taken from a listing of laser ranging ground stations from the International Laser Ranging Service. Results show reductions in state covariance estimates when utilizing laser ranging measurements to solve for the satellite s position component of the state vector. Results also show dependency on the number of ground stations providing laser ranging measurements, orientation of the satellite to the ground stations, and the initial covariance of the satellite's state vector.

Validation of MODIS integrated water vapor product against reference GPS data at the Iberian Peninsula

NASA Astrophysics Data System (ADS)

Vaquero-Martínez, Javier; Antón, Manuel; Ortiz de Galisteo, José Pablo; Cachorro, Victoria E.; Costa, Maria João; Román, Roberto; Bennouna, Yasmine S.

2017-12-01

In this work, the water vapor product from MODIS (MODerate-resolution Imaging Spectroradiometer) instrument, on-board Aqua and Terra satellites, is compared against GPS water vapor data from 21 stations in the Iberian Peninsula as reference. GPS water vapor data is obtained from ground-based receiver stations which measure the delay caused by water vapor in the GPS microwave signals. The study period extends from 2007 until 2012. Regression analysis in every GPS station show that MODIS overestimates low integrated water vapor (IWV) data and tends to underestimate high IWV data. R2 shows a fair agreement, between 0.38 and 0.71. Inter-quartile range (IQR) in every station is around 30-45%. The dependence on several parameters was also analyzed. IWV dependence showed that low IWV are highly overestimated by MODIS, with high IQR (low precision), sharply decreasing as IWV increases. Regarding dependence on solar zenith angle (SZA), performance of MODIS IWV data decreases between 50° and 90°, while night-time MODIS data (infrared) are quite stable. The seasonal cycles of IWV and SZA cause a seasonal dependence on MODIS performance. In summer and winter, MODIS IWV tends to overestimate the reference IWV value, while in spring and autumn the tendency is to underestimate. Low IWV from coastal stations is highly overestimated (∼60%) and quite imprecise (IQR around 60%). On the contrary, high IWV data show very little dependence along seasons. Cloud-fraction (CF) dependence was also studied, showing that clouds display a negligible impact on IWV over/underestimation. However, IQR increases with CF, except in night-time satellite values, which are quite stable.

A Comparative Study of Precise Point Positioning (PPP) Accuracy Using Online Services

NASA Astrophysics Data System (ADS)

Malinowski, Marcin; Kwiecień, Janusz

2016-12-01

Precise Point Positioning (PPP) is a technique used to determine the position of receiver antenna without communication with the reference station. It may be an alternative solution to differential measurements, where maintaining a connection with a single RTK station or a regional network of reference stations RTN is necessary. This situation is especially common in areas with poorly developed infrastructure of ground stations. A lot of research conducted so far on the use of the PPP technique has been concerned about the development of entire day observation sessions. However, this paper presents the results of a comparative analysis of accuracy of absolute determination of position from observations which last between 1 to 7 hours with the use of four permanent services which execute calculations with PPP technique such as: Automatic Precise Positioning Service (APPS), Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP), GNSS Analysis and Positioning Software (GAPS) and magicPPP - Precise Point Positioning Solution (magicGNSS). On the basis of acquired results of measurements, it can be concluded that at least two-hour long measurements allow acquiring an absolute position with an accuracy of 2-4 cm. An evaluation of the impact on the accuracy of simultaneous positioning of three points test network on the change of the horizontal distance and the relative height difference between measured triangle vertices was also conducted. Distances and relative height differences between points of the triangular test network measured with a laser station Leica TDRA6000 were adopted as references. The analyses of results show that at least two hours long measurement sessions can be used to determine the horizontal distance or the difference in height with an accuracy of 1-2 cm. Rapid products employed in calculations conducted with PPP technique reached the accuracy of determining coordinates on a close level as in elaborations which employ Final products.

A Medical Decision Support System for the Space Station Health Maintenance Facility

PubMed Central

Ostler, David V.; Gardner, Reed M.; Logan, James S.

1988-01-01

NASA is developing a Health Maintenance Facility (HMF) to provide the equipment and supplies necessary to deliver medical care in the Space Station. An essential part of the Health Maintenance Facility is a computerized Medical Decision Support System (MDSS) that will enhance the ability of the medical officer (“paramedic” or “physician”) to maintain the crew's health, and to provide emergency medical care. The computer system has four major functions: 1) collect and integrate medical information into an electronic medical record from Space Station medical officers, HMF instrumentation, and exercise equipment; 2) provide an integrated medical record and medical reference information management system; 3) manage inventory for logistical support of supplies and secure pharmaceuticals; 4) supply audio and electronic mail communications between the medical officer and ground based flight surgeons. ImagesFigure 1

Space-to-Ground: Light Storm: 180216

NASA Image and Video Library

2018-02-16

This week on station, a spacewalk and vehicle docking. NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station. For more information about STEM on Station: https://www.nasa.gov/audience/foreducators/stem_on_station/

Satellite power systems (SPS) concept definition study. Volume 2, part 1: System engineering

NASA Technical Reports Server (NTRS)

Hanley, G. M.

1980-01-01

Top level trade studies are presented, including comparison of solid state and klystron concepts, higher concentration on the solar cells, composite and aluminum structure, and several variations to the reference concept. Detailed trade studies are presented in each of the subsystem areas (solar array, power distribution, structures, thermal control, attitude control and stationkeeping, microwave transmission, and ground receiving station). A description of the selected point design is also presented.

Technologies for Refueling Spacecraft On-Orbit

NASA Technical Reports Server (NTRS)

Chato, David J.

2000-01-01

This paper discusses the current technologies for on-orbit refueling of spacecraft. The findings of 55 references are reviewed and summarized. Highlights include: (1) the Russian Progress system used by the International Space Station; (2) a flight demonstration of superfluid helium transfer; and (3) ground tests of large cryogenic systems. Key technologies discussed include vapor free liquid outflow, control of fluid inflow to prevent liquid venting, and quick disconnects for on-orbit mating of transfer lines.

Establishing a Modern Ground Network for Space Geodesy Applications

NASA Technical Reports Server (NTRS)

Pearlman, M.; Pavlis, E.; Altamimi, Z.; Noll, C.

2010-01-01

Ground-based networks of co-located space-geodesy techniques (VLBI, SLR, GLASS, DORIS) are the basis for the development and maintenance of the :International Terrestrial deference Frame (ITRE), which is the basis for our metric measurements of global change. The Global Geodetic Observing System (GGOS) within the International Association of Geodesy has established a task to develop a strategy to design, integrate and maintain the fundamental geodetic network and supporting infrastructure in a sustainable way to satisfy the long-term requirements for the reference frame. The GGOS goal is an origin definition at I mm or better and a temporal stability on the order of 0.1 mm/y, with similar numbers for the scale and orientation components. These goals are based on scientific requirements to address sea level rise with confidence. As a first step, simulations focused on establishing the optimal global SLR and VLBI network, since these two techniques alone are sufficient to define the reference frame. The GLASS constellations will then distribute the reference frame to users anywhere on the Earth. Using simulated data to be collected by the future networks, we investigated various designs and the resulting accuracy in the origin, scale and orientation of the resulting ITRF. We present here the results of extensive simulation studies aimed at designing optimal global geodetic networks to support GGOS science products. Current estimates are the network will require 24 - 32 globally distributed co-location sites. Stations in the near global network will require geologically stable sites witla good weather, established infrastructure, and local support and personnel. EGOS will seek groups that are interested in participation. GGOS intends to issues a Call for Participation of groups that would like to take part in the network implementation and operation_ Some examples of integrated stations currently in operation or under development will be presented. We will examine necessary conditions and challenges in designing a co-location station.

Characteristics of train noise in above-ground and underground stations with side and island platforms

NASA Astrophysics Data System (ADS)

Shimokura, Ryota; Soeta, Yoshiharu

2011-04-01

Railway stations can be principally classified by their locations, i.e., above-ground or underground stations, and by their platform styles, i.e., side or island platforms. However, the effect of the architectural elements on the train noise in stations is not well understood. The aim of the present study is to determine the different acoustical characteristics of the train noise for each station style. The train noise was evaluated by (1) the A-weighted equivalent continuous sound pressure level ( LAeq), (2) the amplitude of the maximum peak of the interaural cross-correlation function (IACC), (3) the delay time ( τ1) and amplitude ( ϕ1) of the first maximum peak of the autocorrelation function. The IACC, τ1 and ϕ1 are related to the subjective diffuseness, pitch and pitch strength, respectively. Regarding the locations, the LAeq in the underground stations was 6.4 dB higher than that in the above-ground stations, and the pitch in the underground stations was higher and stronger. Regarding the platform styles, the LAeq on the side platforms was 3.3 dB higher than on the island platforms of the above-ground stations. For the underground stations, the LAeq on the island platforms was 3.3 dB higher than that on the side platforms when a train entered the station. The IACC on the island platforms of the above-ground stations was higher than that in the other stations.

The Global Geodetic Observing System: Space Geodesy Networks for the Future

NASA Technical Reports Server (NTRS)

Pearlman, Michael; Pavlis, Erricos; Ma, Chopo; Altamini, Zuheir; Noll, Carey; Stowers, David

2011-01-01

Ground-based networks of co-located space geodetic techniques (VLBI, SLR, GNSS. and DORIS) are the basis for the development and maintenance of the International Terrestrial Reference frame (ITRF), which is our metric of reference for measurements of global change, The Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG) has established a task to develop a strategy to design, integrate and maintain the fundamental geodetic network and supporting infrastructure in a sustainable way to satisfy the long-term requirements for the reference frame. The GGOS goal is an origin definition at 1 mm or better and a temporal stability on the order of 0.1 mm/y, with similar numbers for the scale and orientation components. These goals are based on scientific requirements to address sea level rise with confidence, but other applications are not far behind. Recent studies including one by the US National Research Council has strongly stated the need and the urgency for the fundamental space geodesy network. Simulations are underway to examining accuracies for origin, scale and orientation of the resulting ITRF based on various network designs and system performance to determine the optimal global network to achieve this goal. To date these simulations indicate that 24 - 32 co-located stations are adequate to define the reference frame and a more dense GNSS and DORIS network will be required to distribute the reference frame to users anywhere on Earth. Stations in the new global network will require geologically stable sites with good weather, established infrastructure, and local support and personnel. GGOS wil seek groups that are interested in participation. GGOS intends to issues a Call for Participation of groups that would like to contribute in the network implementation and operation. Some examples of integrated stations currently in operation or under development will be presented. We will examine necessary conditions and challenges in designing a co-location station.

Accuracy and coverage of the modernized Polish Maritime differential GPS system

NASA Astrophysics Data System (ADS)

Specht, Cezary

2011-01-01

The DGPS navigation service augments The NAVSTAR Global Positioning System by providing localized pseudorange correction factors and ancillary information which are broadcast over selected marine reference stations. The DGPS service position and integrity information satisfy requirements in coastal navigation and hydrographic surveys. Polish Maritime DGPS system has been established in 1994 and modernized (in 2009) to meet the requirements set out in IMO resolution for a future GNSS, but also to preserve backward signal compatibility of user equipment. Having finalized installation of the new technology L1, L2 reference equipment performance tests were performed.The paper presents results of the coverage modeling and accuracy measuring campaign based on long-term signal analyses of the DGPS reference station Rozewie, which was performed for 26 days in July 2009. Final results allowed to verify the coverage area of the differential signal from reference station and calculated repeatable and absolute accuracy of the system, after the technical modernization. Obtained field strength level area and position statistics (215,000 fixes) were compared to past measurements performed in 2002 (coverage) and 2005 (accuracy), when previous system infrastructure was in operation.So far, no campaigns were performed on differential Galileo. However, as signals, signal processing and receiver techniques are comparable to those know from DGPS. Because all satellite differential GNSS systems use the same transmission standard (RTCM), maritime DGPS Radiobeacons are standardized in all radio communication aspects (frequency, binary rate, modulation), then the accuracy results of differential Galileo can be expected as a similar to DGPS.Coverage of the reference station was calculated based on unique software, which calculate the signal strength level based on transmitter parameters or field signal strength measurement campaign, done in the representative points. The software works based on Baltic sea vector map, ground electric parameters and models atmospheric noise level in the transmission band.

Ground measurements of the vertical E-field on mountains and the "Austausch" effect

NASA Astrophysics Data System (ADS)

Yaniv, Roy; Mkrtchyan, Hripsime; Yair, Yoav; Price, Colin; Reymers, Artur

2016-04-01

The global electric circuit (GEC) on earth is driven by electrified shower clouds and thunderstorms that act as current generators. The current flows up to the ionosphere and returns back to earth in areas known as fair weather regions. One of the GEC parameters that is routinely measured is the vertical electrical field (Ez) with a typical fair weather value between 100-300 V/m near ground. The Ez was found to correlate with the diurnal global thunderstorm activity in what is known as the Carnegie curve (Rycroft et al., 2012). Five ground based stations that measure the daily mean variations of the Ez during fair weather are currently operational in Israel and Armenia. The Israeli stations are located in the arid region of Mitzpe Ramon, Negev desert in southern Israel (30.6N, 34.76E, altitude 860 a.s.l) [Yaniv et al 2015] and at the Tel-Aviv University Cosmic Ray Observatory on Mount Hermon, in northern Israel (33.3N 35.78E, 2100 a.s.l). The Armenian stations are located in Yerevan, (40.205N, 44.486E, 1090m a.s.l.) and additional two on Mount Aragats: Nor Amberd (40.37N, 44.26E, 2000m a.s.l.) and Aragats (40.47N, 44.18E, 3200m a.s.l.). We present preliminary results of the mean daily variations of Ez recorded in these five stations, showing a strong mid-day effect in the mountainous stations (Hermon, Aragatz and Nor Amberd) that is absent from non-mountain stations (Yerevan and Mitzpe Ramon). This strong mid-day local effect in mountainous regions were previously observed by several authors and referred to as "Austausch" - The rising of the boundary layer and the accumulated charge within it due to solar morning heating of the ground. The transport of electrical charge results in an increase of the local Ez [Chalmers 1965, Cobb et al 1967, Israël 1970]. We used monthly averages of the time of increase of the electrical field and correlated these times with the local sun-rise times in the different geograpical locations. Positive correlations were found, indicating that morning solar heating results in the uplift of the charged layer to the mountain tops by anabatic (upslope) winds.

Space-to-Ground: Quick Work: 10/13/2017

NASA Image and Video Library

2017-10-12

Astronauts continue maintenance outside the International Space Station...and artificial gravity on the station? Space to Ground is your weekly update on what's happening aboard the International Space Station.

Site Effects in the City of Port au Prince (Haiti) Inferred From 2010 Earthquake Aftershocks Recordings.

NASA Astrophysics Data System (ADS)

ST Fleur, S.; Courboulex, F.; Bertrand, E.; Deschamps, A.; Mercier De Lepinay, B. F.; Boisson, D.; Prepetit, C.; Hough, S. E.

2014-12-01

The Haitian earthquake of 12 January 2010 (Mw=7) caused an unprecedented disaster in Port-au-Prince as well as in smaller cities close to the epicenter. The extent of damage appears to be initially attributed to the proximity of the earthquake in Port-au-Prince, the extreme vulnerability of many structures, and a high population density. However, the damage distribution for this earthquake suggests a general correlation of damage with small-scale topographical features and local geological structure. The main objective of this work is to investigate site effects in the city of Port-au-Prince. It is also to better define the response of different sites to earthquakes and establish transfer functions between each site and a particular site defined as a reference site. Specific soil columns is determined in the vicinity of each station in order to carry out 1D simulations of soil response at these sites. About 90 earthquakes (2

NPS-SCAT: Electrical Power System

DTIC Science & Technology

2009-09-01

ground station . An initial low power receive mode will allow the ground station to contact SCAT 16 M.P. Schroer, NPS-SCAT; A... station . As shown in Table 6, the power loads of the subsystems using the Watt hour method discussed in section B above, it can be seen that 0.966...telemetry data back to the NPS ground station , the only subsystem open to manipulation with respect to power saving is the beacon secondary transmissions

Land-mobile satellite communication system

NASA Technical Reports Server (NTRS)

Yan, Tsun-Yee (Inventor); Rafferty, William (Inventor); Dessouky, Khaled I. (Inventor); Wang, Charles C. (Inventor); Cheng, Unjeng (Inventor)

1993-01-01

A satellite communications system includes an orbiting communications satellite for relaying communications to and from a plurality of ground stations, and a network management center for making connections via the satellite between the ground stations in response to connection requests received via the satellite from the ground stations, the network management center being configured to provide both open-end service and closed-end service. The network management center of one embodiment is configured to provides both types of service according to a predefined channel access protocol that enables the ground stations to request the type of service desired. The channel access protocol may be configured to adaptively allocate channels to open-end service and closed-end service according to changes in the traffic pattern and include a free-access tree algorithm that coordinates collision resolution among the ground stations.

Analysis of meteorological variables in the Australasian region using ground- and space-based GPS techniques

NASA Astrophysics Data System (ADS)

Kuleshov, Yuriy; Choy, Suelynn; Fu, Erjiang Frank; Chane-Ming, Fabrice; Liou, Yuei-An; Pavelyev, Alexander G.

2016-07-01

Results of analysis of meteorological variables (temperature and moisture) in the Australasian region using the global positioning system (GPS) radio occultation (RO) and GPS ground-based observations verified with in situ radiosonde (RS) data are presented. The potential of using ground-based GPS observations for retrieving column integrated precipitable water vapour (PWV) over the Australian continent has been demonstrated using the Australian ground-based GPS reference stations network. Using data from the 15 ground-based GPS stations, the state of the atmosphere over Victoria during a significant weather event, the March 2010 Melbourne storm, has been investigated, and it has been shown that the GPS observations has potential for monitoring the movement of a weather front that has sharp moisture contrast. Temperature and moisture variability in the atmosphere over various climatic regions (the Indian and the Pacific Oceans, the Antarctic and Australia) has been examined using satellite-based GPS RO and in situ RS observations. Investigating recent atmospheric temperature trends over Antarctica, the time series of the collocated GPS RO and RS data were examined, and strong cooling in the lower stratosphere and warming through the troposphere over Antarctica has been identified, in agreement with outputs of climate models. With further expansion of the Global Navigation Satellite Systems (GNSS) system, it is expected that GNSS satellite- and ground-based measurements would be able to provide an order of magnitude larger amount of data which in turn could significantly advance weather forecasting services, climate monitoring and analysis in the Australasian region.

Ground-water flow in the shallow aquifer system at the Naval Weapons Station Yorktown, Virginia

USGS Publications Warehouse

Smith, Barry S.

2001-01-01

The Environmental Directorate of the Naval Weapons Station Yorktown, Virginia, is concerned about possible contamination of ground water at the Station. Ground water at the Station flows through a shallow system of layered aquifers and leaky confining units. The units of the shallow aquifer system are the Columbia aquifer, the Cornwallis Cave confining unit, the Cornwallis Cave aquifer, the Yorktown confining unit, and the Yorktown-Eastover aquifer. The Eastover-Calvert confining unit separates the shallow aquifer system from deeper confined aquifers beneath the Station. A three-dimensional, finite-difference, ground-water flow model was used to simulate steady-state ground-water flow of the shallow aquifer system in and around the Station. The model simulated ground-water flow from the peninsular drainage divide that runs across the Lackey Plain near the southern end of the Station north to King Creek and the York River and south to Skiffes Creek and the James River. The model was calibrated by minimizing the root mean square error between 4 7 measured and corresponding simulated water levels. The calibrated model was used to determine the ground-water budget and general directions of ground-water flow. A particle-tracking routine was used with the calibrated model to estimate groundwater flow paths, flow rates, and traveltimes from selected sites at the Station. Simulated ground-water flow velocities of the Station-area model were small beneath the interstream areas of the Lackey Plain and Croaker Flat, but increased outward toward the streams and rivers where the hydraulic gradients are larger. If contaminants from the land surface entered the water table at or near the interstream areas of the Station, where hydraulic gradients are smaller, they would migrate more slowly than if they entered closer to the streams or the shores of the rivers where gradients commonly are larger. The ground-water flow simulations indicate that some ground water leaks downward from the water table to the Yorktown confining unit and, where the confining unit is absent, to the Yorktown-Eastover aquifer. The velocities of advective-driven contaminants would decrease considerably when entering the Yorktown confining unit because the hydraulic conductivity of the confining unit is small compared to that of the aquifers. Any contaminants that moved with advective ground-water flow near the groundwater divide of the Lackey Plain would move relatively slowly because the hydraulic gradients are small there. The direction in which the contaminants would move, however, would be determined by precisely where the contaminants entered the water table. The model was not designed to accurately simulate ground-water flow paths through local karst features. Beneath Croaker Flat, ground water flows downward through the Columbia aquifer and the Yorktown confining unit into the Yorktown-Eastover aquifer. Analyses of the movement of simulated particles from two adjacent sites at Croaker Flat indicated that ground-water flow paths were similar at first but diverged and discharged to different tributaries of Indian Field Creek or to the York River. These simulations indicate that complex and possibly divergent flow paths and traveltimes are possible at the Station. Although the Station-area model is not detailed enough to simulate ground-water flow at the scales commonly used to track and remediate contaminants at specific sites, general concepts about possible contaminant migration at the Station can be inferred from the simulations.

Space-to-Ground: Successful Spacewalk: 02/23/2018

NASA Image and Video Library

2018-02-22

NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station. For more information about STEM on Station: https://www.nasa.gov/audience/foreducators/stem_on_station/

ATS-F ground station integration

NASA Technical Reports Server (NTRS)

1975-01-01

The ATS ground stations were described, including a system description, operational frequencies and bandwidth, and a discussion of individual subsystems. Each station configuration is described as well as its floor plan. The station performance, as tested by the GSI, is displayed in chart form providing a summary of the more important parameters tested. This chart provides a listing of test data, by site, for comparison purposes. Also included is a description of the ATS-6 experiments, the equipment, and interfaces required to perform these experiments. The ADP subsystem and its role in the experiments is also described. A description of each program task and a summary of the activities performed were then given. These efforts were accomplished at the Rosman II Ground Station, located near Rosman N.C., the Mojave Ground Station, located near Barstow Ca., and the GSI Contractors plant located near Baltimore, Md.

From a single Neutron Monitor to an International Network: the Real-Time Database for High-Resolution Neutron Monitor Measurements (NMDB)

NASA Astrophysics Data System (ADS)

Steigies, C. T.

2016-12-01

Cosmic rays are routinely measured by standardized ground-based Neutron Monitors (NM) around the world. Stations provide measurements as 1-hour averages to the World-Data Center for Cosmic Rays, but most stations can also provide high-resolution measurements at 1-minute cadence. Measurements of one station provide information about the cosmic ray intensity over time at this location. By correcting the measurement for changes in atmospheric pressure, the intensity of the incoming radiation at the top of the atmosphere can be determined. Studying this time series gives information about long-term changes in the heliospheric environment (11 and 22 year solar cycles), as well as information on shorter (Forbush decrease, Fd) and impulsive (Ground Level Enhancement, GLE) events. Since the measurement of a NM is a cumulative measurement a single station can provide only limited information on the spectrum of the incoming radiation. The whole network of Neutron Monitors, however, can act as a large spectrometer. By combining the measurements of many NM stations, the direction and the spectrum of the incoming radiation can be modeled. With this method, high energy solar particle events (that lead to GLEs) and the precursors of Coronal Mass Ejections (CME, manifesting as a Fd) can be detected by the ground-based instruments before the lower energy particles can harm satellites or astronauts. These ALERT systems require the availability of NM data in real-time, which wass one of the goals of the NMDB project. The easy to use NEST interface (nest.nmdb.eu) to NMDB data allows everyone to plot and download data for all participating stations. Since the project started, not only space agencies and ALERT systems make use of the data, but NMDB has attracted several users outside the cosmic ray community. This data is now also used for example as reference value for soil humidity measurements with cosmic rays, or by the DHS for radiation monitors at border crossings, as well as for computer companies testing the susceptibility of their ICs to cosmic rays. These new uses have only become possible since the individual stations have agreed to share their data freely. We encourage all NM stations that are not yet part of NMDB to join the network, and the space and funding agencies to continue to support these important measurements.

Regional-Scale High-Latitude Extreme Geoelectric Fields Pertaining to Geomagnetically Induced Currents

NASA Technical Reports Server (NTRS)

Pulkkinen, Antti; Bernabeu, Emanuel; Eichner, Jan; Viljanen, Ari; Ngwira, Chigomezyo

2015-01-01

Motivated by the needs of the high-voltage power transmission industry, we use data from the high-latitude IMAGE magnetometer array to study characteristics of extreme geoelectric fields at regional scales. We use 10-s resolution data for years 1993-2013, and the fields are characterized using average horizontal geoelectric field amplitudes taken over station groups that span about 500-km distance. We show that geoelectric field structures associated with localized extremes at single stations can be greatly different from structures associated with regionally uniform geoelectric fields, which are well represented by spatial averages over single stations. Visual extrapolation and rigorous extreme value analysis of spatially averaged fields indicate that the expected range for 1-in-100-year extreme events are 3-8 V/km and 3.4-7.1 V/km, respectively. The Quebec reference ground model is used in the calculations.

Direct determination of geocenter motion by combining SLR, VLBI, GNSS, and DORIS time series

NASA Astrophysics Data System (ADS)

Wu, X.; Abbondanza, C.; Altamimi, Z.; Chin, T. M.; Collilieux, X.; Gross, R. S.; Heflin, M. B.; Jiang, Y.; Parker, J. W.

2013-12-01

The longest-wavelength surface mass transport includes three degree-one spherical harmonic components involving hemispherical mass exchanges. The mass load causes geocenter motion between the center-of-mass of the total Earth system (CM) and the center-of-figure of the solid Earth surface (CF), and deforms the solid Earth. Estimation of the degree-1 surface mass changes through CM-CF and degree-1 deformation signatures from space geodetic techniques can thus complement GRACE's time-variable gravity data to form a complete change spectrum up to a high resolution. Currently, SLR is considered the most accurate technique for direct geocenter motion determination. By tracking satellite motion from ground stations, SLR determines the motion between CM and the geometric center of its ground network (CN). This motion is then used to approximate CM-CF and subsequently for deriving degree-1 mass changes. However, the SLR network is very sparse and uneven in global distribution. The average number of operational tracking stations is about 20 in recent years. The poor network geometry can have a large CN-CF motion and is not ideal for the determination of CM-CF motion and degree-1 mass changes. We recently realized an experimental Terrestrial Reference Frame (TRF) through station time series using the Kalman filter and the RTS smoother. The TRF has its origin defined at nearly instantaneous CM using weekly SLR measurement time series. VLBI, GNSS and DORIS time series are combined weekly with those of SLR and tied to the geocentric (CM) reference frame through local tie measurements and co-motion constraints on co-located geodetic stations. The unified geocentric time series of the four geodetic techniques provide a much better network geometry for direct geodetic determination of geocenter motion. Results from this direct approach using a 90-station network compares favorably with those obtained from joint inversions of GPS/GRACE data and ocean bottom pressure models. We will also show that a previously identified discrepancy in X-component between direct SLR orbit-tracking and inverse determined geocenter motions is largely reconciled with the new unified network.

A method of time transfer between remote stations via LRO

NASA Astrophysics Data System (ADS)

Hoffman, Evan; Sun, Xiaoli; Skillman, David R.; McGarry, Jan F.; Mao, Dandan

2014-05-01

Satellite Laser Ranging (SLR) is a standard geodetic technique that uses the round trip time of light from a ground station to a satellite to determine distance. When combined with a spacecraft detector and timing system, this technique can also be used to transfer time between ground stations, demonstrated by the Time Transfer by Laser Link (T2L2) project by the Centre National d'Etudes Spatiaes (CNES) and Observatorire de la Cote d'Azur (OCA) as well as the Laser Time Transfer (LTT) project by the Shanghai Astronomical Observatory. We describe an additional method of time transfer using simultaneous one-way laser ranging (LR) by two or more ground stations to the Lunar Reconnaissance Orbiter (LRO). A one way ranging is necessary, as two way ranging via retroreflectors for time transfer becomes impractical at lunar distances. The method will utilize the one-way LR currently being performed as a part of the LRO mission, allowing time transfer to be a by-product of the conventional usage of the data. Each ground station is referenced to a Master Clock using a multifrequency all-view GPS receiver at both the ground station and Master Clock locations.The Master Clock is located close enough to the ground station to make ionospheric differences in signal path negligible. Two or more stations range to LRO at the same time and their times of arrival are compared. Results from a ground-based experiment are shown, with sub-nanosecond precision shown to be achievable. Ultimately this measurement will provide a more precise and accurate relation of timing standards between stations, leading to a marked improvement in orbit determination.

Gaussian entanglement distribution via satellite

NASA Astrophysics Data System (ADS)

Hosseinidehaj, Nedasadat; Malaney, Robert

2015-02-01

In this work we analyze three quantum communication schemes for the generation of Gaussian entanglement between two ground stations. Communication occurs via a satellite over two independent atmospheric fading channels dominated by turbulence-induced beam wander. In our first scheme, the engineering complexity remains largely on the ground transceivers, with the satellite acting simply as a reflector. Although the channel state information of the two atmospheric channels remains unknown in this scheme, the Gaussian entanglement generation between the ground stations can still be determined. On the ground, distillation and Gaussification procedures can be applied, leading to a refined Gaussian entanglement generation rate between the ground stations. We compare the rates produced by this first scheme with two competing schemes in which quantum complexity is added to the satellite, thereby illustrating the tradeoff between space-based engineering complexity and the rate of ground-station entanglement generation.

Comparison of atmospheric CO2 mole fractions and source-sink characteristics at four WMO/GAW stations in China

NASA Astrophysics Data System (ADS)

Cheng, Siyang; Zhou, Lingxi; Tans, Pieter P.; An, Xingqin; Liu, Yunsong

2018-05-01

As CO2 is a primary driving factor of climate change, the mole fraction and source-sink characteristics of atmospheric CO2 over China are constantly inferred from multi-source and multi-site data. In this paper, we compared ground-based CO2 measurements with satellite retrievals and investigated the source-sink regional representativeness at China's four WMO/GAW stations. The results indicate that, firstly, atmospheric CO2 mole fractions from ground-based sampling measurement and Greenhouse Gases Observing Satellite (GOSAT) products reveal similar seasonal variation. The seasonal amplitude of the column-averaged CO2 mole fractions is smaller than that of the ground-based CO2 at all stations. The extrema of the seasonal cycle of ground-based and column CO2 mole fractions are basically synchronous except a slight phase delay at Lin'an (LAN) station. For the two-year average, the column CO2 is lower than ground-based CO2, and both of them reveal the lowest CO2 mole fraction at Waliguan (WLG) station. The lowest (∼4 ppm) and largest (∼8 ppm) differences between the column and ground-based CO2 appear at WLG and Longfengshan (LFS) stations, respectively. The CO2 mole fraction and its difference between GOSAT and ground-based measurement are smaller in summer than in winter. The differences of summer column CO2 among these stations are also much smaller than their ground-based counterparts. In winter, the maximum of ground-based CO2 mole fractions and the greatest difference between the two (ground-based and column) datasets appear at the LFS station. Secondly, the representative areas of the monthly CO2 background mole fractions at each station were found by employing footprints and emissions. Smaller representative areas appeared at Shangdianzi (SDZ) and LFS, whereas larger ones were seen at WLG and LAN. The representative areas in summer are larger than those in winter at WLG and SDZ, but the situation is opposite at LAN and LFS. The representative areas for the stations are different in summer and winter, distributed in four typical regions. The CO2 net fluxes in these representative areas show obvious seasonal cycles with similar trends but different varying ranges and different time of the strongest sink. The intensities and uncertainties of the CO2 fluxes are different at different stations in different months and source-sink sectors. Overall, the WLG station is almost a carbon sink, but the other three stations present stronger carbon sources for most of the year. These findings could be conducive to the application of multi-source CO2 data and the understanding of regional CO2 source-sink characteristics and patterns over China.

Satellite power system concept development and evaluation program. Volume 1: Technical assessment summary report

NASA Technical Reports Server (NTRS)

1980-01-01

Candidate satellite power system (SPS) concepts were identified and evaluated in terms of technical and cost factors. A number of alternative technically feasible approaches and system concepts were investigated. A reference system was defined to facilitate economic, environmental, and societal assessments by the Department of Energy. All elements of the reference system were defined including the satellite and all its subsystems, the orbital construction and maintenance bases, all elements of the space transportation system, the ground receiving station, and the associated industrial facilities for manufacturing the required hardware. The reference conclusions and remaining issues are stated for the following topical areas: system definition; energy conversion and power management; power transmission and reception; structures, controls, and materials; construction and operations; and space transportation.

Water Resources Data for Oregon, Water Year 2002

USGS Publications Warehouse

Herrett, T.A.; Hess, G.W.; House, J.G.; Ruppert, G.P.; Courts, M.L.

2003-01-01

The annual Oregon hydrologic data report is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and quality of water provide the hydrologic information needed by State, local and Federal agencies, and the private sector for developing and managing our Nation's land and water resources. This report includes records on both surface and ground water in the State and contains discharge records for 181 stream-gaging stations, 47 partial-record or miscellaneous streamflow stations, and 8 crest-stage partial-record streamflow stations; stage-only records for 6 gaging stations; stage and content records for 26 lakes and reservoirs; and water-quality records for 127 streamflow-gaging stations, 2 atmospheric deposition stations, and 11 ground-water sites.

Water Resources Data for Oregon, Water Year 2003

USGS Publications Warehouse

Herrett, T.A.; Hess, G.W.; House, J.G.; Ruppert, G.P.; Courts, M.L.

2004-01-01

The annual Oregon hydrologic data report is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and quality of water provide the hydrologic information needed by State, local and Federal agencies, and the private sector for developing and managing our Nation's land and water resources. This report includes records on both surface and ground water in Oregon and contains discharge records for 199 stream-gaging stations, 25 partial-record or miscellaneous streamflow stations, and 8 crest-stage partial-record streamflow stations; stage-only records for 6 gaging stations; stage and content records for 26 lakes and reservoirs; and water-quality records collected at 127 streamflow-gaging stations, 2 atmospheric deposition stations, and 11 ground-water sites.

Results of Kirari optical communication demonstration experiments with NICT optical ground station (KODEN) aiming for future classical and quantum communications in space

NASA Astrophysics Data System (ADS)

Toyoshima, Morio; Takenaka, Hideki; Shoji, Yozo; Takayama, Yoshihisa; Koyama, Yoshisada; Kunimori, Hiroo

2012-05-01

Bi-directional ground-to-satellite laser communication experiments were successfully performed between the optical ground station developed by the National Institute of Information and Communications Technology (NICT), located in Koganei City in suburban Tokyo, and a low earth orbit (LEO) satellite, the "Kirari" Optical Inter-orbit Communications Engineering Test Satellite (OICETS). The experiments were conducted in cooperation with the Japan Aerospace Exploration Agency (JAXA), and called the Kirari Optical communication Demonstration Experiments with the NICT optical ground station (or KODEN). The ground-to-OICETS laser communication experiment was the first in-orbit demonstration involving the LEO satellite. The laser communication experiment was conducted since March 2006. The polarization characteristics of an artificial laser source in space, such as Stokes parameters, and the degree of polarization were measured through space-to-ground atmospheric transmission paths, which results contribute to the link estimation for quantum key distribution via space and provide the potential for enhancements in quantum cryptography on a global scale in the future. The Phase-5 experiment, international laser communications experiments were also successfully conducted with four optical ground stations located in the United States, Spain, Germany, and Japan from April 2009 to September 2009. The purpose of the Phase-5 experiment was to establish OICETS-to-ground laser communication links from the different optical ground stations and the statistical analyses such as the normalized power, scintillation index, probability density function, auto-covariance function, and power spectral density were performed. Thus the applicability of the satellite laser communications was demonstrated, aiming not only for geostationary earth orbit-LEO links but also for ground-to-LEO optical links. This paper presents the results of the KODEN experiments and mainly introduces the common analyses among the different optical ground stations.

Validation of integrated water vapor from OMI satellite instrument against reference GPS data at the Iberian Peninsula.

PubMed

Vaquero-Martínez, Javier; Antón, Manuel; Ortiz de Galisteo, José Pablo; Cachorro, Victoria E; Wang, Huiqun; González Abad, Gonzalo; Román, Roberto; Costa, Maria João

2017-02-15

This paper shows the validation of integrated water vapor (IWV) measurements retrieved from the Ozone Monitoring Instrument (OMI), using as reference nine ground-based GPS stations in the Iberian Peninsula. The study period covers from 2007 to 2009. The influence of two factors, - solar zenith angle (SZA) and IWV -, on OMI-GPS differences was studied in detail, as well as the seasonal dependence. The pseudomedian of the relative differences is -1 ± 1% and the inter-quartile range (IQR) is 41%. Linear regressions calculated over each station show an acceptable agreement (R 2 up to 0.77). The OMI-GPS differences display a clear dependence on IWV values. Hence, OMI substantially overestimates the lower IWV data recorded by GPS (∼ 40%), while underestimates the higher IWV reference values (∼ 20%). In connection to this IWV dependence, the relative differences also show an evident SZA dependence when the whole range of IWV values are analyzed (OMI overestimates for high SZA values while underestimates for low values). Finally, the seasonal variation of the OMI-GPS differences is also associated with the strong IWV dependence found in this validation exercise. Copyright © 2016 Elsevier B.V. All rights reserved.

Recent Advances in Observations of Ground-level Auroral Kilometric Radiation

NASA Astrophysics Data System (ADS)

Labelle, J. W.; Ritter, J.; Pasternak, S.; Anderson, R. R.; Kojima, H.; Frey, H. U.

2011-12-01

Recently LaBelle and Anderson [2011] reported the first definitive observations of AKR at ground level, confirmed through simultaneous measurements on the Geotail spacecraft and at South Pole Station, Antarctica. The initial observations consisted of three examples recorded in 2004. An Antarctic observing site is critical for observing ground level AKR which is obscured by man-made broadcast signals at northern hemisphere locations. Examination of 2008 austral winter radio data from Antarctic Automatic Geophysical Observatories (AGOs) of the Polar Experiment Network for Geospace Upper-atmosphere Investigations (PENGUIn) network and South Pole Station reveals 37 ground level AKR events on 23 different days, 30 of which are confirmed by correlation with AKR observed with the Geotail spacecraft. The location of the Geotail spacecraft appears to be a significant factor enabling coincident measurements. Six of the AKR events are detected at two or three ground-level observatories separated by approximately 500 km, suggesting that the events illuminate an area comparable to a 500-km diameter. For 14 events on ten nights, photometer and all-sky imager data from South Pole and AGOs were examined; in ten cases, locations of auroral arcs could be determined at the times of the events. In eight of those cases, the AKR was detected at observatories poleward of the auroral arcs, and in the other two cases the aurora was approximately overhead at the observatory where AKR was detected. These observations suggest that the AKR signals may be ducted to ground level along magnetic field lines rather than propagating directly from the AKR source region of approximately 5000 km altitude. Correlations between structures in the AKR and intensifications of auroral arcs are occasionally observed but are rare. The ground-level AKR events have a local time distribution similar to that of AKR observed from satellites, peaking in the pre-midnight to midnight sector. This data base of >30 events observed coincidentally at ground level and on the Geotail spacecraft, including several events detected at multiple ground stations, will provide a measurements of the ratio of the ground level intensity to that observed on the satellite, with the latter adjusted for distance. This ratio of intensities, not well-determined from the original three events [LaBelle and Anderson, 2011], places an important constraint on the generation mechanism. Reference: LaBelle, J., and R.R. Anderson (2011), Ground-level detection of Auroral Kilometric Radiation, Geophys. Res. Lett., 38, L04104, doi:10.1029/2010GL046411.

Assessment of NPP VIIRS Albedo Over Heterogeneous Crop Land in Northern China

NASA Astrophysics Data System (ADS)

Wu, Xiaodan; Wen, Jianguang; Xiao, Qing; Yu, Yunyue; You, Dongqin; Hueni, Andreas

2017-12-01

In this paper, the accuracy of Suomi National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite (VIIRS) land surface albedo, which is derived from the direct estimation algorithm, was assessed using ground-based albedo observations from a wireless sensor network over a heterogeneous cropland in the Huailai station, northern China. Data from six nodes spanning 2013-2014 over vegetation, bare soil, and mixed terrain surfaces were utilized to provide ground reference at VIIRS pixel scale. The performance of VIIRS albedo was also compared with Global LAnd Surface Satellite (GLASS) and Moderate Resolution Imaging Spectroradiometer (MODIS) albedos (Collection 5 and 6). The results indicate that the current granular VIIRS albedo has a high accuracy with a root-mean-square error of 0.02 for typical land covers. They are significantly correlated with ground references indicated by a correlation coefficient (R) of 0.73. The VIIRS albedo shows distinct advantages to GLASS and MODIS albedos over bare soil and mixed-cover surfaces, while it is inferior to the other two products over vegetated surfaces. Furthermore, its time continuity and the ability to capture the abrupt change of surface albedo are better than that of GLASS and MODIS albedo.

Improvement of the orbit of the Spektr-R spacecraft in the RadioAstron mission and required conditions for improvement using a Kalman filter

NASA Astrophysics Data System (ADS)

Zhamkov, A. S.; Zharov, V. E.

2017-05-01

This paper is concerned with improvement of the state vector of the Spektr-R spacecraft of the RadioAstron mission. The state vector includes three coordinates of the position of the spacecraft and three components of its velocity in the Geocentric Celestial Reference System. Improvement of the orbit of the spacecraft is understood as improvement of the state vector. The results are compared with the original orbits determined at the Keldysh Institute of Applied Mathematics (IAM). The paper considers both using the Kalman filter based on a single set of radio-range and Doppler data from ground-based stations and the analysis of conditions that will lead to improvement of the orbit. It has been shown that using three ground-based stations that perform simultaneous measurements the problem is solved completely, even when a poor initial approximation is used. Based on the results, a list of requirements is obtained that will provide more accurate information on the orbit of the Spektr-R spacecraft.

Simulation of olive grove gross primary production by the combination of ground and multi-sensor satellite data

NASA Astrophysics Data System (ADS)

Brilli, L.; Chiesi, M.; Maselli, F.; Moriondo, M.; Gioli, B.; Toscano, P.; Zaldei, A.; Bindi, M.

2013-08-01

We developed and tested a methodology to estimate olive (Olea europaea L.) gross primary production (GPP) combining ground and multi-sensor satellite data. An eddy-covariance station placed in an olive grove in central Italy provided carbon and water fluxes over two years (2010-2011), which were used as reference to evaluate the performance of a GPP estimation methodology based on a Monteith type model (modified C-Fix) and driven by meteorological and satellite (NDVI) data. A major issue was related to the consideration of the two main olive grove components, i.e. olive trees and inter-tree ground vegetation: this issue was addressed by the separate simulation of carbon fluxes within the two ecosystem layers, followed by their recombination. In this way the eddy covariance GPP measurements were successfully reproduced, with the exception of two periods that followed tillage operations. For these periods measured GPP could be approximated by considering synthetic NDVI values which simulated the expected response of inter-tree ground vegetation to tillages.

The ESA SMOS Validation Rehearsal Campaign at the Valencia Anchor Station Area in the Framework of the SMOS Cal/Val AO Project no. 3252

NASA Astrophysics Data System (ADS)

Lopez-Baeza, E.

2009-04-01

Since 2001, the Valencia Anchor Station is currently being prepared for the validation of SMOS land products. The site has recently been selected by the Mission as a core validation site, mainly due to the reasonable homogeneous characteristics of the area which make it appropriate to undertake the validation of SMOS Level 2 land products during the Mission Commissioning Phase, before attempting more complex areas. Close to SMOS launch, ESA defined and designed the SMOS Validation Rehearsal Campaign Plan with the purpose of repeating the Commissioning Phase execution with all centers, all tools, all participants, all structures, all data available, assuming that all tools and structures are ready and trying to produce as close as possible the post-launch conditions. The aim was to test the readiness, the ensemble coordination and the speed of operations to be able to avoid as far as possible any unexpected deficiencies of the plan and procedure during the real Commissioning Phase campaigns. For the rehearsal activity which successfully took place in April 2008, a control area of 10 x 10 km2 was chosen at the Valencia Anchor Station study area where a network of ground soil moisture measuring stations is being set up based on the definition of homogeneous physio-hydrological units, attending to climatic, soil type, lithology, geology, elevation, slope and vegetation cover conditions. These stations are linked via a wireless communication system to a master post accessible via internet. Complementary to the ground measurements, flight operations were performed over the control area using the Helsinki University of Technology TKK Short Skyvan research aircraft. The payload for the campaign consisted of the following instruments: (i) L-band radiometer EMIRAD (Technical University of Denmark, TUD), (ii) HUT-2D L-band imaging interferometric radiometer (TKK), (iii) PARIS GPS reflectrometry system (Institute for Space Studies of Catalonia, IEEC), (iv) IR sensor (Finnish Institute of Maritime Research, FIMR). Together with the ground soil moisture measurements, other ground and meteorological measurements from the Valencia Anchor Station area, kindly provided by other institutions, are currently been used to simulate passive microwave brightness temperature to have satellite "match ups" for validation purposes and to test the retrieval algorithms. The spatialization of the ground measurements up to a SMOS pixel is carried out by using a Soil-Vegetation-Atmosphere-Transfer (SVAT) model (SURFEX, SURFace EXternalisée) from Météo France. Output data, particularly soil moisture, will then be used to simulate the L-band surface emission through the use of the L-MEB (L-band Microwave Emission of the Biosphere) model. For that purpose, the microwave model uses specific ground information regarding the soil and vegetation properties provided by the validation teams. The aggregation of the brightness temperatures at the SMOS pixel scale is then carried out in an operational way taking into account the SMOS viewing configuration and antenna properties. This paper presents an overview of the ESA SMOS Validation Rehearsal Campaign at the Valencia Anchor Station area making more emphasis on the development of the ground activities which are significant for the performance of the different validation components and giving an outline of the methodology to be used for the whole SMOS Reference Pixel.

Finding international Landsat data online

USGS Publications Warehouse

,

1997-01-01

The Global Land Information System (GLIS) lists Landsat multispectral scanner (MSS) and thematic mapper (TM) data available from the participating international ground stations shown below. These databases of the Landsat Ground Station Operations Working Group (LGSOWG) can be searched, but not ordered, using GLIS. To order Landsat scenes identified on the GLIS data search, contact the international ground station where those scenes are available, indicated by the second character of the Entity ID.

Space-to-Ground: Night Launch: 03/23/2018

NASA Image and Video Library

2018-03-22

Three more crewmembers are on their way to the International Space Station...the crew readies for a spacewalk...and can an astronaut's movement affect the station's orbit? NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Space-to-Ground: Tracking a Monster: 09/08/2017

NASA Image and Video Library

2017-09-07

Three crew members said farewell to the station...the station had eyes on a monstrous storm...and what kind of weather can you have in space? NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Helicopter flight test demonstration of differential GPS

NASA Technical Reports Server (NTRS)

Denaro, R. P.; Beser, J.

1985-01-01

An off-line post-mission processing facility is being established by NASA Ames Research Center to analyze differential GPS flight tests. The current and future differential systems are described, comprising an airborne segment in an SH-3 helicopter, a GPS ground reference station, and a tracking system. The post-mission processing system provides for extensive measurement analysis and differential computation. Both differential range residual corrections and navigation corrections are possible. Some preliminary flight tests were conducted in a landing approach scenario and statically. Initial findings indicate the possible need for filter matching between airborne and ground systems (if used in a navigation correction technique), the advisability of correction smoothing before airborne incorporation, and the insensitivity of accuracy to either of the differential techniques or to update rates.

A Comparison of TOMS Version 8 Total Column Ozone Data with Data from Groundstations

NASA Technical Reports Server (NTRS)

Labow, G. J.; McPeters, R. D.; Bhartia, P. K.

2004-01-01

The Nimbus-7 and Earth Probe Total Ozone Mapping Spectrometer (TOMS) data have been reprocessed with a new retrieval algorithm, (Version 8) and an updated calibration procedure. These data have been systematically compared to total ozone data from Brewer and Dobson spectrophotometers for 73 individual ground stations. The comparisons were made as a function of latitude, solar zenith angle, reflectivity and total ozone. Results show that the accuracy of the TOMS retrieval'is much improved when aerosols are present in the atmosphere, when snow/ice and sea glint are present, and when ozone in the northern hemisphere is extremely low. TOMS overpass data are derived from the single TOMS best match measurement, almost always located within one degree of the ground station and usually made within an hour of local noon. The version 8 Earth Probe TOMS ozone values have decreased by an average of about 1% due to a much better understanding of the calibration of the instrument. The remaining differences between TOMS and ground stations suggest that there are still small errors in the TOMS retrievals. But if TOMS is used as a transfer standard to compare ground stations, the large station-to-station differences suggest the possibility of significant instrument errors at some ground stations.

GARS O'Higgins as a core station for geodesy in Antarctica

NASA Astrophysics Data System (ADS)

Klügel, Thomas; Diedrich, Erhard; Falk, Reinhard; Hessels, Uwe; Höppner, Kathrin; Kühmstedt, Elke; Metzig, Robert; Plötz, Christian; Reinhold, Andreas; Schüler, Torben; Wojdziak, Reiner

2014-05-01

The German Antarctic Receiving Station GARS O'Higgins at the northern tip of the Antarctic Peninsula is a dual purpose facility for Earth observation since more than 20 years. It serves as a satellite ground station for payload data downlink and telecommanding of remote sensing satellites as well as a geodetic observatory for global reference frames and global change. Both applications use the same 9m diameter radio telescope. For space geodesy and astrometry the radio telescope significantly improves the coverage on the southern hemisphere and plays an essential role within the global Very Long Baseline Interferometry (VLBI) network. In particular the determination of the Earth Orientation Parameters (EOP) and the sky coverage of the International Celectial Reference Frame (ICRF) benefit from the location at high southern latitude. Further geodetic instrumentation includes different permanent GNSS receivers (since 1995), two SAR corner reflectors (since 2013) and in the past a PRARE system (1996 - 2004). In addition absolute gravity measurements were performed in 1997 and 2011. All geodetic reference points are tied together by a local survey network. The various geodetic instrumentation and the long time series at O'Higgins allow a reliable determination of crustal motions. VLBI station velocities, continuous GNSS time series and absolute gravity measurements consistently document an uplift rate of about 5 mm/a. A pressure gauge and a radar tide gauge being refererenced to space by a GNSS antenna on top allow the measurement of sea level changes independently from crustal motions, and the determination of the ellipsoidal height of the sea surface, which is, the geoid height plus the mean dynamic topography. The outstanding location on the Antarctic continent makes GARS O'Higgins also in future attractive for polar orbiting satellite missions and an essential station for the global VLBI network. Future plans envisage a development towards an observatory for environmentally relevant research.

A new approach to estimating evaporation from lakes and reservoirs based on energy balance and remote sensing data

NASA Astrophysics Data System (ADS)

Majidi, Maysam; Sadeghi, Morteza; Shafiei, Mojtaba; Alizadeh, Amin; Farid, Alireza; Azad, Mohammadreza; Vazifedoust, Majid

2016-04-01

Estimating evaporation from water bodies such as lakes and reservoirs is commonly a difficult task, especially due to the lack of reliable and available ground data. Remote sensing (RS) data has shown a great potential for filling the gap. Nonetheless, interpretation of the RS data (e.g. optical reflectance, thermal emission, etc.) for estimating water evaporation has remained as a challenge. In this paper, we present a novel approach for estimating water evaporation based on satellite RS data and some readily measurable ground data. In the proposed approach, named as "Reference and Water surface Energy Balance (RWEB)", we define a reference surface and then solve the energy balance equation simultaneously for the reference surfaces and water surface. This approach was tested over the Doosti dam reservoir (north east of Iran) using whether station and RS data as well as water temperature measured biweekly along the study. Accuracy of the RWEB algorithm was examined by comparison to the standard "Bowen Ratio Energy Balance (BREB)" RS algorithm. The RMSD value of 0.047 mm/year indicated a good agreement between RWEB and BREB algorithms, while RWEB provides an easier-to-use approach regarding its required input variables.

Space-to-Ground_171_170407

NASA Image and Video Library

2017-04-07

NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station. Got a question or comment? Use #spacetoground to talk to us. ________________________________________ FOLLOW THE SPACE STATION! Twitter: https://twitter.com/Space_Station Facebook: https://www.facebook.com/ISS Instagram: https://instagram.com/iss/

Ground Motion Relations While TBM Drilling in Unconsolidated Sediments

NASA Astrophysics Data System (ADS)

Grund, Michael; Ritter, Joachim R. R.; Gehrig, Manuel

2016-05-01

The induced ground motions due to the tunnel boring machine (TBM), which has been used for the drilling of the urban metro tunnel in Karlsruhe (SW Germany), has been studied using the continuous recordings of seven seismological monitoring stations. The drilling has been undertaken in unconsolidated sediments of the Rhine River system, relatively close to the surface at 6-20 m depth and in the vicinity of many historic buildings. Compared to the reference values of DIN 4150-3 (1-80 Hz), no exceedance of the recommended peak ground velocity (PGV) limits (3-5 mm/s) was observed at the single recording site locations on building basements during the observation period between October 2014 and February 2015. Detailed analyses in the time and frequency domains helped with the detection of the sources of several specific shaking signals in the recorded time series and with the comparison of the aforementioned TBM-induced signals. The amplitude analysis allowed for the determination of a PGV attenuation relation (quality factor Q ~ 30-50) and the comparison of the TBM-induced ground motion with other artificially induced and natural ground motions of similar amplitudes.

Protocol Architecture Model Report

NASA Technical Reports Server (NTRS)

Dhas, Chris

2000-01-01

NASA's Glenn Research Center (GRC) defines and develops advanced technology for high priority national needs in communications technologies for application to aeronautics and space. GRC tasked Computer Networks and Software Inc. (CNS) to examine protocols and architectures for an In-Space Internet Node. CNS has developed a methodology for network reference models to support NASA's four mission areas: Earth Science, Space Science, Human Exploration and Development of Space (REDS), Aerospace Technology. This report applies the methodology to three space Internet-based communications scenarios for future missions. CNS has conceptualized, designed, and developed space Internet-based communications protocols and architectures for each of the independent scenarios. The scenarios are: Scenario 1: Unicast communications between a Low-Earth-Orbit (LEO) spacecraft inspace Internet node and a ground terminal Internet node via a Tracking and Data Rela Satellite (TDRS) transfer; Scenario 2: Unicast communications between a Low-Earth-Orbit (LEO) International Space Station and a ground terminal Internet node via a TDRS transfer; Scenario 3: Multicast Communications (or "Multicasting"), 1 Spacecraft to N Ground Receivers, N Ground Transmitters to 1 Ground Receiver via a Spacecraft.

GRAVSAT/GEOPAUSE refraction study

NASA Technical Reports Server (NTRS)

Llewellyn, S. K.

1977-01-01

A ground station network tracked a high altitude spacecraft which in turn tracked a low orbiting satellite. Orbit data are relayed back to the ground stations. A refraction study was performed on this configuration to compute ionospheric and tropospheric refraction effects along the satellite and ground links.

The Deep Space Network

NASA Technical Reports Server (NTRS)

1979-01-01

Deep Space Network progress in flight project support, tracking and data acquisition, research and technology, network engineering, hardware and software implementation, and operations is cited. Topics covered include: tracking and ground based navigation; spacecraft/ground communication; station control and operations technology; ground communications; and deep space stations.

Recent field experiments with commercial satellite imagery direct downlink.

PubMed

Gonzalez, Anthony R; Amber, Samuel H

US Pacific Command's strategy includes assistance to United States government relief agencies and nongovernment organizations during humanitarian aid and disaster relief operations in the Asia-Pacific region. Situational awareness during these operations is enhanced by broad interagency access to unclassified commercial satellite imagery. The Remote Ground Terminal-a mobile satellite downlink ground station-has undergone several technology demonstrations and participated in an overseas deployment exercise focused on a natural disaster scenario. This ground station has received new commercial imagery within 20 minutes, hastening a normally days-long process. The Army Geospatial Center continues to manage technology development and product improvement for the Remote Ground Terminal. Furthermore, this ground station is now on a technology transition path into the Distributed Common Ground System-Army program of record.

Knightsat Flight Design Review

DTIC Science & Technology

2007-08-03

spring loaded hinges were obtained from McMaster under part number 15205A42. The fasteners used to attach each shutter to its corresponding hinge were... Coefficient of thermal expansion) is fairly well matched to the cell’s germanium substrate. Copper is not a good choice since it expands and contracts...Temperature: K Ground Station Transmission Line Temp.: 290 K Ground Station Sky Temperature: 450 K G.S. Transmission Line Coefficient : 0.7943 Ground Station

Design and Performance of the Acts Gigabit Satellite Network High Data-Rate Ground Station

NASA Technical Reports Server (NTRS)

Hoder, Doug; Kearney, Brian

1995-01-01

The ACTS High Data-Rate Ground stations were built to support the ACTS Gigabit Satellite Network (GSN). The ACTS GSN was designed to provide fiber-compatible SONET service to remote nodes and networks through a wideband satellite system. The ACTS satellite is unique in its extremely wide bandwidth, and electronically controlled spot beam antennas. This paper discusses the requirements, design and performance of the RF section of the ACTS High Data-Rate Ground Stations and constituent hardware. The ACTS transponder systems incorporate highly nonlinear hard limiting. This introduced a major complexity in to the design and subsequent modification of the ground stations. A discussion of the peculiarities of the A CTS spacecraft transponder system and their impact is included.

Some Long-Standing Issues Arising From Comparisons Between TOMS and The Ground-Based Ozone Network

NASA Technical Reports Server (NTRS)

Labow, Gordon J.; McPeters, Richard; Stolarski, Richard; Einaudi, Franco (Technical Monitor)

2000-01-01

Data from the series of Total Ozone Mapping Spectrometers (TOMS) have been compared to column ozone measurements taken by ground-based systems (Dobsons, Brewers and Filtermeters). On average, the comparisons show good agreement, with approximately 80% of the ground stations having less than a 2.5% standard deviation when compared to TOMS on a monthly mean basis. There are, however, differences that imply possible errors either in the TOMS ozone retrieval algorithm or in the basic assumptions used by the ground-based instruments. Some of the issues arising from these differences are: What are the relative calibrations of TOMS instruments? Why do the calibrations of the ground-based stations vary as much as they do with respect to TOMS as a transfer standard? Why are the TOMS data so much larger (approximately 6%) than the ground-based data in Antarctica and other ice-covered locations? Why is there seasonality in the difference between TOMS and ground-based stations in the Southern Hemisphere? Why are the differences a function of total ozone? Where and why are the differences a function of reflectivity? Why do some terrain and land-sea boundary features appear in the TOMS ozone data? The above issues will be highlighted by using data from TOMS and the ground stations. Plots of the individual station differences will be available.

47 CFR 87.349 - Frequencies.

Code of Federal Regulations, 2014 CFR

2014-10-01

... for ground vehicle identification and collision avoidance; (3) No more than two hundred 1090 MHz... utility station at an airport served by a control tower, RCO or FAA flight service station is the frequency used by the control tower for ground traffic control or by the flight service station for...

Characterization of an In-Situ Ground Terminal via a Geostationary Satellite

NASA Technical Reports Server (NTRS)

Piasecki, Marie T.; Welch, Bryan W.; Mueller, Carl H.

2015-01-01

In 2015, the Space Communications and Navigation (SCaN) Testbed project completed an S-Band ground station located at the NASA Glenn Research Center in Cleveland, Ohio. This S-Band ground station was developed to create a fully characterized and controllable dynamic link environment when testing novel communication techniques for Software Defined Radios and Cognitive Communication Systems. In order to provide a useful environment for potential experimenters, it was necessary to characterize various RF devices at both the component level in the laboratory and at the system level after integration. This paper will discuss some of the laboratory testing of the ground station components, with a particular focus/emphasis on the near-field measurements of the antenna. It will then describe the methodology for characterizing the installed ground station at the system level via a Tracking and Data Relay Satellite (TDRS), with specific focus given to the characterization of the ground station antenna pattern, where the max TDRS transmit power limited the validity of the non-noise floor received power data to the antenna main lobe region. Finally, the paper compares the results of each test as well as provides lessons learned from this type of testing methodology.

Characterization of an In-Situ Ground Terminal via a Geostationary Satellite

NASA Technical Reports Server (NTRS)

Piasecki, Marie; Welch, Bryan; Mueller, Carl

2015-01-01

In 2015, the Space Communications and Navigation (SCaN) Testbed project completed an S-Band ground station located at the NASA Glenn Research Center in Cleveland, Ohio. This S-Band ground station was developed to create a fully characterized and controllable dynamic link environment when testing novel communication techniques for Software Defined Radios and Cognitive Communication Systems. In order to provide a useful environment for potential experimenters, it was necessary to characterize various RF devices at both the component level in the laboratory and at the system level after integration. This paper will discuss some of the laboratory testing of the ground station components, with a particular focus emphasis on the near-field measurements of the antenna. It will then describe the methodology for characterizing the installed ground station at the system level via a Tracking and Data Relay Satellite (TDRS), with specific focus given to the characterization of the ground station antenna pattern, where the max TDRS transmit power limited the validity of the non-noise floor received power data to the antenna main lobe region. Finally, the paper compares the results of each test as well as provides lessons learned from this type of testing methodology.

Empirical Site Amplification Factors Incorporating Soil Nonlinearity in Taiwan

NASA Astrophysics Data System (ADS)

Kuo, C. H.; Chung, C. H.; Che-Min, L.; Huang, J. Y.; Wen, K. L.

2017-12-01

Characteristics of site amplifications caused by both crustal and subduction earthquakes are important in Taiwan. For example, seismic waves were amplified and led to significant building damages in the Taipei Basin by the 1986 Hualien offshore (subduction interface) and the 1999 Chi-Chi earthquakes (crustal), for which the epicentral distances were about 100 km. To understand local site amplifications in Taiwan, empirical site amplification factors for horizontal ground motions are studied using recently constructed strong motion and site databases for the free-field TSMIP stations in Taiwan. Records of large magnitude earthquakes of ML larger than six from 1994 to 2014 were selected for this study. Site amplification factors at site conditions with Vs30 of 120 m/s to 1500 m/s and base accelerations up to 0.7g were inferred from intensity ratios of station pairs within specific distances. The reference site condition is assumed as Vs30 of 760 m/s (B/C boundary). Preliminary results indicate: 1. Soil nonlinearity is more obviously at short periods (PGA, Sa0.3) than long periods (PGV, Sa1.0). 2. Soil nonlinearity is significant for stations belong to site classes of B, C, D, and E in Taiwan. 3. Effect of station-pair distance is seen at short periods (PGA and Sa0.3). 4. No significant different is found in site amplifications of crustal and subduction earthquakes. The result could be a reference for the Fa and Fv in Taiwan's building code.

Space to Ground: A Fleet of CUBESATS: 05/19/2017

NASA Image and Video Library

2017-05-18

NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station. Got a question or comment? Use #spacetoground to talk to us. ________________________________________ FOLLOW THE SPACE STATION! Twitter: https://twitter.com/Space_Station Facebook: https://www.facebook.com/ISS Instagram: https://instagram.com/iss/

Optimal link budget to maximize data receiving from remote sensing satellite at different ground stations

NASA Astrophysics Data System (ADS)

Godse, Vinay V.; Rukmini, B.

2016-10-01

Earth observation satellite plays a significant role for global situation awareness. The earth observation satellite uses imaging payloads in RF and IR bands, which carry huge amount of data, needs to be transferred during visibility of satellite over the ground station. Location of ground station plays a very important role in communication with LEO satellites, as orbital speed of LEO satellite is much higher than earth rotation speed. It will be accessible for particular equatorial ground station for a very short duration. In this paper we want to maximize data receiving by optimizing link budget and receiving data at higher elevation links. Data receiving at multiple ground stations is preferred to counter less pass duration due to higher elevation links. Our approach is to calculate link budget for remote sensing satellite with a fixed power input and varying different minimum elevation angles to obtain maximum data. The minimum pass duration should be above 3 minutes for effective communication. We are proposing to start process of command handling as soon as satellite is visible to particular ground station with low elevation angle up to 5 degree and start receiving data at higher elevation angles to receive data with higher speed. Cartosat-2B LEO earth observation satellite is taken for the case study. Cartosat-2B will complete around 14 passes over equator in a day, out of which only 4-5 passes will be useful for near equator ground stations. Our aim is to receive data at higher elevation angles at higher speed and increase amount of data download, criteria being minimum pass duration of 3 minutes, which has been set for selecting minimum elevation angle.

Analysis Method for Non-Nominal First Acquisition

NASA Technical Reports Server (NTRS)

Sieg, Detlef; Mugellesi-Dow, Roberta

2007-01-01

First this paper describes a method how the trajectory of the launcher can be modelled for the contingency analysis without having much information about the launch vehicle itself. From a dense sequence of state vectors a velocity profile is derived which is sufficiently accurate to enable the Flight Dynamics Team to integrate parts of the launcher trajectory on its own and to simulate contingency cases by modifying the velocity profile. Then the paper focuses on the thorough visibility analysis which has to follow the contingency case or burn performance simulations. In the ideal case it is possible to identify a ground station which is able to acquire the satellite independent from the burn performance. The correlations between the burn performance and the pointing at subsequent ground stations are derived with the aim of establishing simple guidelines which can be applied quickly and which significantly improve the chance of acquisition at subsequent ground stations. In the paper the method is applied to the Soyuz/Fregat launch with the MetOp satellite. Overall the paper shows that the launcher trajectory modelling with the simulation of contingency cases in connection with a ground station visibility analysis leads to a proper selection of ground stations and acquisition methods. In the MetOp case this ensured successful contact of all ground stations during the first hour after separation without having to rely on any early orbit determination result or state vector update.

Local Variability in Firn Layering and Compaction Rates Using GPR Data, Depth-Density Profiles, and In-Situ Reflectors in the Dry Snow Zone Near Summit Station, Greenland

NASA Astrophysics Data System (ADS)

Lines, A.; Elliott, J.; Ray, L.; Albert, M. R.

2017-12-01

Understanding the surface mass balance (SMB) of the Greenland ice sheet is critical to evaluating its response to a changing climate. A key factor in translating satellite and airborne elevation measurements of the ice sheet to SMB is understanding natural variability of firn layer depth and the relative compaction rate of these layers. A site near Summit Station, Greenland was chosen to investigate the variation in layering across a 100m by 100m grid using a 900 MHz and a 2.6 GHz ground penetrating radar (GPR) antenna. These radargrams were ground truthed by taking depth density profiles of five 2m snow pits and five 5m firn cores within the 100m by 100m grid. Combining these measurements with the accumulation data from the nearby ICECAPS weekly bamboo forest measurements, it's possible to see how the snow deposition from individual storm events can vary over a small area. Five metal reflectors were also placed on the surface of the snow in the bounds of the grid to serve as reference reflectors for similar measurements that will be taken in the 2018 field season at Summit Station. This will assist in understanding how one year of accumulation in the dry snow zone impacts compaction and how this rate can vary over a small area.

Early use of Space Station Freedom for NASA's Microgravity Science and Applications Program

NASA Technical Reports Server (NTRS)

Rhome, Robert C.; O'Malley, Terence F.

1992-01-01

The paper describes microgravity science opportunities inherent to the restructured Space Station and presents a synopsis of the scientific utilization plan for the first two years of ground-tended operations. In the ground-tended utilization mode the Space Station is a large free-flyer providing a continuous microgravity environment unmatched by any other platform within any existing U.S. program. It is pointed out that the importance of this period of early Space Station mixed-mode utilization between crew-tended and ground-tended approaches is of such magnitude that Station-based microgravity science experiments many become benchmarks to the disciplines involved. The traffic model that is currently being pursued is designed to maximize this opportunity for the U.S. microgravity science community.

Ground control station software design for micro aerial vehicles

NASA Astrophysics Data System (ADS)

Walendziuk, Wojciech; Oldziej, Daniel; Binczyk, Dawid Przemyslaw; Slowik, Maciej

2017-08-01

This article describes the process of designing the equipment part and the software of a ground control station used for configuring and operating micro unmanned aerial vehicles (UAV). All the works were conducted on a quadrocopter model being a commonly accessible commercial construction. This article contains a characteristics of the research object, the basics of operating the micro aerial vehicles (MAV) and presents components of the ground control station model. It also describes the communication standards for the purpose of building a model of the station. Further part of the work concerns the software of the product - the GIMSO application (Generally Interactive Station for Mobile Objects), which enables the user to manage the actions and communication and control processes from the UAV. The process of creating the software and the field tests of a station model are also presented in the article.

An AI Approach to Ground Station Autonomy for Deep Space Communications

NASA Technical Reports Server (NTRS)

Fisher, Forest; Estlin, Tara; Mutz, Darren; Paal, Leslie; Law, Emily; Stockett, Mike; Golshan, Nasser; Chien, Steve

1998-01-01

This paper describes an architecture for an autonomous deep space tracking station (DS-T). The architecture targets fully automated routine operations encompassing scheduling and resource allocation, antenna and receiver predict generation. track procedure generation from service requests, and closed loop control and error recovery for the station subsystems. This architecture has been validated by the construction of a prototype DS-T station, which has performed a series of demonstrations of autonomous ground station control for downlink services with NASA's Mars Global Surveyor (MGS).

Validation of Brewer and Pandora measurements using OMI total ozone

NASA Astrophysics Data System (ADS)

Baek, Kanghyun; Kim, Jae H.; Herman, Jay R.; Haffner, David P.; Kim, Jhoon

2017-07-01

Korea will launch the Geostationary Environment Monitoring Spectrometer (GEMS) instrument in 2018 onboard the Geostationary Korean Multi-Purpose Satellite to monitor tropospheric gas concentrations with high temporal and spatial resolutions. The purpose of this study is to examine the performance of total column ozone (TCO) measurements from ground-based Pandora and Brewer instruments that will be used for validation of the GEMS ozone product. Satellite measurements can be used to detect erroneous outliers at a particular ground station, which deviate significantly from co-located satellite measurements relative to other stations. This is possible because a single satellite retrieval algorithm is used to process the entire satellite dataset, and instrument characteristics typically change slowly over the life of the satellite. Thus, the short-term stability (months) of satellite measurements can be used to estimate the performance of the ground-based measurement network as well as to identify potential problems at individual stations. As a reference for satellite ozone measurements, we have selected TCO data derived from OMI-TOMS V8.5 algorithm, because it is a robust algorithm that has been well studied to identify its various error sources. We validated ground-based Brewer and Pandora TCO measurements using OMI-TOMS TCO data collected over South Korea from March 2012 to December 2014. The Brewer TCO measurements at Pohang showed significant deviation from overall seasonal variation during the study period. In addition, in the presence of clouds, Pandora TCO measurements are unusually ∼7% higher than OMI-TOMS TCO data. To filter out these cloud-contaminated data, we applied a Kalman filter to the Pandora measurements. The diurnal variation in the Kalman-filtered Pandora data agrees well with the Brewer data, and the correlation of Kalman-filtered Pandora data with OMI-TOMS TCO is significantly improved from 0.89 to 0.99 at Seoul and from 0.93 to 0.99 at Busan.

Space vehicle field unit and ground station system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Judd, Stephen; Dallmann, Nicholas; Delapp, Jerry

A field unit and ground station may use commercial off-the-shelf (COTS) components and share a common architecture, where differences in functionality are governed by software. The field units and ground stations may be easy to deploy, relatively inexpensive, and be relatively easy to operate. A novel file system may be used where datagrams of a file may be stored across multiple drives and/or devices. The datagrams may be received out of order and reassembled at the receiving device.

Space vehicle field unit and ground station system

DOEpatents

Judd, Stephen; Dallmann, Nicholas; Delapp, Jerry; Proicou, Michael; Seitz, Daniel; Michel, John; Enemark, Donald

2016-10-25

A field unit and ground station may use commercial off-the-shelf (COTS) components and share a common architecture, where differences in functionality are governed by software. The field units and ground stations may be easy to deploy, relatively inexpensive, and be relatively easy to operate. A novel file system may be used where datagrams of a file may be stored across multiple drives and/or devices. The datagrams may be received out of order and reassembled at the receiving device.

ACTS TDMA network control. [Advanced Communication Technology Satellite

NASA Technical Reports Server (NTRS)

Inukai, T.; Campanella, S. J.

1984-01-01

This paper presents basic network control concepts for the Advanced Communications Technology Satellite (ACTS) System. Two experimental systems, called the low-burst-rate and high-burst-rate systems, along with ACTS ground system features, are described. The network control issues addressed include frame structures, acquisition and synchronization procedures, coordinated station burst-time plan and satellite-time plan changes, on-board clock control based on ground drift measurements, rain fade control by means of adaptive forward-error-correction (FEC) coding and transmit power augmentation, and reassignment of channel capacities on demand. The NASA ground system, which includes a primary station, diversity station, and master control station, is also described.

Cost and Performance Comparison of an Earth-Orbiting Optical Communication Relay Transceiver and a Ground-Based Optical Receiver Subnet

NASA Astrophysics Data System (ADS)

Wilson, K. E.; Wright, M.; Cesarone, R.; Ceniceros, J.; Shea, K.

2003-01-01

Optical communications can provide high-data-rate telemetry from deep-space probes with subsystems that have lower mass, consume less power, and are smaller than their radio frequency (RF) counterparts. However, because optical communication is more affected by weather than is RF communication, it requires ground station site diversity to mitigate the adverse effects of inclement weather on the link. An optical relay satellite is not affected by weather and can provide 24-hour coverage of deep-space probes. Using such a relay satellite for the deep-space link and an 8.4-GHz (X-band) link to a ground station would support high-data-rate links from small deep-space probes with very little link loss due to inclement weather. We have reviewed past JPL-funded work on RF and optical relay satellites, and on proposed clustered and linearly dispersed optical subnets. Cost comparisons show that the life cycle costs of a 7-m optical relay station based on the heritage of the Next Generation Space Telescope is comparable to that of an 8-station subnet of 10-m optical ground stations. This makes the relay link an attractive option vis-a-vis a ground station network.

A preliminary design for a satellite power system

NASA Technical Reports Server (NTRS)

Enriquez, Clara V.; Kokaly, Ray; Nandi, Saumya; Timmons, Mike; Garrard, Mark; Mercado, Rommel; Rogers, Brian; Ugaz, Victor

1991-01-01

Outlined here is a preliminary design for a Solar Power Satellite (SPS) system. The SPS will provide a clean, reliable source of energy for mass consumption. The system will use satellites in geostationary orbits around the Earth to capture the sun's energy. The intercepted sunlight will be converted to laser beam energy which can be transmitted to the Earth's surface. Ground systems on the Earth will convert the transmissions from space into electric power. The preliminary design for the SPS consists of one satellite in orbit around the Earth transmitting to one ground station. The SPs technology uses multi-layer solar cell technology arranged on a 20 sq km planar array to intercept sunlight and convert it to an electric voltage. Power conditioning devices then send the electricity to a laser, which transmits the power to the surface of the Earth. A ground station will convert the beam into electricity. Construction will take place in low Earth orbit and array sections, 20 in total, will be sailed on the solar wind out to the GEO location in 150 days. These individual transportation sections are referred to as solar sailing panels (SSAPs). The primary truss elements used to support the arrays are composed on composite tubular members in a pentahedral arrangement. Smart segments consisting of passive and active damping devices will increase the control of dynamic SPS modes.

Training augmentation device for the Air Force satellite Control Network

NASA Technical Reports Server (NTRS)

Shoates, Keith B.

1993-01-01

From the 1960's and into the early 1980's satellite operations and control were conducted by Air Force Systems Command (AFSC), now Air Force Materiel Command (AFMC), out of the Satellite Control Facility at Onizuka AFB, CA. AFSC was responsible for acquiring satellite command and control systems and conducting routine satellite operations. The daily operations, consisting of satellite health and status contacts and station keeping activities, were performed for AFSC by a Mission Control Team (MCT) staffed by civilian contractors who were responsible for providing their own technically 'qualified' personnel as satellite operators. An MCT consists of five positions: mission planner, ground controller, planner analyst, orbit analyst, and ranger controller. Most of the training consisted of On-the-Job-Training (OJT) with junior personnel apprenticed to senior personnel until they could demonstrate job proficiency. With most of the satellite operators having 15 to 25 years of experience, there was minimal risk to the mission. In the mid 1980's Air Force Space Command (AFSPACOM) assumed operational responsibility for a newly established control node at Falcon AFB (FAFB) in CO. The satellites and ground system program offices (SPO's) are organized under AFSC's Space and Missiles Systems Center (SMC) to function as a systems engineering and acquisition agency for AFSPACECOM. The collection of the satellite control nodes, ground tracking stations, computer processing equipment, and connecting communications links is referred to as the Air Force Satellite Control Network (AFSCN).

Remote Sensing Analysis of Temperature and Suspended Sediment Concentration in Ayeyarwady River in Myanmar

NASA Astrophysics Data System (ADS)

Thanda Ko, Nyein; Rutten, Martine

2017-04-01

Detailed spatial coverage of water quality parameters are crucial to better manage rivers. However, collection of water quality parameters is both time consuming and costly for large rivers. This study demonstrates that Operational Land Image (OLI) Sensor on board of Landsat 8 can be successfully applied for the detection of spatial patterns of water temperature as well as suspended sediment concentration (SSC) using the Ayeyarwady river, Myanmar as a case study. Water temperature estimation was obtained from the brightness thermal Band 10 by using the Split-Window algorithm. The study finds that there is a close agreement between the remote sensing temperature and in-situ temperature with relative error in the range from 4.5% to 8.2%. The sediment load of Ayeyarwady river is ranked as the third-largest sediment load among the world's rivers but there is very little known about this important parameter, due to a lack of adequate gauge data. The single band reflectance of Landsat image (Band 5) seems a good indicator for the estimation of SSC with relative error in the range of less than 10% but the developed empirical formula by the power relation with the only seven ground reference points is uncertain to apply for the entire river basin. It is to note that an important constraint for the sediment analysis is the availability of spatial and temporal ground reference data. Future studies should also focus on the improvement of ground reference data points to become more reliable, because most of the river in Asia, especially in Myanmar, don't have readily available continuous ground sediment data points due to lack of measurement gauge stations through the river.

Looking at Earth from space

NASA Technical Reports Server (NTRS)

1994-01-01

This vendor equipment list was developed with NASA funding by the Dallas Remote Imaging Group (DRIG) and the Maryland Pilot Earth Science and Technology Education Network (MAPS-NET) project as a reference guide to low-cost ground station equipment for direct readout, the capability to acquire information directly from environmental satellites. Products were tested with the following standards in mind: ease of use; user friendliness and completeness of manual and instructions; total system cost for computer, geostationary operational environmental satellites (GOES), and automatic picture transmission (APT) capability under $4000; and vendor stability in the industry.

Integrated failure detection and management for the Space Station Freedom external active thermal control system

NASA Technical Reports Server (NTRS)

Mesloh, Nick; Hill, Tim; Kosyk, Kathy

1993-01-01

This paper presents the integrated approach toward failure detection, isolation, and recovery/reconfiguration to be used for the Space Station Freedom External Active Thermal Control System (EATCS). The on-board and on-ground diagnostic capabilities of the EATCS are discussed. Time and safety critical features, as well as noncritical failures, and the detection coverage for each provided by existing capabilities are reviewed. The allocation of responsibility between on-board software and ground-based systems, to be shown during ground testing at the Johnson Space Center, is described. Failure isolation capabilities allocated to the ground include some functionality originally found on orbit but moved to the ground to reduce on-board resource requirements. Complex failures requiring the analysis of multiple external variables, such as environmental conditions, heat loads, or station attitude, are also allocated to ground personnel.

Water resources data for Oregon, water year 2004

USGS Publications Warehouse

Herrett, Thomas A.; Hess, Glenn W.; House, Jon G.; Ruppert, Gregory P.; Courts, Mary-Lorraine

2005-01-01

The annual Oregon water data report is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and quality of water provide the hydrologic information needed by State, local, Tribal, and Federal agencies and the private sector for developing and managing our Nation's land and water resources. This report contains water year 2004 data for both surface and ground water, including discharge records for 209 streamflow-gaging stations, 42 partial-record or miscellaneous streamflow stations, and 9 crest-stage partial-record streamflow stations; stage-only records for 6 gaging stations; stage and content records for 15 lakes and reservoirs; water-level records from 12 long-term observation wells; and water-quality records collected at 133 streamflow-gaging stations and 1 atmospheric deposition station.

The Role of Anchor Stations in the Validation of Earth Observation Satellite Data and Products. The Valencia and the Alacant Anchor Stations

NASA Astrophysics Data System (ADS)

Lopez-Baeza, Ernesto; Geraldo Ferreira, A.; Saleh-Contell, Kauzar

Space technology facilitates humanity and science with a global revolutionary view of the Earth through the acquisition of Earth Observation satellite data. Satellites capture information over different spatial and temporal scales and assist in understanding natural climate processes and in detecting and explaining climate change. Accurate Earth Observation data is needed to describe climate processes by improving the parameterisations of different climate elements. Algorithms to produce geophysical parameters from raw satellite observations should go through selection processes or participate in inter-comparison programmes to ensure performance reliability. Geophysical parameter datasets, obtained from satellite observations, should pass a quality control before they are accepted in global databases for impact, diagnostic or sensitivity studies. Calibration and Validation, or simply "Cal/Val", is the activity that endeavours to ensure that remote sensing products are highly consistent and reproducible. This is an evolving scientific activity that is becoming increasingly important as more long-term studies on global change are undertaken, and new satellite missions are launched. Calibration is the process of quantitatively defining the system responses to known, controlled signal inputs. Validation refers to the process of assessing, by independent means, the quality of the data products derived from the system outputs. These definitions are generally accepted and most often used in the remote sensing context to refer specifically and respectively to sensor radiometric calibration and geophysical parameter validation. Anchor Stations are carefully selected locations at which instruments measure quantities that are needed to run, calibrate or validate models and algorithms. These are needed to quanti-tatively evaluate satellite data and convert it into geophysical information. The instruments collect measurements of basic quantities over a long timescale. Measurements are made of meteorological and hydrological background data, and of quantities not readily assessed at operational stations. Anchor Stations also offer infrastructure to undertake validation experi-ments. These are more detailed measurements over shorter intensive observation periods. The Valencia Anchor Station is showing its capabilities and conditions as a reference validation site in the framework of low spatial resolution remote sensing missions such as CERES, GERB and SMOS. The Alacant Anchor Station is a reference site in studies on the interactions between desertification and climate. This paper presents the activities so far carried out at both Anchor Stations, the precise and detailed ground and aircraft experiments carefully designed to develop a specific methodology to validate low spatial resolution satellite data and products, and the knowledge exchange currently being exercised between the University of Valencia, Spain, and FUNCEME, Brazil, in common objectives of mutual interest.

47 CFR 22.867 - Effective radiated power limits.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Effective radiated power limits. The effective radiated power (ERP) of ground and airborne stations... peak ERP of airborne mobile station transmitters must not exceed 12 Watts. (b) The peak ERP of ground...

Space to Ground: Launches and Landings: 06/08/2018

NASA Image and Video Library

2018-06-08

This week, one crew launched to the International Space Station, while another returned to Earth. NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Space-to-Ground: Genes in Space: 04/13/2018

NASA Image and Video Library

2018-04-12

Can the Polymerase Chain Reaction be used to study DNA alterations on the International Space Station? NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Bird's Eye View - A 3-D Situational Awareness Tool for the Space Station

NASA Technical Reports Server (NTRS)

Dershowitz, Adam; Chamitoff, Gregory

2002-01-01

Even as space-qualified computer hardware lags well behind the latest home computers, the possibility of using high-fidelity interactive 3-D graphics for displaying important on board information has finally arrived, and is being used on board the International Space Station (ISS). With the quantity and complexity of space-flight telemetry, 3-D displays can greatly enhance the ability of users, both onboard and on the ground, to interpret data quickly and accurately. This is particularly true for data related to vehicle attitude, position, configuration, and relation to other objects on the ground or in-orbit Bird's Eye View (BEV) is a 3-D real-time application that provides a high degree of Situational Awareness for the crew. Its purpose is to instantly convey important motion-related parameters to the crew and mission controllers by presenting 3-D simulated camera views of the International Space Station (ISS) in its actual environment Driven by actual telemetry, and running on board, as well as on the ground, the user can visualize the Space Station relative to the Earth, Sun, stars, various reference frames, and selected targets, such as ground-sites or communication satellites. Since the actual ISS configuration (geometry) is also modeled accurately, everything from the alignment of the solar panels to the expected view from a selected window can be visualized accurately. A virtual representation of the Space Station in real time has many useful applications. By selecting different cameras, the crew or mission control can monitor the station's orientation in space, position over the Earth, transition from day to night, direction to the Sun, the view from a particular window, or the motion of the robotic arm. By viewing the vehicle attitude and solar panel orientations relative to the Sun, the power status of the ISS can be easily visualized and understood. Similarly, the thermal impacts of vehicle attitude can be analyzed and visually confirmed. Communication opportunities can be displayed, and line-of-sight blockage due to interference by the vehicle structure (or the Earth) can be seen easily. Additional features in BEV display targets on the ground and in-orbit, including cities, communication sites, landmarks, satellites, and special sites of scientific interest for Earth observation and photography. Any target can be selected and tracked. This gives the user a continual line-of-sight to the target of current interest, and real-time knowledge about its visibility. Similarly, the vehicle ground-track, and an option to show "visibility circles" around displayed ground sites, provide continuous insight regarding current and future visibility to any target BEV was designed with inputs from many disciplines in the flight control and operations community both at NASA and from the International Partners. As such, BEV is setting the standards for interactive 3-D graphics for spacecraft applications. One important contribution of BEV is a generic graphical interface for camera control that can be used for any 3-D applications. This interface has become part of the International Display and Graphics Standards for the 16-nation ISS partnership. Many other standards related to camera properties, and the display of 3-D data, also have been defined by BEV. Future enhancements to BEV will include capabilities related to simulating ahead of the current time. This will give the user tools for analyzing off-nominal and future scenarios, as well as for planning future operations.

Phase change references for in-flight recalibration of orbital thermometry

NASA Astrophysics Data System (ADS)

Topham, T. S.; Latvakoski, H.; Watson, M.

2013-09-01

Several critical questions need to be answered to determine the potential utility of phase change materials as long-term orbital references: How accurate and repeatable will phase change reference implementations be after incorporating necessary design trade-offs to accommodate launch and the space environment? How can the temperature of phase transitions be transferred to something useful for calibration such as a black body. How, if at all, will the microgravity environment affect the phase transitions? To help answer some of these questions, three experiments will be conducted on the International Space Station (ISS). The experiments will test melts and freezes of three different phase change materials in various containment apparatus. This paper addresses the current status of the ISS experiments, as well as results from ground testing of several concepts for space application of PCM recalibration systems in the CORSAIR (Calibration Observations of Radiance Spectra in the far Infrared) black body.

Space to Ground: Who Doesn't Enjoy a Good View of Planet Earth?: 02/10/2017

NASA Image and Video Library

2017-02-10

NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station. Got a question or comment? Use #spacetoground to talk to us. ________________________________________ FOLLOW THE SPACE STATION! Twitter: https://twitter.com/Space_Station Facebook: https://www.facebook.com/ISS Instagram: https://instagram.com/iss/

Validation of Global Climatologies of Trace Gases Using NASA Global Tropospheric Experiment (GTE) Data

NASA Technical Reports Server (NTRS)

Courchaine, Brian; Venable, Jessica C.

1995-01-01

Methane is an important trace gas because it is a greenhouse gas that affects the oxidative capacity of the atmosphere. It is produced from biological and anthropogenic sources, and is increasing globally at a rate of approximately 0.6% per year [Climate Change 1992, IPCC]. By using National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory (NOAA/CMDL) ground station data, a global climatology of methane values was produced. Unfortunately, because the NOAA/CMDL ground stations are so sparse, the global climatology is low resolution. In order to compensate for this low resolution data, it was compared to in-situ flight data obtained from the NASA Global Tropospheric Experiment (GTE). The smoothed ground station data correlated well with the flight data. Thus, for the first time it is shown that the smoothing process used to make global contours of methane using the ground stations is a plausible way to approximate global atmospheric concentrations of the gas. These verified climatologies can be used for testing large-scale models of chemical production, destruction, and transport. This project develops the groundwork for further research in building global climatologies from sparse ground station data and studying the transport and distribution of trace gases.

Performance Predictions for the Adaptive Optics System at LCRD's Ground Station 1

NASA Technical Reports Server (NTRS)

Roberts, Lewis C., Jr.; Burruss, Rick; Roberts, Jennifer E.; Piazzolla, Sabino; Dew, Sharon; Truong, Tuan; Fregoso, Santos; Page, Norm

2015-01-01

NASA's LCRD mission will lay the foundation for future laser communication systems. We show the design of the Table Mountain ground station's AO system and time series of predicted coupling efficiency.

Space-to-Ground: Neuromapping: 03/16/2018

NASA Image and Video Library

2018-03-15

Another science-filled week aboard the space station, and can you see the Great Wall of China from Space? NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Space-to-Ground: Some Serious Science: 02/08/2018

NASA Image and Video Library

2018-02-08

With a breather between spacewalks, it was time for some serious science on the International Space Station. NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Space-to-Ground: A Unique Experience: 03/09/2018

NASA Image and Video Library

2018-03-08

Science continued on the station with the Expedition 55 crew, and Scott Tingle shared a surreal training experience. NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Space-to-Ground: 2017: 12/22/2017

NASA Image and Video Library

2017-12-21

We look back at a record-breaking year, and forward to what should be a transformational year on station. NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Modeling continuous seismic velocity changes due to ground shaking in Chile

NASA Astrophysics Data System (ADS)

Gassenmeier, Martina; Richter, Tom; Sens-Schönfelder, Christoph; Korn, Michael; Tilmann, Frederik

2015-04-01

In order to investigate temporal seismic velocity changes due to earthquake related processes and environmental forcing, we analyze 8 years of ambient seismic noise recorded by the Integrated Plate Boundary Observatory Chile (IPOC) network in northern Chile between 18° and 25° S. The Mw 7.7 Tocopilla earthquake in 2007 and the Mw 8.1 Iquique earthquake in 2014 as well as numerous smaller events occurred in this area. By autocorrelation of the ambient seismic noise field, approximations of the Green's functions are retrieved. The recovered function represents backscattered or multiply scattered energy from the immediate neighborhood of the station. To detect relative changes of the seismic velocities we apply the stretching method, which compares individual autocorrelation functions to stretched or compressed versions of a long term averaged reference autocorrelation function. We use time windows in the coda of the autocorrelations, that contain scattered waves which are highly sensitive to minute changes in the velocity. At station PATCX we observe seasonal changes in seismic velocity as well as temporary velocity reductions in the frequency range of 4-6 Hz. The seasonal changes can be attributed to thermal stress changes in the subsurface related to variations of the atmospheric temperature. This effect can be modeled well by a sine curve and is subtracted for further analysis of short term variations. Temporary velocity reductions occur at the time of ground shaking usually caused by earthquakes and are followed by a recovery. We present an empirical model that describes the seismic velocity variations based on continuous observations of the local ground acceleration. Our hypothesis is that not only the shaking of earthquakes provokes velocity drops, but any small vibrations continuously induce minor velocity variations that are immediately compensated by healing in the steady state. We show that the shaking effect is accumulated over time and best described by the integrated envelope of the ground acceleration over 1 day which is the discretization interval of the velocity measurements. In our model the amplitude of the velocity reduction as well as the recovery time are proportional to the size of the excitation. This model with the two free scaling parameters for the shaking induced velocity variation fits the data in remarkable detail. Additionally, a linear trend is observed that might be related to a recovery process from one or more earthquakes before our measurement period. For the Tocopilla earthquake in 2007 and the Iquique earthquake in 2014 velocity reductions are also observed at other stations of the IPOC network. However, a clear relationship between the ground shaking and the induced velocity reductions is not visible at other stations. We attribute the outstanding sensitivity of PATCX to ground shaking to the special geological setting of the station, where the material consists of relatively loose conglomerate with high pore volume.

Analysis Methodology for Optimal Selection of Ground Station Site in Space Missions

NASA Astrophysics Data System (ADS)

Nieves-Chinchilla, J.; Farjas, M.; Martínez, R.

2013-12-01

Optimization of ground station sites is especially important in complex missions that include several small satellites (clusters or constellations) such as the QB50 project, where one ground station would be able to track several spatial vehicles, even simultaneously. In this regard the design of the communication system has to carefully take into account the ground station site and relevant signal phenomena, depending on the frequency band. To propose the optimal location of the ground station, these aspects become even more relevant to establish a trusted communication link due to the ground segment site in urban areas and/or selection of low orbits for the space segment. In addition, updated cartography with high resolution data of the location and its surroundings help to develop recommendations in the design of its location for spatial vehicles tracking and hence to improve effectiveness. The objectives of this analysis methodology are: completion of cartographic information, modelling the obstacles that hinder communication between the ground and space segment and representation in the generated 3D scene of the degree of impairment in the signal/noise of the phenomena that interferes with communication. The integration of new technologies of geographic data capture, such as 3D Laser Scan, determine that increased optimization of the antenna elevation mask, in its AOS and LOS azimuths along the horizon visible, maximizes visibility time with spatial vehicles. Furthermore, from the three-dimensional cloud of points captured, specific information is selected and, using 3D modeling techniques, the 3D scene of the antenna location site and surroundings is generated. The resulting 3D model evidences nearby obstacles related to the cartographic conditions such as mountain formations and buildings, and any additional obstacles that interfere with the operational quality of the antenna (other antennas and electronic devices that emit or receive in the same bandwidth). To check/test the spatial proposal of the ground station site, this analysis methodology uses mission simulation software of spatial vehicles to analyze and quantify how the geographic accuracy of the position of the spatial vehicles along the horizon visible from the antenna, increases communication time with the ground station. Experimental results that have been obtained from a ground station located at ETSIT-UPM in Spain (QBito Nanosatellite, UPM spacecraft mission within the QB50 project) show that selection of the optimal site increases the field of view from the antenna and hence helps to meet mission requirements.

Preparation of X-ray astronomy satellite experiment Development of computer programs for the Salyut-HEXE X-ray experiment ground station

NASA Astrophysics Data System (ADS)

Petrik, J.

The engineering model of the Salyut-HEXE experiment is described. The detector system, electronics box, and ground station are addressed. The microprocessor system is considered, discussing the cards and presenting block diagrams of their functions. The telemetry is examined, including the various modes and the direct and indirect transmission modes. The ground station programs are discussed, including the tasks, program development, input and output programs, status, power supply, count rates, telemetry dump, hard copy, and checksum.

SCaN Network Ground Station Receiver Performance for Future Service Support

NASA Technical Reports Server (NTRS)

Estabrook, Polly; Lee, Dennis; Cheng, Michael; Lau, Chi-Wung

2012-01-01

Objectives: Examine the impact of providing the newly standardized CCSDS Low Density Parity Check (LDPC) codes to the SCaN return data service on the SCaN SN and DSN ground stations receivers: SN Current Receiver: Integrated Receiver (IR). DSN Current Receiver: Downlink Telemetry and Tracking (DTT) Receiver. Early Commercial-Off-The-Shelf (COTS) prototype of the SN User Service Subsystem Component Replacement (USS CR) Narrow Band Receiver. Motivate discussion of general issues of ground station hardware design to enable simple and cheap modifications for support of future services.

Ecological Aspects of Condition of Ground Deposits in Shershnevsky Reservoir

NASA Astrophysics Data System (ADS)

Arkanova, I. A.; Denisov, S. E.; Knutarev, D. Yu

2017-11-01

The article considers the aspects of the condition of ground deposits influencing the operating conditions of the water intake facilities in the Shershnevsky reservoir being the only source of the utility and drinking water supply in Chelyabinsk. The object of the research is a section near the Sosnovskie intake stations of the Shershnevsky reservoir. Based on the hydrometric surveys of the studied section and using the Kriging method and the Surfer suite, we calculated the volume of ground deposits. As a result of the analyses, the authors have proved that ground deposits in the studied section have a technology-related nature which is connected with the annual growth of the volume of ground deposits which is inadmissible in the operating conditions of the pump stations of water intake facilities whereas ground deposits will fully block the intake windows of pump stations. In case the bed area of the Shershnevsky reservoir is not timely treated, the ground deposits here will complicate the operation of the pump stations which will result in a technological problem of the treatment facilities operation up to a transfer of the pump station premises to other territories less exposed to the deposits. The treatment of the Shershnevsky reservoir from the ground deposits accumulated in the course of time will help to considerably increase its actual capacity, which will allow one to increase water circulation paths and to improve the water quality indices. In its turn, the water quality improvement will decrease the supply of suspended solids into the water intake facilities and cut the reagent costs in the course of the treatment water works operation.

Tracking and data relay satellite system configuration and tradeoff study. Volume 5: User impact and ground station design, part 1

NASA Technical Reports Server (NTRS)

Hill, T. E.

1972-01-01

The configuration of the user transponder on the Tracking and Data Relay satellite is described. The subjects discussed are: (1) transponder concepts and trades, (2) ground station design, (3) antenna configurations for ground equipment, (4) telemetry facilities, (5) signal categories, and (6) satellite tracking.

Space-to-Ground: Prepping for a Spacewalk: 01/19/2018

NASA Image and Video Library

2018-01-18

Some station science has successfully returned to Earth, and crewmembers are gearing up for a pair of spacewalks. NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Space-to-Ground: California Wildfires: 12/08/2017

NASA Image and Video Library

2017-12-07

Orbital ATK's Cygnus left the station carrying a record amount, and astronauts got a harrowing view of the California wildfires. NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Space to Ground: A Closer Look: 08/11/2017

NASA Image and Video Library

2017-08-10

More crewmembers, more eyes on science, SpaceX Dragon to launch to station, and Fischer was featured on JSC podcast. NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Historical Analysis and Charaterization of Ground Level Ozone for Canada and United State

NASA Astrophysics Data System (ADS)

Lin, H.; Li, H.; Auld, H.

2003-12-01

Ground-level ozone has long been recognized as an important health and ecosystem-related air quality concern in Canada and the United States. In this work we seek to understand the characteristics of ground level ozone conditions for Canada and United States to support the Ozone Annex under the Canada-U.S. Air Quality Agreement. Our analyses are based upon the data collected by Canadian National Air Pollution Surveillance (NAPS, the NAPS database has also been expanded to include U.S. EPA ground level ozone data) network. Historical ozone data from 1974 to 2002 at a total of 538 stations (253 Canadian stations and 285 U.S. stations) were statistically analyzed using several methodologies including the Canada Wide Standard (CWS). A more detailed analysis including hourly, daily, monthly, seasonally and yearly ozone concentration distributions and trends was undertaken for 54 stations.

Orion Navigation Sensitivities to Ground Station Infrastructure for Lunar Missions

NASA Technical Reports Server (NTRS)

Getchius, Joel; Kukitschek, Daniel; Crain, Timothy

2008-01-01

The Orion Crew Exploration Vehicle (CEV) will replace the Space Shuttle and serve as the next-generation spaceship to carry humans to the International Space Station and back to the Moon for the first time since the Apollo program. As in the Apollo and Space Shuttle programs, the Mission Control Navigation team will utilize radiometric measurements to determine the position and velocity of the CEV. In the case of lunar missions, the ground station infrastructure consisting of approximately twelve stations distributed about the Earth and known as the Apollo Manned Spaceflight Network, no longer exists. Therefore, additional tracking resources will have to be allocated or constructed to support mission operations for Orion lunar missions. This paper examines the sensitivity of Orion navigation for lunar missions to the number and distribution of tracking sites that form the ground station infrastructure.

Hybrid Ground Station Technology for RF and Optical Communication Links

NASA Technical Reports Server (NTRS)

Davarian, Faramaz; Hoppe, D.; Charles, J.; Vilnrotter, V.; Sehic, A.; Hanson, T.; Gam, E.

2012-01-01

To support future enhancements of NASA's deep space and planetary communications and tracking services, the Jet Propulsion Laboratory is developing a hybrid ground station that will be capable of simultaneously supporting RF and optical communications. The main reason for adding optical links to the existing RF links is to significantly increase the capacity of deep space communications in support of future solar system exploration. It is envisioned that a mission employing an optical link will also use an RF link for telemetry and emergency purposes, hence the need for a hybrid ground station. A hybrid station may also reduce operations cost by requiring fewer staff than would be required to operate two stations. A number of approaches and techniques have been examined. The most promising ones have been prototyped for field examination and validation.

Ground-water hydrology and simulation of ground-water flow at Operable Unit 3 and surrounding region, U.S. Naval Air Station, Jacksonville, Florida

USGS Publications Warehouse

Davis, J.H.

1998-01-01

The Naval Air Station, Jacksonville (herein referred to as the Station), occupies 3,800 acres adjacent to the St. Johns River in Duval County, Florida. Operable Unit 3 (OU3) occupies 134 acres on the eastern side of the Station and has been used for industrial and commercial purposes since World War II. Ground water contaminated by chlorinated organic compounds has been detected in the surficial aquifer at OU3. The U.S. Navy and U.S. Geological Survey (USGS) conducted a cooperative hydrologic study to evaluate the potential for ground water discharge to the neighboring St. Johns River. A ground-water flow model, previously developed for the area, was recalibrated for use in this study. At the Station, the surficial aquifer is exposed at land surface and forms the uppermost permeable unit. The aquifer ranges in thickness from 30 to 100 feet and consists of unconsolidated silty sands interbedded with local beds of clay. The low-permeability clays of the Hawthorn Group form the base of the aquifer. The USGS previously conducted a ground-water investigation at the Station that included the development and calibration of a 1-layer regional ground-water flow model. For this investigation, the regional model was recalibrated using additional data collected after the original calibration. The recalibrated model was then used to establish the boundaries for a smaller subregional model roughly centered on OU3. Within the subregional model, the surficial aquifer is composed of distinct upper and intermediate layers. The upper layer extends from land surface to a depth of approximately 15 feet below sea level; the intermediate layer extends from the upper layer down to the top of the Hawthorn Group. In the northern and central parts of OU3, the upper and intermediate layers are separated by a low-permeability clay layer. Horizontal hydraulic conductivities in the upper layer, determined from aquifer tests, range from 0.19 to 3.8 feet per day. The horizontal hydraulic conductivity in the intermediate layer, determined from one aquifer test, is 20 feet per day. An extensive stormwater drainage system is present at OU3 and the surrounding area. Some of the stormwater drains have been documented to be draining ground water from the upper layer of the surficial aquifer, whereas other drains are only suspected to be draining ground water. The subregional model contained 78 rows and 148 columns of square model cells that were 100 feet on each side. Vertically, the surficial aquifer was divided into two layers; layer 1 represented the upper layer and layer 2 represented the intermediate layer. Steady-state ground-water flow conditions were assumed. The model was calibrated to head data collected on October 29 and 30, 1996. After calibration, the model matched all 67 measured heads to within the calibration criterion of 1 foot; and 48 of 67 simulated heads (72 percent) were within 0.5 foot. Model simulated recharge rates ranged from 0.4 inch per year in areas that were largely paved to 13.0 inches per year in irrigated areas. Simulated hydraulic conductivities in the upper layer at OU3 ranged from 0.5 foot per day in the north to 1.0 foot per day in the south. Simulated vertical leakance between the upper and intermediate layers ranged from 1.0x10-6 per day in an area with low-permeability clays to 4.3x10-2 per day in an area that had been dredged. Simulated transmissivities in the intermediate layer ranged from 25 feet squared per day in an area of low-permeability channel-fill deposits to a high of 1,200 feet squared per day in areas covering most of OU3. Simulated riverbed conductances ranged from 4 to 60 feet squared per day and simulated bottom conductances of leaking stormwater drains ranged from 5 to 20 feet squared per day. The direction and velocity of ground-water flow was determined using particle-tracking techniques. Ground-water flow in the upper layer was generally eastward toward the St. Johns River. However, leaking stormwat

Experiments Using a Ground-Based Electrostatic Levitator and Numerical Modeling of Melt Convection for the Iron-Cobalt System in Support of Space Experiments

NASA Astrophysics Data System (ADS)

Lee, Jonghyun; SanSoucie, Michael P.

2017-08-01

Materials research is being conducted using an electromagnetic levitator installed in the International Space Station. Various metallic alloys were tested to elucidate unknown links among the structures, processes, and properties. To accomplish the mission of these space experiments, several ground-based activities have been carried out. This article presents some of our ground-based supporting experiments and numerical modeling efforts. Mass evaporation of Fe50Co50, one of flight compositions, was predicted numerically and validated by the tests using an electrostatic levitator (ESL). The density of various compositions within the Fe-Co system was measured with ESL. These results are being served as reference data for the space experiments. The convection inside a electromagnetically-levitated droplet was also modeled to predict the flow status, shear rate, and convection velocity under various process parameters, which is essential information for designing and analyzing the space experiments of some flight compositions influenced by convection.

IDS plot tools for time series of DORIS station positions and orbit residuals

NASA Astrophysics Data System (ADS)

Soudarin, L.; Ferrage, P.; Moreaux, G.; Mezerette, A.

2012-12-01

DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) is a Doppler satellite tracking system developed for precise orbit determination and precise ground location. It is onboard the Cryosat-2, Jason-1, Jason-2 and HY-2A altimetric satellites and the remote sensing satellites SPOT-4 and SPOT-5. It also flew with SPOT-2, SPOT-3, TOPEX/POSEIDON and ENVISAT. Since 1994 and thanks to its worldwide distributed network of more than fifty permanent stations, DORIS contributes to the realization and maintenance of the ITRS (International Terrestrial Reference System). 3D positions and velocities of the reference sites at a cm and mm/yr accuracy lead to scientific studies in geodesy and geophysics. The primary objective of the International DORIS Service (IDS) is to provide a support, through DORIS data and products, to research and operational activities. In order to promote the use of the DORIS products, the IDS has made available on its web site (ids-doris.org) a new set of tools, called Plot tools, to interactively build and display graphs of DORIS station coordinates time series and orbit residuals. These web tools are STCDtool providing station coordinates time series (North, East, Up position evolution) from the IDS Analysis Centers, and POEtool providing statistics time series (orbit residuals and number of measurements for the DORIS stations) from CNES (the French Space Agency) Precise Orbit Determination processing. Complementary data about station and satellites events can also be displayed (e.g. antenna changes, system failures, degraded data...). Information about earthquakes obtained from USGS survey service can also be superimposed on the position time series. All these events can help in interpreting the discontinuities in the time series. The purpose of this presentation is to show the functionalities of these tools and their interest for the monitoring of the crustal deformation at DORIS sites.

Current Trends and Challenges in Satellite Laser Ranging

NASA Astrophysics Data System (ADS)

Appleby, Graham M.; Bianco, Giuseppe; Noll, Carey E.; Pavlis, Erricos C.; Pearlman, Michael R.

2016-12-01

Satellite Laser Ranging (SLR) is used to measure accurately the distance from ground stations to retro-reflectors on satellites and on the Moon. SLR is one of the fundamental space-geodetic techniques that define the International Terrestrial Reference Frame (ITRF), which is the basis upon which many aspects of global change over space, time, and evolving technology are measured; with VLBI the two techniques define the scale of the ITRF; alone the SLR technique defines its origin (geocenter). The importance of the reference frame has recently been recognized at the inter-governmental level through the United Nations, which adopted in February 2015 the Resolution "Global Geodetic Reference Frame for Sustainable Development." Laser Ranging provides precision orbit determination and instrument calibration and validation for satellite-borne altimeters for the better understanding of sea level change, ocean dynamics, ice mass-balance, and terrestrial topography. It is also a tool to study the dynamics of the Moon and fundamental constants and theories. With the exception of the currently in-orbit GPS constellation, all GNSS satellites now carry retro-reflectors for improved orbit determination, harmonization of reference frames, and in-orbit co-location and system performance validation; the next generation of GPS satellites due for launch from 2019 onwards will also carry retro-reflectors. The ILRS delivers weekly realizations that are accumulated sequentially to extend the ITRF and the Earth Orientation Parameter series with a daily resolution. SLR technology continues to evolve towards the next-generation laser ranging systems and it is expected to successfully meet the challenges of the GGOS2020 program for a future Global Space Geodetic Network. Ranging precision is improving as higher repetition rate, narrower pulse lasers, and faster detectors are implemented within the network. Automation and pass interleaving at some stations is expanding temporal coverage and greatly enhancing efficiency. Discussions are ongoing with some missions that will allow the SLR network stations to provide crucial, but energy-safe, range measurements to optically vulnerable satellites. New retro-reflector designs are improving the signal link and enable daylight ranging that is now the norm for many stations. We discuss many of these laser ranging activities and some of the tough challenges that the SLR network currently faces.

Satellite-Relayed Intercontinental Quantum Network.

PubMed

Liao, Sheng-Kai; Cai, Wen-Qi; Handsteiner, Johannes; Liu, Bo; Yin, Juan; Zhang, Liang; Rauch, Dominik; Fink, Matthias; Ren, Ji-Gang; Liu, Wei-Yue; Li, Yang; Shen, Qi; Cao, Yuan; Li, Feng-Zhi; Wang, Jian-Feng; Huang, Yong-Mei; Deng, Lei; Xi, Tao; Ma, Lu; Hu, Tai; Li, Li; Liu, Nai-Le; Koidl, Franz; Wang, Peiyuan; Chen, Yu-Ao; Wang, Xiang-Bin; Steindorfer, Michael; Kirchner, Georg; Lu, Chao-Yang; Shu, Rong; Ursin, Rupert; Scheidl, Thomas; Peng, Cheng-Zhi; Wang, Jian-Yu; Zeilinger, Anton; Pan, Jian-Wei

2018-01-19

We perform decoy-state quantum key distribution between a low-Earth-orbit satellite and multiple ground stations located in Xinglong, Nanshan, and Graz, which establish satellite-to-ground secure keys with ∼kHz rate per passage of the satellite Micius over a ground station. The satellite thus establishes a secure key between itself and, say, Xinglong, and another key between itself and, say, Graz. Then, upon request from the ground command, Micius acts as a trusted relay. It performs bitwise exclusive or operations between the two keys and relays the result to one of the ground stations. That way, a secret key is created between China and Europe at locations separated by 7600 km on Earth. These keys are then used for intercontinental quantum-secured communication. This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 km optical ground connection between Xinglong and Beijing. Our work clearly confirms the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, and points towards an efficient solution for an ultralong-distance global quantum network.

Satellite-Relayed Intercontinental Quantum Network

NASA Astrophysics Data System (ADS)

Liao, Sheng-Kai; Cai, Wen-Qi; Handsteiner, Johannes; Liu, Bo; Yin, Juan; Zhang, Liang; Rauch, Dominik; Fink, Matthias; Ren, Ji-Gang; Liu, Wei-Yue; Li, Yang; Shen, Qi; Cao, Yuan; Li, Feng-Zhi; Wang, Jian-Feng; Huang, Yong-Mei; Deng, Lei; Xi, Tao; Ma, Lu; Hu, Tai; Li, Li; Liu, Nai-Le; Koidl, Franz; Wang, Peiyuan; Chen, Yu-Ao; Wang, Xiang-Bin; Steindorfer, Michael; Kirchner, Georg; Lu, Chao-Yang; Shu, Rong; Ursin, Rupert; Scheidl, Thomas; Peng, Cheng-Zhi; Wang, Jian-Yu; Zeilinger, Anton; Pan, Jian-Wei

2018-01-01

We perform decoy-state quantum key distribution between a low-Earth-orbit satellite and multiple ground stations located in Xinglong, Nanshan, and Graz, which establish satellite-to-ground secure keys with ˜kHz rate per passage of the satellite Micius over a ground station. The satellite thus establishes a secure key between itself and, say, Xinglong, and another key between itself and, say, Graz. Then, upon request from the ground command, Micius acts as a trusted relay. It performs bitwise exclusive or operations between the two keys and relays the result to one of the ground stations. That way, a secret key is created between China and Europe at locations separated by 7600 km on Earth. These keys are then used for intercontinental quantum-secured communication. This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 km optical ground connection between Xinglong and Beijing. Our work clearly confirms the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, and points towards an efficient solution for an ultralong-distance global quantum network.

8. Photocopy of Station Grounding drawing showing floor plans (from ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. Photocopy of Station Grounding drawing showing floor plans (from the BPA Engineering Vault, Drawing 005319, 3 May 1939) - Bonneville Power Administration South Bank Substation, I-84, South of Bonneville Dam Powerhouse, Bonneville, Multnomah County, OR

Space-to-Ground: Rocket and Groot: 01/12/2018

NASA Image and Video Library

2018-01-11

The SpaceX Dragon will depart the station...it's always growing season on ISS...and "Rocket and Groot" powers a student challenge! NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Estimating the Geocenter from GNSS Observations

NASA Astrophysics Data System (ADS)

Dach, Rolf; Michael, Meindl; Beutler, Gerhard; Schaer, Stefan; Lutz, Simon; Jäggi, Adrian

2014-05-01

The satellites of the Global Navigation Satellite Systems (GNSS) are orbiting the Earth according to the laws of celestial mechanics. As a consequence, the satellites are sensitive to the coordinates of the center of mass of the Earth. The coordinates of the (ground) tracking stations are referring to the center of figure as the conventional origin of the reference frame. The difference between the center of mass and center of figure is the instantaneous geocenter. Following this definition the global GNSS solutions are sensitive to the geocenter. Several studies demonstrated strong correlations of the GNSS-derived geocenter coordinates with parameters intended to absorb radiation pressure effects acting on the GNSS satellites, and with GNSS satellite clock parameters. One should thus pose the question to what extent these satellite-related parameters absorb (or hide) the geocenter information. A clean simulation study has been performed to answer this question. The simulation environment allows it in particular to introduce user-defined shifts of the geocenter (systematic inconsistencies between the satellite's and station's reference frames). These geocenter shifts may be recovered by the mentioned parameters - provided they were set up in the analysis. If the geocenter coordinates are not estimated, one may find out which other parameters absorb the user-defined shifts of the geocenter and to what extent. Furthermore, the simulation environment also allows it to extract the correlation matrix from the a posteriori covariance matrix to study the correlations between different parameter types of the GNSS analysis system. Our results show high degrees of correlations between geocenter coordinates, orbit-related parameters, and satellite clock parameters. These correlations are of the same order of magnitude as the correlations between station heights, troposphere, and receiver clock parameters in each regional or global GNSS network analysis. If such correlations are accepted in a GNSS analysis when estimating station coordinates, geocenter coordinates must be considered as mathematically estimable in a global GNSS analysis. The geophysical interpretation may of course become difficult, e.g., if insufficient orbit models are used.

Beyond the Baseline: Proceedings of the Space Station Evolution Symposium. Volume 2, Part 2; Space Station Freedom Advanced Development Program

NASA Technical Reports Server (NTRS)

1990-01-01

This report contains the individual presentations delivered at the Space Station Evolution Symposium in League City, Texas on February 6, 7, 8, 1990. Personnel responsible for Advanced Systems Studies and Advanced Development within the Space Station Freedom program reported on the results of their work to date. Systems Studies presentations focused on identifying the baseline design provisions (hooks and scars) necessary to enable evolution of the facility to support changing space policy and anticipated user needs. Also emphasized were evolution configuration and operations concepts including on-orbit processing of space transfer vehicles. Advanced Development task managers discussed transitioning advanced technologies to the baseline program, including those near-term technologies which will enhance the safety and productivity of the crew and the reliability of station systems. Special emphasis was placed on applying advanced automation technology to ground and flight systems. This publication consists of two volumes. Volume 1 contains the results of the advanced system studies with the emphasis on reference evolution configurations, system design requirements and accommodations, and long-range technology projections. Volume 2 reports on advanced development tasks within the Transition Definition Program. Products of these tasks include: engineering fidelity demonstrations and evaluations on Station development testbeds and Shuttle-based flight experiments; detailed requirements and performance specifications which address advanced technology implementation issues; and mature applications and the tools required for the development, implementation, and support of advanced technology within the Space Station Freedom Program.

Space to Ground: Clearing the Cosmos: 06/22/2018

NASA Image and Video Library

2018-06-21

A new experiment is looking at how to clean up the growing risk of space junk, and science on station was positively lit! NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Space-to-Ground: A Learning Doubleheader: 04/06/2018

NASA Image and Video Library

2018-04-05

The SpaceX Dragon arrives at the space station, more Lettuce leaves are growing onboard, and what do baseball and astronauts have in common? NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

PREDICTS

NASA Technical Reports Server (NTRS)

Zhou, Hanying

2007-01-01

PREDICTS is a computer program that predicts the frequencies, as functions of time, of signals to be received by a radio science receiver in this case, a special-purpose digital receiver dedicated to analysis of signals received by an antenna in NASA s Deep Space Network (DSN). Unlike other software used in the DSN, PREDICTS does not use interpolation early in the calculations; as a consequence, PREDICTS is more precise and more stable. The precision afforded by the other DSN software is sufficient for telemetry; the greater precision afforded by PREDICTS is needed for radio-science experiments. In addition to frequencies as a function of time, PREDICTS yields the rates of change and interpolation coefficients for the frequencies and the beginning and ending times of reception, transmission, and occultation. PREDICTS is applicable to S-, X-, and Ka-band signals and can accommodate the following link configurations: (1) one-way (spacecraft to ground), (2) two-way (from a ground station to a spacecraft to the same ground station), and (3) three-way (from a ground transmitting station to a spacecraft to a different ground receiving station).

Water resources data, North Carolina, water year 2004. Volume 2: Ground-water records

USGS Publications Warehouse

Howe, S.S.; Breton, P.L.; Chapman, M.J.

2005-01-01

Water-resources data for the 2004 water year for North Carolina consist of records of stage, discharge, water quality for streams; stage and contents for lakes and reservoirs; precipitation; and ground-water levels and water quality of ground water. Volume 1 contains discharge records for 217 gaging stations; stage and contents for 58 lakes and reservoirs; stage only records for 22 gaging stations; elevations for 9 stations; water quality for 39 gaging stations and 5 miscellaneous sites, and continuous water quality for 35 sites; and continuous precipitation at 127 sites. Volume 2 contains ground-water-level data from 161 observation wells, ground-water-quality data from 38 wells, continuous water quality for 7 sites and continuous precipitation at 7 sites. Additional water data were collected at 51 sites not involved in the systematic data-collection program, and are published as miscellaneous measurements in Volume 1. The collection of water-resources data in North Carolina is a part of the National Water-Data System operated by the U.S. Geological Survey in cooperation with State, municipal, and Federal agencies.

ERTS operations and data processing

NASA Technical Reports Server (NTRS)

Gonzales, L.; Sos, J. Y.

1974-01-01

The overall communications and data flow between the ERTS spacecraft and the ground stations and processing centers are generally described. Data from the multispectral scanner and the return beam vidicon are telemetered to a primary ground station where they are demodulated, processed, and recorded. The tapes are then transferred to the NASA Data Processing Facility (NDPF) at Goddard. Housekeeping data are relayed from the prime ground stations to the Operations Control Center at Goddard. Tracking data are processed at the ground stations, and the calculated parameters are transmitted by teletype to the orbit determination group at Goddard. The ERTS orbit has been designed so that the same swaths of the ground coverage pattern viewed during one 18-day coverage cycle are repeated by the swaths viewed on all subsequent cycles. The Operations Control Center is the focal point for all communications with the spacecraft. NDPF is a job-oriented facility which processes and stores all sensor data, and which disseminates large quantities of these data to users in the form of films, computer-compatible tapes, and data collection system data.

Solar power satellite system definition study. Part 1 and part 2, volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1977-01-01

The Solar Power Satellite principle is illustrated and it shows that in a geostationary orbit 36,000 km above the earth's equator, each SPS is in sunlight 99% of the time and in continuous line of sight contact with its ground receiving station. Electrical power produced on the satellite by photovoltaic or heat engine conversion of sunlight is then converted to radio frequency energy at high efficiency, and formed into a focused beam precisely aimed at the SP ground stations. The ground station receiving antenna reconverts the energy into electricity for distribution.

Water Resources Data, West Virginia, Water Year 2003

USGS Publications Warehouse

Ward, S.M.; Rosier, M.T.; Crosby, G.R.

2004-01-01

Water-resources data for the 2003 water year for West Virginia consists of records of stream discharge, reservoir and ground-water levels, and water quality of streams and ground-water wells. This report contains discharge records for 70 streamflow-gaging stations; discharge records provided by adjacent states for 8 streamflow-gaging stations; annual maximum discharge at 16 crest-stage partial-record stations; stage records for 6 detention reservoirs; water-quality records for 2 stations; and water-level records for 8 observation wells. Locations of streamflow, detention reservoir, and water-quality stations are shown on figure 4. Locations of ground-water observation wells are shown on figure 5. Additional water data were collected at various sites, not involved in the systematic data-collection program, and are published as miscellaneous sites. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in West Virginia.

Water resources data-West Virginia, water year 2004

USGS Publications Warehouse

Ward, S.M.; Rosier, M.T.; Crosby, G.R.

2005-01-01

Water-resources data for the 2004 water year for West Virginia consist of records of stream discharge, reservoir and ground-water levels, and water quality of streams and ground-water wells. This report contains discharge records for 65 streamflow-gaging stations; discharge records provided by adjacent states for 8 streamflow-gaging stations; annual maximum discharge at 17 crest-stage partial-record stations; stage records for 14 detention reservoirs; water-quality records for 2 stations; and water-level records for 10 observation wells. Locations of streamflow, detention reservoir, and water-quality stations are shown on figure 4. Locations of ground-water observation wells are shown on figure 5. Additional water-quality data were collected at various sites, not involved in the systematic data collection program, and are published as miscellaneous sites. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in West Virginia.

Space-to-Ground: Out the Door: 10/06/2017

NASA Image and Video Library

2017-10-05

The first of three October spacewalks took place this week…it’s growing season once again onboard station…and how many airlocks are on station? NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Remote Sensing and Remote Control Activities in Europe and America: Part 2--Remote Sensing Ground Stations in Europe,

DTIC Science & Technology

1996-04-08

Development tasks and products of remote sensing ground stations in Europe are represented by the In-Sec Corporation and the Schlumberger Industries Corporation. The article presents the main products of these two corporations.

Space-to-Ground: Stuffed with Science: 11/17/2017

NASA Image and Video Library

2017-11-16

S.S. Gene Cernan arrives to station...Experiment will examine how microgravity affects the bacteria's ability to thrive...and who answers astronauts questions about experiments? NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Contributions to reference systems from Lunar Laser Ranging using the IfE analysis model

NASA Astrophysics Data System (ADS)

Hofmann, Franz; Biskupek, Liliane; Müller, Jürgen

2018-01-01

Lunar Laser Ranging (LLR) provides various quantities related to reference frames like Earth orientation parameters, coordinates and velocities of ground stations in the Earth-fixed frame and selenocentric coordinates of the lunar retro-reflectors. This paper presents the recent results from LLR data analysis at the Institut für Erdmessung, Leibniz Universität Hannover, based on all LLR data up to the end of 2016. The estimates of long-periodic nutation coefficients with periods between 13.6 days and 18.6 years are obtained with an accuracy in the order of 0.05-0.7 milliarcseconds (mas). Estimations of the Earth rotation phase Δ UT are accurate at the level of 0.032 ms if more than 14 normal points per night are included. The tie between the dynamical ephemeris frame to the kinematic celestial frame is estimated from pure LLR observations by two angles and their rates with an accuracy of 0.25 and 0.02 mas per year. The estimated station coordinates and velocities are compared to the ITRF2014 solution and the geometry of the retro-reflector network with the DE430 solution. The given accuracies represent 3 times formal errors of the parameter fit. The accuracy for Δ UT is based on the standard deviation of the estimates with respect to the reference C04 solution.

SCALES: SEVIRI and GERB CaL/VaL area for large-scale field experiments

NASA Astrophysics Data System (ADS)

Lopez-Baeza, Ernesto; Belda, Fernando; Bodas, Alejandro; Crommelynck, Dominique; Dewitte, Steven; Domenech, Carlos; Gimeno, Jaume F.; Harries, John E.; Jorge Sanchez, Joan; Pineda, Nicolau; Pino, David; Rius, Antonio; Saleh, Kauzar; Tarruella, Ramon; Velazquez, Almudena

2004-02-01

The main objective of the SCALES Project is to exploit the unique opportunity offered by the recent launch of the first European METEOSAT Second Generation geostationary satellite (MSG-1) to generate and validate new radiation budget and cloud products provided by the GERB (Geostationary Earth Radiation Budget) instrument. SCALES" specific objectives are: (i) definition and characterization of a large reasonably homogeneous area compatible to GERB pixel size (around 50 x 50 km2), (ii) validation of GERB TOA radiances and fluxes derived by means of angular distribution models, (iii) development of algorithms to estimate surface net radiation from GERB TOA measurements, and (iv) development of accurate methodologies to measure radiation flux divergence and analyze its influence on the thermal regime and dynamics of the atmosphere, also using GERB data. SCALES is highly innovative: it focuses on a new and unique space instrument and develops a new specific validation methodology for low resolution sensors that is based on the use of a robust reference meteorological station (Valencia Anchor Station) around which 3D high resolution meteorological fields are obtained from the MM5 Meteorological Model. During the 1st GERB Ground Validation Campaign (18th-24th June, 2003), CERES instruments on Aqua and Terra provided additional radiance measurements to support validation efforts. CERES instruments operated in the PAPS mode (Programmable Azimuth Plane Scanning) focusing the station. Ground measurements were taken by lidar, sun photometer, GPS precipitable water content, radiosounding ascents, Anchor Station operational meteorological measurements at 2m and 15m., 4 radiation components at 2m, and mobile stations to characterize a large area. In addition, measurements during LANDSAT overpasses on June 14th and 30th were also performed. These activities were carried out within the GIST (GERB International Science Team) framework, during GERB Commissioning Period.

Persistent summit subsidence at Volcán de Colima, México, 1982 1999: strong evidence against Mogi deflation

NASA Astrophysics Data System (ADS)

Murray, John B.; Wooller, Luke K.

2002-09-01

This paper re-examines recent ground-deformation measurements at Volcán de Colima, Mexico, to test the hypothesis that the observed movements are in response to pressure changes within a sub-volcanic magma chamber, as suggested for other volcanoes by [Mogi (1958) Earthq. Res. Inst. 36, 99-134]. Measurements of vertical ground deformation across the summit dome complex of Volcán de Colima from a precise levelling network between 1982 and 1999, together with vertical and horizontal displacements derived from dual-frequency GPS measurements in 1994 and 1997, show continuous subsidence. The deformation pattern derived from the levelling shows that subsidence increases towards the summit. The closest stations to the summit (1.1 km distant) show a mean subsidence rate of 5 mm per year compared to the reference station at 2.3 km distance, which may be subsiding itself. Vertical displacements of individual stations since 1982 show that the subsidence has been fairly continuous. The GPS stations, which are distributed more widely and include some close to the edge of the active dome, confirm summit subsidence. The largest measured value, a decrease of 280 mm, or 93 mm subsidence per year, was obtained at the edge of the dome. Horizontal displacements measured during 1994-1997 also show the largest values at the summit, but these are much smaller than the vertical displacements, with the maximum rate of 23 mm per year recorded close to the dome. It is conclusively shown that these measured movements cannot be due to deflation of a buried Mogi source, as vertical and horizontal displacements for some stations are in contrary directions to those predicted by the model, and there is no consistent pattern to the horizontal movements. We attribute the measured deformation to downslope creep, settling and compaction of the edifice, gravitational spreading, or a combination of these processes.

The astrobiological mission EXPOSE-R on board of the International Space Station

NASA Astrophysics Data System (ADS)

Rabbow, Elke; Rettberg, Petra; Barczyk, Simon; Bohmeier, Maria; Parpart, Andre; Panitz, Corinna; Horneck, Gerda; Burfeindt, Jürgen; Molter, Ferdinand; Jaramillo, Esther; Pereira, Carlos; Weiß, Peter; Willnecker, Rainer; Demets, René; Dettmann, Jan

2015-01-01

EXPOSE-R flew as the second of the European Space Agency (ESA) EXPOSE multi-user facilities on the International Space Station. During the mission on the external URM-D platform of the Zvezda service module, samples of eight international astrobiology experiments selected by ESA and one Russian guest experiment were exposed to low Earth orbit space parameters from March 10th, 2009 to January 21st, 2011. EXPOSE-R accommodated a total of 1220 samples for exposure to selected space conditions and combinations, including space vacuum, temperature cycles through 273 K, cosmic radiation, solar electromagnetic radiation at >110, >170 or >200 nm at various fluences up to GJ m-2. Samples ranged from chemical compounds via unicellular organisms and multicellular mosquito larvae and seeds to passive radiation dosimeters. Additionally, one active radiation measurement instrument was accommodated on EXPOSE-R and commanded from ground in accordance with the facility itself. Data on ultraviolet radiation, cosmic radiation and temperature were measured every 10 s and downlinked by telemetry and data carrier every few months. The EXPOSE-R trays and samples returned to Earth on March 9th, 2011 with Shuttle flight, Space Transportation System (STS)-133/ULF 5, Discovery, after successful total mission duration of 27 months in space. The samples were analysed in the individual investigators laboratories. A parallel Mission Ground Reference experiment was performed on ground with a parallel set of hardware and samples under simulated space conditions following to the data transmitted from the flight mission.

Correlative measurements of the stratospheric aerosols

NASA Astrophysics Data System (ADS)

Santer, R.; Brogniez, C.; Herman, M.; Diallo, S.; Ackerman, M.

1992-12-01

Joint experiments were organized or available during stratospheric flights of a photopolarimeter, referred to as RADIBAL (radiometer balloon). In May 1984, RADIBAL flew simultaneously with another balloonborne experiment conducted by the Institut d'Aeronomie Spatiale de Belgique (IASB), which provides multiwavelength vertical profiles of the aerosol scattering coefficient. At this time, the El Chichon layer was observable quite directly from mountain sites. A ground-based station set up at Pic du Midi allowed an extensive description of the aerosol optical properties. The IASB and the Pic du Midi observations are consistent with the aerosol properties derived from the RADIBAL measurement analysis.

The 727 approach energy management system avionics specification (preliminary)

NASA Technical Reports Server (NTRS)

Jackson, D. O.; Lambregts, A. A.

1976-01-01

Hardware and software requirements for an Approach Energy Management System (AEMS) consisting of an airborne digital computer and cockpit displays are presented. The displays provide the pilot with a visual indication of when to manually operate the gear, flaps, and throttles during a delayed flap approach so as to reduce approach time, fuel consumption, and community noise. The AEMS is an independent system that does not interact with other navigation or control systems, and is compatible with manually flown or autopilot coupled approaches. Operational use of the AEMS requires a DME ground station colocated with the flight path reference.

Definition of technology development missions for early space stations orbit transfer vehicle serving. Phase 2, task 1: Space station support of operational OTV servicing

NASA Technical Reports Server (NTRS)

1983-01-01

Representative space based orbital transfer vehicles (OTV), ground based vehicle turnaround assessment, functional operational requirements and facilities, mission turnaround operations, a comparison of ground based versus space based tasks, activation of servicing facilities prior to IOC, fleet operations requirements, maintenance facilities, OTV servicing facilities, space station support requirements, and packaging for delivery are discussed.

Space Communication and Navigation Testbed Communications Technology for Exploration

NASA Technical Reports Server (NTRS)

Reinhart, Richard

2013-01-01

NASA developed and launched an experimental flight payload (referred to as the Space Communication and Navigation Test Bed) to investigate software defined radio, networking, and navigation technologies, operationally in the space environment. The payload consists of three software defined radios each compliant to NASAs Space Telecommunications Radio System Architecture, a common software interface description standard for software defined radios. The software defined radios are new technology developed by NASA and industry partners. The payload is externally mounted to the International Space Station truss and available to NASA, industry, and university partners to conduct experiments representative of future mission capability. Experiment operations include in-flight reconfiguration of the SDR waveform functions and payload networking software. The flight system communicates with NASAs orbiting satellite relay network, the Tracking, Data Relay Satellite System at both S-band and Ka-band and to any Earth-based compatible S-band ground station.

NASA Communications Augmentation network

NASA Technical Reports Server (NTRS)

Omidyar, Guy C.; Butler, Thomas E.; Laios, Straton C.

1990-01-01

The NASA Communications (Nascom) Division of the Mission Operations and Data Systems Directorate (MO&DSD) is to undertake a major initiative to develop the Nascom Augmentation (NAUG) network to achieve its long-range service objectives for operational data transport to support the Space Station Freedom Program, the Earth Observing System (EOS), and other projects. The NAUG is the Nascom ground communications network being developed to accommodate the operational traffic of the mid-1990s and beyond. The NAUG network development will be based on the Open Systems Interconnection Reference Model (OSI-RM). This paper describes the NAUG network architecture, subsystems, topology, and services; addresses issues of internetworking the Nascom network with other elements of the Space Station Information System (SSIS); discusses the operations environment. This paper also notes the areas of related research and presents the current conception of how the network will provide broadband services in 1998.

Instrumentation, Control and Communication Systems for Sounding Rockets and Shuttle-Borne Experiments

DTIC Science & Technology

1991-07-02

at the Plumbrook Station located in Sundusky, Ohio was conducted during November 1987 to confirm payload operation under vacuum and to calibrate the...DURATION STAFF TIM SDC, AZ SPIRIT-II 11/2/87 to O’Connor 11/6/87 VACUUM TEST Plumbrook SPEAR-I 11/3/87 to Wheeler Station , 11/6/87 & Sweeney Sandusky...reception by the ground stations , that signal also will be received in the payload and relayed to the ground stations . 2.5.2 Overview The LIFE I 17

ERTS-1 DCS technical support provided by Wallops Station. [ground truth stations and DCP repair depot

NASA Technical Reports Server (NTRS)

Smith, R.

1975-01-01

Wallops Station accepted the tasks of providing ground truth to several ERTS investigators, operating a DCP repair depot, designing and building an airborne DCP Data Acquisition System, and providing aircraft underflight support for several other investigators. Additionally, the data bank is generally available for use by ERTS and other investigators that have a scientific interest in data pertaining to the Chesapeake Bay area. Working with DCS has provided a means of evaluating the system as a data collection device possibly applicable to ongoing Earth Resources Program activities in the Chesapeake Bay area as well as providing useful data and services to other ERTS investigators. The two areas of technical support provided by Wallops, ground truth stations and repair for DCPs, are briefly discussed.

Space-to-Ground: Teacher On Board: 10/20/2017

NASA Image and Video Library

2017-10-20

The crew completed their third and final spacewalk for the month...We kicked off a year of education on station...and we talk about the importance of astronaut photography. Space to Ground is your weekly update on what's happening aboard the International Space Station.

High accuracy analysis of whistlers measured simultaneously on ground station and on board of the DEMETER satellite

NASA Astrophysics Data System (ADS)

Hamar, D.; Ferencz, Cs.; Steinbach, P.; Lichtenberger, J.; Ferencz, O. E.; Parrot, M.

2009-04-01

Examining the mechanism and effect of the coupling of the electromagnetic signals from the lower ionosphere into the Earth-ionosphere waveguide (EIWG) can be maintained with the analysis of simultaneous broadband VLF recordings acquired at ground station (Tihany, Hungary) and on LEO orbiting satellite (DEMETER) during nearby passes. Single hop whistlers, selected from concurrent broadband VLF data sets were analyzed with high accuracy applying the matched filtering (MF) technique, developed previously for signal analysis. The accuracy of the frequency-time-amplitude pattern and the resolution of the closely spaced whistler traces were further increased with least-square estimation of the parameters of the output of MF procedure. One result of this analysis is the fine structure of the whistler which can not be recognized in conventional spectrogram. The comparison of the detailed fine structure of the whistlers measured on board and on the ground enabled us to select reliably the corresponding signal pairs. The remarkable difference seen in the fine structure of matching whistler occurrences in the satellite and the ground data series can be addressed e.g. to the effect of the inhomogeneous ionospheric plasma (trans-ionosperic impulse propagation) or the process of wave energy leaking out from the ionized medium into the EIWG. This field needs further investigations. References: Ferencz Cs., Ferencz O. E., Hamar D. and Lichtenberger, J., (2001) Whistler Phenomena, Short Impulse Propagation; Kluwer Academic Publisher, ISBN 0-7923-6995-5, Netherlands Lichtenberger, J., Hamar D. and Ferencz Cs.,(2003) Methods for analyzing the structure and propagation characteristics of whistlers, in: Very Low Frequency (VLF) Phenomena, Narosa Publishing House, New Delhi, p. 88-107.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hunter, C.; Simpson, J.; Kovats, Z.

Sediments from Soda Creek were evaluated using the Sediment Quality Triad as part of investigations being conducted at the Monsanto Company plant in Soda Springs, Idaho. Information collected by an ecological assessment included metal concentrations (arsenic, cadmium, copper, molybdenum, nickel, selenium, silver, and vanadium), benthic fauna community structure, and sediment toxicity. The collected sediments were composed of sandy-silt sized particles, with 2.4% to 9.1% organic carbon. Metal concentrations at sample stations were elevated relative to sediments collected from reference stations. For example, average cadmium concentrations ranged from 13 to 48 mg/kg at sample stations and 0.72 to 3.2 mg/kg atmore » reference stations; selenium concentrations ranged from 4.7 to 91 mg/kg at sample stations and 0.82 to 2.7 mg/kg at reference stations. Soda Creek has a relatively low flow gradient and the benthic fauna at both reference and sample stations was dominated by oligochaete worms and chironomid midge larvae. Taxonomic richness at individual sites ranged from 4.3 to 6.7 and 6 to 10.3 at reference and sample sites, respectively. There was no significant evidence of toxicity at any location sampled. Cluster analysis showed that the benthic community structure of many of the sample stations could not be distinguished from the reference stations. Canonical correlation analysis showed there was a significant relationship between benthic fauna and metal concentration, but there was not a consistent difference between sample and reference stations. For Soda Creek, local phenomena were more significant to benthic community structure than large-scale patterns of metal accumulation. Using the Triad approach, the authors concluded there has been no adverse effect of metal concentrations on the benthic community of Soda Creek.« less

Three years coherent space to ground links: performance results and outlook for the optical ground station equipped with adaptive optics

NASA Astrophysics Data System (ADS)

Gregory, M.; Troendle, D.; Muehlnikel, G.; Heine, F.; Meyer, R.; Lutzer, M.; Czichy, R.

2013-03-01

Tesat is performing inter-satellite links (ISLs) for over 5 years now. Besides the successful demonstration of the suitability of coherent laser communication for high speed data transmission in space, Tesat has also conducted two major satellite to ground link (SGL) campaigns during the last 3 years. A transportable ground station has been developed to measure the impact of atmospheric turbulence to the coherent system. The SGLs have been performed between the Tesat optical ground station and the two LEO satellites TerraSAR-X and NFIRE, both equipped with a Tesat LCT. The capability of the LCTs of measuring the signal intensity on a direct detection sensor and on a coherent sensor simultaneously makes the system unique for investigating the atmospheric distortion impacts. In this paper the main results of the SGL campaigns are presented, including BER performance for the uplink and downlink. Measured scintillation profiles versus elevation angles at different weather conditions are illustrated. Finally preliminary results of an adaptive optics system are presented that has been developed to be used in the transportable adaptive optical ground station (T-AOGS) acting as the counter terminal for the LCT mounted on Alphasat, a geostationary satellite of the European Space Agency (ESA), in autumn 2013.

Data storage systems technology for the Space Station era

NASA Technical Reports Server (NTRS)

Dalton, John; Mccaleb, Fred; Sos, John; Chesney, James; Howell, David

1987-01-01

The paper presents the results of an internal NASA study to determine if economically feasible data storage solutions are likely to be available to support the ground data transport segment of the Space Station mission. An internal NASA effort to prototype a portion of the required ground data processing system is outlined. It is concluded that the requirements for all ground data storage functions can be met with commercial disk and tape drives assuming conservative technology improvements and that, to meet Space Station data rates with commercial technology, the data will have to be distributed over multiple devices operating in parallel and in a sustained maximum throughput mode.

Time-transfer experiments between satellite laser ranging ground stations via one-way laser ranging to the Lunar Reconnaissance Orbiter

NASA Astrophysics Data System (ADS)

Mao, D.; Sun, X.; Skillman, D. R.; Mcgarry, J.; Hoffman, E.; Neumann, G. A.; Torrence, M. H.; Smith, D. E.; Zuber, M. T.

2014-12-01

Satellite laser ranging (SLR) has long been used to measure the distance from a ground station to an Earth-orbiting satellite in order to determine the spacecraft position in orbit, and to conduct other geodetic measurements such as plate motions. This technique can also be used to transfer time between the station and satellite, and between remote SLR sites, as recently demonstrated by the Time Transfer by Laser Link (T2L2) project by the Centre National d'Etudes Spatiaes (CNES) and Observatorire de la Cote d'Azur (OCA) as well as the Laser Time Transfer (LTT) project by the Shanghai Astronomical Observatory, where two-way and one-way measurements were obtained at the same time. Here we report a new technique to transfer time between distant SLR stations via simultaneous one-way laser ranging (LR) to the Lunar Reconnaissance Orbiter (LRO) spacecraft at lunar distance. The major objectives are to establish accurate ground station times and to improve LRO orbit determination via these measurements. The results of these simultaneous LR measurements are used to compare the SLR station times or transfer time from one to the other using times-of-flight estimated from conventional radio frequency tracking of LRO. The accuracy of the time transfer depends only on the difference of the times-of-flight from each ground station to the spacecraft, and is expected to be at sub-nano second level. The technique has been validated by both a ground-based experiment and an experiment that utilized LRO. Here we present the results to show that sub-nanosecond precision and accuracy are achievable. Both experiments were carried out between the primary LRO-LR station, The Next Generation Satellite Laser Ranging (NGSLR) station, and its nearby station, Mobile Laser System (MOBLAS-7), both at Greenbelt, Maryland. The laser transmit time from both stations were recorded by the same event timer referenced to a Hydrogen maser. The results have been compared to data from a common All-View GPS, and showed < 1 nanosecond precision and accuracy over 6 months. Time transfer experiments between NGSLR and McDonald Observatory SLR station at Fort Davis, Texas have also been conducted and analysis of the data will be presented.

Autonomous Navigation With Ground Station One-Way Forward-Link Doppler Data

NASA Technical Reports Server (NTRS)

Horstkamp, G. M.; Niklewski, D. J.; Gramling, C. J.

1996-01-01

The National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) has spent several years developing operational onboard navigation systems (ONS's) to provide real time autonomous, highly accurate navigation products for spacecraft using NASA's space and ground communication systems. The highly successful Tracking and Data Relay Satellite (TDRSS) ONS (TONS) experiment on the Explorer Platform/Extreme Ultraviolet (EP/EUV) spacecraft, launched on June 7, 1992, flight demonstrated the ONS for high accuracy navigation using TDRSS forward link communication services. In late 1994, a similar ONS experiment was performed using EP/EUV flight hardware (the ultrastable oscillator and Doppler extractor card in one of the TDRSS transponders) and ground system software to demonstrate the feasibility of using an ONS with ground station forward link communication services. This paper provides a detailed evaluation of ground station-based ONS performance of data collected over a 20 day period. The ground station ONS (GONS) experiment results are used to project the expected performance of an operational system. The GONS processes Doppler data derived from scheduled ground station forward link services using a sequential estimation algorithm enhanced by a sophisticated process noise model to provide onboard orbit and frequency determination. Analysis of the GONS experiment performance indicates that real time onboard position accuracies of better than 125 meters (1 sigma) are achievable with two or more 5-minute contacts per day for the EP/EUV 525 kilometer altitude, 28.5 degree inclination orbit. GONS accuracy is shown to be a function of the fidelity of the onboard propagation model, the frequency/geometry of the tracking contacts, and the quality of the tracking measurements. GONS provides a viable option for using autonomous navigation to reduce operational costs for upcoming spacecraft missions with moderate position accuracy requirements.

Roads, railways, and childhood cancers

PubMed Central

Knox, E G

2006-01-01

Study objectives To locate geographical sources of engine exhaust emissions in Great Britain and to link them with the birth addresses of children dying from cancer. To estimate the cancer initiating roles of nearby roads and railways and to measure effective ranges. Design Birth and death addresses of all children born between 1955 and 1980 in Great Britain, and dying from leukaemia or other cancer during those years, were linked to locations of railway stations, bus stations, ferry terminals, railways, roads, canals, and rivers. Nearest distances to births and deaths were measured, and migration data relating to children who had moved house were analysed. Excesses of close to hazard birth addresses, compared with close to hazard death addresses, indicate a high prenatal or early postnatal risk of cancer initiation. Setting and subjects Child cancer birth and death addresses and their map references were extracted from an earlier inquiry. Map references of putative hazards were downloaded from the Ordnance Survey national digital map of Great Britain. These data are recorded to a precision of one metre and have ground accuracies around 20 metres. Main results Significant birth excesses were found within short distances of bus stations, railway stations, ferries, railways, and A,B class roads, with a relative risk of 2.1 within 100 m, tapering to neutral after 3.0 km. About 24% of child cancers were attributable to these joint birth proximities. Roads exerted the major effect. Conclusions Child cancer initiations are strongly determined by prenatal or early postnatal exposures to engine exhaust gases, probably through maternal inhalation and accumulation of carcinogens over many months. The main active substance is probably 1,3‐butadiene. PMID:16415262

Detecting Tsunami Genesis and Scales Directly from Coastal GPS Stations

NASA Astrophysics Data System (ADS)

Song, Y. Tony

2013-04-01

Different from the conventional approach to tsunami warnings that rely on earthquake magnitude estimates, we have found that coastal GPS stations are able to detect continental slope displacements of faulting due to big earthquakes, and that the detected seafloor displacements are able to determine tsunami source energy and scales instantaneously. This method has successfully replicated several historical tsunamis caused by the 2004 Sumatra earthquake, the 2005 Nias earthquake, the 2010 Chilean earthquake, and the 2011 Tohoku-Oki earthquake, respectively, and has been compared favorably with the conventional seismic solutions that usually take hours or days to get through inverting seismographs (reference listed). Because many coastal GPS stations are already in operation for measuring ground motions in real time as often as once every few seconds, this study suggests a practical way of identifying tsunamigenic earthquakes for early warnings and reducing false alarms. Reference Song, Y. T., 2007: Detecting tsunami genesis and scales directly from coastal GPS stations, Geophys. Res. Lett., 34, L19602, doi:10.1029/2007GL031681. Song, Y. T., L.-L. Fu, V. Zlotnicki, C. Ji, V. Hjorleifsdottir, C.K. Shum, and Y. Yi, 2008: The role of horizontal impulses of the faulting continental slope in generating the 26 December 2004 Tsunami, Ocean Modelling, doi:10.1016/j.ocemod.2007.10.007. Song, Y. T. and S.C. Han, 2011: Satellite observations defying the long-held tsunami genesis theory, D.L. Tang (ed.), Remote Sensing of the Changing Oceans, DOI 10.1007/978-3-642-16541-2, Springer-Verlag Berlin Heidelberg. Song, Y. T., I. Fukumori, C. K. Shum, and Y. Yi, 2012: Merging tsunamis of the 2011 Tohoku-Oki earthquake detected over the open ocean, Geophys. Res. Lett., doi:10.1029/2011GL050767 (Nature Highlights, March 8, 2012).

Elimination of Coptotermes lacteus (Froggatt) (Blattodea: Rhinotemitidae) Colonies Using Bistrifluron Bait Applied through In-Ground Bait Stations Surrounding Mounds.

PubMed

Webb, Garry

2017-09-12

The efficacy of bistrifluron termite bait was evaluated using in-ground bait stations placed around Coptotermes lacteus mounds in south-eastern Australia during late summer and autumn (late February to late May 2012). Four in-ground bait stations containing timber billets were placed around each of twenty mounds. Once sufficient numbers of in-ground stations were infested by termites, mounds were assigned to one of four groups (one, two, three or four 120 g bait canisters or 120 to 480 g bait in total per mound) and bait canisters installed. One mound, nominally assigned treatment with two canisters ultimately had no termite interception in any of the four in-ground stations and not treated. Eighteen of the remaining 19 colonies were eliminated by 12 weeks after bait placement, irrespective of bait quantity removed (range 43 to 480 g). Measures of colony decline-mound repair capability and internal core temperature-did not accurately reflect the colony decline, as untreated colonies showed a similar pattern of decline in both repair capability and internal mound core temperature. However, during the ensuing spring-summer period, capacity to repair the mound was restored in untreated colonies and the internal core temperature profile was similar to the previous spring-summer period which indicated that these untreated colonies remained healthy.

Determination of specific yield and water-table changes using temporal microgravity surveys collected during the second injection, storage, and recovery test at Lancaster, Antelope Valley, California, November 1996 through April 1997

USGS Publications Warehouse

Howle, James F.; Phillips, Steven P.; Denlinger, Roger P.; Metzger, Loren F.

2003-01-01

To evaluate the feasibility of artificially recharging the ground-water system in the Lancaster area of the Antelope Valley, California, the U.S. Geological Survey, in cooperation with the Los Angeles County Department of Public Works and the Antelope Valley-East Kern Water Agency, conducted a series of injection, storage, and recovery tests between September 1995 and September 1998. A key component of this study was to measure the response of the water table to injection, which was difficult because the water table averaged 300 feet below land surface. Rather than install many expensive piezometers, microgravity surveys were conducted to determine specific yield and to measure the development of a ground-water mound during the injection of about 1,050 acre-feet of fresh water into an alluvial-aquifer system. The surveys were done prior to, during, and near the end of a 5-month injection period (November 12, 1996, to April 17, 1997). Results of the surveys indicate increases in gravity of as much as 66 microgals between a bedrock reference station and 20 gravity stations within a 1-square-mile area surrounding the injection site. The changes were assumed to have been caused by changes in the ground-water elevation. Gravity and ground-water levels were measured simultaneously at an existing well (7N/12W-34B1). The coupled measurements were used to calculate a specific yield of 0.13 for the alluvial aquifer near the well. To determine the gravitational effect of the injection mound on the gravity measurements made near well 7N/12W-34B1, a two-dimensional gravity model was used. Results of the model simulation show that the effect on gravity associated with the mass of the injection mound was minor and thus had a negligible effect on the calculation of specific yield. The specific yield of 0.13, therefore, was used to infer water-level changes at other gravity stations within the study area. The gravity-derived water-level changes were compared with simulated water-table changes.

Collection, quality control and delivery of ground-based magnetic data during ESA's Swarm mission

NASA Astrophysics Data System (ADS)

Macmillan, Susan; Humphries, Thomas; Flower, Simon; Swan, Anthony

2016-04-01

Ground-based magnetic data are used in a variety of ways when analysing satellite data. Selecting satellite data often involves the use of magnetic disturbance indices derived from ground-based stations and inverting satellite magnetic data for models of fields from various sources often requires ground-based data. Ground-based data can also be valuable independent data for validation purposes. We summarise data collection and quality control procedures in place at the British Geological Survey for global ground-based observatory and repeat station data. Whilst ongoing participation in the ICSU World Data System and INTERMAGNET facilitates this work, additional procedures have been specially developed for the Swarm mission. We describe these in detail.

Large File Transfers from Space Using Multiple Ground Terminals and Delay-Tolerant Networking

NASA Technical Reports Server (NTRS)

Ivancic, William D.; Paulsen, Phillip; Stewart, Dave; Eddy, Wesley; McKim, James; Taylor, John; Lynch, Scott; Heberle, Jay; Northam, James; Jackson, Chris;

Ground Motion Prediction Equations for Western Saudi Arabia from a Reference Model

NASA Astrophysics Data System (ADS)

Kiuchi, R.; Mooney, W. D.; Mori, J. J.; Zahran, H. M.; Al-Raddadi, W.; Youssef, S.

2017-12-01

Western Saudi Arabia is surrounded by several active seismic zones such as the Red Sea and the Gulf of Aqaba where a destructive magnitude 7.3 event occurred in 1995. Over the last decade, the Saudi Geological Survey (SGS) has deployed a dense seismic network that has made it possible to monitor seismic activity more accurately. For example, the network has detected multiple seismic swarms beneath the volcanic fields in western Saudi Arabia. The most recent damaging event was a M5.7 earthquake that occurred in 2009 at Harrat Lunayyir. In terms of seismic hazard assessment, Zahran et al. (2015; 2016) presented a Probabilistic Seismic Hazard Assessment (PSHA) for western Saudi Arabia that was developed using published Ground Motion Prediction Equations (GMPEs) from areas outside of Saudi Arabia. In this study, we consider 41 earthquakes of M 3.0 - 5.4, recorded on 124 stations of the SGS network, to create a set of 442 peak ground acceleration (PGA) and peak ground velocity (PGV) records with a range of epicentral distances from 3 km to 400 km. We use the GMPE model BSSA14 (Boore et al., 2014) as a reference model to estimate our own best-fitting coefficients from a regression analysis using the events occurred in western Saudi Arabia. For epicentral distances less than 100 km, our best fitting model has different source scaling in comparison with the GMPE of BSSA14 adjusted for the California region. In addition, our model indicates that the peak amplitudes have less attenuation in western Saudi Arabia than in California.

The CTBTO Link to the database of the International Seismological Centre (ISC)

NASA Astrophysics Data System (ADS)

Bondar, I.; Storchak, D. A.; Dando, B.; Harris, J.; Di Giacomo, D.

2011-12-01

The CTBTO Link to the database of the International Seismological Centre (ISC) is a project to provide access to seismological data sets maintained by the ISC using specially designed interactive tools. The Link is open to National Data Centres and to the CTBTO. By means of graphical interfaces and database queries tailored to the needs of the monitoring community, the users are given access to a multitude of products. These include the ISC and ISS bulletins, covering the seismicity of the Earth since 1904; nuclear and chemical explosions; the EHB bulletin; the IASPEI Reference Event list (ground truth database); and the IDC Reviewed Event Bulletin. The searches are divided into three main categories: The Area Based Search (a spatio-temporal search based on the ISC Bulletin), the REB search (a spatio-temporal search based on specific events in the REB) and the IMS Station Based Search (a search for historical patterns in the reports of seismic stations close to a particular IMS seismic station). The outputs are HTML based web-pages with a simplified version of the ISC Bulletin showing the most relevant parameters with access to ISC, GT, EHB and REB Bulletins in IMS1.0 format for single or multiple events. The CTBTO Link offers a tool to view REB events in context within the historical seismicity, look at observations reported by non-IMS networks, and investigate station histories and residual patterns for stations registered in the International Seismographic Station Registry.

Design for an integrated discipline operations control center for Space Station Freedom

NASA Technical Reports Server (NTRS)

Haines, Richard F.

1993-01-01

This paper presents selected features of a human factors oriented plan for a Space Station Freedom (SSF) ground Discipline Operations Center (DOC) that is integrated with other work areas used by multidisciplinary life scientists. This combined facility is referred to as an integrated DOC or IDOC. This plan is based upon the assumption that there will be a constantly changing array of specialized equipment and procedures used by life sciences principal investigators (PI) on the ground which must be linked to SSF through various DOC systems. Other sites will also be able to communicate with SSF (Anon., 1992). It is also assumed that cost reduction will be a major design consideration and that one integrated structure will be less expensive to build and operate than two separate ones. Since both the DOC personnel and PIs will need to communicate with the flight crew aboard SSF, the general interconnect architecture of the PIs' communication linkage is considered here. Key human factor design elements of this plan include: a candidate facility layout which accommodates three (3), multipurpose, rapidly reconfigurable work areas (suites) and consequent user traffic flow considerations, a multimedia telecommunications support capability, functional (human) traffic flow, optimized internal illumination and acoustics requirements, selected volumetric and safety requirements, and other architectural design parameters.

76 FR 53883 - Proposed Information Collection; Comment Request; NOAA Satellite Ground Station Customer...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-30

... Collection; Comment Request; NOAA Satellite Ground Station Customer Questionnaire AGENCY: National Oceanic... questionnaire about the types of data received, its use, the equipment involved, and similar subjects. The data... questionnaire. III. Data OMB Control Number: 0648-0227. Form Number: None. Type of Review: Regular submission...

Space-to-Ground: Russian Spacewalk: 02/02/2018

NASA Image and Video Library

2018-02-02

This week on station, one spacewalk took place, and another one was moved Also, what advice would an astronaut give to students who want to be a part of the exploration of space? NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Quantifying the spatio-temporal pattern of the ground impact of space weather events using dynamical networks formed from the SuperMAG database of ground based magnetometer stations.

NASA Astrophysics Data System (ADS)

Dods, Joe; Chapman, Sandra; Gjerloev, Jesper

2016-04-01

Quantitative understanding of the full spatial-temporal pattern of space weather is important in order to estimate the ground impact. Geomagnetic indices such as AE track the peak of a geomagnetic storm or substorm, but cannot capture the full spatial-temporal pattern. Observations by the ~100 ground based magnetometers in the northern hemisphere have the potential to capture the detailed evolution of a given space weather event. We present the first analysis of the full available set of ground based magnetometer observations of substorms using dynamical networks. SuperMAG offers a database containing ground station magnetometer data at a cadence of 1min from 100s stations situated across the globe. We use this data to form dynamic networks which capture spatial dynamics on timescales from the fast reconfiguration seen in the aurora, to that of the substorm cycle. Windowed linear cross-correlation between pairs of magnetometer time series along with a threshold is used to determine which stations are correlated and hence connected in the network. Variations in ground conductivity and differences in the response functions of magnetometers at individual stations are overcome by normalizing to long term averages of the cross-correlation. These results are tested against surrogate data in which phases have been randomised. The network is then a collection of connected points (ground stations); the structure of the network and its variation as a function of time quantify the detailed dynamical processes of the substorm. The network properties can be captured quantitatively in time dependent dimensionless network parameters and we will discuss their behaviour for examples of 'typical' substorms and storms. The network parameters provide a detailed benchmark to compare data with models of substorm dynamics, and can provide new insights on the similarities and differences between substorms and how they correlate with external driving and the internal state of the magnetosphere. We can also investigate the solar wind control of the magnetospheric-ionospheric convection system using dynamical networks. The dynamical networks are first interpolated onto a regular grid. Statistically averaged network responses are then formed for a variety of solar wind conditions, including investigating the network response to southward turnings. [1] Dods, J., S. C. Chapman, and J. W. Gjerloev (2015), Network analysis of geomagnetic substorms using the SuperMAG database of ground-based magnetometer stations, J. Geophys. Res. Space Physics, 120, 7774-7784, doi:10.1002/2015JA021456

Environmental assessment for the satellite power system concept development and evaluation program: nonmicrowave health and ecological effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, M R

1980-11-01

A Concept Development and Evaluation Program is being carried out for a proposed Satellite Power System (SPS). For purposes of this evaluation, a preliminary reference system has been developed. SPS, as described in the reference system, would collect solar energy on satellites in geosychronous orbit in space. The energy would be converted to microwaves and beamed to an earth-receiving antenna (rectenna). One task in the environmental part of the program is the assessment of the nonmicrowave effects on health and the environment. These effects would result from all phases of SPS development and operation. This report covers the current knowledgemore » regarding these effects, and is based on the reference system. The assessment is summarized as to scope, methodology, impacts of terrestrial development, launch and recovery of spacecraft, space activities (including health effects of the space environment, ionizing radiation, electromagnetic exposure, spacecraft charging and environmental interactions, occupational hazards, etc.) and construction and operation of rectenna (ground receiving station).« less

Induced Abnormality In Mir- and Earth-Grown Super Dwarf Wheat

NASA Technical Reports Server (NTRS)

Bubenheim, David L.; Stieber, Joseph; Campbell, William F.; Salisbury, Frank B.; Levinski, Margarita; Sytchev, Vladimir; Podolsky, Igor; Chernova, Lola; Ivanova, Irene; Kliss, Mark (Technical Monitor)

1998-01-01

Super-dwarf wheat grown on the Mir space station using the Svet "Greenhouse" exhibited morphological, metabolic and reproductive abnormalities compared with normal wheat. Of prominent importance were the abnormalities associated with reproductive ontogeny and the total absence of seed formation on Mir. Changes in the apical meristem associated with transition from the vegetative phase to floral initiation and development of the reproductive spike were all typical of 'Super Dwarf' wheat up to the point of anthesis. Observation of ruptured anthers from the Mir-grown plants revealed what appeared to be normally developed pollen. These pollen grains however, contain only one nucleus, while normal viable pollen is trinucleate. A potentially important difference in the flight experiment, compared with ground reference studies, was identified - a high level of atmospheric ethylene (1200 ppb). Ground studies conducted exposing "Super-dwarf" wheat to ethylene at just prior to anthesis resulted in manifestation of the same abnormalities observed in the space flight samples.

Effects of LEO Environment on Tensile Properties of PEEK Films

NASA Astrophysics Data System (ADS)

Nakamura, Takashi; Nakamura, Hiroshi; Shimamura, Hiroyuki

2009-01-01

To clarify the effects of space environment on mechanical properties of polymer, exposure experiments were conducted utilizing the International Space Station Russian Service Module. Poly-ether-ether-ketone (PEEK) films under tensile stress were exposed to low Earth orbit (LEO) environment, and reference samples were irradiated with atomic oxygen (AO), electron beam (EB), and ultraviolet light (UV) in ground facilities. By comparing the results of flight and ground tests, the degradation behavior and the influential factors in LEO were investigated. The following results were obtained. (1) UV was found to be the harshest factor in LEO on tensile properties, since it decreased elongation to 15% of pristine sample after 46-months exposure. (2) AO in LEO eroded the specimen surface with a cone-like morphology and reduced the thickness; however, it had no significant effect on tensile properties. (3) EB irradiation in LEO had no measurable effects on the material properties.

Orbiting Deep Space Relay Station (ODSRS). Volume 1: Requirement determination

NASA Technical Reports Server (NTRS)

Hunter, J. A.

1979-01-01

The deep space communications requirements of the post-1985 time frame are described and the orbiting deep space relay station (ODSRS) is presented as an option for meeting these requirements. Under current conditions, the ODSRS is not yet cost competitive with Earth based stations to increase DSN telemetry performance, but has significant advantages over a ground station, and these are sufficient to maintain it as a future option. These advantages include: the ability to track a spacecraft 24 hours per day with ground stations located only in the USA; the ability to operate at higher frequencies that would be attenuated by Earth's atmosphere; and the potential for building very large structures without the constraints of Earth's gravity.

Distribution and identification of airborne fungi in railway stations in Tokyo, Japan.

PubMed

Kawasaki, Tamami; Kyotani, Takashi; Ushiogi, Tomoyoshi; Izumi, Yasuhiko; Lee, Hunjun; Hayakawa, Toshio

2010-01-01

The current study was performed to (1) understand the distribution of airborne fungi culturable on dichloran-glycerol agar (DG18) media over a one-year monitoring period, (2) identify the types of airborne fungi collected, and (3) compare and contrast under- and above-ground spaces, in two railway stations in Tokyo, Japan. Measurements of airborne fungi were taken at stations A and B located in Tokyo. Station A had under- and above-ground concourses and platforms whereas station B had spaces only above-ground. Airborne fungi at each measurement position were collected with an air sampler on DG18 media. After cultivation of the sample plates, the number of fungi colonies was counted on each agar plate. In station A, the underground platform was characterized as (1) having the highest humidity and (2) a high concentration of airborne fungi, with (3) a high proportion of non-sporulating fungi (NSF) and Aspergillus versicolor. There was a strong positive correlation between the concentrations of airborne particles and fungi in station A. Common aspects of the two stations were (1) that fungi were mostly detected in autumn, and (2) there was no correlation between the humidity and concentration of fungi throughout the year. The results of this study indicate that the distribution and composition of fungi differ depending on the structure of the station.

No Further Action Decision Under CERCLA Study Area 43N Historic Gas Station Sites Fort Devens, Massachusetts

DTIC Science & Technology

1995-01-01

SITES FORT DEVENS , MASSACHUSETTS CONTRACT DAAA15-91-0008 U.S. ARMY ENVIRONMENTAL CENTER ABERDEEN PROVING GROUND, MARYLAND JANUARY 1995 PRINTED ON...HISTORIC GAS STATION SITES FORT DEVENS , MASSACHUSETTS I . Prepared for: U.S. Army Environmental Center Aberdeen Proving Ground, Maryland Contract DAAA15-91...DECISION UNDER CERCLA STUDY AREA 43N HISTORIC GAS STATION SITES FORT DEVENS , MASSACHUSETTS 3 TABLE OF CONTENTS U Section Title Page No. EXECUTIVE SUMMARY

Laser based bi-directional Gbit ground links with the Tesat transportable adaptive optical ground station

NASA Astrophysics Data System (ADS)

Heine, Frank; Saucke, Karen; Troendle, Daniel; Motzigemba, Matthias; Bischl, Hermann; Elser, Dominique; Marquardt, Christoph; Henninger, Hennes; Meyer, Rolf; Richter, Ines; Sodnik, Zoran

2017-02-01

Optical ground stations can be an alternative to radio frequency based transmit (forward) and receive (return) systems for data relay services and other applications including direct to earth optical communications from low earth orbit spacecrafts, deep space receivers, space based quantum key distribution systems and Tbps capacity feeder links to geostationary spacecrafts. The Tesat Transportable Adaptive Optical Ground Station is operational since September 2015 at the European Space Agency site in Tenerife, Spain.. This paper reports about the results of the 2016 experimental campaigns including the characterization of the optical channel from Tenerife for an optimized coding scheme, the performance of the T-AOGS under different atmospheric conditions and the first successful measurements of the suitability of the Alphasat LCT optical downlink performance for future continuous variable quantum key distribution systems.

Limitation and applicability of microtremor records for site-response estimation

NASA Astrophysics Data System (ADS)

Song, G.; Kang, T.; Park, S.

2010-12-01

Site effects are the modifications of seismic motions which are traveling through near-surface materials. The impedance contrast between the topmost layer and bedrock may significantly amplify ground motions and augment their durations. Inelastic behavior of the geological media such as highly fractured/weathered rocks and unconsolidated sediments may absorb seismic energy, and thus damp the resulting ground motions. It is inherently most desirable to evaluate the site effects using seismic records from large earthquakes. If there are only small events that will be recorded by several seismograph stations, it becomes difficult to evaluate site effects using earthquake data. Recently a number of studies pay attention to microtremor records to assess site effects. The main reason of such efforts is that measurements are relatively easy regardless of site condition and cost-effective without necessity of waiting for earthquakes or of using active sources. Especially microtremor measurements are exclusively a useful option to assess site effects, and thus seismic microzonation, in the urban area and/or region of low to moderate seismicity. Spectral ratios of horizontal components to vertical component (HVSR) of microtremor records have been popular for estimation of site resonant frequency. Although some studies have shown that the amplitude of spectral ratios is an indicator of site amplification relative to bedrock motion, there are still debates on it. This discrepancy may originate from the deficiency of our understanding on the nature of microtremor. Therefore, it is important to understand the limitation and applicability of microtremor records for site-effect assessments. The focus on this problem is how microtremor responses on the subsurface structures and their physical properties, and how parameters deduced from microtremor analyses are related to site responses during earthquake ground motions. In order to investigate how these issues have a practical meaning in real cases, results obtained using the microtremor method were compared with results from a field test, a spectral inversion method, and the reference station method for sites of strong motion stations in the southern Korean Peninsula.

Infrasound signals from the underground nuclear explosions of North Korea

NASA Astrophysics Data System (ADS)

Che, Il-Young; Park, Junghyun; Kim, Inho; Kim, Tae Sung; Lee, Hee-Il

2014-07-01

We investigated the infrasound signals from seismic ground motions induced by North Korea's underground nuclear explosions, including the recent third explosion on 2013 February 12. For the third explosion, the epicentral infrasound signals were detected not only by three infrasound network stations (KSGAR, ULDAR and YAGAR) in South Korea but also by two nearby International Monitoring System infrasound stations, IS45 and IS30. The detectability of the signals was limited at stations located on the relatively east side of the epicentre, with large azimuth deviations due to very favourable atmospheric conditions for eastward propagation at stratospheric height in 2013. The stratospheric wind direction was the reverse of that when the second explosion was conducted in 2009 May. The source location of the epicentral infrasound with wave parameters determined at the multiple stations has an offset by about 16.6 km from the reference seismic location. It was possible to determine the infrasonic location with moderate accuracy by the correction of the azimuth deviation due to the eastward winds in the stratosphere. In addition to the epicentral infrasonic signals, diffracted infrasound signals were observed from the second underground nuclear explosion in 2009. The exceptional detectability of the diffracted infrasound was a consequence of the temporal formation of a thin atmospheric inversion layer over the ocean surface when the event occurred.

The influence of the reflective environment on the absorption of a human male exposed to representative base station antennas from 300 MHz to 5 GHz.

PubMed

Vermeeren, G; Gosselin, M C; Kühn, S; Kellerman, V; Hadjem, A; Gati, A; Joseph, W; Wiart, J; Meyer, F; Kuster, N; Martens, L

2010-09-21

The environment is an important parameter when evaluating the exposure to radio-frequency electromagnetic fields. This study investigates numerically the variation on the whole-body and peak spatially averaged-specific absorption rate (SAR) in the heterogeneous virtual family male placed in front of a base station antenna in a reflective environment. The SAR values in a reflective environment are also compared to the values obtained when no environment is present (free space). The virtual family male has been placed at four distances (30 cm, 1 m, 3 m and 10 m) in front of six base station antennas (operating at 300 MHz, 450 MHz, 900 MHz, 2.1 GHz, 3.5 GHz and 5.0 GHz, respectively) and in three reflective environments (a perfectly conducting wall, a perfectly conducting ground and a perfectly conducting ground + wall). A total of 72 configurations are examined. The absorption in the heterogeneous body model is determined using the 3D electromagnetic (EM) finite-difference time-domain (FDTD) solver Semcad-X. For the larger simulations, requirements in terms of computer resources are reduced by using a generalized Huygens' box approach. It has been observed that the ratio of the SAR in the virtual family male in a reflective environment and the SAR in the virtual family male in the free-space environment ranged from -8.7 dB up to 8.0 dB. A worst-case reflective environment could not be determined. ICNIRP reference levels not always showed to be compliant with the basic restrictions.

Zenith: A Radiosonde Detector for Rapid-Response Ionizing Atmospheric Radiation Measurements During Solar Particle Events

NASA Astrophysics Data System (ADS)

Dyer, A. C. R.; Ryden, K. A.; Hands, A. D. P.; Dyer, C.; Burnett, C.; Gibbs, M.

2018-03-01

Solar energetic particle events create radiation risks for aircraft, notably single-event effects in microelectronics along with increased dose to crew and passengers. In response to this, some airlines modify their flight routes after automatic alerts are issued. At present these alerts are based on proton flux measurements from instruments onboard satellites, so it is important that contemporary atmospheric radiation measurements are made and compared. This paper presents the development of a rapid-response system built around the use of radiosondes equipped with a radiation detector, Zenith, which can be launched from a Met Office weather station after significant solar proton level alerts are issued. Zenith is a compact, battery-powered solid-state radiation monitor designed to be connected to a Vaisala RS-92 radiosonde, which transmits all data to a ground station as it ascends to an altitude of 33 km. Zenith can also be operated as a stand-alone detector when connected to a laptop, providing real-time count rates. It can also be adapted for use on unmanned aerial vehicles. Zenith has been flown on the Met Office Civil Contingency Aircraft, taken to the European Organization for Nuclear Research-EU high energy Reference Field facility for calibration and launched on a meteorological balloon at the Met Office's weather station in Camborne, Cornwall, UK. During this sounding, Zenith measured the Pfotzer-Regener maximum to be at an altitude of 18-20 km where the count rate was measured to be 1.15 c s-1 cm-2 compared to 0.02 c s-1 cm-2 at ground level.

Global multi-dimensional modeling of ionospheric electron density using GNSS measurements and IRI model

NASA Astrophysics Data System (ADS)

Alizadeh, M.; Schuh, H.; Schmidt, M. G.

2012-12-01

In the last decades Global Navigation Satellite System (GNSS) has turned into a promising tool for probing the ionosphere. The classical input data for developing Global Ionosphere Maps (GIM) is obtained from the dual-frequency GNSS observations. Simultaneous observations of GNSS code or carrier phase at each frequency is used to form a geometric-free linear combination which contains only the ionospheric refraction term and the differential inter-frequency hardware delays. To relate the ionospheric observable to the electron density, a model is used that represents an altitude-dependent distribution of the electron density. This study aims at developing a global multi-dimensional model of the electron density using simulated GNSS observations from about 150 International GNSS Service (IGS) ground stations. Due to the fact that IGS stations are in-homogenously distributed around the world and the accuracy and reliability of the developed models are considerably lower in the area not well covered with IGS ground stations, the International Reference Ionosphere (IRI) model has been used as a background model. The correction term is estimated by applying spherical harmonics expansion to the GNSS ionospheric observable. Within this study this observable is related to the electron density using different functions for the bottom-side and top-side ionosphere. The bottom-side ionosphere is represented by an alpha-Chapman function and the top-side ionosphere is represented using the newly proposed Vary-Chap function.aximum electron density, IRI background model (elec/m3), day 202 - 2010, 0 UT eight of maximum electron density, IRI background model (km), day 202 - 2010, 0 UT

New Downhole Strong-Motion Data Recorded at Tarzana Array

NASA Astrophysics Data System (ADS)

Graizer, V.; Shakal, A.; Haddadi, H.

2001-12-01

Significantly amplified ground accelerations at the Tarzana station were recorded during many, but not all, earthquakes (e.g., Shakal et al., 1988). Peak horizontal ground acceleration at the Tarzana station during the M7.1 Hector Mine earthquake was almost twice as large as the accelerations recorded at nearby stations. After the Northridge earthquake the California Strong Motion Instrumentation Program (CSMIP) significantly increased instrumentation at Tarzana to study the unusual site amplification effect. Current instrumentation at Tarzana consists of an accelerograph at the top of Tarzana hill (Tarzana - Cedar Hill B), a downhole instrument at 60 m depth, and an accelerograph at the foot of the hill (Tarzana - Clubhouse), 180 m from the Cedar Hill B station. The original station, Tarzana - Cedar Hill Nursery A, was lost in 1999 due to construction. Thirteen events, including the Hector Mine earthquake, were simultaneously recorded by these instruments at Tarzana. The downhole instrument (A) was used as a reference site to compare the amplification effects at the top of Tarzana hill (B) and at the foot of the hill (C). Spectral amplification from the bottom of the hole to the top of the hill (B/A) and to the foot of the hill (C/A) is similar along the component parallel to the strike of Tarzana hill. But B/A is almost double C/A along the component transverse to the strike of the hill in period range from 0.04 to 0.8 sec (1.2 to 25 Hz). Comparison of the response spectra demonstrates clear directional site response resonance (perpendicular to the strike of the hill) at Tarzana. In contrast to accelerations recorded during the Mw 7.1 Hector Mine earthquake (high frequency part of seismic signal), displacements (relatively low frequency part of seismic signal) demonstrate almost no site amplification from the bottom of the hole to the surface (B/A) at periods greater than 1.5 sec, in either direction. Ground displacements at other CSMIP downhole arrays which recorded the Hector Mine earthquake also demonstrate almost no near-surface site amplification at long periods. Comparison of empirical and theoretical site amplification effects at Tarzana was performed using SHAKE91 modeling motion separately in the longitudinal and transverse directions. The source of the site amplification that produces large motions at Tarzana is still under investigation. The topography, shear-wave velocity profile and three-dimensional structure of the site apparently all contribute to the higher amplification of ground motion at the Tarzana site. The studies of Tarzana were co-funded by CSMIP and by the National Science Foundation (NSF) through the Resolution of Site Response Issues from the Northridge Earthquake Project (ROSRINE).

Ultra Small Aperture Terminal: System Design and Test Results

NASA Technical Reports Server (NTRS)

Sohn, Philip Y.; Reinhart, Richard C.

1996-01-01

The Ultra Small Aperture Terminal (USAT) has been developed to test and demonstrate remote and broadcast satcom applications via the Advanced Communications Technology Satellite (ACTS). The design of these ground stations emphasize small size, low power consumption, portable and rugged terminals. Each ground station includes several custom design parts such as 35 cm diameter antenna, 1/4 Watt transmitter with built-in upconverter, and 4.0 dB Noise Figure (NF) receiver with built-in downconverter. In addition, state-of-the-art commercial parts such as highly stable ovenized crystal oscillators and dielectric resonator oscillators are used in the ground station design. Presented in this paper are system level design description, performance, and sample applications.

High Bandwidth Optical Links for Micro-Satellite Support

NASA Technical Reports Server (NTRS)

Chao, Tien-Hsin (Inventor); Wilson, Keith E. (Inventor); Coste, Keith (Inventor)

2016-01-01

A method, systems, apparatus and device enable high bandwidth satellite communications. An onboard tracking detector, installed in a low-earth orbit satellite, detects a position of an incoming optical beam received/transmitted from a first ground station of one or more ground stations. Tracker electronics determine orientation information of the incoming optical beam based on the position. Control electronics receive the orientation information from the tracker electronics, and control a waveguide drive electronics. The waveguide drive electronics control a voltage that is provided to an electro-optic waveguide beam steering device. The electro-optic waveguide beam steering device steers an outgoing optical beam to one of the one or more ground stations based on the voltage.

Evaluation of Early Ground Control Station Configurations for Interacting with a UAS Traffic Management (UTM) System

NASA Technical Reports Server (NTRS)

Dao, Arik-Quang V.; Martin, Lynne; Mohlenbrink, Christoph; Bienert, Nancy; Wolte, Cynthia; Gomez, Ashley; Claudatos, Lauren; Mercer, Joey

2017-01-01

The purpose of this paper is to report on a human factors evaluation of ground control station design concepts for interacting with an unmanned traffic management system. The data collected for this paper comes from recent field tests for NASA's Unmanned Traffic Management (UTM) project, and covers the following topics; workload, situation awareness, as well as flight crew communication, coordination, and procedures. The goal of this evaluation was to determine if the various software implementations for interacting with the UTM system can be described and classified into design concepts to provide guidance for the development of future UTM interfaces. We begin with a brief description of NASA's UTM project, followed by a description of the test range configuration related to a second development phase. We identified (post hoc) two classes in which the ground control stations could be grouped. This grouping was based on level of display integration. The analysis was exploratory and informal. It was conducted to compare ground stations across those two classes and against the aforementioned topics. Herein, we discuss the results.

On-Orbit Constraints Test - Performing Pre-Flight Tests with Flight Hardware, Astronauts and Ground Support Equipment to Assure On-Orbit Success

NASA Technical Reports Server (NTRS)

Haddad, Michael E.

2008-01-01

On-Orbit Constraints Test (OOCT's) refers to mating flight hardware together on the ground before they will be mated on-orbit. The concept seems simple but it can be difficult to perform operations like this on the ground when the flight hardware is being designed to be mated on-orbit in a zero-g and/or vacuum environment of space. Also some of the items are manufactured years apart so how are mating tasks performed on these components if one piece is on-orbit before its mating piece is planned to be built. Both the Internal Vehicular Activity (IVA) and Extra-Vehicular Activity (EVA) OOCT's performed at Kennedy Space Center will be presented in this paper. Details include how OOCT's should mimic on-orbit operational scenarios, a series of photographs will be shown that were taken during OOCT's performed on International Space Station (ISS) flight elements, lessons learned as a result of the OOCT's will be presented and the paper will conclude with possible applications to Moon and Mars Surface operations planned for the Constellation Program.

Advanced Communications Architecture Demonstration Made Significant Progress

NASA Technical Reports Server (NTRS)

Carek, David Andrew

2004-01-01

Simulation for a ground station located at 44.5 deg latitude. The Advanced Communications Architecture Demonstration (ACAD) is a concept architecture to provide high-rate Ka-band (27-GHz) direct-to-ground delivery of payload data from the International Space Station. This new concept in delivering data from the space station targets scientific experiments that buffer data onboard. The concept design provides a method to augment the current downlink capability through the Tracking Data Relay Satellite System (TDRSS) Ku-band (15-GHz) communications system. The ACAD concept pushes the limits of technology in high-rate data communications for space-qualified systems. Research activities are ongoing in examining the various aspects of high-rate communications systems including: (1) link budget parametric analyses, (2) antenna configuration trade studies, (3) orbital simulations (see the preceding figure), (4) optimization of ground station contact time (see the following graph), (5) processor and storage architecture definition, and (6) protocol evaluations and dependencies.

Turnaround operations analysis for OTV. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1988-01-01

Anaylses performed for ground processing, both expendable and reusable ground-based Orbital Transfer Vehicles (OTVs) launched on the Space Transportation System (STS), a reusable space-based OTV (SBOTV) launched on the STS, and a reusable ground-based OTV (GBOTV) launched on an unmanned cargo vehicle and recovered by the Orbiter are summarized. Also summarized are the analyses performed for space processing the reusable SBOTV at the Space Station in low Earth orbit (LEO) as well as the maintenance and servicing of the SBOTV accommodations at the Space Station. In addition, the candidate OTV concepts, design and interface requirements, and the Space Station design, support, and interface requirements are summarized. A development schedule and associated costs for the required SBOTV accommodations at the Space Station are presented. Finallly, the technology development plan to develop the capability to process both GBOTVs and SBOTVs are summarized.

Temporal upscaling of instantaneous evapotranspiration on clear-sky days using the constant reference evaporative fraction method with fixed or variable surface resistances at two cropland sites

NASA Astrophysics Data System (ADS)

Tang, Ronglin; Li, Zhao-Liang; Sun, Xiaomin; Bi, Yuyun

2017-01-01

Surface evapotranspiration (ET) is an important component of water and energy in land and atmospheric systems. This paper investigated whether using variable surface resistances in the reference ET estimates from the full-form Penman-Monteith (PM) equation could improve the upscaled daily ET estimates in the constant reference evaporative fraction (EFr, the ratio of actual to reference grass/alfalfa ET) method on clear-sky days using ground-based measurements. Half-hourly near-surface meteorological variables and eddy covariance (EC) system-measured latent heat flux data on clear-sky days were collected at two sites with different climatic conditions, namely, the subhumid Yucheng station in northern China and the arid Yingke site in northwestern China and were used as the model input and ground-truth, respectively. The results showed that using the Food and Agriculture Organization (FAO)-PM equation, the American Society of Civil Engineers-PM equation, and the full-form PM equation to estimate the reference ET in the constant EFr method produced progressively smaller upscaled daily ET at a given time from midmorning to midafternoon. Using all three PM equations produced the best results at noon at both sites regardless of whether the energy imbalance of the EC measurements was closed. When the EC measurements were not corrected for energy imbalance, using variable surface resistance in the full-form PM equation could improve the ET upscaling in the midafternoon, but worse results may occur in the midmorning to noon. Site-to-site and time-to-time variations were found in the performances of a given PM equation (with fixed or variable surface resistances) before and after the energy imbalance was closed.

Cost and Performance Comparison of an Earth-Orbiting Optical Communication Relay Transceiver and a Ground-Based Optical Receiver Subnet

NASA Technical Reports Server (NTRS)

Wilson, K. E.; Wright, M.; Cesarone, R.; Ceniceros, J.; Shea, K.

2003-01-01

Optical communications can provide high-data-rate telemetry from deep-space probes with subsystems that have lower mass, consume less power, and are smaller than their radio frequency (RF) counterparts. However, because optical communication is more a.ected by weather than is RF communication, it requires groundstation site diversity to mitigate the adverse e.ects of inclement weather on the link. An optical relay satellite is not a.ected by weather and can provide 24-hour coverage of deep-space probes. Using such a relay satellite for the deep-space link and an 8.4-GHz (X-band) link to a ground station would support high-data-rate links from small deep-space probes with very little link loss due to inclement weather. We have reviewed past JPL-funded work on RF and optical relay satellites, and on proposed clustered and linearly dispersed optical subnets. Cost comparisons show that the life cycle costs of a 7-m optical relay station based on the heritage of the Next Generation Space Telescope is comparable to that of an 8-station subnet of 10- m optical ground stations. This makes the relay link an attractive option vis- a-vis a ground-station network.

The reference frame of figure-ground assignment.

PubMed

Vecera, Shaun P

2004-10-01

Figure-ground assignment involves determining which visual regions are foreground figures and which are backgrounds. Although figure-ground processes provide important inputs to high-level vision, little is known about the reference frame in which the figure's features and parts are defined. Computational approaches have suggested a retinally based, viewer-centered reference frame for figure-ground assignment, but figural assignment could also be computed on the basis of environmental regularities in an environmental reference frame. The present research used a newly discovered cue, lower region, to examine the reference frame of figure-ground assignment. Possible reference frames were misaligned by changing the orientation of viewers by having them tilt their heads (Experiments 1 and 2) or turn them upside down (Experiment 3). The results of these experiments indicated that figure-ground perception followed the orientation of the viewer, suggesting a viewer-centered reference frame for figure-ground assignment.

Geodetic positioning of the Aerospace Electronics Research Lab (ERL) Osborne Time Transfer Receiver (TTR) using the GPS NAVSTAR Block I satellites

NASA Technical Reports Server (NTRS)

Liu, Anthony S.

1990-01-01

Aerospace has routinely processed the Osborne Time Transfer Receiver (TTR) data for the purpose of monitoring the performance of ground and GPS atomic clocks in near real-time with on-line residual displays and characterizing clock stability with Allan Variance calculations. Recently, Aerospace added the ability to estimate the TTR's location by differentially correcting the TTR's location in the WGS84 reference system. This new feature is exercised on a set of TTR clock phase data and Sub-meter accurate station location estimates of the TTR at the Aerospace Electronic Research Lab (ERL) are obtained.

Survey of quantitative data on the solar energy and its spectra distribution

NASA Technical Reports Server (NTRS)

Thekaekara, M. P.

1976-01-01

This paper presents a survey of available quantitative data on the total and spectral solar irradiance at ground level and outside the atmosphere. Measurements from research aircraft have resulted in the currently accepted NASA/ASTM standards of the solar constant and zero air mass solar spectral irradiance. The intrinsic variability of solar energy output and programs currently under way for more precise measurements from spacecraft are discussed. Instrumentation for solar measurements and their reference radiation scales are examined. Insolation data available from the records of weather stations are reviewed for their applicability to solar energy conversion. Two alternate methods of solarimetry are briefly discussed.

Measurements of aquifer-storage change and specific yield using gravity surveys

USGS Publications Warehouse

Pool, D.R.; Eychaner, J.H.

1995-01-01

Pinal Creek is an intermittent stream that drains a 200-square-mile alluvial basin in central Arizona. Large changes in water levels and aquifer storage occur in an alluvial aquifer near the stream in response to periodic recharge and ground-water withdrawals. Outflow components of the ground-water budget and hydraulic properties of the alluvium are well-defined by field measurements; however, data are insufficient to adequately describe recharge, aquifer-storage change, and specific-yield values. An investigation was begun to assess the utility of temporal-gravity surveys to directly measure aquifer-storage change and estimate values of specific yield.The temporal-gravity surveys measured changes in the differences in gravity between two reference stations on bedrock and six stations at wells; changes are caused by variations in aquifer storage. Specific yield was estimated by dividing storage change by water-level change. Four surveys were done between February 21, 1991, and March 31, 1993. Gravity increased as much as 158 microGal ± 1 to 6 microGal, and water levels rose as much as 58 feet. Average specific yield at wells ranged from 0.16 to 0.21, and variations in specific yield with depth correlate with lithologic variations. Results indicate that temporal-gravity surveys can be used to estimate aquifer-storage change and specific yield of water-table aquifers where significant variations in water levels occur. Direct measurement of aquifer-storage change can eliminate a major unknown from the ground-water budget of arid basins and improve residual estimates of recharge.

Moon view period tabulations (with station masking) for Manned Space Flight Network stations, book 1

NASA Technical Reports Server (NTRS)

Gattie, M. M.; Williams, R. L.

1970-01-01

The times during which MSFN stations can view the moon are tabulated. Station view periods for each month are given. All times and dates refer to Greenwich Mean Time. AOS and LOS refer to the center of the moon at zero degrees elevation for moon rise and set, respectively.

Method of remotely estimating a rest or best lock frequency of a local station receiver using telemetry

NASA Technical Reports Server (NTRS)

Fielhauer, Karl B. (Inventor); Jensen, James R. (Inventor)

2007-01-01

A system includes a remote station and a local station having a receiver. The receiver operates in an unlocked state corresponding to its best lock frequency (BLF). The local station derives data indicative of a ratio of the BLF to a reference frequency of the receiver, and telemeters the data to the remote station. The remote station estimates the BLF based on (i) the telemetered data, and (ii) a predetermined estimate of the reference frequency.

1. Credit USAF, ca. 1942. Original housed in the Muroc ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Credit USAF, ca. 1942. Original housed in the Muroc Flight Test Base, Unit History, 1 September 1942 - 30 June 1945. Alfred F. Simpson Historical Research Agency. United States Air Force. Maxwell AFB, Alabama. Historical view looks west southwest at construction of Building 4317, Deluge Water Pumping Station (then designated Pump House No. 3). This in-ground structure houses fire pumps which draw water from an in-ground reservoir, Building 4316 (See HAER photos CA-170-I). Pumping station was built in-ground to take advantage of gravity, since water flows from reservoir to prime the pumps, and fire system piping is underground. Opening in far wall is to stairs leading up to ground level. Earth mound in background is part of water reservoir construction (Building 4316). - Edwards Air Force Base, North Base, Deluge Water Pumping Station, Near Second & D Streets, Boron, Kern County, CA

Feasibility of utilizing Cherenkov Telescope Array gamma-ray telescopes as free-space optical communication ground stations.

PubMed

Carrasco-Casado, Alberto; Vilera, Mariafernanda; Vergaz, Ricardo; Cabrero, Juan Francisco

2013-04-10

The signals that will be received on Earth from deep-space probes in future implementations of free-space optical communication will be extremely weak, and new ground stations will have to be developed in order to support these links. This paper addresses the feasibility of using the technology developed in the gamma-ray telescopes that will make up the Cherenkov Telescope Array (CTA) observatory in the implementation of a new kind of ground station. Among the main advantages that these telescopes provide are the much larger apertures needed to overcome the power limitation that ground-based gamma-ray astronomy and optical communication both have. Also, the large number of big telescopes that will be built for CTA will make it possible to reduce costs by economy-scale production, enabling optical communications in the large telescopes that will be needed for future deep-space links.

Water Resources Data for Illinois - Water Year 2005 (Includes Historical Data)

USGS Publications Warehouse

LaTour, J.K.; Weldon, E.A.; Dupre, D.H.; Halfar, T.M.

2006-01-01

This annual Water-Data Report for Illinois contains current water year (Oct. 1, 2004, to Sept. 30, 2005) and historical data of discharge, stage, water quality and biology of streams; stage of lakes and reservoirs; levels and quality of ground water; and records of precipitation, air temperature, dew point, solar radiation, and wind speed. The current year's (2005) data provided in this report include (1) discharge for 182 surface-water gaging stations and for 9 crest-stage partial-record stations; (2) stage for 33 surface-water gaging stations; (3) water-quality records for 10 surface-water stations; (4) sediment-discharge records for 14 surface-water stations; (5) water-level records for 98 ground-water wells; (6) water-quality records for 17 ground-water wells; (7) precipitation records for 48 rain gages; (8) records of air temperature, dew point, solar radiation and wind speed for 1 meteorological station; and (9) biological records for 6 sample sites. Also included are miscellaneous data collected at various sites not in the systematic data-collection network. Data were collected and compiled as a part of the National Water Information System (NWIS) maintained by the U.S. Geological Survey in cooperation with Federal, State, and local agencies.

Best Longitudinal Adjustment of Satellite Trajectories for the Observation of Forest Fires (Blastoff): A Stochastic Programming Approach to Satellite System Design

NASA Astrophysics Data System (ADS)

Hoskins, Aaron B.

Forest fires cause a significant amount of damage and destruction each year. Optimally dispatching resources reduces the amount of damage a forest fire can cause. Models predict the fire spread to provide the data required to optimally dispatch resources. However, the models are only as accurate as the data used to build them. Satellites are one valuable tool in the collection of data for the forest fire models. Satellites provide data on the types of vegetation, the wind speed and direction, the soil moisture content, etc. The current operating paradigm is to passively collect data when possible. However, images from directly overhead provide better resolution and are easier to process. Maneuvering a constellation of satellites to fly directly over the forest fire provides higher quality data than is achieved with the current operating paradigm. Before launch, the location of the forest fire is unknown. Therefore, it is impossible to optimize the initial orbits for the satellites. Instead, the expected cost of maneuvering to observe the forest fire determines the optimal initial orbits. A two-stage stochastic programming approach is well suited for this class of problem where initial decisions are made with an uncertain future and then subsequent decisions are made once a scenario is realized. A repeat ground track orbit provides a non-maneuvering, natural solution providing a daily flyover of the forest fire. However, additional maneuvers provide a second daily flyover of the forest fire. The additional maneuvering comes at a significant cost in terms of additional fuel, but provides more data collection opportunities. After data are collected, ground stations receive the data for processing. Optimally selecting the ground station locations reduce the number of built ground stations and reduces the data fusion issues. However, the location of the forest fire alters the optimal ground station sites. A two-stage stochastic programming approach optimizes the selection of ground stations to maximize the expected amount of data downloaded from a satellite. The approaches of selecting initial orbits and ground station locations including uncertainty will provide a robust system to reduce the amount of damage caused by forest fires.

PROMIS series. Volume 8: Midlatitude ground magnetograms

NASA Technical Reports Server (NTRS)

Fairfield, D. H.; Russell, C. T.

1990-01-01

This is the eighth in a series of volumes pertaining to the Polar Region Outer Magnetosphere International Study (PROMIS). This volume contains 24 hour stack plots of 1-minute average, H and D component, ground magnetograms for the period March 10 through June 16, 1986. Nine midlatitude ground stations were selected from the UCLA magnetogram data base that was constructed from all available digitized magnetogram stations. The primary purpose of this publication is to allow users to define universal times and onset longitudes of magnetospheric substorms.

Veg-03 Ground Harvest

NASA Image and Video Library

2016-12-05

Inside the Veggie flight laboratory in the Space Station Processing Facility at NASA’s Kennedy Space Center in Florida, a research scientist harvests a portion of the 'Outredgeous' red romaine lettuce from the Veg-03 ground control unit. The purpose of the ground Veggie system is to provide a control group to compare against the lettuce grown in orbit on the International Space Station. Veg-03 will continue NASA’s deep space plant growth research to benefit the Earth and the agency’s journey to Mars.

A magnetotelluric feasibility study of the Alps

NASA Astrophysics Data System (ADS)

Ritter, O.; Weckmann, U.

2016-12-01

The Alps are a famous and extensive mountain range system in central Europe. The mountains were formed as the African and Eurasian tectonic plates collided and they have been a prime target for geological and geophysical investigations since the beginning of modern geosciences. Consequently, the Alps have been investigated with active and passive seismological methods and extensive sets of potential field data exist. Hardly anything is known, however, about the deep electrical conductivity structure, as it has been notoriously difficult to acquire magnetotelluric (MT) data in the Alps. The Alps are densely populated and a lot of infrastructure for tourism has been built over the years. MT measurements, which rely on natural variations of the electromagnetic background fields, are severely hampered by this man-made noise. Here, we report on a feasibility study to acquire MT data in the Alps, where all stations are deployed outside the valleys, on high mountain ranges and alpine pastures. Overall we recorded MT data at 7 stations, along an approximately north-south profile centred on Mayrhofen in the Austrian Alps. The average station spacing was 5 kilometers. The data were processed using robust remote-reference processing and the results clearly show that MT measurements are feasible. We used Mare2DEM for 2D inversion to include a somewhat realistic topography. The 2D section indicates moderate resistivity for the top 2 - 5 km, consistent with the regional geology, which suggests (meta-) sedimentary sequences. From depths of 5 km and below resistivities exceed 5,000 Ohmm. This means we can sense very deep with MT but also, that we should be cautious with an interpretation of this short profile. The data also clearly indicate 3D effects. We therefore propose to deploy an array of stations covering the entire Alps in USArray style, e.g. with a station spacing of approximately 50 km, to derive a 3D model of the deep electrical resistivity structure of the Alps. Such a model could also serve as reference for more detailed investigations of key structures such as major fault systems or nappe structures. It will be essential to install stations on high ground, as far away as possible from valleys and cultural installations.

GNSS RTK-networks: The significance and issues to realize a recent reference coordinate system

NASA Astrophysics Data System (ADS)

Umnig, Elke; Möller, Gregor; Weber, Robert

2014-05-01

The upcoming release of the new global reference frame ITRF2013 will provide high accurate reference station positions and station velocities at the mm- and mm/year level, respectively. ITRF users benefit from this development in various ways. For example, this new frame allows for embedding high accurate GNSS baseline observations to an underlying reference of at least the same accuracy. Another advantage is that the IGS products are fully consistent with this frame and therefore all GNSS based zero-difference positioning results (Precise Point Positioning (PPP)) will be aligned to the ITRF2013. Unfortunately the transistion to a new frame (or just to a new epoch) implies also issues in particular for providers and users of real time positioning services. Thus providers have to perform arrangements, such as the readjustment of the reference station coordinates and the update of the transformation parameters from the homogenous GNSS coordinate frame into the national datum. Finally providers have to inform their clients appropriately about these changes and significant adjustments. Furthermore the aspect of the continental reference frame has to be considered: In Europe the use of the continental reference system/reference frame ETRS89/ETRF2000 is, due to cross-national guidelines, recommend by most national mapping authorities. Subsequently GNSS post-processing applications are degraded by the concurrent use of the reference systems and reference frames, to which terrestrial site coordinates and satellite coordinates are aligned. In this presentation we highlight all significant steps and hurdles which have to be jumped over when introducing a new reference frame from point of view of a typical regional RTK-reference station network provider. This network is located in Austria and parts of the neighbouring countries and consists of about 40 reference stations. Moreover, we discuss the significance of permanently monitoring the stability of the reference network sites and the determination of station velocities/rates for geodynamical investigations.

Current Trends in Satellite Laser Ranging

NASA Technical Reports Server (NTRS)

Pearlman, M. R.; Appleby, G. M.; Kirchner, G.; McGarry, J.; Murphy, T.; Noll, C. E.; Pavlis, E. C.; Pierron, F.

2010-01-01

Satellite Laser Ranging (SLR) techniques are used to accurately measure the distance from ground stations to retroreflectors on satellites and the moon. SLR is one of the fundamental techniques that define the international Terrestrial Reference Frame (iTRF), which is the basis upon which we measure many aspects of global change over space, time, and evolving technology. It is one of the fundamental techniques that define at a level of precision of a few mm the origin and scale of the ITRF. Laser Ranging provides precision orbit determination and instrument calibration/validation for satellite-borne altimeters for the better understanding of sea level change, ocean dynamics, ice budget, and terrestrial topography. Laser ranging is also a tool to study the dynamics of the Moon and fundamental constants. Many of the GNSS satellites now carry retro-reflectors for improved orbit determination, harmonization of reference frames, and in-orbit co-location and system performance validation. The GNSS Constellations will be the means of making the reference frame available to worldwide users. Data and products from these measurements support key aspects of the GEOSS 10-Year implementation Plan adopted on February 16, 2005, The ITRF has been identified as a key contribution of the JAG to GEOSS and the ILRS makes a major contribution for its development since its foundation. The ILRS delivers weekly additional realizations that are accumulated sequentially to extend the ITRF and the Earth Orientation Parameter (EOP) series with a daily resolution. Additional products are currently under development such as precise orbits of satellites, EOP with daily availability, low-degree gravitational harmonics for studies of Earth dynamics and kinematics, etc. SLR technology continues to evolve toward the next generation laser ranging systems as programmatic requirements become more stringent. Ranging accuracy is improving as higher repetition rate, narrower pulse lasers and faster detectors are implemented. Automation and pass interleaving at some stations is already expanding temporal coverage. Web-based safety keys are allowing the SLR network stations to range to optically vulnerable satellites. Some stations are experimenting with two-wavelength operation as a means of better understanding the atmospheric refraction and with very low power laser to improve eye-safety conditions. New retroreflector designs are improving the signal link and enable daylight ranging. Dramatic improvements have also been made with lunar ranging with the new APOLLO Site in New ?Mexico, USA and the upgraded lunar station "MEO" in Grasse,

Water Resources Data, Alabama, Water Year 2002

USGS Publications Warehouse

Pearman, J.L.; Stricklin, V.E.; Psinakis, W.L.

2003-01-01

Water resources data for the 2002 water year for Alabama consist of records of stage, discharge, and water quality of streams; stages and contents of lakes and reservoirs; and water levels in wells. This report includes records on both surface and ground water in the State. Specifically, it contains: (1) discharge records for 131 streamflow-gaging stations, for 41 partial-record or miscellaneous streamflow stations; (2) stage and content records for 14 lakes and reservoirs and stage at 47 stations; (3) water-quality records for 12 streamflow-gaging stations, for 17 ungaged streamsites, and for 2 precipitation stations; (4) water temperature at 14 surfacewater stations; (5) specific conductance and dissolved oxygen at 12 stations; (6) turbidity at 3 stations; (7) sediment data at 6 stations; (8) water-level records for 2 recording observation wells; and (9) water-quality records for 21 ground-water stations. Also included are lists of active and discontinued continuous-record surface-water-quality stations, and partial-record and miscellaneous surface-water-quality stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Alabama.

Water Resources Data, Alabama, Water Year 2003

USGS Publications Warehouse

Psinakis, W.L.; Lambeth, D.S.; Stricklin, V.E.; Treece, M.W.

2004-01-01

Water resources data for the 2003 water year for Alabama consist of records of stage, discharge, and water quality of streams; stages and contents of lakes and reservoirs; and water levels in wells. This report includes records on both surface and ground water in the State. Specifically, it contains: (1) discharge records for 130 streamflow-gaging stations, for 29 partial-record or miscellaneous streamflow stations; (2) stage and content records for 14 lakes and reservoirs and stage at 46 stations; (3) water-quality records for 12 streamflow-gaging stations, for 29 ungaged streamsites, and for 1 precipitation stations; (4) water temperature at 12 surfacewater stations; (5) specific conductance and dissolved oxygen at 12 stations; (6) turbidity at 3 stations; (7) sediment data at 6 stations; (8) water-level records for 2 recording observation wells; and (9) water-quality records for 9 ground-water stations. Also included are lists of active and discontinued continuous-record surface-water-quality stations, and partial-record and miscellaneous surface-water-quality stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Alabama.

Water Resources Data, Alabama, Water Year 2004

USGS Publications Warehouse

Psinakis, W.L.; Lambeth, D.S.; Stricklin, V.E.; Treece, M.W.

2005-01-01

Water resources data for the 2004 water year for Alabama consist of records of stage, discharge, and water quality of streams; stages and contents of lakes and reservoirs; and water levels in wells. This report includes records on both surface and ground water in the State. Specifically, it contains: (1) discharge records for 131 streamflow-gaging stations, for 19 partial-record or miscellaneous streamflow stations; (2) stage and content records for 16 lakes and reservoirs and stage at 44 stations; (3) water-quality records for 21 streamflow-gaging stations, for 11 ungaged streamsites, and for 1 precipitation stations; (4) water temperature at 20 surface-water stations; (5) specific conductance and dissolved oxygen at 20 stations; (6) turbidity at 5 stations; (7) sediment data at 6 stations; (8) water-level records for 2 recording observa-tion wells; and (9) water-quality records for 6 ground-water stations. Also included are lists of active and discontinued continuous-record surface-water-quality stations, and partial-record and miscellaneous sur-face-water-quality stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Alabama.

Water Resources Data, Alabama, Water Year 2005

USGS Publications Warehouse

Psinakis, W.L.; Lambeth, D.S.; Stricklin, V.E.; Treece, M.W.

2006-01-01

Water resources data for the 2005 water year for Alabama consist of records of stage, discharge, and water quality of streams; stages and contents of lakes and reservoirs; and water levels in wells. This report includes records on both surface and ground water in the State. Specifically, it contains: (1) discharge records for 131 streamflow-gaging stations and 23 partial-record or miscellaneous streamflow stations; (2) stage and content records for 14 lakes and reservoirs and stage at 44 stations; (3) water-quality records for 125 streamflow-gaging stations and 67 ungaged streamsites; (4) water temperature at 179 surface-water stations; (5) specific conductance at 180 stations; (6) dissolved oxygen at 17 stations; (7) turbidity at 52 stations; (8) sediment data at 2 stations; (9) water-level records for 2 recording observation wells; and (10) water-quality records for 6 ground-water stations. Also included are lists of active and discontinued continuous-record surface-water-quality stations, and partial-record and miscellaneous surface- water-quality stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Alabama.

LANDSAT-4 to ground station interface description

NASA Technical Reports Server (NTRS)

1983-01-01

The LANDSAT 4 to ground station interface is described in detail. The radiometric specifications, internal calibration, sensor output format, and data processing constants for the multispectral scanner and the thematic mapper are discussed. The mission payload telemetry, onboard computer telemetry, and engineering telemetry formats are described. In addition, the telemetry time signals and the onboard clock resetting procedure are addressed.

A new venous infusion pathway monitoring system.

PubMed

Maki, Hiromichi; Yonezawa, Yoshiharu; Ogawa, Hidekuni; Ninomiya, Ishio; Sata, Koji; Hamada, Shingo; Caldwell, W Morton

2007-01-01

A new infusion catheter pathway monitoring system employing linear integrated circuits and a low-power 8-bit single chip microcomputer has been developed for hospital and home use. The sensor consists of coaxial three-layer conductive tapes wrapped around the polyvinyl chloride infusion tube. The inner tape is the main electrode, which records an AC (alternating current) voltage induced on the patient's body by electrostatic coupling from the normal 100 volt, 60 Hz AC power line wiring field in the patient's room. The outside tape layer is a reference electrode to monitor the AC voltage around the main electrode. The center tape layer is connected to system ground and functions as a shield. The microcomputer calculates the ratio of the induced AC voltages recorded by the main and reference electrodes and if the ratio indicates a detached infusion, alerts the nursing station, via the nurse call system or low transmitting power mobile phone.

KA-102 Film/EO Standoff System

NASA Astrophysics Data System (ADS)

Turpin, Richard T.

1984-12-01

The KA-102 is an in-flight selectable film or electro-optic (EU) visible reconnaissance camera with a real-time data link. The lens is a 66-in., f/4 refractor with a 4° field-of-view. The focal plane is a continuous line array of 10,240 COD elements that opera tes in the pushbroom mode. In the film mode, the camera use standard 5-in.-wide 3414 or 3412 film. The E0 imagery is transmitted up to 500 n.mi. to the ground station over a 75-Mbit/sec )(- band data link via a relay aircraft (see Figure 1). The camera may be controlled from the ground station via an uplink or from the cockpit control panel. The 8-ft-diameter ground tracking antenna is located on high ground and linked to the ground station via a 1-mile-long, two-way fiber optic system. In the ground station the imagery is calibrated and displayed in real time on three crt's. Selected imagery may be stored on disk and enhanced, analyzed, and annotated in near-real-time. The imagery may be enhanced and magnified in real time. Hardcopy frames may be made on 8 x 10-in. Polaroid, 35-1m film, or dry silver paper. All the received image and engineering data is recorded on a high-density tape recorder. The aircraft track is recorded on a map plotter. Ground support equipment (GSE), manuals, spares, and training are included in the system. Falcon 20 aircraft were modified on a subcontract to Dynelectron--Ft. Worth.

47 CFR 22.807 - General aviation air-ground application requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 2 2011-10-01 2011-10-01 false General aviation air-ground application... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.807 General aviation air-ground application requirements. In addition to the information...

47 CFR 22.807 - General aviation air-ground application requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 2 2014-10-01 2014-10-01 false General aviation air-ground application... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.807 General aviation air-ground application requirements. In addition to the information...

47 CFR 22.807 - General aviation air-ground application requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 2 2012-10-01 2012-10-01 false General aviation air-ground application... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.807 General aviation air-ground application requirements. In addition to the information...

47 CFR 22.807 - General aviation air-ground application requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 2 2013-10-01 2013-10-01 false General aviation air-ground application... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.807 General aviation air-ground application requirements. In addition to the information...

47. Aerial view of station in 1956, three years after ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

47. Aerial view of station in 1956, three years after the National Park Service (NPS) acquired the grounds. Photographer unknown. - Bodie Island Light Station, Off Highway 12, Nags Head, Dare County, NC

Study of flywheel energy storage for space stations

NASA Technical Reports Server (NTRS)

Gross, S.

1984-01-01

The potential of flywheel systems for space stations using the Space Operations Center (SOC) as a point of reference is discussed. Comparisons with batteries and regenerative fuel cells are made. In the flywheel energy storage concept, energy is stored in the form of rotational kinetic energy using a spinning wheel. Energy is extracted from the flywheel using an attached electrical generator; energy is provided to spin the flywheel by a motor, which operates during sunlight using solar array power. The motor and the generator may or may not be the same device. Flywheel energy storage systems have a very good potential for use in space stations. This system can be superior to alkaline secondary batteries and regenerable fuel cells in most of the areas that are important in spacecraft applications. Of special impotance relative to batteries, are high energy density (lighter weight), longer cycle and operating life, and high efficiency which minimizes the amount of orbital makeup fuel required. In addition, flywheel systems have a long shelf life, give a precise state of charge indication, have modest thermal control needs, are capable of multiple discharges per orbit, have simple ground handling needs, and have the potential for very high discharge rate. Major disadvantages are noted.

Simulating air temperature in an urban street canyon in all weather conditions using measured data at a reference meteorological station

NASA Astrophysics Data System (ADS)

Erell, E.; Williamson, T.

2006-10-01

A model is proposed that adapts data from a standard meteorological station to provide realistic site-specific air temperature in a city street exposed to the same meso-scale environment. In addition to a rudimentary description of the two sites, the canyon air temperature (CAT) model requires only inputs measured at standard weather stations; yet it is capable of accurately predicting the evolution of air temperature in all weather conditions for extended periods. It simulates the effect of urban geometry on radiant exchange; the effect of moisture availability on latent heat flux; energy stored in the ground and in building surfaces; air flow in the street based on wind above roof height; and the sensible heat flux from individual surfaces and from the street canyon as a whole. The CAT model has been tested on field data measured in a monitoring program carried out in Adelaide, Australia, in 2000-2001. After calibrating the model, predicted air temperature correlated well with measured data in all weather conditions over extended periods. The experimental validation provides additional evidence in support of a number of parameterisation schemes incorporated in the model to account for sensible heat and storage flux.

Spawning characteristics of Clupea pallasii in the coastal waters off Gyeongnam, Korea, during spawning season

NASA Astrophysics Data System (ADS)

Lee, Yong-Deuk; Choi, Jung Hwa; Moon, Seong Yong; Lee, Sun Kil; Gwak, Woo-Seok

2017-12-01

The purpose of this study is to research the characteristics of spawning grounds of Clupea pallasii found at 1 spawning ground located in the coast of Yeongun-ri, Tongyeong, Gyeongnam, and 3 stations in Jinhae Bay. Diving observation was performed from January to June, 2014 at the coast of Yeongun-ri, and from February to June, 2016 at Jinhae Bay after total 4 stations (A: Gusan-myeon, B: Haengamdong, C: Hacheong-myeon, D: Jam-do) were constituted. During observation period, 1 spawning ground was found in Tongyeong area in January. In Jinhae Bay spawning grounds were found at 3 stations (A, B, D) out of 4 stations in February. Regarding the surrounding environment of spawning ground found at Yeongunri, Tongyeong, various kinds of seaweeds were distributed up to 1-5 m depth, and many branch type red algae were distributed. In case of Jinhae Bay, seaweeds were widely distributed from shallow water to 5 m depth. In addition, the scope that eggs were attached was considerably wide compared to Tongyeong area, and they were found at all the 3 spots, so C. pallasii is thought to use Jinhae Bay for its spawning ground widely. Eggs were attached from the surface to 3-4 m, and like Tongyeong area, eggs were attached to mostly branch type of red algae. The results of this study suggest that the spawning season of the C. pallasii in coast waters off Gyeongnam is until mid-February.

Hydrologic effects of the earthquake of March 27, 1964, outside Alaska, with sections on Hydroseismograms from the Nunn-Bush Shoe Co. well, Wisconsin, and Alaska earthquake effects on ground water in Iowa: Chapter C in The Alaska earthquakes, March 27, 1964: effects on hydrologic regimen

USGS Publications Warehouse

Vorhis, Robert C.; Rexin, Elmer E.; Coble, R.W.

1967-01-01

The Alaska earthquake of March 27, 1964, had widespread hydrologic effects throughout practically all of the United States. More than 1,450 water-level recorders, scattered throughout all the 50 States except Connecticut, Delaware, and Rhode Island, registered the earthquake. Half of the water-level records were obtained from ground-water observation wells and half at surface-water gaging stations. The earthquake is also known to have registered on water-level recorders on wells in Canada, England, Denmark, Belgium, Egypt, Israel, Libya, Philippine Islands, South-West Africa, South Africa, and Northern Territory of Australia. The Alaska earthquake is the first for which widespread surface-water effects are known. The effects were recorded at stations on flowing streams, rivers, reservoirs, lakes, and ponds. The 755 surface-water stations recording effects are spread through 38 States, but are most numerous in the south-central and southeastern States, especially in Florida and Louisiana. Most of the fluctuations recorded can be referred to more precisely as seismic seiches; however, a few stations recorded the quake as a minor change in stage. The largest recorded seiche outside Alaska was 1.83 feet on a reservoir in Michigan. The next largest was 1.45 feet on Lake Ouachita in Arkansas. The largest fluctuation in a well was 23 feet registered by a pressure recorder near Belle Fourche, S. Dak. Fluctuations of more than 10 feet were reported from wells in Alabama, Florida, Georgia, Illinois, Missouri, and Pennsylvania. A 3.40-foot fluctuation was recorded in a well in Puerto Rico. The Alaska earthquake was registered by about seven times as many water-level recorders as recorded the Hebgen Lake, Mont., earthquake of August 19, 1959.

Non-Gimbaled Antenna Pointing: Summary of Results and Analysis

NASA Technical Reports Server (NTRS)

Horan, Stephen

1998-01-01

There is considerable interest at this time in developing small satellites for quick-turnaround missions to investigate near-earth phenomena from space. One problem to be solved in mission planning is the means of communication between the control infrastructure in the ground segment and the satellite in the space segment. A nominal small-satellite mission design often includes an omni-directional or similar wide-pattern antenna on the satellite and a dedicated ground station for telemetry, tracking, and command support. These terminals typically provide up to 15 minutes of coverage during an orbit that is within the visibility of the ground station; however, not all orbits will pass over the ground station so that coverage gaps will exist in the data flow. To overcome this general limitation on data transmission for low-earth orbiting satellites, the Space Network (SN), operated by the National Aeronautics and Space Administration, (NASA) has been designed to transmit data to and from user satellites through the Tracking and Data Relay Satellites (TDRS) in geostationary orbit and interfacing to the White Sands Complex (WSC) in New Mexico for the data's ground entry point. The advantage of the SN over a fixed ground station is that all low-earth-satellite orbits will be within the visibility area of at least one TDRS within the SN for a large part of the orbit and the potential exists to establish a communications link if the user satellite can point an antenna in the direction of any one of the relay satellites. Within NASA, there is considerable interest in seeing that small satellite developers are aware of the advantages to the SN and that designs to include the SN are part of the satellite design. Small satellite users have not often considered using the SN because of: (1) The 26-dB link penalty differential between direct broadcast to a ground station and transmission through a TDRS to the ground; (2) The class of satellite is too small to support high-gain antennas and associated attitude control and drive electronics; (3) The class of satellites is severely weight and power limited; (4) There are perceived problems in scheduling communications for this class of user on the SN. This report addresses the potential for SN access using non-gimbaled, i.e. fixed-pointed, antennas in the design of the small satellite using modest transmission power to achieve the necessary space-to-ground transmissions. The advantage of using the SN is in the reduction of mission costs arising from using the SN infrastructure instead of a dedicated, proprietary ground station using a similar type of communications package. From the simulations and analysis presented, we will show that a modest satellite configuration can be used with the space network to achieve the data transmission goals of a number of users and thereby rival the performance achieved with proprietary ground stations. In this study, we will concentrate on the return data link (from the user satellite through a TDRS to the ground data entry point). The forward command link (from the ground data entry point through a TDRS to the user satellite) will usually be a lower data rate service and the data volume will also be considerably lower than the return link's requirement. Therefore, we assume that if the return link requirements are satisfied, then the forward link requirements can also be satisfied.

New precise astrometric observations of Nereid in 2012-2017

NASA Astrophysics Data System (ADS)

Yu, Y.; Qiao, R. C.; Yan, D.; Cheng, X.; Xi, X. J.; Tang, K.; Luo, H.

2018-03-01

Nereid is one of the most distinctive natural satellites that we know in the Solar system. The orbit of Nereid is highly eccentric and inclined with respect to the equator of its primary, Neptune. Studying Nereid is one of the inspiring ways to acquire better knowledge of the Solar system. Due to its faintness, the ground-based observations of Nereid have been limited and the observation precisions in the past were generally not high. A total of 150 new observed positions of Nereid in the period 2012-2017 were collected by the 0.8 m reflecting telescope at Xinglong station of National Astronomical Observatory and the 2.4 m reflecting telescope at Lijiang station of Yunnan Astronomical Observatory. Thanks to the high-quality reference catalogue Gaia DR1 and suitable processing methods for images, the precision of our new observations of Nereid is 2-3 times higher than those of the previous observations, and the dispersions of our observations are better than 70 mas.

Space Communication and Navigation SDR Testbed, Overview and Opportunity for Experiments

NASA Technical Reports Server (NTRS)

Reinhart, Richard C.

2013-01-01

NASA has developed an experimental flight payload (referred to as the Space Communication and Navigation (SCAN) Test Bed) to investigate software defined radio (SDR) communications, networking, and navigation technologies, operationally in the space environment. The payload consists of three software defined radios each compliant to NASAs Space Telecommunications Radio System Architecture, a common software interface description standard for software defined radios. The software defined radios are new technology developments underway by NASA and industry partners launched in 2012. The payload is externally mounted to the International Space Station truss to conduct experiments representative of future mission capability. Experiment operations include in-flight reconfiguration of the SDR waveform functions and payload networking software. The flight system will communicate with NASAs orbiting satellite relay network, the Tracking and Data Relay Satellite System at both S-band and Ka-band and to any Earth-based compatible S-band ground station. The system is available for experiments by industry, academia, and other government agencies to participate in the SDR technology assessments and standards advancements.

47 CFR 95.25 - Land station description.

Code of Federal Regulations, 2011 CFR

2011-10-01

...). (b) The point from which every land station transmits must be within an area where radio services are... antenna no more than 6.1 meters (20 feet) above the ground or above the building or tree on which it is... the ground or above the building or tree on which it is mounted (see § 95.51); and (2) Transmits with...

47 CFR 95.25 - Land station description.

Code of Federal Regulations, 2014 CFR

2014-10-01

...). (b) The point from which every land station transmits must be within an area where radio services are... antenna no more than 6.1 meters (20 feet) above the ground or above the building or tree on which it is... the ground or above the building or tree on which it is mounted (see § 95.51); and (2) Transmits with...

47 CFR 95.25 - Land station description.

Code of Federal Regulations, 2010 CFR

2010-10-01

...). (b) The point from which every land station transmits must be within an area where radio services are... antenna no more than 6.1 meters (20 feet) above the ground or above the building or tree on which it is... the ground or above the building or tree on which it is mounted (see § 95.51); and (2) Transmits with...

Water Resources Data - New Jersey, Water Year 1999, Volume 3, Water-Quality Data

USGS Publications Warehouse

DeLuca, M.J.; Romanok, K.M.; Riskin, M.L.; Mattes, G.L.; Thomas, A.M.; Gray, B.J.

2000-01-01

Water-resources data for the 1999 water year for New Jersey are presented in three volumes, and consists of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs; and water levels and water quality of ground water. Volume 3 contains a summary of surface and ground water hydrologic conditions for the 1999 water year, a listing of current water-resource projects in New Jersey, a bibliography of water-related reports, articles, and fact sheets for New Jersey completed by the Geological Survey in recent years, water-quality records of chemical analyses from 133 surface-water stations, 46 miscellaneous surface-water sites, 30 ground-water stations, 41 miscellaneous ground-water sites, and records of daily statistics of temperature and other physical measurements from 17 continuous-monitoring stations. Locations of water-quality stations are shown in figures 11 and 17-20. Locations of miscellaneous water-quality sites are shown in figures 29-32 and 34. These data represent the part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in New Jersey.

Steerable Space Fed Lens Array for Low-Cost Adaptive Ground Station Applications

NASA Technical Reports Server (NTRS)

Lee, Richard Q.; Popovic, Zoya; Rondineau, Sebastien; Miranda, Felix A.

2007-01-01

The Space Fed Lens Array (SFLA) is an alternative to a phased array antenna that replaces large numbers of expensive solid-state phase shifters with a single spatial feed network. SFLA can be used for multi-beam application where multiple independent beams can be generated simultaneously with a single antenna aperture. Unlike phased array antennas where feed loss increases with array size, feed loss in a lens array with more than 50 elements is nearly independent of the number of elements, a desirable feature for large apertures. In addition, SFLA has lower cost as compared to a phased array at the expense of total volume and complete beam continuity. For ground station applications, both of these tradeoff parameters are not important and can thus be exploited in order to lower the cost of the ground station. In this paper, we report the development and demonstration of a 952-element beam-steerable SFLA intended for use as a low cost ground station for communicating and tracking of a low Earth orbiting satellite. The dynamic beam steering is achieved through switching to different feed-positions of the SFLA via a beam controller.

A low-cost transportable ground station for capture and processing of direct broadcast EOS satellite data

NASA Technical Reports Server (NTRS)

Davis, Don; Bennett, Toby; Short, Nicholas M., Jr.

1994-01-01

The Earth Observing System (EOS), part of a cohesive national effort to study global change, will deploy a constellation of remote sensing spacecraft over a 15 year period. Science data from the EOS spacecraft will be processed and made available to a large community of earth scientists via NASA institutional facilities. A number of these spacecraft are also providing an additional interface to broadcast data directly to users. Direct broadcast of real-time science data from overhead spacecraft has valuable applications including validation of field measurements, planning science campaigns, and science and engineering education. The success and usefulness of EOS direct broadcast depends largely on the end-user cost of receiving the data. To extend this capability to the largest possible user base, the cost of receiving ground stations must be as low as possible. To achieve this goal, NASA Goddard Space Flight Center is developing a prototype low-cost transportable ground station for EOS direct broadcast data based on Very Large Scale Integration (VLSI) components and pipelined, multiprocessing architectures. The targeted reproduction cost of this system is less than $200K. This paper describes a prototype ground station and its constituent components.

Space Station reference configuration description

NASA Technical Reports Server (NTRS)

1984-01-01

The data generated by the Space Station Program Skunk Works over a period of 4 months which supports the definition of a Space Station reference configuration is documented. The data were generated to meet these objectives: (1) provide a focal point for the definition and assessment of program requirements; (2) establish a basis for estimating program cost; and (3) define a reference configuration in sufficient detail to allow its inclusion in the definition phase Request for Proposal (RFP).

Design and operation of a Loran-C time reference station

NASA Technical Reports Server (NTRS)

Putkovich, K.

1974-01-01

Some of the practical questions that arise when one decides to use Loran-C in a time reference system are explored. An extensive effort is made to provide basic, practical information on establishing and operating a reference station. Four areas were covered: (1) the design, configuration and operational concepts which should be considered prior to establishing and operating a reference station using Loran-C, (2) the options and tradeoffs available regarding capabilities, cost, size, versatility, ease of operation, etc., that are available to the designer, (3) what measurements are made, how they are made and what they mean, and (4) the experience the U.S. Naval Observatory Time Service Division has had in the design and operation of such stations.

Terrestrial Reference Frame from GPS and SLR

NASA Astrophysics Data System (ADS)

Weiss, Jan; Bertiger, Willy; Desai, Shailen; Haines, Bruce; Sibois, Aurore

2015-04-01

We present strategies for realizing the terrestrial reference frame (TRF) using tracking data from terrestrial GPS receivers alone and in tandem with the GRACE and LAGEOS satellites. We generate solutions without apriori ties to the International Terrestrial Reference Frame (ITRF). Our approach relies on processing multi-day orbit arcs to take advantage of the satellite dynamics, GPS receiver and transmitter calibrations derived from low-Earth orbiter (LEO) data, and estimation strategies tuned for realizing a stable and accurate TRF. We furthermore take advantage of the geometric diversity provided by GPS tracking from GRACE, and explore the impacts of including ground-based satellite laser range (SLR) measurements to LAGEOS-1 and -2 with local ties relating the two geodetic techniques. We process data from 2003-2014 and compute Helmert transformations relative to ITRF/IGb08. With GPS alone we achieve a 3D origin offset and rate of <7 mm and <1 mm/yr, and reduce the offset to <4 mm when GRACE is included in the global solutions. Scale bias and rate are 3.1 ppb and 0.01 ppb/yr in either solution. Including SLR tracking from 11 ground stations to the LAGEOS satellites from 2012-2014 yields a reduction in scale bias of 0.5-1.0 ppb depending on the weight assigned to the SLR measurements. However, scatter is increased due to the relatively sparse SLR tracking network. We conclude with approaches for improving the TRF realized from GPS and SLR combined at the measurement level.

47 CFR 22.805 - Channels for general aviation air-ground service.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 2 2013-10-01 2013-10-01 false Channels for general aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.805 Channels for general aviation air-ground service. The following channels are allocated...

47 CFR 22.805 - Channels for general aviation air-ground service.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 2 2012-10-01 2012-10-01 false Channels for general aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.805 Channels for general aviation air-ground service. The following channels are allocated...

47 CFR 22.805 - Channels for general aviation air-ground service.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 2 2014-10-01 2014-10-01 false Channels for general aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.805 Channels for general aviation air-ground service. The following channels are allocated...

47 CFR 22.805 - Channels for general aviation air-ground service.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 2 2011-10-01 2011-10-01 false Channels for general aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.805 Channels for general aviation air-ground service. The following channels are allocated...

47 CFR 22.805 - Channels for general aviation air-ground service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Channels for general aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service General Aviation Air-Ground Stations § 22.805 Channels for general aviation air-ground service. The following channels are allocated...

Interoperable web applications for sharing data and products of the International DORIS Service

NASA Astrophysics Data System (ADS)

Soudarin, L.; Ferrage, P.

2017-12-01

The International DORIS Service (IDS) was created in 2003 under the umbrella of the International Association of Geodesy (IAG) to foster scientific research related to the French satellite tracking system DORIS and to deliver scientific products, mostly related to the International Earth rotation and Reference systems Service (IERS). Since its start, the organization has continuously evolved, leading to additional and improved operational products from an expanded set of DORIS Analysis Centers. In addition, IDS has developed services for sharing data and products with the users. Metadata and interoperable web applications are proposed to explore, visualize and download the key products such as the position time series of the geodetic points materialized at the ground tracking stations. The Global Geodetic Observing System (GGOS) encourages the IAG Services to develop such interoperable facilities on their website. The objective for GGOS is to set up an interoperable portal through which the data and products produced by the IAG Services can be served to the user community. We present the web applications proposed by IDS to visualize time series of geodetic observables or to get information about the tracking ground stations and the tracked satellites. We discuss the future plans for IDS to meet the recommendations of GGOS. The presentation also addresses the needs for the IAG Services to adopt common metadata thesaurus to describe data and products, and interoperability standards to share them.

Configuration management and software measurement in the Ground Systems Development Environment (GSDE)

NASA Technical Reports Server (NTRS)

Church, Victor E.; Long, D.; Hartenstein, Ray; Perez-Davila, Alfredo

1992-01-01

A set of functional requirements for software configuration management (CM) and metrics reporting for Space Station Freedom ground systems software are described. This report is one of a series from a study of the interfaces among the Ground Systems Development Environment (GSDE), the development systems for the Space Station Training Facility (SSTF) and the Space Station Control Center (SSCC), and the target systems for SSCC and SSTF. The focus is on the CM of the software following delivery to NASA and on the software metrics that relate to the quality and maintainability of the delivered software. The CM and metrics requirements address specific problems that occur in large-scale software development. Mechanisms to assist in the continuing improvement of mission operations software development are described.

Water Resources Data, Nebraska, Water Year 2003

USGS Publications Warehouse

Hitch, D.E.; Hull, S.H.; Walczyk, V.C.; Miller, J.D.; Drudik, R.A.

2004-01-01

The Nebraska water resources data report for water year 2003 includes records of stage, discharge, and water quality of streams; water elevation and/or contents of lakes and reservoirs; and water levels and quality of ground water in wells. This report contains records of stream stage for 3 stations; stream discharge for 103 continuous and 5 crest-stage gaging stations, and 5 miscellaneous sites; stream water quality for 14 gaging stations and 5 miscellaneous sites; water elevation and/or contents for 2 lakes and 1 reservoir; ground-water levels for 40 observation wells; and ground-water quality for 132 wells. These data represent that part of the National Water Data System collected in and near Nebraska by the U.S. Geological Survey and cooperating local, State, and Federal agencies.

Water resources data, Nebraska, water year 2004

USGS Publications Warehouse

Hitch, D. E.; Soensken, P.J.; Sebree, S.K.; Wilson, K.E.; Walczyk, V.C.; Drudik, R.A.; Miller, J.D.; Hull, S.H.

2005-01-01

The Nebraska water resources data report for water year 2004 includes records of stage, discharge, and water quality of streams; water elevation and/or contents of lakes and reservoirs; and water levels and quality of ground water in wells. This report contains records of stream stage for 3 stations; stream discharge for 101 continuous and 5 crest-stage gaging stations, and 6 miscellaneous sites; stream water quality for 7 gaging stations and 40 miscellaneous sites; water elevation and/or contents for 2 lakes and 1 reservoir; ground-water levels for 74 observation wells; and ground-water quality for 200 wells. These data represent that part of the National Water Data System collected in and near Nebraska by the U.S. Geological Survey and cooperating Federal, State, and local agencies.

Veg-03 Ground Harvest

NASA Image and Video Library

2016-12-05

Inside the Veggie flight laboratory in the Space Station Processing Facility at NASA’s Kennedy Space Center in Florida, Matthew Romeyn, a NASA Pathways intern from the University of Edinburgh in Scotland, harvests a portion of the 'Outredgeous' red romaine lettuce from the Veg-03 ground control unit. The purpose of the ground Veggie system is to provide a control group to compare against the lettuce grown in orbit on the International Space Station. Veg-03 will continue NASA’s deep space plant growth research to benefit the Earth and the agency’s journey to Mars.

Observation and modeling of compressional Pi 3 magnetic pulsations

NASA Technical Reports Server (NTRS)

Matsuoka, Hitoshi; Takahashi, K.; Yumoto, K.; Anderson, B. J.; Sibeck, D. G.

1995-01-01

Compressional magnetic pulsations with irregular waveforms and periods longer than 150 s (here termed Pi 3) have been studied by using data from Active Magnetospheric Particle Tracer Explorers Charge Composition Explorer (AMPTE/CCE) and GOES 5 and 6 in the dayside magnetosphere and compared with signatures on the ground at low latitudes by using data from Kakioka station (L = 1.25). On the ground, the pulsations appear in the horizontal component. A study of 17 such concurrent events during a 2-month period in 1986 reveals the following pulsation characteristics. (1) The peak-to-peak amplitudes in space (delta B(sub T)) and on the ground (delta H) are comparable and are in the range of 0.5-7 nT. (2) On the ground the pulsations can be seen at all local times, even at midnight, while at geostationary orbit they are observed only on the dayside with a clear amplitude maximum at noon. (3) The pulsations on the ground lag those observed by CCE near local noon, and the lag increases as the local time separation between CCE and the ground station increases. The time lag is 1-2 min longer when the ground station is on the nightside than when it is on the dayside. (4) The time lag between pulsations observed at geostationary orbit and near noon by CCE varies systematically with local time and is about 2 min per 6 hours of local time separation. These observations indicate that some nightside pulsations in the Pi 3 band have dayside origins. The position dependence of the pulsation amplitude can be explained well by changes in the magnetopause current, which are in turn presumably caused by changes in the solar wind dynamic pressure. The time lags observed in space are consistent with signal propagation in the MHD fast mode, but the variation in space-ground time lags with ground station local time must be attributed to another mechanism.

Ground motion amplification at rock sites: the competing role of topography and fractured rocks in the San Giovanni fault, central Italy

NASA Astrophysics Data System (ADS)

Pischiutta, M.; Cara, F.; Di Giulio, G.; Vassallo, M.; Cultrera, G.

2017-12-01

Amplification at rock sites in areas of high topographic relief has been increasingly observed in the last years, with unexpected level of damage after strong earthquakes. In regions affected by recent tectonic activity, topographic irregularities can include fault damage zones. In such conditions, seismic waves can be locally amplified as a double effect of wave focusing along the topography and /or the presence of fractures/joints or locally weakened rocks. The role of topography vs. geological complexities in controlling the ground motion amplification at rock sites is a newly debated issue in the seismological community. The most crucial questions regard what is the real contribution of the topography shape and fracturing, and how to parameterize such effects for their inclusion in the seismic design codes. In this framework, the EMERSITO INGV task force installed 7 seismic stations across the San Giovanni fault, after the Amatrice mainshock of the 2016 sequence in Central Italy. This active normal fault is located in the area of the Montereale intermountain basin (Abruzzi region, Italy) and bounds the southwestern slope of Mt. Mozzano, a roughly 2D-shaped, up to 1450 m high pronounced topography. Moreover, this fault has been recently studied by several authors who performed detailed geological and geophysical surveys. Our stations recorded more than 100 earthquakes with magnitude ranging from 2.5 to 3.9 as well as a 4.4 M earthquake with hypocenter in Capitignano district, few kilometres far. We have analyzed in detail the recorded signals calculating the traditional spectral ratios at single station (HVSRs) and using the reference site (SSRs) using both ambient noise and earthquakes. In order to obtain a robust estimate of the site amplification effect at each station, we have investigated the influence of backazimuth and epicentral distance. We have also applied the time-domain covariance matrix analysis and the frequency domain polarization analysis. We have found that, in spite of the complexity of the seismic data, the observed polarization pattern is generally oriented orthogonal to the ridge elongation, as well as to the fault strike, suggesting the existence of a high angle relation between ground motion polarization and fracture systems.

TDRSS data handling and management system study. Ground station systems for data handling and relay satellite control

NASA Technical Reports Server (NTRS)

1973-01-01

Results of a two-phase study of the (Data Handling and Management System DHMS) are presented. An original baseline DHMS is described. Its estimated costs are presented in detail. The DHMS automates the Tracking and Data Relay Satellite System (TDRSS) ground station's functions and handles both the forward and return link user and relay satellite data passing through the station. Direction of the DHMS is effected via a TDRSS Operations Control Central (OCC) that is remotely located. A composite ground station system, a modified DHMS (MDHMS), was conceptually developed. The MDHMS performs both the DHMS and OCC functions. Configurations and costs are presented for systems using minicomputers and midicomputers. It is concluded that a MDHMS should be configured with a combination of the two computer types. The midicomputers provide the system's organizational direction and computational power, and the minicomputers (or interface processors) perform repetitive data handling functions that relieve the midicomputers of these burdensome tasks.

KSC ground operations planning for Space Station

NASA Technical Reports Server (NTRS)

Lyon, J. R.; Revesz, W., Jr.

1993-01-01

At the Kennedy Space Center (KSC) in Florida, processing facilities are being built and activated to support the processing, checkout, and launch of Space Station elements. The generic capability of these facilities will be utilized to support resupply missions for payloads, life support services, and propellants for the 30-year life of the program. Special Ground Support Equipment (GSE) is being designed for Space Station hardware special handling requirements, and a Test, Checkout, and Monitoring System (TCMS) is under development to verify that the flight elements are ready for launch. The facilities and equipment used at KSC, along with the testing required to accomplish the mission, are described in detail to provide an understanding of the complexity of operations at the launch site. Assessments of hardware processing flows through KSC are being conducted to minimize the processing flow times for each hardware element. Baseline operations plans and the changes made to improve operations and reduce costs are described, recognizing that efficient ground operations are a major key to success of the Space Station.

Tightly-coupled real-time analysis of GPS and accelerometer data for translational and rotational ground motions and application to earthquake and tsunami early warning

NASA Astrophysics Data System (ADS)

Geng, J.; Bock, Y.; Melgar, D.; Hasse, J.; Crowell, B. W.

2013-12-01

High-rate GPS can play an important role in earthquake early warning (EEW) systems for large (>M6) events by providing permanent displacements immediately as they are achieved, to be used in source inversions that can be repeatedly updated as more information becomes available. This is most valuable to implement at a site very near the potential source rupture, where broadband seismometers are likely to clip, and accelerometer data cannot be objectively integrated to produce reliable displacements in real time. At present, more than 525 real-time GPS stations have been established in western North America, which are being integrated into EEW systems. Our analysis technique relies on a tightly-coupled combination of GPS and accelerometer data, an extension of precise point positioning with ambiguity resolution (PPP-AR). We operate a PPP service based on North American stations available through the IGS and UNAVCO/PBO. The service provides real-time satellite clock and fractional-cycle bias products that allow us to position individual client stations in the zone of deformation. The service reference stations are chosen to be further than 200 km from the primary zones of tectonic deformation in the western U.S. to avoid contamination of the satellite products during a large seismic event. At client stations, accelerometer data are applied as tight constraints on the positions between epochs in PPP-AR, which improves cycle-slip repair and rapid ambiguity resolution after GPS outages. Furthermore, we estimate site displacements, seismic velocities, and coseismic ground tilts to facilitate the analysis of ground motion characteristics and the inversion for source mechanisms. The seismogeodetic displacement and velocity waveforms preserves the detection of P wave arrivals, and provides P-wave arrival displacement that is key new information for EEW. Our innovative solution method for coseismic tilts mitigates an error source that has continually plagued strong motion data analysis, and has a resolution of about 0.01 degrees. At present, there are few collocations of GPS and accelerometers in western North America (the exception being the BARD network in northern California) so we have developed a cost-effective way to upgrade existing real-time GPS stations with low-cost MEMS accelerometers; fifteen PBO and SCIGN stations in southern California have already been upgraded. We demonstrate our method of recovering broadband displacement and tilt waveforms using 13 experiments from the single-axis George E. Brown Jr. Network for Earthquake Engineering Simulation Large High-Performance Outdoor Shake Table at the University of California San Diego. Then we apply the method to data from the 2010 Mw 7.2 El Mayor-Cucapah earthquake and the 2011 Mw 9.0 Tohoku-oki earthquake to illustrate the improvement over standard base-line correction acceleration techniques and to demonstrate the order of magnitude of tilt errors present in typical observations.

A calibrated, high-resolution goes satellite solar insolation product for a climatology of Florida evapotranspiration

USGS Publications Warehouse

Paech, S.J.; Mecikalski, J.R.; Sumner, D.M.; Pathak, C.S.; Wu, Q.; Islam, S.; Sangoyomi, T.

2009-01-01

Estimates of incoming solar radiation (insolation) from Geostationary Operational Environmental Satellite observations have been produced for the state of Florida over a 10-year period (1995-2004). These insolation estimates were developed into well-calibrated half-hourly and daily integrated solar insolation fields over the state at 2 km resolution, in addition to a 2-week running minimum surface albedo product. Model results of the daily integrated insolation were compared with ground-based pyranometers, and as a result, the entire dataset was calibrated. This calibration was accomplished through a three-step process: (1) comparison with ground-based pyranometer measurements on clear (noncloudy) reference days, (2) correcting for a bias related to cloudiness, and (3) deriving a monthly bias correction factor. Precalibration results indicated good model performance, with a station-averaged model error of 2.2 MJ m-2/day (13%). Calibration reduced errors to 1.7 MJ m -2/day (10%), and also removed temporal-related, seasonal-related, and satellite sensor-related biases. The calibrated insolation dataset will subsequently be used by state of Florida Water Management Districts to produce statewide, 2-km resolution maps of estimated daily reference and potential evapotranspiration for water management-related activities. ?? 2009 American Water Resources Association.

The ESA FRM4DOAS project: Towards a quality-controlled MAXDOAS Centralized Processing System

NASA Astrophysics Data System (ADS)

Hendrick, Francois; Fayt, Caroline; Friess, Udo; Kreher, Karin; Piters, Ankie; Richter, Andreas; Wagner, Thomas; Cede, Alexander; Spinei, Elena; von Bismarck, Jonas; Fehr, Thorsten; Van Roozendael, Michel

2017-04-01

The Fiducial Reference Measurements for Ground-Based DOAS Air-Quality Observations (FRM4DOAS) is a two-year project funded by the European Space Agency (ESA). Started in July 2016, FRM4DOAS aims at further harmonizing MAXDOAS measurements and data sets, through (1) the specification of best practices for instrument operation, (2) the selection of state-of-the art retrieval algorithms, procedures, and settings, (3) the demonstration of a centralised rapid-delivery (6-24h latency) processing system for MAXDOAS instruments to be operated within the international Network for the Detection of Atmospheric Composition Change (NDACC). The project also links with the Pandonia initiative. In a first phase, the system concentrates on the development of 3 key products: NO2 vertical profiles, total O3 and tropospheric HCHO profiles, which will be retrieved at 11 MAXDOAS pilot stations. The system will also be tested and validated on data from the CINDI-2 campaign, and designed to allow further extension after commissioning. These activities will help and guarantee that homogenous, fully traceable, and quality-controlled datasets are generated from reference ground-based UV-vis instruments, which will play a crucial role in the validation of future ESA/Copernicus Sentinel satellite missions S-5P, S-4, and S-5.

Compilation of water-resources data and hydrogeologic setting for four research stations in the Piedmont and Blue Ridge physiographic provinces of North Carolina, 2000-2004

USGS Publications Warehouse

Huffman, Brad A.; Pfeifle, Cassandra A.; Chapman, Melinda J.; Bolich, Richard E.; Campbell, Ted R.; Geddes, Donald J.; Pippin, Charles G.

2006-01-01

Water-resources data were collected to describe the hydrologic conditions at four research stations in the Piedmont and Blue Ridge Physiographic Provinces of North Carolina. Data collected by the U.S. Geological Survey and the North Carolina Department of Environment and Natural Resources, Division of Water Quality, from September 2000 through September 2004 are presented in this report. The locations and periods of data collection are as follows: the Lake Wheeler Road research station (Raleigh) from April 2001 to September 2004, the Langtree Peninsula research station (Mooresville) from September 2000 to September 2004, the Upper Piedmont research station (Reidsville) from March 2002 to September 2004, and the Bent Creek research station (Asheville) from July 2002 to September 2004. Data presented in this report include well-construction characteristics for 110 wells, periodic ground-water-level measurements for 96 wells, borehole geophysical logs for 23 wells, hourly ground-water-level measurements for 12 wells, continuous-stage measurements for 2 streams, continuous water-quality measurements for 8 wells and 2 streams, periodic water-quality samples for 57 wells and 6 stream sites, slug-test results for 38 wells, and shallow ground-water-flow maps. In addition, the geology and hydrogeology at each site are summarized.

A Unified Global Reference Frame of Vertical Crustal Movements by Satellite Laser Ranging.

PubMed

Zhu, Xinhui; Wang, Ren; Sun, Fuping; Wang, Jinling

2016-02-08

Crustal movement is one of the main factors influencing the change of the Earth system, especially in its vertical direction, which affects people's daily life through the frequent occurrence of earthquakes, geological disasters, and so on. In order to get a better study and application of the vertical crustal movement,as well as its changes, the foundation and prerequisite areto devise and establish its reference frame; especially, a unified global reference frame is required. Since SLR (satellite laser ranging) is one of the most accurate space techniques for monitoring geocentric motion and can directly measure the ground station's geocentric coordinates and velocities relative to the centre of the Earth's mass, we proposed to take the vertical velocity of the SLR technique in the ITRF2008 framework as the reference frame of vertical crustal motion, which we defined as the SLR vertical reference frame (SVRF). The systematic bias between other velocity fields and the SVRF was resolved by using the GPS (Global Positioning System) and VLBI (very long baseline interferometry) velocity observations, and the unity of other velocity fields and SVRF was realized,as well. The results show that it is feasible and suitable to take the SVRF as a reference frame, which has both geophysical meanings and geodetic observations, so we recommend taking the SLR vertical velocity under ITRF2008 as the global reference frame of vertical crustal movement.

Commanding Constellations (Pipeline Architecture)

NASA Technical Reports Server (NTRS)

Ray, Tim; Condron, Jeff

2003-01-01

Providing ground command software for constellations of spacecraft is a challenging problem. Reliable command delivery requires a feedback loop; for a constellation there will likely be an independent feedback loop for each constellation member. Each command must be sent via the proper Ground Station, which may change from one contact to the next (and may be different for different members). Dynamic configuration of the ground command software is usually required (e.g. directives to configure each member's feedback loop and assign the appropriate Ground Station). For testing purposes, there must be a way to insert command data at any level in the protocol stack. The Pipeline architecture described in this paper can support all these capabilities with a sequence of software modules (the pipeline), and a single self-identifying message format (for all types of command data and configuration directives). The Pipeline architecture is quite simple, yet it can solve some complex problems. The resulting solutions are conceptually simple, and therefore, reliable. They are also modular, and therefore, easy to distribute and extend. We first used the Pipeline architecture to design a CCSDS (Consultative Committee for Space Data Systems) Ground Telecommand system (to command one spacecraft at a time with a fixed Ground Station interface). This pipeline was later extended to include gateways to any of several Ground Stations. The resulting pipeline was then extended to handle a small constellation of spacecraft. The use of the Pipeline architecture allowed us to easily handle the increasing complexity. This paper will describe the Pipeline architecture, show how it was used to solve each of the above commanding situations, and how it can easily be extended to handle larger constellations.

A methodology to estimate representativeness of LAI station observation for validation: a case study with Chinese Ecosystem Research Network (CERN) in situ data

NASA Astrophysics Data System (ADS)

Xu, Baodong; Li, Jing; Liu, Qinhuo; Zeng, Yelu; Yin, Gaofei

2014-11-01

Leaf Area Index (LAI) is known as a key vegetation biophysical variable. To effectively use remote sensing LAI products in various disciplines, it is critical to understand the accuracy of them. The common method for the validation of LAI products is firstly establish the empirical relationship between the field data and high-resolution imagery, to derive LAI maps, then aggregate high-resolution LAI maps to match moderate-resolution LAI products. This method is just suited for the small region, and its frequencies of measurement are limited. Therefore, the continuous observing LAI datasets from ground station network are important for the validation of multi-temporal LAI products. However, due to the scale mismatch between the point observation in the ground station and the pixel observation, the direct comparison will bring the scale error. Thus it is needed to evaluate the representativeness of ground station measurement within pixel scale of products for the reasonable validation. In this paper, a case study with Chinese Ecosystem Research Network (CERN) in situ data was taken to introduce a methodology to estimate representativeness of LAI station observation for validating LAI products. We first analyzed the indicators to evaluate the observation representativeness, and then graded the station measurement data. Finally, the LAI measurement data which can represent the pixel scale was used to validate the MODIS, GLASS and GEOV1 LAI products. The result shows that the best agreement is reached between the GLASS and GEOV1, while the lowest uncertainty is achieved by GEOV1 followed by GLASS and MODIS. We conclude that the ground station measurement data can validate multi-temporal LAI products objectively based on the evaluation indicators of station observation representativeness, which can also improve the reliability for the validation of remote sensing products.

Laser Ranging to the Lunar Reconnaissance Orbiter: improved timing and orbits

NASA Astrophysics Data System (ADS)

Mao, D.; Mcgarry, J.; Sun, X.; Torrence, M. H.; Skillman, D.; Hoffman, E.; Mazarico, E.; Rowlands, D. D.; Golder, J.; Barker, M. K.; Neumann, G. A.; Smith, D. E.; Zuber, M. T.

2013-12-01

The Laser ranging (LR) experiment to the Lunar Reconnaissance Orbiter (LRO) has been under operation for more than 4 years, since the launch of the spacecraft in June 2009. Led by NASA's Next Generation Satellite Laser Ranging(NGSLR) station at Greenbelt, Maryland, ten laser ranging stations over the world have been participating in the experiment and have collected over 3,200 hours of ranging data. These range measurements are used to monitor the behavior of the LRO clock and to generate orbital solutions for LRO. To achieve high-quality results in range, ground stations like NGSLR are using H-maser clocks to obtain a stable and continuous time baseline for the orbit solutions. An All-View GPS receiver was included at NGSLR since January 2013 which monitors the H-maser time against the master clock at the United State Naval Observatory (USNO) via the GPS satellites. NGSLR has successfully established nano-second level epoch time accuracy and 10-15 clock stability since then. Time transfer experiments using LRO as a common receiver have been verified in ground testing between NGSLR and MOBLAS7 via a ground terminal with a Lunar Orbiter Laser Altimeter (LOLA)-like receiver at Greenbelt, Maryland. Two hour-long ground tests using a LOLA-like detector and two different ground targets yielded results consistent with each other, and those from the previous 10-minute test completed one year ago. Time transfer tests between NGSLR and MOBLAS7 via LRO are ongoing. More time transfer tests are being planned from NGSLR to McDonald Laser Ranging Station (MLRS) in Texas and later from NGSLR to European satellite laser ranging (SLR) stations. Upon the completion of these time transfer experiments, nanosecond-level epoch time accuracy will be brought to stations besides NGSLR, and such high precision of the ground time can contribute to the LRO precision orbit determination (POD) process. Presently, by using the high-resolution GRAIL gravity models, the LRO orbits determined from LR data alone have a total position error of 10 meters in average, and show the same quality as those generated using conventional radiometric tracking data. In these LR orbital solutions, a bias was adjusted to compensate both the ground and spacecraft clock characteristics. By taking advantage of the knowledge we have gained through LR of the long-term stability of the LRO clock, the spacecraft clock behavior is separated from the ground station clocks and modeled over a 10-month time span in our current POD process. Here we present the results from this new approach, and further improvements in the quality of the orbital reconstruction.

Calibration of Subsurface Amplification Factors Using Surface/Borehole Strong-motion Records from the KiK-net

NASA Astrophysics Data System (ADS)

Hayashida, T.; Tajima, F.

2007-12-01

The Real-time Earthquake Information System (REIS, Horiuchi et al., 2005) detects earthquakes and determines event parameters using the Hi-net (High-sensitivity seismograph network Japan) data in Japan. The system also predicts the arrival time and seismic intensity at a given site before ground motions arrive. Here, the seismic intensity is estimated based on the intensity magnitude which is derived from data of the Hi-net. As the Hi-net stations are located in the boreholes, intensity estimation on the ground surface is evaluated using a constant for subsurface amplification. But the estimated intensities based on the conventionally used amplification constants are not always in agreement with those observed at specific sites on the ground surface. The KiK-net (KIBAN Kyoshin network Japan) consists of strong motion instruments. Each station has two sets of accelerometers, one set is installed on the ground surface and the other one is co-located with a Hi-net station in the borehole. We use data recorded at the KiK-net stations to calibrate subsurface site amplification factors between the borehole and the ground surface. We selected data recorded for over 200 events during the period of 1997 to 2006 in Hiroshima prefecture and calculated the ratios of peak velocity amplitudes on the ground surface ( Asurf) to those in the borehole ( Abor). The subsurface amplification varies from station to station showing dependency on the propagation distance as well as on the incident direction of seismic waves. Results suggest that the site amplification factors shall be described as a function of distance and incident direction, and are not constants. Thus, we derived empirical amplification formulas between Asurf and the peak velocity amplitudes on the engineering bedrock ( Abed) as a function of distance in place of the conventionally used amplification constants. Here, the engineering bedrock is defined as the depth where the S- wave velocity is 600 m/s. The estimated intensities show substantial improvement in the accuracy at most stations as compared with those calculated using conventional constants. When the amplification dependence on the incident direction was accounted for, the estimated intensities somewhat improved. This calibration will help an earthquake early warning system such as REIS provide more accurate intensity estimates.

33 CFR 110.215 - Anaheim Bay Harbor, California; U.S. Naval Weapons Station, Seal Beach, California; Naval...

Code of Federal Regulations, 2011 CFR

2011-07-01

....S. Naval Weapons Station, Seal Beach, California; Naval Explosives Anchorage. 110.215 Section 110... REGULATIONS Anchorage Grounds § 110.215 Anaheim Bay Harbor, California; U.S. Naval Weapons Station, Seal Beach... permission from the Commanding Officer, Naval Weapons Station, Seal Beach, California. This officer will...

33 CFR 110.215 - Anaheim Bay Harbor, California; U.S. Naval Weapons Station, Seal Beach, California; Naval...

Code of Federal Regulations, 2010 CFR

2010-07-01

....S. Naval Weapons Station, Seal Beach, California; Naval Explosives Anchorage. 110.215 Section 110... REGULATIONS Anchorage Grounds § 110.215 Anaheim Bay Harbor, California; U.S. Naval Weapons Station, Seal Beach... permission from the Commanding Officer, Naval Weapons Station, Seal Beach, California. This officer will...

33 CFR 110.215 - Anaheim Bay Harbor, California; U.S. Naval Weapons Station, Seal Beach, California; Naval...

Code of Federal Regulations, 2012 CFR

2012-07-01

....S. Naval Weapons Station, Seal Beach, California; Naval Explosives Anchorage. 110.215 Section 110... REGULATIONS Anchorage Grounds § 110.215 Anaheim Bay Harbor, California; U.S. Naval Weapons Station, Seal Beach... permission from the Commanding Officer, Naval Weapons Station, Seal Beach, California. This officer will...

33 CFR 110.215 - Anaheim Bay Harbor, California; U.S. Naval Weapons Station, Seal Beach, California; Naval...

Code of Federal Regulations, 2014 CFR

2014-07-01

....S. Naval Weapons Station, Seal Beach, California; Naval Explosives Anchorage. 110.215 Section 110... REGULATIONS Anchorage Grounds § 110.215 Anaheim Bay Harbor, California; U.S. Naval Weapons Station, Seal Beach... permission from the Commanding Officer, Naval Weapons Station, Seal Beach, California. This officer will...

33 CFR 110.215 - Anaheim Bay Harbor, California; U.S. Naval Weapons Station, Seal Beach, California; Naval...

Code of Federal Regulations, 2013 CFR

2013-07-01

....S. Naval Weapons Station, Seal Beach, California; Naval Explosives Anchorage. 110.215 Section 110... REGULATIONS Anchorage Grounds § 110.215 Anaheim Bay Harbor, California; U.S. Naval Weapons Station, Seal Beach... permission from the Commanding Officer, Naval Weapons Station, Seal Beach, California. This officer will...

Networked differential GPS system

NASA Technical Reports Server (NTRS)

Sheynblat, Leonid (Inventor); Kalafus, Rudolph M. (Inventor); Loomis, Peter V. W. (Inventor); Mueller, K. Tysen (Inventor)

1994-01-01

An embodiment of the present invention relates to a worldwide network of differential GPS reference stations (NDGPS) that continually track the entire GPS satellite constellation and provide interpolations of reference station corrections tailored for particular user locations between the reference stations Each reference station takes real-time ionospheric measurements with codeless cross-correlating dual-frequency carrier GPS receivers and computes real-time orbit ephemerides independently. An absolute pseudorange correction (PRC) is defined for each satellite as a function of a particular user's location. A map of the function is constructed, with iso-PRC contours. The network measures the PRCs at a few points, so-called reference stations and constructs an iso-PRC map for each satellite. Corrections are interpolated for each user's site on a subscription basis. The data bandwidths are kept to a minimum by transmitting information that cannot be obtained directly by the user and by updating information by classes and according to how quickly each class of data goes stale given the realities of the GPS system. Sub-decimeter-level kinematic accuracy over a given area is accomplished by establishing a mini-fiducial network.

Water resources data, North Carolina, water year 2001. Volume 1A: Surface-water records

USGS Publications Warehouse

Ragland, B.C.; Walters, D.A.; Cartano, G.D.; Taylor, J.E.

2002-01-01

Water-resources data for the 2001 water year for North Carolina consist of records of stage, discharge, water-quality for streams; stage and contents for lakes and reservoirs; precipitation; and ground water levels and water-quality of ground-water. Volume 1 contains discharge records for 209 gaging stations; stage and contents for 62 lakes and reservoirs; stage for 52 gaging stations; water quality for 101 gaging stations and 91 miscellaneous sites; continuous daily tide stage at 4 sites; and continuous precipitation at 98 sites. Volume 2 contains ground-water-level data from 136 observation wells and ground-water-quality data from 68 wells. Additional water data were collected at 84 sites not involved in the systematic data-collection program, and are published as miscellaneous measurements in Volume 1. The collection of water-resources data in North Carolina is a part of the National Water-Data System operated by the U.S. Geological Survey in cooperation with State, municipal, and Federal agencies.

Water resources data, North Carolina, water year 2002. Volume 1B: Surface-water records

USGS Publications Warehouse

Ragland, B.C.; Barker, R.G.; Robinson, J.B.

2003-01-01

Water-resources data for the 2002 water year for North Carolina consist of records of stage, discharge, water quality for streams; stage and contents for lakes and reservoirs; precipitation; and ground-water levels and water quality of ground water. Volume 1 contains discharge records for 211 gaging stations; stage and contents for 62 lakes and reservoirs; stage for 20 gaging stations; water quality for 52 gaging stations and 7 miscellaneous sites, and continuous water quality for 30 sites; and continuous precipitation at 109 sites. Volume 2 contains ground-water-level data from 143 observation wells and ground-water-quality data from 72 wells. Additional water data were collected at 85 sites not involved in the systematic data-collection program, and are published as miscellaneous measurements in Volume 1. The collection of water-resources data in North Carolina is a part of the National Water-Data System operated by the U.S. Geological Survey in cooperation with State, municipal, and Federal agencies.

Benefits of rotational ground motions for planetary seismology

NASA Astrophysics Data System (ADS)

Donner, S.; Joshi, R.; Hadziioannou, C.; Nunn, C.; van Driel, M.; Schmelzbach, C.; Wassermann, J. M.; Igel, H.

2017-12-01

Exploring the internal structure of planetary objects is fundamental to understand the evolution of our solar system. In contrast to Earth, planetary seismology is hampered by the limited number of stations available, often just a single one. Classic seismology is based on the measurement of three components of translational ground motion. Its methods are mainly developed for a larger number of available stations. Therefore, the application of classical seismological methods to other planets is very limited. Here, we show that the additional measurement of three components of rotational ground motion could substantially improve the situation. From sparse or single station networks measuring translational and rotational ground motions it is possible to obtain additional information on structure and source. This includes direct information on local subsurface seismic velocities, separation of seismic phases, propagation direction of seismic energy, crustal scattering properties, as well as moment tensor source parameters for regional sources. The potential of this methodology will be highlighted through synthetic forward and inverse modeling experiments.

47 CFR 87.319 - Scope of service.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AVIATION SERVICES Aviation Support Stations § 87.319 Scope of service. Aviation support stations are used for the following... aircraft and ground stations; (d) Coordination between aircraft and aviation service organizations located...

47 CFR 87.319 - Scope of service.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AVIATION SERVICES Aviation Support Stations § 87.319 Scope of service. Aviation support stations are used for the following... aircraft and ground stations; (d) Coordination between aircraft and aviation service organizations located...

47 CFR 87.319 - Scope of service.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AVIATION SERVICES Aviation Support Stations § 87.319 Scope of service. Aviation support stations are used for the following... aircraft and ground stations; (d) Coordination between aircraft and aviation service organizations located...

47 CFR 87.319 - Scope of service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AVIATION SERVICES Aviation Support Stations § 87.319 Scope of service. Aviation support stations are used for the following... aircraft and ground stations; (d) Coordination between aircraft and aviation service organizations located...

FOOT experiment (Foot/Ground Reaction Forces during Space Flight)

NASA Image and Video Library

2005-06-29

ISS011-E-09831 (29 June 2005) --- Astronaut John L. Phillips, Expedition 11 NASA Space Station science officer and flight engineer, works at the Canadarm2 controls while participating in the Foot/Ground Reaction Forces During Spaceflight (FOOT) experiment in the Destiny laboratory of the International Space Station. Phillips wore the specially instrumented Lower Extremity Monitoring Suit (LEMS), cycling tights outfitted with sensors, during the experiment.

FOOT experiment (Foot/Ground Reaction Forces during Space Flight)

NASA Image and Video Library

2005-06-29

ISS011-E-09825 (29 June 2005) --- Astronaut John L. Phillips, Expedition 11 NASA Space Station science officer and flight engineer, enters data into a computer while participating in the Foot/Ground Reaction Forces During Spaceflight (FOOT) experiment in the Destiny laboratory of the International Space Station. Phillips wore the specially instrumented Lower Extremity Monitoring Suit (LEMS), cycling tights outfitted with sensors, during the experiment.

Distributed operating system for NASA ground stations

NASA Technical Reports Server (NTRS)

Doyle, John F.

1987-01-01

NASA ground stations are characterized by ever changing support requirements, so application software is developed and modified on a continuing basis. A distributed operating system was designed to optimize the generation and maintenance of those applications. Unusual features include automatic program generation from detailed design graphs, on-line software modification in the testing phase, and the incorporation of a relational database within a real-time, distributed system.

Ambient Noise Green's Function Simulation of Long-Period Ground Motions for Reverse Faulting

NASA Astrophysics Data System (ADS)

Miyake, H.; Beroza, G. C.

2009-12-01

Long-time correlation of ambient seismic noise has been demonstrated as a useful tool for strong ground motion prediction [Prieto and Beroza, 2008]. An important advantage of ambient noise Green's functions is that they can be used for ground motion simulation without resorting to either complex 3-D velocity structure to develop theoretical Green’s functions, or aftershock records for empirical Green’s function analysis. The station-to-station approach inherent to ambient noise Green’s functions imposes some limits to its application, since they are band-limited, applied at the surface, and for a single force. We explore the applicability of this method to strong motion prediction using the 2007 Chuetsu-oki, Japan, earthquake (Mw 6.6, depth = 9 km), which excited long-period ground motions in and around the Kanto basin almost 200 km from the epicenter. We test the performance of ambient noise Green's function for long-period ground motion simulation. We use three components of F-net broadband data at KZK station, which is located near the source region, as a virtual source, and three components of six F-net stations in and around the Kanto basin to calculate the response. An advantage to applying this approach in Japan is that ambient-noise sources are active in diverse directions. The dominant period of the ambient noise for the F-net datasets is mostly 7 s over the year, and amplitudes are largest in winter. This period matches the dominant periods of the Kanto and Niigata basins. For the 9 components of the ambient noise Green’s functions, we have confirmed long-period components corresponding to Love wave and Rayleigh waves that can be used for simulation of the 2007 Chuetsu-oki earthquake. The relative amplitudes, phases, and durations of the ambient noise Green’s functions at the F-net stations in and around the Kanto basin respect to F-net KZK station are fairly well matched with those of the observed ground motions for the 2007 Chuetsu-oki earthquake.

47 CFR 25.109 - Cross-reference.

Code of Federal Regulations, 2014 CFR

2014-10-01

... General § 25.109 Cross-reference. (a) Space and earth stations in the Amateur Satellite Service are licensed under 47 CFR part 97. (b) Ship earth stations in the Maritime Mobile-Satellite Service transmitting in the 1626.5-1646.5 MHz band are subject to licensing under 47 CFR part 80. (c) Earth stations in...

47 CFR 25.109 - Cross-reference.

Code of Federal Regulations, 2013 CFR

2013-10-01

... General § 25.109 Cross-reference. (a) Space and earth stations in the Amateur Satellite Service are licensed under 47 CFR part 97. (b) Ship earth stations in the Maritime Mobile-Satellite Service transmitting in the 1626.5-1646.5 MHz band are subject to licensing under 47 CFR part 80. (c) Earth stations in...

Microwave-based navigation of femtosatellites using on-off keying

NASA Astrophysics Data System (ADS)

Kamte, Namrata Jagdish

The objective of this research is to validate that a custom-built microchip-scale satellite transmitting a signal modulated with a Pseudo Random Noise code using On-Off Keying, can be tracked. The weak GPS satellite signal is modulated with a Pseudo Random Noise (PRN) code that provides a mathematical gain. Our signal is modulated with the same PRN code using On-Off Keying (OOK) unlike Phase Shift Keying used in GPS satellites. Our goal is to obtain timing and positioning information from the microchip-scale satellite via a ground station using the concepts of PRN encoding and the OOK modulation technique. Decimeter scale satellites, with a mass of 2--6 kilograms, referred to as picosatellites, have been tracked successfully by ground stations. The microchip-scale satellite, called the femtosatellite is smaller with even less mass, at most 100 grams. At this size the satellite can take advantage of small-scale physics to perform maneuver, such as solar pressure, which only slightly perturb large spacecraft. Additionally, the reduced size decreases the cost of launch as compared to the picosatellites. A swarm of such femtosatellites can serve as environmental probes, interplanetary chemists or in-orbit inspectors of the parent spacecraft. In May 2011, NASA's last space shuttle mission STS-134 carried femtosatellites developed by Cornell researchers called "Sprites". The sprites were deployed from the International Space Station but ground stations on Earth failed to track them. In an effort to develop an alternative femtosatellite design, we have built our own femtosatellite prototype. Our femtosatellite prototype contains the AVR microcontroller on an Arduino board. This assembly is connected to a radio transmitter and a custom antenna transmitting a 433 Mhz radio frequency signal. The prototype transmits a PRN code modulated onto the signal using OOK. Our ground station consists of a Universal Software Radio Peripheral (USRP) with a custom antenna for reception of the 433 MHz signal. The USRP is driven by an open source software-defined radio application called GNU Radio. The required components of the signal are extracted from GNU Radio and processed in order to plot the received data. Benchtop testing of these OOK signals has yielded a reception sensitivity of upto 1 microsecond, which translates into a ranging capability similar to that of GPS satellites. We have correlated the received and replica PRN sequences and demonstrated that they match. The correlation can be used to obtain the identity and position of the femtosatellite prototype. This demonstrates the ability to track a femtosatellite signal that is lower than ambient noise, just like the signals broadcast from GPS satellites. Further, we have performed a system analysis and recognized key system behavioral problems. Thus we have determinately developed an optimum femtosatellite prototype and designed a novel positioning signal, providing a stepping- stone in the journey of successful femtosatellite communication.

Control and Non-Payload Communications (CNPC) Prototype Radio - Generation 2 Flight Test Report

NASA Technical Reports Server (NTRS)

Ishac, Joseph A.; Iannicca, Dennis C.; Shalkhauser, Kurt A.; Kachmar, Brian A.

2014-01-01

NASA Glenn Research Center conducted a series of flight tests for the purpose of evaluating air-to-ground communications links for future unmanned aircraft systems (UAS). The primary objective of the test effort was to evaluate the transition of the aircraft communications from one ground station to the next, and to monitor data flow during the "hand-off" event. To facilitate the testing, ground stations were installed at locations in Cleveland, Ohio and Albany, Ohio that each provides line-of-sight radio communications with an overflying aircraft. This report describes results from the flight tests including flight parameters, received signal strength measurements, data latency times, and performance observations for the air-to-ground channel.

A precise time synchronization method for 5G based on radio-over-fiber network with SDN controller

NASA Astrophysics Data System (ADS)

He, Linkuan; Wei, Baoguo; Yang, Hui; Yu, Ao; Wang, Zhengyong; Zhang, Jie

2018-02-01

There is an increasing demand on accurate time synchronization with the growing bandwidth of network service for 5G. In 5G network, it's necessary for base station to achieve accurate time synchronization to guarantee the quality of communication. In order to keep accuracy time for 5G network, we propose a time synchronization system for satellite ground station based on radio-over-fiber network (RoFN) with software defined optical network (SDON) controller. The advantage of this method is to improve the accuracy of time synchronization of ground station. The IEEE 1588 time synchronization protocol can solve the problems of high cost and lack of precision. However, in the process of time synchronization, distortion exists during the transmission of digital time signal. RoF uses analog optical transmission links and therefore analog transmission can be implemented among ground stations instead of digital transmission, which means distortion and bandwidth waste in the process of digital synchronization can be avoided. Additionally, the thought of SDN, software defined network, can optimize RoFN with centralized control and simplifying base station. Related simulation had been carried out to prove its superiority.

Free acquisition and dissemination of data through remote sensing. [Landsat program legal aspects

NASA Technical Reports Server (NTRS)

Hosenball, S. N.

1976-01-01

Free acquisition and dissemination of data through remote sensing is discussed with reference to the Landsat program. The role of the Scientific and Technical Subcommittee of the U.N. General Assembly's Committee on the Peaceful Uses of Outer Space has made recommendations on the expansion of existing ground stations and on the establishment of an experimental center for training in remote sensing. The working group for the legal subcommittee of the same U.N. committee indicates that there are common elements in the three drafts on remote sensing submitted to it: a call for international cooperation and the belief that remote sensing should be conducted for the benefit of all mankind.

GGOS working group on ground networks and communications

NASA Technical Reports Server (NTRS)

Pearlman, M.; Altamimi, Z.; Beck, N.; Forsberg, R.; Gurtner, W.; Kenyon, S.; Behrend, D.; Lemoine, F. G.; Ma, C.; Noll, C. E.;

Advances in Robotic Servicing Technology Development

NASA Technical Reports Server (NTRS)

Gefke, Gardell G.; Janas, Alex; Pellegrino, Joseph; Sammons, Matthew; Reed, Benjamin

2015-01-01

NASA's Satellite Servicing Capabilities Office (SSCO) has matured robotic and automation technologies applicable to in-space robotic servicing and robotic exploration over the last six years. This paper presents the progress of technology development activities at the Goddard Space Flight Center Servicing Technology Center and on the ISS, with an emphasis on those occurring in the past year. Highlighted advancements are design reference mission analysis for servicing in low Earth orbit (LEO) and near Earth asteroid boulder retrieval; delivery of the engineering development unit of the NASA Servicing Arm; an update on International Space Station Robotic Refueling Mission; and status of a comprehensive ground-based space robot technology demonstration expanding in-space robotic servicing capabilities beginning fall 2015.

Advances in Robotic Servicing Technology Development

NASA Technical Reports Server (NTRS)

Gefke, Gardell G.; Janas, Alex; Pellegrino, Joseph; Sammons, Matthew; Reed, Benjamin

2015-01-01

NASA's Satellite Servicing Capabilities Office (SSCO) has matured robotic and automation technologies applicable to in-space robotic servicing and robotic exploration over the last six years. This paper presents the progress of technology development activities at the Goddard Space Flight Center Servicing Technology Center and on the ISS, with an emphasis on those occurring in the past year. Highlighted advancements are design reference mission analysis for servicing in low Earth orbit (LEO) and asteroid redirection; delivery of the engineering development unit of the NASA Servicing Arm; an update on International Space Station Robotic Refueling Mission; and status of a comprehensive ground-based space robot technology demonstration expanding in-space robotic servicing capabilities beginning fall 2015.

Requirements, Resource Planning, and Management for Decrewing/Recrewing Scenarios of the International Space Station

NASA Technical Reports Server (NTRS)

Bach, David A.; Brand, Susan N.; Hasbrook, Peter V.

2013-01-01

Following the failure of 44 Progress (44P) on launch in August 2011, and the subsequent grounding of all Russian Soyuz rocket based launches, the International Space Station (ISS) ground teams engaged in an effort to determine how long the ISS could remain crewed, what would be required to safely configure the ISS for decrewing, and what would be required to recrew the ISS upon resumption of Soyuz rocket launches if decrewing became necessary. This White Paper was written to capture the processes and lessons learned from real-time time events and to provide a reference and training document for ISS Program teams in the event decrewing of the ISS is needed. Through coordination meetings and assessments, teams identified six decrewing priorities for ground and crew operations. These priorities were integrated along with preflight priorities through the Increment re-planning process. Additionally, the teams reviewed, updated, and implemented changes to the governing documentation for the configuration of the ISS for a contingency decrewing event. Steps were taken to identify critical items for disposal prior to decrewing, as well as identifying the required items to be strategically staged or flown with the astronauts and cosmonauts who would eventually recrew the ISS. After the successful launches and dockings of both 45P and 28 Soyuz (28S), the decrewing team transitioned to finalizing and publishing the documentation for standardizing the decrewing flight rules. With the continued launching of crews and cargo to the ISS, utilization and science is again a high priority; both Increment pairs 29 and 30, and Increment 31 and 32 reaching the milestone of at least 35 hours per week average utilization.

Requirements, Resource Planning and Management for Decrewing/Recrewing Scenarios of the International Space Station

NASA Astrophysics Data System (ADS)

Bach, David A.; Brand, Susan N.; Hasbrook, Peter V.

2013-09-01

Following the failure of 44 Progress (44P) on launch in August 2011, and the subsequent grounding of all Russian Soyuz rocket based launches, the International Space Station (ISS) ground teams engaged in an effort to determine how long the ISS could remain crewed, what would be required to safely configure the ISS for decrewing, and what would be required to recrew the ISS upon resumption of Soyuz rocket launches if decrewing became necessary. This White Paper was written to capture the processes and lessons learned from real-time time events and to provide a reference and training document for ISS Program teams in the event decrewing of the ISS is needed.Through coordination meetings and assessments, teams identified six decrewing priorities for ground and crew operations. These priorities were integrated along with preflight priorities through the Increment re-planning process. Additionally, the teams reviewed, updated, and implemented changes to the governing documentation for the configuration of the ISS for a contingency decrewing event. Steps were taken to identify critical items for disposal prior to decrewing, as well as identifying the required items to be strategically staged or flown with the astronauts and cosmonauts who would eventually recrew the ISS.After the successful launches and dockings of both 45P and 28 Soyuz (28S), the decrewing team transitioned to finalizing and publishing the documentation for standardizing the decrewing flight rules. With the continued launching of crews and cargo to the ISS, utilization and science is again a high priority; both Increment pairs 29 and 30, and Increment 31 and 32 reaching the milestone of at least 35 hours per week average utilization.

Two-dimensional resistivity investigation along West Fork Trinity River, Naval Air Station-Joint Reserve Base, Carswell Field, Fort Worth, Texas, October 2004

USGS Publications Warehouse

Shah, Sachin D.; Stanton, Gregory P.

2006-01-01

Naval Air Station-Joint Reserve Base Carswell Field (NAS-JRB) at Fort Worth, Tex., constitutes a government-owned, contractor-operated facility that has been in operation since 1942. Contaminants, primarily volatile organic compounds and metals, have entered the ground-water-flow system through leakage from waste-disposal sites and manufacturing processes. Ground water flows from west to east toward the West Fork Trinity River. During October 2004, the U.S. Geological Survey conducted a two-dimensional (2D) resistivity investigation at a site along the West Fork Trinity River at the eastern boundary of NAS-JRB to characterize the distribution of subsurface resistivity. Five 2D resistivity profiles were collected, which ranged from 500 to 750 feet long and extended to a depth of 25 feet. The Goodland Limestone and the underlying Walnut Formation form a confining unit that underlies the alluvial aquifer. The top of this confining unit is the top of bedrock at NAS-JRB. The bedrock confining unit is the zone of interest because of the potential for contaminated ground water to enter the West Fork Trinity River through saturated bedrock. The study involved a capacitively-coupled resistivity survey and inverse modeling to obtain true or actual resistivity from apparent resistivity. The apparent resistivity was processed using an inverse modeling software program. The results of this program were used to generate distributions (images) of actual resistivity referred to as inverted sections or profiles. The images along the five profiles show a wide range of resistivity values. The two profiles nearest the West Fork Trinity River generally showed less resistivity than the three other profiles.

Hydrogeologic setting, ground-water flow, and ground-water quality at the Lake Wheeler Road research station, 2001-03 : North Carolina Piedmont and Mountains Resource Evaluation Program

USGS Publications Warehouse

Chapman, Melinda J.; Bolich, Richard E.; Huffman, Brad A.

2005-01-01

Results of a 2-year field study of the regolith-fractured bedrock ground-water system at the Lake Wheeler Road research station in Wake County, North Carolina, indicate both disconnection and interaction among components of the ground-water system. The three components of the ground-water system include (1) shallow, porous regolith; (2) a transition zone, including partially weathered rock, having both secondary (fractures) and primary porosity; and (3) deeper, fractured bedrock that has little, if any, primary porosity and is dominated by secondary fractures. The research station includes 15 wells (including a well transect from topographic high to low settings) completed in the three major components of the ground-water-flow system and a surface-water gaging station on an unnamed tributary. The Lake Wheeler Road research station is considered representative of a felsic gneiss hydrogeologic unit having steeply dipping foliation and a relatively thick overlying regolith. Bedrock foliation generally strikes N. 10? E. to N. 30? E. and N. 20? W. to N. 40? W. to a depth of about 400 feet and dips between 70? and 80? SE. and NE., respectively. From 400 to 600 feet, the foliation generally strikes N. 70? E. to N. 80? E., dipping 70? to 80? SE. Depth to bedrock locally ranges from about 67 to 77 feet below land surface. Fractures in the bedrock generally occur in two primary sets: low dip angle, stress relief fractures that cross cut foliation, and steeply dipping fractures parallel to foliation. Findings of this study generally support the conceptual models of ground-water flow from high to low topographic settings developed for the Piedmont and Blue Ridge Provinces in previous investigations, but are considered a refinement of the generalized conceptual model based on a detailed local-scale investigation. Ground water flows toward a surface-water boundary, and hydraulic gradients generally are downward in recharge areas and upward in discharge areas; however, local variations in vertical gradients are apparent. Water-quality sampling and monitoring efforts were conducted to characterize the interaction of components of the ground-water system. Elevated nitrate concentrations as high as 22 milligrams per liter were detected in shallow ground water from the regolith at the study site. These elevated nitrate concentrations likely are related to land use, which includes agricultural practices that involve animal feeding operations and crop fertilization. Continuous ground-water-quality data indicate seasonal fluctuations in field water-quality properties, differences with respect to depth, and fluctuations during recharge events. Water-quality properties recorded in the regolith well following rainfall indicate the upwelling of deeper ground water in the discharge area, likely from ground water in the transition-zone fractures. Additionally, interaction with a surface-water boundary appears likely in the ground-water discharge area, as water levels in all three ground-water zones, including the deep bedrock, mimic the surface-water rise during rainfall.

Application of ground-penetrating radar at McMurdo Station, Antarctica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stefano, J.E.

1992-05-01

Argonne National Laboratory initiated a site investigation program at McMurdo Station, Antarctica, to characterize environmental contamination. The performance and usefulness of ground-penetrating radar (GPR) was evaluated under antarctic conditions during the initial site investigation in January 1991. Preliminary surveys were successful in defining the contact between reworked pyroclastic material and in the prefill, undisturbed pyroclastics and basalts at some sites. Interference from radio traffic at McMurdo Station was not observed, but interference was a problem in work with unshielded antennas near buildings. In general, the results of this field test suggest that high-quality, high-resolution, continuous subsurface profiles can be producedmore » with GPR over most of McMurdo Station.« less

Application of ground-penetrating radar at McMurdo Station, Antarctica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stefano, J.E.

1992-01-01

Argonne National Laboratory initiated a site investigation program at McMurdo Station, Antarctica, to characterize environmental contamination. The performance and usefulness of ground-penetrating radar (GPR) was evaluated under antarctic conditions during the initial site investigation in January 1991. Preliminary surveys were successful in defining the contact between reworked pyroclastic material and in the prefill, undisturbed pyroclastics and basalts at some sites. Interference from radio traffic at McMurdo Station was not observed, but interference was a problem in work with unshielded antennas near buildings. In general, the results of this field test suggest that high-quality, high-resolution, continuous subsurface profiles can be producedmore » with GPR over most of McMurdo Station.« less

A local network integrated into a balloon-borne apparatus

NASA Astrophysics Data System (ADS)

Imori, Masatosi; Ueda, Ikuo; Shimamura, Kotaro; Maeno, Tadashi; Murata, Takahiro; Sasaki, Makoto; Matsunaga, Hiroyuki; Matsumoto, Hiroshi; Shikaze, Yoshiaki; Anraku, Kazuaki; Matsui, Nagataka; Yamagami, Takamasa

A local network is incorporated into an apparatus for a balloon-borne experiment. A balloon-borne system implemented in the apparatus is composed of subsystems interconnected through a local network, which introduces modular architecture into the system. The network decomposes the balloon-borne system into subsystems, which are similarly structured from the point of view that the systems is kept under the control of a ground station. The subsystem is functionally self-contained and electrically independent. A computer is integrated into a subsystem, keeping the subsystem under the control. An independent group of batteries, being dedicated to a subsystem, supplies the whole electricity of the subsystem. The subsystem could be turned on and off independently of the other subsystems. So communication among the subsystems needs to be based on such a protocol that could guarantee the independence of the individual subsystems. An Omninet protocol is employed to network the subsystems. A ground station sends commands to the balloon-borne system. The command is received and executed at the system, then results of the execution are returned to the ground station. Various commands are available so that the system borne on a balloon could be controlled and monitored remotely from the ground station. A subsystem responds to a specific group of commands. A command is received by a transceiver subsystem and then transferred through the network to the subsystem to which the command is addressed. Then the subsystem executes the command and returns results to the transceiver subsystem, where the results are telemetered to the ground station. The network enhances independence of the individual subsystems, which enables programs of the individual subsystems to be coded independently. Independence facilitates development and debugging of programs, improving the quality of the system borne on a balloon.

Mars rover/sample return mission requirements affecting space station

NASA Technical Reports Server (NTRS)

1988-01-01

The possible interfaces between the Space Station and the Mars Rover/Sample Return (MRSR) mission are defined. In order to constrain the scope of the report a series of seven design reference missions divided into three major types were assumed. These missions were defined to span the probable range of Space Station-MRSR interactions. The options were reduced, the MRSR sample handling requirements and baseline assumptions about the MRSR hardware and the key design features and requirements of the Space Station are summarized. Only the aspects of the design reference missions necessary to define the interfaces, hooks and scars, and other provisions on the Space Station are considered. An analysis of each of the three major design reference missions, is reported, presenting conceptual designs of key hardware to be mounted on the Space Station, a definition of weights, interfaces, and required hooks and scars.

Testing an automated method to estimate ground-water recharge from streamflow records

USGS Publications Warehouse

Rutledge, A.T.; Daniel, C.C.

1994-01-01

The computer program, RORA, allows automated analysis of streamflow hydrographs to estimate ground-water recharge. Output from the program, which is based on the recession-curve-displacement method (often referred to as the Rorabaugh method, for whom the program is named), was compared to estimates of recharge obtained from a manual analysis of 156 years of streamflow record from 15 streamflow-gaging stations in the eastern United States. Statistical tests showed that there was no significant difference between paired estimates of annual recharge by the two methods. Tests of results produced by the four workers who performed the manual method showed that results can differ significantly between workers. Twenty-two percent of the variation between manual and automated estimates could be attributed to having different workers perform the manual method. The program RORA will produce estimates of recharge equivalent to estimates produced manually, greatly increase the speed od analysis, and reduce the subjectivity inherent in manual analysis.

Induced abnormality in Mir- and Earth grown Super Dwarf wheat.

PubMed

Bubenheim, D L; Stieber, J; Campbell, W F; Salisbury, F B; Levinski, M; Sytchev, V; Podolsky, I; Chernova, L; Pdolsky, I

2003-01-01

Super-dwarf wheat grown on the Mir space station using the Svet "Greenhouse" exhibited morphological, metabolic and reproductive abnormalities compared with Earth-grown wheat. Of prominent importance were the abnormalities associated with reproductive ontogeny and the total absence of seed formation on Mir. Changes in the apical meristem associated with transition from the vegetative phase to floral initiation and development of the reproductive spike were all typical of 'Super-Dwarf' wheat up to the point of anthesis. Observation of ruptured anthers from the Mir-grown plants revealed what appeared to be normally developed pollen. These pollen gains, however, contained only one nuclei, while normal viable pollen is tri-nucleate. A potentially important difference in the flight experiment, compared with ground reference studies, was the presence of a high level of atmospheric ethylene (1,200 ppb). Ground studies conducted by exposing 'Super-Dwarf' wheat to ethylene just prior to anthesis resulted in manifestation of the same abnormalities observed in the space flight samples. c2002 Published by Elsevier Science Ltd on behalf of COSPAR.

Induced abnormality in Mir- and Earth grown Super Dwarf wheat

NASA Technical Reports Server (NTRS)

Bubenheim, D. L.; Stieber, J.; Campbell, W. F.; Salisbury, F. B.; Levinski, M.; Sytchev, V.; Podolsky, I.; Chernova, L.; Pdolsky, I.

2003-01-01

Super-dwarf wheat grown on the Mir space station using the Svet "Greenhouse" exhibited morphological, metabolic and reproductive abnormalities compared with Earth-grown wheat. Of prominent importance were the abnormalities associated with reproductive ontogeny and the total absence of seed formation on Mir. Changes in the apical meristem associated with transition from the vegetative phase to floral initiation and development of the reproductive spike were all typical of 'Super-Dwarf' wheat up to the point of anthesis. Observation of ruptured anthers from the Mir-grown plants revealed what appeared to be normally developed pollen. These pollen gains, however, contained only one nuclei, while normal viable pollen is tri-nucleate. A potentially important difference in the flight experiment, compared with ground reference studies, was the presence of a high level of atmospheric ethylene (1,200 ppb). Ground studies conducted by exposing 'Super-Dwarf' wheat to ethylene just prior to anthesis resulted in manifestation of the same abnormalities observed in the space flight samples. c2002 Published by Elsevier Science Ltd on behalf of COSPAR.

Reduced-Gravity Measurements of the Effect of Oxygen on Properties of Zirconium

NASA Technical Reports Server (NTRS)

Zhao, J.; Lee, J.; Wunderlich, R.; Fecht, H.-J.; Schneider, S.; SanSoucie, M.; Rogers, J.; Hyers, R.

2016-01-01

The influence of oxygen on the thermophysical properties of zirconium is being investigated using MSL-EML (Material Science Laboratory - Electromagnetic Levitator) on ISS (International Space Station) in collaboration with NASA, ESA (European Space Agency), and DLR (German Aerospace Center). Zirconium samples with different oxygen concentrations will be put into multiple melt cycles, during which the density, viscosity, surface tension, heat capacity, and electric conductivity will be measured at various undercooled temperatures. The facility check-up of MSL-EML and the first set of melting experiments have been successfully performed in 2015. The first zirconium sample will be tested near the end of 2015. As part of ground support activities, the thermophysical properties of zirconium and ZrO were measured using a ground-based electrostatic levitator located at the NASA Marshall Space Flight Center. The influence of oxygen on the measured surface tension was evaluated. The results of this research will serve as reference data for those measured in ISS.

An occultation satellite system for determining pressure levels in the atmosphere

NASA Technical Reports Server (NTRS)

Morrison, A. R.; Vngar, S. G.; Lusignan, B. B.

1974-01-01

A two-satellite microwave occultation system is described that will fix, as an absolute function of altitude, the pressure-temperature profile generated by a passive infrared sounder. The 300 mb pressure level is determined to within 24 m rms, assuming the temperture errors produced by the infrared sensor are not greater than 2 K rms. Error caused by water vapor in the radio path is corrected by climatological adjustments. A ground test of the proposed system is described. A microwave signal propagating between two mountain tops was found to be subject to periods of intense fading. Computer analysis of the raypath between the transmitting and receiving stations indicates that multipath and defocusing were responsible for this fading. It is unlikely that an operational pressure-reference-level system will be subject to the deep fades observed in the ground test, because the phenomena are associated with lower altitudes than the closest approach altitude of an occultation-system raypath.

Fuzzy Control/Space Station automation

NASA Technical Reports Server (NTRS)

Gersh, Mark

1990-01-01

Viewgraphs on fuzzy control/space station automation are presented. Topics covered include: Space Station Freedom (SSF); SSF evolution; factors pointing to automation & robotics (A&R); astronaut office inputs concerning A&R; flight system automation and ground operations applications; transition definition program; and advanced automation software tools.

Underground and ground-level particulate matter concentrations in an Italian metro system

NASA Astrophysics Data System (ADS)

Cartenì, Armando; Cascetta, Furio; Campana, Stefano

2015-01-01

All around the world, many studies and experimental results have assessed elevated concentrations of Particulate Matter (PM) in underground metro systems, with non-negligible implications for human health due to protracted exposure to fine particles. Starting from this consideration, an intensive particulate sampling campaign was carried out in January 2014 measuring the PM concentrations in the Naples (Italy) Metro Line 1, both at station platforms and inside trains. Naples Metro Line 1 is about 18 km long, with 17 stations (3 ground-level and 14 below-ground ones). Experimental results show that the average PM10 concentrations measured in the underground station platforms range between 172 and 262 μg/m3 whilst the average PM2.5 concentrations range between 45 and 60 μg/m3. By contrast, in ground-level stations no significant difference between stations platforms and urban environment measurements was observed. Furthermore, a direct correlation between trains passage and PM concentrations was observed, with an increase up to 42% above the average value. This correlation is possibly caused by the re-suspension of the particles due to the turbulence induced by trains. The main original finding was the real-time estimations of PM levels inside the trains travelling both in ground-level and underground sections of Line 1. The results show that high concentrations of both PM10 (average values between 58 μg/m3 and 138 μg/m3) and PM2.5 (average values between 18 μg/m3 and 36 μg/m3) were also measured inside trains. Furthermore, measurements show that windows left open on trains caused the increase in PM concentrations inside trains in the underground section, while in the ground-level section the clean air entering the trains produced an environmental "washing effect". Finally, it was estimated that every passenger spends on average about 70 min per day exposed to high levels of PM.

10 Gbps Shuttle-to-Ground Adjunct Communication Link Capability Experiment

NASA Technical Reports Server (NTRS)

Ceniceros, J. M.; Sandusky, J. V.; Hemmati, H.

1999-01-01

A 1.2 Gbps space-to-ground laser communication experiment being developed for use on an EXpedite the PRocessing of Experiments to the Space Station (EXPRESS) Pallet Adapter can be adapted to fit the Hitchhiker cross-bay-carrier pallet and upgraded to data rates exceeding 1O Gbps. So modified, this instrument would enable both real-time data delivery and increased data volume for payloads using the Space Shuttle. Applications such as synthetic aperture radar and multispectral imaging collect large data volumes at a high rate and would benefit from the capability for real-time data delivery and from increased data downlink volume. Current shuttle downlink capability is limited to 50 Mbps, forcing such instruments to store large amounts of data for later analysis. While the technology is not yet sufficiently proven to be relied on as the primary communication link, when in view of the ground station it would increase the shuttle downlink rate capability 200 times, with typical total daily downlinks of 200 GB - as much data as the shuttle could downlink if it were able to maintain its maximum data rate continuously for one day. The lasercomm experiment, the Optical Communication Demonstration and High-Rate Link Facility (OCDHRLF), is being developed by the Jet Propulsion Laboratory's (JPL) Optical Communication Group through support from the International Space Station Engineering Research and Technology Development program. It is designed to work in conjunction with the Optical Communication Telescope Laboratory (OCTL) NASA's first optical communication ground station, which is under construction at JPL's Table Mountain Facility near Wrightwood, California. This paper discusses the modifications to the preliminary design of the flight system that would be necessary to adapt it to fit the Hitchhiker Cross-Bay Carrier. It also discusses orbit geometries which are favorable to the OCTL and potential non-NASA ground stations, anticipated burst-error-rates and bit-error-rates, and requirements for data collection on the ground.

Aerospace laser communications technology as enabler for worldwide quantum key distribution

NASA Astrophysics Data System (ADS)

Moll, Florian; Weinfurter, Harald; Rau, Markus; Schmidt, Christopher; Melén, Gwen; Vogl, Tobias; Nauerth, Sebastian; Fuchs, Christian

2016-04-01

A worldwide growing interest in fast and secure data communications pushes technology development along two lines. While fast communications can be realized using laser communications in fiber and free-space, inherently secure communications can be achieved using quantum key distribution (QKD). By combining both technologies in a single device, many synergies can be exploited, therefore reducing size, weight and power of future systems. In recent experiments we demonstrated quantum communications over large distances as well as between an aircraft and a ground station which proved the feasibility of QKD between moving partners. Satellites thus may be used as trusted nodes in combination with QKD receiver stations on ground, thereby enabling fast and secure communications on a global scale. We discuss the previous experiment with emphasis on necessary developments to be done and corresponding ongoing research work of German Aerospace Center (DLR) and Ludwig Maximilians University Munich (LMU). DLR is performing research on satellite and ground terminals for the high-rate laser communication component, which are enabling technologies for the QKD link. We describe the concept and hardware of three generations of OSIRIS (Optical High Speed Infrared Link System) laser communication terminals for low Earth orbiting satellites. The first type applies laser beam pointing solely based on classical satellite control, the second uses an optical feedback to the satellite bus and the third, currently being in design phase, comprises of a special coarse pointing assembly to control beam direction independent of satellite orientation. Ongoing work also targets optical terminals for CubeSats. A further increase of beam pointing accuracy can be achieved with a fine pointing assembly. Two ground stations will be available for future testing, an advanced stationary ground station and a transportable ground station. In parallel the LMU QKD source size will be reduced by more than an order of magnitude thereby simplifying its integration into future free-space optical communication links with CubeSats.

Centimeter-Level Robust Gnss-Aided Inertial Post-Processing for Mobile Mapping Without Local Reference Stations

NASA Astrophysics Data System (ADS)

Hutton, J. J.; Gopaul, N.; Zhang, X.; Wang, J.; Menon, V.; Rieck, D.; Kipka, A.; Pastor, F.

2016-06-01

For almost two decades mobile mapping systems have done their georeferencing using Global Navigation Satellite Systems (GNSS) to measure position and inertial sensors to measure orientation. In order to achieve cm level position accuracy, a technique referred to as post-processed carrier phase differential GNSS (DGNSS) is used. For this technique to be effective the maximum distance to a single Reference Station should be no more than 20 km, and when using a network of Reference Stations the distance to the nearest station should no more than about 70 km. This need to set up local Reference Stations limits productivity and increases costs, especially when mapping large areas or long linear features such as roads or pipelines. An alternative technique to DGNSS for high-accuracy positioning from GNSS is the so-called Precise Point Positioning or PPP method. In this case instead of differencing the rover observables with the Reference Station observables to cancel out common errors, an advanced model for every aspect of the GNSS error chain is developed and parameterized to within an accuracy of a few cm. The Trimble Centerpoint RTX positioning solution combines the methodology of PPP with advanced ambiguity resolution technology to produce cm level accuracies without the need for local reference stations. It achieves this through a global deployment of highly redundant monitoring stations that are connected through the internet and are used to determine the precise satellite data with maximum accuracy, robustness, continuity and reliability, along with advance algorithms and receiver and antenna calibrations. This paper presents a new post-processed realization of the Trimble Centerpoint RTX technology integrated into the Applanix POSPac MMS GNSS-Aided Inertial software for mobile mapping. Real-world results from over 100 airborne flights evaluated against a DGNSS network reference are presented which show that the post-processed Centerpoint RTX solution agrees with the DGNSS solution to better than 2.9 cm RMSE Horizontal and 5.5 cm RMSE Vertical. Such accuracies are sufficient to meet the requirements for a majority of airborne mapping applications.

Disaster warning satellite study

NASA Technical Reports Server (NTRS)

1971-01-01

The Disaster Warning Satellite System is described. It will provide NOAA with an independent, mass communication system for the purpose of warning the public of impending disaster and issuing bulletins for corrective action to protect lives and property. The system consists of three major segments. The first segment is the network of state or regional offices that communicate with the central ground station; the second segment is the satellite that relays information from ground stations to home receivers; the third segment is composed of the home receivers that receive information from the satellite and provide an audio output to the public. The ground stations required in this system are linked together by two, separate, voice bandwidth communication channels on the Disaster Warning Satellites so that a communications link would be available in the event of disruption of land line service.

Pre-Flight Tests with Astronauts, Flight and Ground Hardware, to Assure On-Orbit Success

NASA Technical Reports Server (NTRS)

Haddad Michael E.

2010-01-01

On-Orbit Constraints Test (OOCT's) refers to mating flight hardware together on the ground before they will be mated on-orbit or on the Lunar surface. The concept seems simple but it can be difficult to perform operations like this on the ground when the flight hardware is being designed to be mated on-orbit in a zero-g/vacuum environment of space or low-g/vacuum environment on the Lunar/Mars Surface. Also some of the items are manufactured years apart so how are mating tasks performed on these components if one piece is on-orbit/on Lunar/Mars surface before its mating piece is planned to be built. Both the Internal Vehicular Activity (IVA) and Extra-Vehicular Activity (EVA) OOCT's performed at Kennedy Space Center will be presented in this paper. Details include how OOCT's should mimic on-orbit/Lunar/Mars surface operational scenarios, a series of photographs will be shown that were taken during OOCT's performed on International Space Station (ISS) flight elements, lessons learned as a result of the OOCT's will be presented and the paper will conclude with possible applications to Moon and Mars Surface operations planned for the Constellation Program.

Time evolution of an SLR reference frame

NASA Astrophysics Data System (ADS)

Angermann, D.; Gerstl, M.; Kelm, R.; Müller, H.; Seemüller, W.; Vei, M.

2002-07-01

On the basis of LAGEOS-1 and LAGEOS-2 data we computed a 10-years (1990-2000) solution for SLR station positions and velocities. The paper describes the data processing with the DGFI software package DOGS. We present results for station coordinates and their time variation for 41 stations of the global SLR network, and discuss the stability and time evolution of the SLR reference frame established in the same way. We applied different methods to assess the quality and consistency of the SLR results. The results presented in this paper include: (1) a time series of weekly estimated station coordinates; (2) a comparison of a 10-year LAGEOS-1 and LAGEOS-2 solution; (3) a comparison of 2.5-year solutions with the combined 10-year solution to assess the internal stability and the time evolution of the SLR reference frame; (4) a comparison of the SLR reference frame with ITRF97; and (5) a comparison of SLR station velocities with those of ITRF97 and NNR NUVEL-1A.

Agile Information Exchange in Autonomous Air Systems

DTIC Science & Technology

2013-06-01

proportional to the information the pilot has on the target. Figure 5: Modified Procerus Unicorn UAV D. Equipment The UAV used in this experiment is...a modified Procerus Unicorn (Figure 5). Unicorns are electrically powered, Styrofoam flying wings with a 72” wingspan. Stock Unicorns are...controlled by a Kestrel autopilot, which communicates to a ground-station over a 900MHz radio link. Through the ground-station, the Unicorn operator can

FOOT experiment (Foot/Ground Reaction Forces during Space Flight)

NASA Image and Video Library

2005-06-29

ISS011-E-09822 (29 June 2005) --- Astronaut John L. Phillips, Expedition 11 NASA Space Station science officer and flight engineer, uses the Cycle Ergometer with Vibration Isolation System (CEVIS) while participating in the Foot/Ground Reaction Forces During Spaceflight (FOOT) experiment in the Destiny laboratory of the International Space Station. Phillips wore the specially instrumented Lower Extremity Monitoring Suit (LEMS), cycling tights outfitted with sensors, during the experiment.

Federated Ground Station Network Model and Interface Specification

DTIC Science & Technology

2014-12-01

interface definition language JSON JavaScript Object Notation LEO low Earth orbit LNA low-noise amplifier MC3 Mobile CubeSat Command and Control...Naval Research Laboratory OQPSK offset quadrature phase-shift keying xviii P2P peer-to-peer PKI public key infrastructure REST Representational...enhanced our work being performed on the Mobile CubeSat Command and Control (MC3) ground station network. You also provided crucial guidance from

DoD Comprehensive Military Unmanned Aerial Vehicle Smart Device Ground Control Station Threat Model

DTIC Science & Technology

2015-04-01

design , imple- mentation, and test evaluation were interviewed to evaluate the existing gaps in the DoD processes for cybersecurity. This group exposed...such as antenna design and signal reception have made satellite communication networks a viable solution for smart devices on the battlefield...DoD Comprehensive Military Unmanned AERIAL VEHICLE SMART DEVICE GROUND CONTROL STATION THREAT MODEL  Image designed by Diane Fleischer Report

Spaceflight tracking and data network operational reliability computer output for MTBF and availability. Appendix V to CSC-1-395

NASA Technical Reports Server (NTRS)

Seneca, V. I.; Mlynarczyk, R. H.

1974-01-01

Tables of data are provided to show the availability of Skylab data to selected ground stations during the phases of Skylab preflight, Skylab unmanned condition, and Skylab manned condition. The mean time between failure (MTBF) of the same Skylab functions is tabulated for the selected ground stations. All reliability data are based on a 90 percent confidence interval.

Antarctica as a testing ground for manned missions to the Moon and Mars

NASA Astrophysics Data System (ADS)

Demidov, N. E.; Lukin, V. V.

2017-03-01

This paper is concerned with the study of expedition activity in Antarctica as a part of the search for useful analogies and solutions which can be taken into account in planning manned missions to the Moon and Mars. The following is considered: natural analogies, human factors, station facilities, means of transportation, scientific programs, safety issues, and historical and political analogies. A rationalization is given for the idea of creating a testing ground in Antarctica (stations Vostok, Novolazarevskaya, Jetty Oasis) for ground-based simulation of functioning of a lunar and Martian base.

The Earth Based Ground Stations Element of the Lunar Program

NASA Technical Reports Server (NTRS)

Gal-Edd, Jonathan; Fatig, Curtis; Schier, James; Lee, Charles

2007-01-01

The Lunar Architecture Team (LAT) is responsible for developing a concept for building and supporting a lunar outpost with several exploration capabilities such as rovers, colonization, and observatories. The lunar outpost is planned to be located at the Moon's South Pole. The LAT Communications and Navigation Team (C&N) is responsible for defining the network infrastructure to support the lunar outpost. The following elements are needed to support lunar outpost activities: A Lunar surface network based on industry standard wireless 802.xx protocols, relay satellites positioned 180 degrees apart to provide South Pole coverage for the half of the lunar 28-day orbit that is obscured from Earth view, earth-based ground stations deployed at geographical locations 120 degrees apart. This paper will focus on the Earth ground stations of the lunar architecture. Two types of ground station networks are discussed. One provides Direct to Earth (DTE) support to lunar users using Kaband 23/26Giga-Hertz (GHz) communication frequencies. The second supports the Lunar Relay Satellite (LRS) that will be using Ka-band 40/37GHz (Q-band). This paper will discuss strategies to provide a robust operational network in support of various lunar missions and trades of building new antennas at non-NASA facilities, to improve coverage and provide site diversification for handling rain attenuation.

Analysis of One-Way Laser Ranging Data to LRO, Time Transfer and Clock Characterization

NASA Technical Reports Server (NTRS)

Bauer, S.; Hussmann, H.; Oberst, J.; Dirkx, D.; Mao, D.; Neumann, G. A.; Mazarico, E.; Torrence, M. H.; McGarry, J. F.; Smith, D. E.;

Site correction of stochastic simulation in southwestern Taiwan

NASA Astrophysics Data System (ADS)

Lun Huang, Cong; Wen, Kuo Liang; Huang, Jyun Yan

2014-05-01

Peak ground acceleration (PGA) of a disastrous earthquake, is concerned both in civil engineering and seismology study. Presently, the ground motion prediction equation is widely used for PGA estimation study by engineers. However, the local site effect is another important factor participates in strong motion prediction. For example, in 1985 the Mexico City, 400km far from the epicenter, suffered massive damage due to the seismic wave amplification from the local alluvial layers. (Anderson et al., 1986) In past studies, the use of stochastic method had been done and showed well performance on the simulation of ground-motion at rock site (Beresnev and Atkinson, 1998a ; Roumelioti and Beresnev, 2003). In this study, the site correction was conducted by the empirical transfer function compared with the rock site response from stochastic point-source (Boore, 2005) and finite-fault (Boore, 2009) methods. The error between the simulated and observed Fourier spectrum and PGA are calculated. Further we compared the estimated PGA to the result calculated from ground motion prediction equation. The earthquake data used in this study is recorded by Taiwan Strong Motion Instrumentation Program (TSMIP) from 1991 to 2012; the study area is located at south-western Taiwan. The empirical transfer function was generated by calculating the spectrum ratio between alluvial site and rock site (Borcheret, 1970). Due to the lack of reference rock site station in this area, the rock site ground motion was generated through stochastic point-source model instead. Several target events were then chosen for stochastic point-source simulating to the halfspace. Then, the empirical transfer function for each station was multiplied to the simulated halfspace response. Finally, we focused on two target events: the 1999 Chi-Chi earthquake (Mw=7.6) and the 2010 Jiashian earthquake (Mw=6.4). Considering the large event may contain with complex rupture mechanism, the asperity and delay time for each sub-fault is to be concerned. Both the stochastic point-source and the finite-fault model were used to check the result of our correction.

ECLIPS at LMD: Preliminary results of phase 2

NASA Technical Reports Server (NTRS)

Valentin, R.; Menenger, L.; Elouragini, S.; Flamant, P. H.; Pelon, J.

1992-01-01

The LMD (Laboratoire de Meteorologie Dynamique) ground-based backscatter lidar station (48 degrees 4 N, 02 degrees 0 E) near Paris was operated daily during the phase 2 of the Experimental Closed Lidar Pilot Study (ECLIPS) from May 22 to June 19, 1991 simultaneously with a radiometric equipment recording the downward short wavelength (SW) and long wavelength (LW) fluxes. A day-by-day summary of the field measurement as a function of universal time (UT) is given. Considering a 5 days week, there are only two days of missing data (05/31 and 06/06) in our record. The nearby meteorological station (10 km away) provides rawindsounding at 00UT and 12UT. During two days, the French airborne lidar LEANDRE was flown over the ground-based station. The airborne equipment looked down while the ground based equipment looked up. The two lidars were operated at 532 nm, and the on-board radiometers were identical to the ones on the ground. The measurements were synchronized with Advanced Very High Resolution Radiometer (AVHIRR) overpasses as required. We also indicate the Meteosat data corresponding to the period of measurements. Two examples of simultaneous ground-based lidar, pygeometer and pyranometer data are displayed.

Data Gathering and Energy Transfer Dilemma in UAV-Assisted Flying Access Network for IoT.

PubMed

Arabi, Sara; Sabir, Essaid; Elbiaze, Halima; Sadik, Mohamed

2018-05-11

Recently, Unmanned Aerial Vehicles (UAVs) have emerged as an alternative solution to assist wireless networks, thanks to numerous advantages they offer in comparison to terrestrial fixed base stations. For instance, a UAV can be used to embed a flying base station providing an on-demand nomadic access to network services. A UAV can also be used to wirelessly recharge out-of-battery ground devices. In this paper, we aim to deal with both data collection and recharging depleted ground Internet-of-Things (IoT) devices through a UAV station used as a flying base station. To extend the network lifetime, we present a novel use of UAV with energy harvesting module and wireless recharging capabilities. However, the UAV is used as an energy source to empower depleted IoT devices. On one hand, the UAV charges depleted ground IoT devices under three policies: (1) low-battery first scheme; (2) high-battery first scheme; and (3) random scheme. On the other hand, the UAV station collects data from IoT devices that have sufficient energy to transmit their packets, and in the same phase, the UAV exploits the Radio Frequency (RF) signals transmitted by IoT devices to extract and harvest energy. Furthermore, and as the UAV station has a limited coverage time due to its energy constraints, we propose and investigate an efficient trade-off between ground users recharging time and data gathering time. Furthermore, we suggest to control and optimize the UAV trajectory in order to complete its travel within a minimum time, while minimizing the energy spent and/or enhancing the network lifetime. Extensive numerical results and simulations show how the system behaves under different scenarios and using various metrics in which we examine the added value of UAV with energy harvesting module.

A source migration of low frequency earthquakes during the 2000 activity of Miyake-jima volcano, Japan

NASA Astrophysics Data System (ADS)

Kobayashi, T.; Ohminato, T.; Fujita, E.; Ida, Y.

2002-12-01

The volcanic activity of Miyake-jima started at 18:30 (JST) on June 26, 2000 with large ground deformation and earthquake swarms. The seismic activity started at the southern part of the island. The hypocenter distribution migrated northwestward and slipped away out of the island by early in the morning, June 27. Low frequency (LF) earthquakes with dominant frequencies of 0.2 and 0.4 Hz were first observed in the afternoon of June 27. The LF activity lasted till the first summit eruption on July 8. Earthquake Research Institute of Tokyo University and National Research Institute for Earth Science and Disaster Prevention deployed 3 CMG-3T and 4 STS-2 broadband seismometers in the island. More than 300 LF earthquakes are detected during the period from June 27 to July 8. Most of the LF events whose dominant frequency is 0.2Hz occurred before July 1, while LF events with dominant frequency of 0.4Hz mainly occurred after July 2. We determine hypocenters of these LF events by using the following technique. For each LF event, we assume a source location on a grid point in a homogeneous half-space. A reference station is chosen among all the stations. The cross correlation coefficients are computed between the waveform of the reference station and those of other stations. Then, the coefficients for all the stations are summed. In the same manner, summations of the coefficients are computed grid by grid. A grid point that gives the maximum value of the sum of the coefficients is regarded as the best estimate of the source location of the LF event under consideration. The result shows that hypocenters of LF events are spread over the southern to western part of the island and they migrate from south to the west day by day. Hypocenter migrations associated with volcanic activity have been often reported but usually for short period events. This is one of remarkable cases in which a migration of earthquakes with dominant frequencies as low as 0.2 and 0.4Hz are clearly observed.

Environmental control/life support system for Space Station

NASA Technical Reports Server (NTRS)

Miller, C. W.; Heppner, D. B.; Schubert, F. H.; Dahlhausen, M. J.

1986-01-01

The functional, operational, and design load requirements for the Environmental Control/Life Support System (ECLSS) are described. The ECLSS is divided into two groups: (1) an atmosphere management group and (2) a water and waste management group. The interaction between the ECLSS and the Space Station Habitability System is examined. The cruciform baseline station design, the delta and big T module configuration, and the reference Space Station configuration are evaluated in terms of ECLSS requirements. The distribution of ECLSS equipment in a reference Space Station configuration is studied as a function of initial operating conditions and growth orbit capabilities. The benefits of water electrolysis as a Space Station utility are considered.

Summary of astronaut inputs on automation and robotics for Space Station Freedom

NASA Technical Reports Server (NTRS)

Weeks, David J.

1990-01-01

Astronauts and payload specialists present specific recommendations in the form of an overview that relate to the use of automation and robotics on the Space Station Freedom. The inputs are based on on-orbit operations experience, time requirements for crews, and similar crew-specific knowledge that address the impacts of automation and robotics on productivity. Interview techniques and specific questionnaire results are listed, and the majority of the responses indicate that incorporating automation and robotics to some extent and with human backup can improve productivity. Specific support is found for the use of advanced automation and EVA robotics on the Space Station Freedom and for the use of advanced automation on ground-based stations. Ground-based control of in-flight robotics is required, and Space Station activities and crew tasks should be analyzed to assess the systems engineering approach for incorporating automation and robotics.

Water Resources Data, Massachusetts and Rhode Island, Water Year 2003

USGS Publications Warehouse

Socolow, R.S.; Zanca, J.L.; Driskell, T.R.; Ramsbey, L.R.

2004-01-01

Water resources data for the 2003 water year for Massachusetts and Rhode Island consists of records of stage, discharge, and water quality of streams; contents of lakes and reservoirs; and water levels of ground-water wells. This report contains discharge records for 108 gaging stations, stage records for 2 gaging stations, stage records for 3 ponds; monthend contents of 1 reservoir, precipitation totals at 8 gaging stations; water quality for 27 gaging stations, air temperature at 2 climatological stations; water levels for 129 observation wells, and ground-water quality for 15 wells. Miscellaneous hydrologic data were collected at various sites that were not a part of the systematic data-collection program and are published as miscellaneous discharge measurements and miscellaneous surface-water-quality data. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Massachusetts and Rhode Island.

Water resources data for Massachusetts and Rhode Island, water year 2004

USGS Publications Warehouse

Socolow, R.S.; Comeau, L.Y.; Murino, Domenic

2005-01-01

This report includes records of stage, discharge, and water quality of streams; contents and elevation of lakes and ponds; and water levels of ground-water wells. This volume contains discharge records for 112 gaging stations; stage records for 2 gaging stations; stage records for 2 ponds; month-end contents of 1 reservoir; precipitation totals at 6 gaging stations; water quality for 21 gaging stations; air temperature at 2 climatological stations; and water levels for 131 observation wells. Locations of these sites are shown in figures 1 and 2. Hydrologic data were collected at many sites that were not involved in the systematic data-collection program; these data are published as miscellaneous discharge measurements, miscellaneous surface-water-quality, and miscellaneous ground-water-quality data. The data in this report represent that part of the National Water Information System (NWIS) operated by the U.S. Geological Survey and cooperating State and Federal agencies in Massachusetts and Rhode Island.

The Telecommunications and Data Acquisition Report

NASA Technical Reports Server (NTRS)

Posner, E. C. (Editor)

1984-01-01

Tracking and ground-based navigation; communications, spacecraft-ground; station control and system technology; capabilities for new projects; networks consolidation program; and network sustaining are described.

Targeted versus standard bait station placement affects subterranean termite (Isoptera: Rhinotermitidae) infestation rates.

PubMed

Jones, Susan C

2003-10-01

A major challenge to termite baiting in soil habitats is the prolonged time that it may take for subterranean termites (Isoptera: Rhinotermitidae) to infest stations. The objective of this research study was to determine whether the location of food sources (Sentricon in-ground monitoring stations and wooden monitors) influences the likelihood of infestation by termites. In field trials conducted at 15 structures in central Ohio, standard placement of stations at 3-4.5 m intervals was compared with targeted placements based on evidence of termite activity indoors and outdoors as well as conducive moisture conditions. Termites infested significantly more targeted placements (70/374) than standard placements (35/372) around structures. At the targeted placement sites, termites infested more wooden monitors than Sentricon stations, but this was not statistically significant. This implies that placement, rather than cellulose composition, was the more important factor. Termites first infested stations/monitors an average of 38 d sooner at targeted sites than standard placement sites. This research indicates that evidence of termite activity indoors and outdoors should be a prime consideration when placing in-ground stations.

Levels of electric field strength within the immediate vicinity of FM radio stations in Accra, Ghana.

PubMed

Azah, C K; Amoako, J K; Fletcher, J J

2013-10-01

Heightened awareness of the ever-expanding use of radiofrequency (RF) techniques and technology has led to mounting concerns from the general public and the scientific community regarding the possible health effects that may arise as a consequence of exposure to RF radiations and has drawn the attention of many researchers the world over. A survey of the RF electromagnetic radiation at public access points in the vicinity of 20 frequency-modulated (FM) radio stations has been made in Accra, Ghana. The fundamental object was to determine the levels of RF fields from FM broadcast antennae within 10-200 m radius about the foot of the FM base station and at a height of 1.5 m above the ground at selected locations. A spectrum analyser and a bi-conical antenna element sensitive and effective within the frequency band of 30-300 MHz were used. Results obtained indicated that the levels of electric field strength ranged from 5.4E-04 V m(-1) at FM station 'O' to 7.4E-08 V m(-1) at FM station 'D'. At a transmission frequency range of 88-108 MHz, the variation of power densities is from 2.5E-10 to 1.5E-17 Wm(-2). These values are very low and are far below the reference level set by the International Commission on Non-Ionizing Radiation Protection and therefore do not pose any known hazard to the inhabitants of Accra, Ghana. The electric field levels presented in this work are comparable with those reported from epidemiological studies conducted elsewhere.

The relationship between extreme precipitation events and landslides distributions in 2009 in Lower Austria

NASA Astrophysics Data System (ADS)

Katzensteiner, H.; Bell, R.; Petschko, H.; Glade, T.

2012-04-01

The prediction and forecast of widespread landsliding for a given triggering event is an open research question. Numerous studies tried to link spatial rainfall and landslide distributions. This study focuses on analysing the relationship between intensive precipitation and rainfall-triggered shallow landslides in the year 2009 in Lower Austria. Landslide distributions were gained from the building ground register, which is maintained by the Geological Survey of Lower Austria. It contains detailed information of landslides, which were registered due to damage reports. Spatially distributed rainfall estimates were extracted from INCA (Integrated Nowcasting through Comprehensive Analysis) precipitation analysis, which is a combination of station data interpolation and radar data in a spatial resolution of 1km developed by the Central Institute for Meteorology and Geodynamics (ZAMG), Vienna, Austria. The importance of the data source is shown by comparing rainfall data based on reference gauges, spatial interpolation and INCA-analysis for a certain storm period. INCA precipitation data can detect precipitating cells that do not hit a station but might trigger a landslide, which is an advantage over the application of reference stations for the definition of rainfall thresholds. Empirical thresholds at regional scale were determined based on rainfall-intensity and duration in the year 2009 and landslide information. These thresholds are dependent on the criteria which separate the landslide triggering and non-triggering precipitation events from each other. Different approaches for defining thresholds alter the shape of the threshold as well. A temporarily threshold I=8,8263*D^(-0.672) for extreme rainfall events in summer in Lower Austria was defined. A verification of the threshold with similar events of other years as well as following analyses based on a larger landslide database are in progress.

Evaluation of Integration Degree of the ASG-EUPOS Polish Reference Networks With Ukrainian GeoTerrace Network Stations in the Border Area

NASA Astrophysics Data System (ADS)

Siejka, Zbigniew

2017-09-01

GNSS systems are currently the basic tools for determination of the highest precision station coordinates (e.g. basic control network stations or stations used in the networks for geodynamic studies) as well as for land, maritime and air navigation. All of these tasks are carried out using active, large scale, satellite geodetic networks which are complex, intelligent teleinformatic systems offering post processing services along with corrections delivered in real-time for kinematic measurements. Many countries in the world, also in Europe, have built their own multifunctional networks and enhance them with their own GNSS augmentation systems. Nowadays however, in the era of international integration, there is a necessity to consider collective actions in order to build a unified system, covering e.g. the whole Europe or at least some of its regions. Such actions have already been undertaken in many regions of the world. In Europe such an example is the development for EUPOS which consists of active national networks built in central eastern European countries. So far experience and research show, that the critical areas for connecting these networks are border areas, in which the positioning accuracy decreases (Krzeszowski and Bosy, 2011). This study attempts to evaluate the border area compatibility of Polish ASG-EUPOS (European Position Determination System) reference stations and Ukrainian GeoTerrace system reference stations in the context of their future incorporation into the EUPOS. The two networks analyzed in work feature similar hardware parameters. In the ASG-EUPOS reference stations network, during the analyzed period, 2 stations (WLDW and CHEL) used only one system (GPS), while, in the GeoTerrace network, all the stations were equipped with both GPS and GLONASS receivers. The ASG EUPOS reference station network (95.6%) has its average completeness greater by about 6% when compared to the GeoTerrace network (89.8%).

Verification of the Usefulness of the Trimble Rtx Extended Satellite Technology with the Xfill Function in the Local Network Implementing Rtk Measurements

NASA Astrophysics Data System (ADS)

Siejka, Zbigniew

2014-12-01

The paper presents the method of satellite measurements, which gives users the ability of GNSS continuous precise positioning in real time, even in the case of short interruptions in receiving the correction of the local ground system of measurements support. The proposed method is a combination of two satellite positioning technologies RTN GNSS and RTX Extended. In technology RTX Extended the xFill function was used for precise positioning in real time and in the local reference system. This function provides the ability to perform measurement without the need for constant communication with the ground support satellite system. Test measurements were performed on a test basis located in Krakow, and RTN GNSS positioning was done based on the national network of reference stations of the ASGEUPOS. The solution allows for short (up to 5 minutes) interruptions in radio or internet communication. When the primary stream of RTN correction is not available, then the global corrections Trimble xFill broadcasted by satellite are used. The new technology uses in the real-time data from the global network of tracking stations and contributes significantly to improving the quality and efficiency of surveying works. At present according to the authors, technology Trimble CenterPoint RTX can guarantee repeatability of measurements not worse than 3.8 cm (Trimble Survey Division, 2012). In the paper the comparative analysis of measurement results between the two technologies was performed: RTN carried out in the classic way, which was based on the corrections of the terrestrial local network of the Polish system of active geodetic network (ASG-EUPOS) and RTK xFill technology. The results were related to the data of test network, established as error free. The research gave satisfactory results and confirmed the great potential of the use of the new technology in the geodetic work realization. By combining these two technologies of GNSS surveying the user can greatly improve the overall performance of real-time positioning.

Characterization of Unstable Rock Slopes Through Passive Seismic Measurements

NASA Astrophysics Data System (ADS)

Kleinbrod, Ulrike; Burjánek, Jan; Fäh, Donat

2014-05-01

Catastrophic rock slope failures have high social impact, causing significant damage to infrastructure and many casualties throughout the world each year. Both detection and characterization of rock instabilities are therefore of key importance. Analysing unstable rock slopes by means of ambient vibrations might be a new alternative to the already existing methods as for example geotechnical displacement measurements. A systematic measurement campaign has been initiated recently in Switzerland in order to study the seismic response of potential rockslides concerning a broad class of slope failure mechanisms and material conditions. First results are presented in this contribution. Small aperture seismic arrays were deployed at sites of interest for a short period of time (several hours) in order to record ambient vibrations. During each measurement a reference station was installed on a stable part close to the instability. The total number of stations used varies from 16 down to 2, depending on the site scope and resource availability. Instable rock slopes show a highly directional ground motion which is significantly amplified with respect to stable areas. These effects are strongest at certain frequencies which are identified as eigenfrequencies of the unstable rock mass. The eigenfrequencies and predominant directions have been estimated by frequency dependent polarization analysis. Site-to-reference spectral ratios have been calculated as well in order to estimate the relative amplification of ground motion at unstable parts. The retrieved results were compared with independent in-situ observations and other available data. The directions of maximum amplification are in most cases perpendicular to open cracks mapped on the surface and in good agreement with the deformation directions obtained by geodetic measurements. The interpretation of the observed wave field is done through numerical modelling of seismic wave propagation in fractured media with complex topography. For example, a potential relation between eigenfrequencies and unstable rock mass volume is investigated.

Space station program phase B definition: Nuclear reactor-powered space station cost and schedules

NASA Technical Reports Server (NTRS)

1971-01-01

Tabulated data are presented on the costs, schedules, and technical characteristics for the space station phases C and D program. The work breakdown structure, schedule data, program ground rules, program costs, cost-estimating rationale, funding schedules, and supporting data are included.

LEONA for TLE and HEET Research in South America

NASA Astrophysics Data System (ADS)

São Sabbas, F.; Souza, J. R. D.; Guerra, E. M.; Filho, A. C. J.; Galvão, R. M. O.; Branco, R.; Kherani, E. A.; Naccarato, K. P.; Federico, C. A.; Pazianotto, M. T.; Gatto, R. C.; Cisotto, M. V.; Brito, A. F. D.; Fontes, N. R.; Camargo, I. H.; Silva, A. L. G. D.

2017-12-01

In 2014 the core of LEONA, which is the "Transient Luminous Event and Thunderstorm High Energy Emission Collaborative Network in Latin America", was established in Brazil with 4 ground stations equipped to perform Transient Luminous Events - TLEs. This year a neutron detector was also installed to collect data on neutron flashes produced by lightning and thunderstorms themselves. Neutrons are one of the several types of High Energy Emissions from Thunderstorms - HEETs. The TLE stations are operated remotely via internet, by users logged in LEONA website, and the HEET station is continuously and automatically operated. Now a proposal to expand LEONA to have 12 TLE ground stations, 2 HEET ground stations (for neutrons, gamma and X rays) and 1 HEET mobile station (for gamma and X rays) is currently under evaluation by the Brazilian São Paulo Research Foundation - FAPESP, and if funded will start to be carried out in early 2018. The expanded version of LEONA will cover the Central Region of South America, including Southeast and Southern Brazil, Northern Argentina, Paraguay and Uruguay, which compose the most electrically active Region of South America. It will also have one TLE station in the Amazon and Northeast Regions of Brazil. South America is one of the most active thunderstorm regions of the world, with extremely large and long lived thunderstorms. Due to the South Atlantic Magnetic Anomaly - SAMA, covering most of its territory, scientific satellites routinely turn off their equipment while flying over South America, therefore a ground network like LEONA is the only way to make consistent long term measurements of TLEs and HEET in this important region of the world. This paper will present LEONA in detail, its current operational status and its expansion plan over the next 4 years. It will also highlight the main results of the different TLE observations performed from Brazil up to date by the Atmospheric and Space Electrodynamical Coupling - ACATMOS group at the Brazilian National Institute for Space Research - INPE, undertaking this challenging enterprise.

US GEOLOGICAL SURVEY'S NATIONAL SYSTEM FOR PROCESSING AND DISTRIBUTION OF NEAR REAL-TIME HYDROLOGICAL DATA.

USGS Publications Warehouse

Shope, William G.; ,

1987-01-01

The US Geological Survey is utilizing a national network of more than 1000 satellite data-collection stations, four satellite-relay direct-readout ground stations, and more than 50 computers linked together in a private telecommunications network to acquire, process, and distribute hydrological data in near real-time. The four Survey offices operating a satellite direct-readout ground station provide near real-time hydrological data to computers located in other Survey offices through the Survey's Distributed Information System. The computerized distribution system permits automated data processing and distribution to be carried out in a timely manner under the control and operation of the Survey office responsible for the data-collection stations and for the dissemination of hydrological information to the water-data users.

The Engineering Strong Ground Motion Network of the National Autonomous University of Mexico

NASA Astrophysics Data System (ADS)

Velasco Miranda, J. M.; Ramirez-Guzman, L.; Aguilar Calderon, L. A.; Almora Mata, D.; Ayala Hernandez, M.; Castro Parra, G.; Molina Avila, I.; Mora, A.; Torres Noguez, M.; Vazquez Larquet, R.

2014-12-01

The coverage, design, operation and monitoring capabilities of the strong ground motion program at the Institute of Engineering (IE) of the National Autonomous University of Mexico (UNAM) is presented. Started in 1952, the seismic instrumentation intended initially to bolster earthquake engineering projects in Mexico City has evolved into the largest strong ground motion monitoring system in the region. Today, it provides information not only to engineering projects, but also to the near real-time risk mitigation systems of the country, and enhances the general understanding of the effects and causes of earthquakes in Mexico. The IE network includes more than 100 free-field stations and several buildings, covering the largest urban centers and zones of significant seismicity in Central Mexico. Of those stations, approximately one-fourth send the observed acceleration to a processing center in Mexico City continuously, and the rest require either periodic visits for the manual recovery of the data or remote interrogation, for later processing and cataloging. In this research, we document the procedures and telecommunications systems used systematically to recover information. Additionally, we analyze the spatial distribution of the free-field accelerographs, the quality of the instrumentation, and the recorded ground motions. The evaluation criteria are based on the: 1) uncertainty in the generation of ground motion parameter maps due to the spatial distribution of the stations, 2) potential of the array to provide localization and magnitude estimates for earthquakes with magnitudes greater than Mw 5, and 3) adequacy of the network for the development of Ground Motion Prediction Equations due to intra-plate and intra-slab earthquakes. We conclude that the monitoring system requires a new redistribution, additional stations, and a substantial improvement in the instrumentation and telecommunications. Finally, we present an integral plan to improve the current network's monitoring capabilities.

Stratus Ocean Reference Station (20 deg. S, 85 deg. W) : Mooring Recovery and Deployment Cruise, R/V Ronald H. Brown Cruise 05-05, September 26, 2005-October 21, 2005

DTIC Science & Technology

2006-02-01

WHOI- 2006 -06 Woods Hole Oceanographic Institution 1930 Stratus Ocean Reference Station (20°S, 85°W) Mooring Recovery and Deployment Cruise RN Ronald...Environmental Technology Laboratory, 3University of Colorado, CIRES, 4University of Miami, 5University of Concepcion February 2006 Technical Report...Institution Woods Hole, MA 02543 UOP Technical Report 2006 -01 WHOI- 2006 -06 UOP- 2006 -01 Stratus Ocean Reference Station (20*S, 85*W) Mooring Recovery and

Definition of technology development missions for early space stations: Large space structures

NASA Technical Reports Server (NTRS)

1983-01-01

The testbed role of an early (1990-95) manned space station in large space structures technology development is defined and conceptual designs for large space structures development missions to be conducted at the space station are developed. Emphasis is placed on defining requirements and benefits of development testing on a space station in concert with ground and shuttle tests.

An analysis of spatial representativeness of air temperature monitoring stations

NASA Astrophysics Data System (ADS)

Liu, Suhua; Su, Hongbo; Tian, Jing; Wang, Weizhen

2018-05-01

Surface air temperature is an essential variable for monitoring the atmosphere, and it is generally acquired at meteorological stations that can provide information about only a small area within an r m radius ( r-neighborhood) of the station, which is called the representable radius. In studies on a local scale, ground-based observations of surface air temperatures obtained from scattered stations are usually interpolated using a variety of methods without ascertaining their effectiveness. Thus, it is necessary to evaluate the spatial representativeness of ground-based observations of surface air temperature before conducting studies on a local scale. The present study used remote sensing data to estimate the spatial distribution of surface air temperature using the advection-energy balance for air temperature (ADEBAT) model. Two target stations in the study area were selected to conduct an analysis of spatial representativeness. The results showed that one station (AWS 7) had a representable radius of about 400 m with a possible error of less than 1 K, while the other station (AWS 16) had the radius of about 250 m. The representable radius was large when the heterogeneity of land cover around the station was small.

Orbital ATK's Ground Support Equipment (GSE) Delivery for OA-7

NASA Image and Video Library

2016-12-15

Sealed in its shipping container, the ground support equipment for the Orbital ATK OA-7 commercial resupply services mission was moved inside the low bay of the Space Station Processing Facility at NASA's Kennedy Space Center in Florida. The Orbital ATK CRS-7 with the Cygnus cargo module will lift off atop a United Launch Alliance Atlas V rocket from Space launch Complex 41 at Cape Canaveral Air Force Station. The commercial resupply services mission to the International Space Station will deliver thousands of pounds of supplies, equipment and scientific research materials that improve life on Earth and drive progress toward future space exploration.

Nodes

NASA Technical Reports Server (NTRS)

Hanson, John; Martinez, Andres; Petro, Andrew

2015-01-01

Nodes is a technology demonstration mission that is scheduled for launch to the International SpaceStation no earlier than Nov.19, 2015. The two Nodes satellites will be deployed from the Station in early 2016 todemonstrate new network capabilities critical to the operation of swarms of spacecraft. They will demonstrate the ability ofmulti spacecraft swarms to receive and distribute ground commands, exchange information periodically, andautonomously configure the network by determining which spacecraft should communicate with the ground each day ofthe mission.

Preliminary study of GPS orbit determination accuracy achievable from worldwide tracking data

NASA Technical Reports Server (NTRS)

Larden, D. R.; Bender, P. L.

1982-01-01

The improvement in the orbit accuracy if high accuracy tracking data from a substantially larger number of ground stations is available was investigated. Observations from 20 ground stations indicate that 20 cm or better accuracy can be achieved for the horizontal coordinates of the GPS satellites. With this accuracy, the contribution to the error budget for determining 1000 km baselines by GPS geodetic receivers would be only about 1 cm.

A miniaturized digital telemetry system for physiological data transmission

NASA Technical Reports Server (NTRS)

Portnoy, W. M.; Stotts, L. J.

1978-01-01

A physiological date telemetry system, consisting basically of a portable unit and a ground base station was designed, built, and tested. The portable unit to be worn by the subject is composed of a single crystal controlled transmitter with AM transmission of digital data and narrowband FM transmission of voice; a crystal controlled FM receiver; thirteen input channels follwed by a PCM encoder (three of these channels are designed for ECG data); a calibration unit; and a transponder control system. The ground base station consists of a standard telemetry reciever, a decoder, and an FM transmitter for transmission of voice and transponder signals to the portable unit. The ground base station has complete control of power to all subsystems in the portable unit. The phase-locked loop circuit which is used to decode the data, remains in operation even when the signal from the portable unit is interrupted.

Ground operation of robotics on Space Station Freedom

NASA Technical Reports Server (NTRS)

Wojcik, Z. Alex; Hunter, David G.; Cantin, Marc R.

1993-01-01

This paper reflects work carried out on Ground Operated Telerobotics (GOT) in 1992 to refine further the ideas, procedures, and technologies needed to test the procedures in a high latency environment, and to integrate GOT into Space Station Freedom operations. Space Station Freedom (SSF) will be in operation for 30 years, and will depend on robots to carry out a significant part of the assembly, maintenance, and utilization workload. Current plans call for on-orbit robotics to be operated by on-board crew members. This approach implies that on-orbit robotics operations use up considerable crew time, and that these operations cannot be carried out when SSF is unmanned. GOT will allow robotic operations to be operated from the ground, with on-orbit crew interventions only when absolutely required. The paper reviews how GOT would be implemented, how GOT operations would be planned and supported, and reviews GOT issues, critical success factors, and benefits.

Study of spacecraft direct readout meteorological systems

NASA Technical Reports Server (NTRS)

Bartlett, R.; Elam, W.; Hoedemaker, R.

1973-01-01

Characteristics are defined of the next generation direct readout meteorological satellite system with particular application to Tiros N. Both space and ground systems are included. The recommended space system is composed of four geosynchronous satellites and two low altitude satellites in sun-synchronous orbit. The goesynchronous satellites transmit to direct readout ground stations via a shared S-band link, relayed FOFAX satellite cloud cover pictures (visible and infrared) and weather charts (WEFAX). Basic sensor data is transmitted to regional Data Utilization Stations via the same S-band link. Basic sensor data consists of 0.5 n.m. sub-point resolution data in the 0.55 - 0.7 micron spectral region, and 4.0 n.m. resolution data in the 10.5 - 12.6 micron spectral region. The two low altitude satellites in sun-synchronous orbit provide data to direct readout ground stations via a 137 MHz link, a 400 Mhz link, and an S-band link.

Ground operation of robotics on Space Station Freedom

NASA Astrophysics Data System (ADS)

Wojcik, Z. Alex; Hunter, David G.; Cantin, Marc R.

1993-03-01

This paper reflects work carried out on Ground Operated Telerobotics (GOT) in 1992 to refine further the ideas, procedures, and technologies needed to test the procedures in a high latency environment, and to integrate GOT into Space Station Freedom operations. Space Station Freedom (SSF) will be in operation for 30 years, and will depend on robots to carry out a significant part of the assembly, maintenance, and utilization workload. Current plans call for on-orbit robotics to be operated by on-board crew members. This approach implies that on-orbit robotics operations use up considerable crew time, and that these operations cannot be carried out when SSF is unmanned. GOT will allow robotic operations to be operated from the ground, with on-orbit crew interventions only when absolutely required. The paper reviews how GOT would be implemented, how GOT operations would be planned and supported, and reviews GOT issues, critical success factors, and benefits.

Strong ground motion in the Taipei basin from the 1999 Chi-Chi, Taiwan, earthquake

USGS Publications Warehouse

Fletcher, Joe B.; Wen, K.-L.

2005-01-01

The Taipei basin, located in northwest Taiwan about 160 km from the epicenter of the Chi-Chi earthquake, is a shallow, triangular-shaped basin filled with low-velocity fluvial deposits. There is a strong velocity contrast across the basement interface of about 600 m/sec at a depth of about 600-700 m in the deeper section of the basin, suggesting that ground motion should be amplified at sites in the basin. In this article, the ground-motion recordings are analyzed to determine the effect of the basin both in terms of amplifications expected from a 1D model of the sediments in the basin and in terms of the 3D structure of the basin. Residuals determined for peak acceleration from attenuation curves are more positive (amplified) in the basin (average of 5.3 cm/ sec2 compared to - 24.2 cm/sec2 for those stations outside the basin and between 75 and 110 km from the surface projection of the faulted area, a 40% increase in peak ground acceleration). Residuals for peak velocity are also significantly more positive at stations in the basin (31.8 cm/sec compared to 20.0 cm/sec out). The correlation of peak motion with depth to basement, while minor in peak acceleration, is stronger in the peak velocities. Record sections of ground motion from stations in and around the Taipei basin show that the largest long-period arrival, which is coherent across the region, is strongest on the vertical component and has a period of about 10-12 sec. This phase appears to be a Rayleigh wave, probably associated with rupture at the north end of the Chelungpu fault. Records of strong motion from stations in and near the basin have an additional, higher frequency signal: nearest the deepest point in the basin, the signal is characterized by frequencies of about 0.3 - 0.4 Hz. These frequencies are close to simple predictions using horizontal layers and the velocity structure of the basin. Polarizations of the S wave are mostly coherent across the array, although there are significant differences along the northwest edge that may indicate large strains across that edge of the basin. The length of each record after the main S wave are all longer at basin stations compared to those outside. This increase in duration of ground shaking is probably caused by amplification of ground motion at basin stations, although coda Q (0.67 - 1.30 Hz) is slightly larger inside the basin compared to those at local stations outside the basin. Durations correlate with depth to basement. These motions are in the range that can induce damage in buildings and may have contributed to the structural collapse of multistory buildings in the Taipei basin.

Levels at gaging stations

USGS Publications Warehouse

Kenney, Terry A.

2010-01-01

Operational procedures at U.S. Geological Survey gaging stations include periodic leveling checks to ensure that gages are accurately set to the established gage datum. Differential leveling techniques are used to determine elevations for reference marks, reference points, all gages, and the water surface. The techniques presented in this manual provide guidance on instruments and methods that ensure gaging-station levels are run to both a high precision and accuracy. Levels are run at gaging stations whenever differences in gage readings are unresolved, stations may have been damaged, or according to a pre-determined frequency. Engineer's levels, both optical levels and electronic digital levels, are commonly used for gaging-station levels. Collimation tests should be run at least once a week for any week that levels are run, and the absolute value of the collimation error cannot exceed 0.003 foot/100 feet (ft). An acceptable set of gaging-station levels consists of a minimum of two foresights, each from a different instrument height, taken on at least two independent reference marks, all reference points, all gages, and the water surface. The initial instrument height is determined from another independent reference mark, known as the origin, or base reference mark. The absolute value of the closure error of a leveling circuit must be less than or equal to ft, where n is the total number of instrument setups, and may not exceed |0.015| ft regardless of the number of instrument setups. Closure error for a leveling circuit is distributed by instrument setup and adjusted elevations are determined. Side shots in a level circuit are assessed by examining the differences between the adjusted first and second elevations for each objective point in the circuit. The absolute value of these differences must be less than or equal to 0.005 ft. Final elevations for objective points are determined by averaging the valid adjusted first and second elevations. If final elevations indicate that the reference gage is off by |0.015| ft or more, it must be reset.

Apparent chlorofluorocarbon age of ground water of the shallow aquifer system, Naval Weapons Station Yorktown, Yorktown, Virginia

USGS Publications Warehouse

Nelms, David L.; Harlow, George E.; Brockman, Allen R.

2001-01-01

Apparent ages of ground water are useful in the analysis of various components of flow systems, and results of this analysis can be incorporated into investigations of potential pathways of contaminant transport. This report presents the results of a study in 1997 by the U.S. Geological Survey (USGS), in cooperation with the Naval Weapons Station Yorktown, Base Civil Engineer, Environmental Directorate, to describe the apparent age of ground water of the shallow aquifer system at the Station. Chlorofluorocarbons (CFCs), tritium (3H), dissolved gases, stable isotopes, and water-quality field properties were measured in samples from 14 wells and 16 springs on the Station in March 1997.Nitrogen-argon recharge temperatures range from 5.9°C to 17.3°C with a median temperature of 10.9°C, which indicates that ground-water recharge predominantly occurs in the cold months of the year. Concentrations of excess air vary depending upon geohydrologic setting (recharge and discharge areas). Apparent ground-water ages using a CFC-based dating technique range from 1 to 48 years with a median age of 10 years. The oldest apparent CFC ages occur in the upper parts of the Yorktown-Eastover aquifer, whereas the youngest apparent ages occur in the Columbia aquifer and the upper parts of the discharge area setting, especially springs. The vertical distribution of apparent CFC ages indicates that groundwater movement between aquifers is somewhat retarded by the leaky confining units, but the elapsed time is relatively short (generally less than 35 years), as evidenced by the presence of CFCs at depth. The identification of binary mixtures by CFC-based dating indicates that convergence of flow lines occurs not only at the actual point of discharge, but also in the subsurface.The CFC-based recharge dates are consistent with expected 3H concentrations measured in the water samples from the Station. The concentration of 3H in ground water ranges from below the USGS laboratory minimum reporting limit of 0.3 to 15.9 tritium units (TU) with a median value of 10.8 TU. Water-quality field properties are highly variable for ground water with apparent CFC ages less than 15 years because of geochemical processes within local flow systems. Ground water with apparent CFC ages greater than 15 years represents more stable conditions in subregional flow systems.The range of apparent CFC ages is slightly greater than the ranges in time of travel of ground water calculated for shallow wells (less than 60- feet deep) from flow-path analysis. Calculated travel times to springs can be up to two orders of magnitude greater than the CFC-based apparent ages. Reasonable assumptions of values for hydraulic parameters can result in substantial overestimates for time of travel to springs.Recharge rates computed from apparent CFC ages range from 0.29 to 0.89 feet per year (ft/ yr) with an average value of 0.54 ft/yr. The analysis of apparent CFC ages in conjunction with geohydrologic data indicates that young water (less than 50 years) is present at depth (nearly 120 feet) and that both local and subregional flow systems occur in the shallow aquifer system at the Station. The addition of the dimension of time to the three-dimensional framework of Brockman and others (1997) will benefit current (2001) and future remediation activities by providing estimates of advective transport rates and how these rates vary depending upon geohydrologic setting and position within the ground-water-flow system. Estimated ground-water apparent ages and recharge rates can be used as calibration criteria in simulations of ground-water flow on the Station to refine and constrain future ground-water-flow models of the shallow aquifer system.

International mission planning for space Very Long Baseline Interferometry

NASA Technical Reports Server (NTRS)

Ulvestad, James S.

1994-01-01

Two spacecraft dedicated to Very Long Baseline Interferometry (VLBI) will be launched in 1996 and 1997 to make observations using baselines between the space telescopes and many of the world's ground radio telescopes. The Japanese Institute of Space and Astronautical Science (ISAS) will launch VSOP (VLBI Space Observatory Program) in September 1996, while the Russian Astro Space Center (ASC) is scheduled to launch RadioAstron in 1997. Both spacecraft will observe radio sources at frequencies near 1.7, 4.8, and 22 GHz; RadioAstron will also observe at 0.33 GHz. The baselines between space and ground telescopes will provide 3-10 times the resolution available for ground VLBI at the same observing frequencies. Ground tracking stations on four continents will supply the required precise frequency reference to each spacecraft measure the two-way residual phase and Doppler on the ground-space link, and record 128 Megabit/s of VLBI data downlinked from the spacecraft. The spacecraft data are meaningless without cross-correlation against the data from Earth-bound telescopes, which must take place at special-purpose VLBI correlation facilities. Therefore, participation by most of the world's radio observatories is needed to achieve substantial science return from VSOP and RadioAstron. The collaboration of several major space agencies and the ground observatories, which generally follow very different models for allocation of observing time and for routine operations, leads to great complexity in mission planning and in day-to-day operations. This paper describes some of those complications and the strategies being developed to assure productive scientific missions.

High Speed A/D DSP Interface for Carrier Doppler Tracking

NASA Technical Reports Server (NTRS)

Baggett, Timothy

1998-01-01

As on-board satellite systems continue to increase in ability to perform self diagnostic checks, it will become more important for satellites to initiate ground communications contact. Currently, the NASA Space Network requires users to pre-arranged times for satellite communications links through the Tracking and Data Relay Satellite (TDRS). One of the challenges in implementing an on-demand access protocol into the Space Network, is the fact that a low Earth orbiting (LEO) satellite's communications will be subject to a doppler shift which is outside the capability of the NASA ground station to lock onto. In a prearranged system, the satellite's doppler is known a priori, and the ground station is able to lock onto the satellite's signal. This paper describes the development of a high speed analog to digital interface into a Digital Signal Processor (DSP). This system will be used for identifying the doppler shift of a LEO satellite through the Space Network, and aiding the ground station equipment in locking onto the signal. Although this interface is specific to one application, it can be used as a basis for interfacing other devices with a DSP.

Infrasonic sounds excited by seismic waves of the 2011 Tohoku-oki earthquake as visualized in ionograms

NASA Astrophysics Data System (ADS)

Maruyama, Takashi; Shinagawa, Hiroyuki

2014-05-01

After the M 9.0 Tohoku-oki earthquake in 2011, strong deformation of ionogram echo traces, forming multiple cusp signatures (MCSs), were observed at three stations 790-1880 km from the epicenter. The vertical structure of the ionospheric disturbances was determined by true height analysis and compared with broadband seismograph records at stations close to the ionosondes. These ionospheric disturbances were caused by vertically propagating acoustic waves excited by the up/down ground motion of seismic waves. Numerical simulations have shown that acoustic waves with a period of 15-40 s and amplitude of order 1 mm/s at the ground level were sufficient to create MCSs as sharp as those observed. These acoustic wave parameters are consistent with the seismic records if the motion of the air mass on the ground level is assumed to be the same as the ground motion. The travel time diagram of the seismic records along the line connecting the epicenter and ionosondes showed that the first MCS ionogram detected at each station was caused by P waves, while the others were caused by Rayleigh waves.

Narrow Angle Diversity using ACTS Ka-band Signal with Two USAT Ground Stations

NASA Technical Reports Server (NTRS)

Kalu, A.; Emrich, C.; Ventre, J.; Wilson, W.; Acosta, R.

1998-01-01

Two ultra small aperture terminal (USAT) ground stations, separated by 1.2 km in a narrow angle diversity configuration, received a continuous Ka-band tone sent from Cleveland Link Evaluation Terminal (LET). The signal was transmitted to the USAT ground stations via NASA's Advanced Communications Technology Satellite (ACTS) steerable beam. Received signal power at the two sites was measured and analyzed. A dedicated datalogger at each site recorded time-of-tip data from tipping bucket rain gauges, providing rain amount and instantaneous rain rate. WSR-88D data was also obtained for the collection period. Eleven events with ground-to-satellite slant-path precipitation and resultant signal attenuation were observed during the data collection period. Fade magnitude and duration were compared at the two sites and diversity gain was calculated. These results exceeded standard diversity gain model predictions by several decibels. Rain statistics from tipping bucket data and from radar data were also compared to signal attenuation. The nature of Florida's subtropical rainfall, specifically its impact on signal attenuation at the sites, was addressed.

9 CFR 93.410 - Movement from conveyances to quarantine station.

Code of Federal Regulations, 2012 CFR

2012-01-01

... quarantine station. 93.410 Section 93.410 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION... conveyances to quarantine station. Platforms and chutes used for handling imported ruminants shall be cleaned... transferred from the conveyance to the quarantine grounds in boats, cars, or vehicles approved by the...

9 CFR 93.410 - Movement from conveyances to quarantine station.

Code of Federal Regulations, 2011 CFR

2011-01-01

... quarantine station. 93.410 Section 93.410 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION... conveyances to quarantine station. Platforms and chutes used for handling imported ruminants shall be cleaned... transferred from the conveyance to the quarantine grounds in boats, cars, or vehicles approved by the...

9 CFR 93.410 - Movement from conveyances to quarantine station.

Code of Federal Regulations, 2014 CFR

2014-01-01

... quarantine station. 93.410 Section 93.410 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION... conveyances to quarantine station. Platforms and chutes used for handling imported ruminants shall be cleaned... transferred from the conveyance to the quarantine grounds in boats, cars, or vehicles approved by the...

9 CFR 93.410 - Movement from conveyances to quarantine station.

Code of Federal Regulations, 2013 CFR

2013-01-01

... quarantine station. 93.410 Section 93.410 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION... conveyances to quarantine station. Platforms and chutes used for handling imported ruminants shall be cleaned... transferred from the conveyance to the quarantine grounds in boats, cars, or vehicles approved by the...

21. Photocopied from blueprint, Olmstead Station Miscellaneous Drawings Folder, Engineering ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. Photocopied from blueprint, Olmstead Station Miscellaneous Drawings Folder, Engineering Department, Utah Power & Light Co., Salt Lake City, Utah. 'STATION GROUNDS, TELLURIDE POWER CO., PROVO, UTAH.' MAP,1903. - Telluride Power Company, Olmsted Hydroelectric Plant, mouth of Provo River Canyon West of U.S. Route 189, Orem, Utah County, UT

Space station structures and dynamics test program

NASA Technical Reports Server (NTRS)

Moore, Carleton J.; Townsend, John S.; Ivey, Edward W.

1987-01-01

The design, construction, and operation of a low-Earth orbit space station poses unique challenges for development and implementation of new technology. The technology arises from the special requirement that the station be built and constructed to function in a weightless environment, where static loads are minimal and secondary to system dynamics and control problems. One specific challenge confronting NASA is the development of a dynamics test program for: (1) defining space station design requirements, and (2) identifying the characterizing phenomena affecting the station's design and development. A general definition of the space station dynamic test program, as proposed by MSFC, forms the subject of this report. The test proposal is a comprehensive structural dynamics program to be launched in support of the space station. The test program will help to define the key issues and/or problems inherent to large space structure analysis, design, and testing. Development of a parametric data base and verification of the math models and analytical analysis tools necessary for engineering support of the station's design, construction, and operation provide the impetus for the dynamics test program. The philosophy is to integrate dynamics into the design phase through extensive ground testing and analytical ground simulations of generic systems, prototype elements, and subassemblies. On-orbit testing of the station will also be used to define its capability.

Seismic Station Installation Orientation Errors at ANSS and IRIS/USGS Stations

USGS Publications Warehouse

Ringler, Adam T.; Hutt, Charles R.; Persfield, K.; Gee, Lind S.

2013-01-01

Many seismological studies depend on the published orientations of sensitive axes of seismic instruments relative to north (e.g., Li et al., 2011). For example, studies of the anisotropic structure of the Earth’s mantle through SKS‐splitting measurements (Long et al., 2009), constraints on core–mantle electromagnetic coupling from torsional normal‐mode measurements (Dumberry and Mound, 2008), and models of three‐dimensional (3D) velocity variations from surface waves (Ekström et al., 1997) rely on accurate sensor orientation. Unfortunately, numerous results indicate that this critical parameter is often subject to significant error (Laske, 1995; Laske and Masters, 1996; Yoshizawa et al., 1999; Schulte‐Pelkum et al., 2001; Larson and Ekström, 2002). For the Advanced National Seismic System (ANSS; ANSS Technical Integration Committee, 2002), the Global Seismographic Network (GSN; Butler et al., 2004), and many other networks, sensor orientation is typically determined by a field engineer during installation. Successful emplacement of a seismic instrument requires identifying true north, transferring a reference line, and measuring the orientation of the instrument relative to the reference line. Such an exercise is simple in theory, but there are many complications in practice. There are four commonly used methods for determining true north at the ANSS and GSN stations operated by the USGS Albuquerque Seismological Laboratory (ASL), including gyroscopic, astronomical, Global Positioning System (GPS), and magnetic field techniques. A particular method is selected based on site conditions (above ground, below ground, availability of astronomical observations, and so on) and in the case of gyroscopic methods, export restrictions. Once a north line has been determined, it must be translated to the sensor location. For installations in mines or deep vaults, this step can include tracking angles through the one or more turns in the access tunnel leading to the vault (e.g., GSN station WCI in Wyandotte Cave, Indiana). Finally, the third source of error comes from the ability of field engineers to orient the sensor relative to the reference line. In order to quantify bounds on the errors in each step in the orientation process, we conducted a series of tests at the ASL using twelve GSN and ANSS field engineers. The results from this exercise allow us to estimate upper bounds on the precision of our ability to orient instruments, as well as identify the sources of error in the procedures. We are also able to identify systematic bias of various true‐north‐finding methods relative to one another. Although we are unable to estimate the absolute accuracy of our orientation measurements due to our inability to identify true north without some error, the agreement between independent methods for finding true north provides confidence in the different approaches, assuming no systematic bias. Finally, our study neglects orientation errors that are beyond the control of the field engineer during a station visit. These additional errors can arise from deviations in the sensitive axes of the instruments relative to the case markings, processing errors (Holcomb, 2002) when comparing horizontal orientations relative to other sensors (e.g., borehole installations), and deviations of the sensitive axes of instruments from true orthogonality (e.g., instruments with separate modules such as the Streckeisen STS‐1).

Ecotoxicological studies of environmental samples from Buenos Aires area using a standardized amphibian embryo toxicity test (AMPHITOX).

PubMed

Herkovits, Jorge; Perez-Coll, Cristina; Herkovits, Francisco D

2002-01-01

The toxicity of 34 environmental samples from potentially polluted and reference stations were evaluated by means of the AMPHITOX test from acute to chronic exposure according to the toxicity found in each sample. The samples were obtained from surface and ground water, leaches, industrial effluents and soils. The data, expressed in acute, short-term chronic and chronic Toxicity Units (TUa, TUstc and TUc) resulted in a maximal value of 1000 TUc, found in a leach, while the lower toxicity value was 1.4 TUa corresponding to two surface water samples. In five samples (four providing from reference places) no toxicity was detected. The results point out the possibility of evaluating the toxicity of a wide diversity of samples by means of AMPHITOX as a customized toxicity test. The fact that almost all samples with suspected toxicity in rivers and streams from the Metropolitan area of Buenos Aires city resulted toxic, indicates the need of enhanced stewardship of chemical substances for environmental and human health protection purposes.

Data Processing of LAPAN-A3 Thermal Imager

NASA Astrophysics Data System (ADS)

Hartono, R.; Hakim, P. R.; Syafrudin, AH

2018-04-01

As an experimental microsatellite, LAPAN-A3/IPB satellite has an experimental thermal imager, which is called as micro-bolometer, to observe earth surface temperature for horizon observation. The imager data is transmitted from satellite to ground station by S-band video analog signal transmission, and then processed by ground station to become sequence of 8-bit enhanced and contrasted images. Data processing of LAPAN-A3/IPB thermal imager is more difficult than visual digital camera, especially for mosaic and classification purpose. This research aims to describe simple mosaic and classification process of LAPAN-A3/IPB thermal imager based on several videos data produced by the imager. The results show that stitching using Adobe Photoshop produces excellent result but can only process small area, while manual approach using ImageJ software can produce a good result but need a lot of works and time consuming. The mosaic process using image cross-correlation by Matlab offers alternative solution, which can process significantly bigger area in significantly shorter time processing. However, the quality produced is not as good as mosaic images of the other two methods. The simple classifying process that has been done shows that the thermal image can classify three distinct objects, i.e.: clouds, sea, and land surface. However, the algorithm fail to classify any other object which might be caused by distortions in the images. All of these results can be used as reference for development of thermal imager in LAPAN-A4 satellite.

Collaborative Software Development Approach Used to Deliver the New Shuttle Telemetry Ground Station

NASA Technical Reports Server (NTRS)

Kirby, Randy L.; Mann, David; Prenger, Stephen G.; Craig, Wayne; Greenwood, Andrew; Morsics, Jonathan; Fricker, Charles H.; Quach, Son; Lechese, Paul

2003-01-01

United Space Alliance (USA) developed and used a new software development method to meet technical, schedule, and budget challenges faced during the development and delivery of the new Shuttle Telemetry Ground Station at Kennedy Space Center. This method, called Collaborative Software Development, enabled KSC to effectively leverage industrial software and build additional capabilities to meet shuttle system and operational requirements. Application of this method resulted in reduced time to market, reduced development cost, improved product quality, and improved programmer competence while developing technologies of benefit to a small company in California (AP Labs Inc.). Many modifications were made to the baseline software product (VMEwindow), which improved its quality and functionality. In addition, six new software capabilities were developed, which are the subject of this article and add useful functionality to the VMEwindow environment. These new software programs are written in C or VXWorks and are used in conjunction with other ground station software packages, such as VMEwindow, Matlab, Dataviews, and PVWave. The Space Shuttle Telemetry Ground Station receives frequency-modulation (FM) and pulse-code-modulated (PCM) signals from the shuttle and support equipment. The hardware architecture (see figure) includes Sun workstations connected to multiple PCM- and FM-processing VersaModule Eurocard (VME) chassis. A reflective memory network transports raw data from PCM Processors (PCMPs) to the programmable digital-to-analog (D/A) converters, strip chart recorders, and analysis and controller workstations.

The Telecommunications and Data Acquisition Report

NASA Technical Reports Server (NTRS)

Posner, E. C. (Editor)

1988-01-01

Deep Space Network and Systems topics addressed include: tracking and ground-base navigation; communications, spacecraft-ground; station control and system technology; capabilities for existing projects; and network upgrading and sustaining.

LEO to ground optical communications from a small satellite platform

NASA Astrophysics Data System (ADS)

Rose, T. S.; Janson, S. W.; LaLumondiere, S.; Werner, N.; Hinkley, D. H.; Rowen, D. W.; Fields, R. A.; Welle, R. P.

2015-03-01

A pair of 2.2 kg CubeSats using COTS hardware is being developed for a proof-of-principle optical communications demo from a 450-600 km LEO orbit to ground. The 10x10x15 cm platform incorporates a 25% wall-plug efficient 10-W Yb fiber transmitter emitting at 1.06 μm. Since there are no gimbals on board, the entire spacecraft is body-steered toward the ground station. The pointing accuracy of the LEO craft, which governs the data rate capability, is expected to be ~ 0.1-0.2 deg. Two optical ground stations, located at the Mt. Wilson observatory, have receiver apertures of 30 and 80 cm. Launch of the CubeSat pair is anticipated to be mid to late 2015.

Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at the Langtree Peninsula Research Station, Iredell County, North Carolina, 2000-2005

USGS Publications Warehouse

Pippin, Charles G.; Chapman, Melinda J.; Huffman, Brad A.; Heller, Matthew J.; Schelgel, Melissa E.

2008-01-01

A 6-year intensive field study (2000-2005) of a complex, regolith-fractured bedrock ground-water system was conducted at the Langtree Peninsula research station on the Davidson College Lake Campus in Iredell County, North Carolina. This research station was constructed as part of the Piedmont and Mountains Resource Evaluation Program, a cooperative study being conducted by the North Carolina Department of Environment and Natural Resources and the U.S. Geological Survey. Results of the study characterize the distinction and interaction of a two-component ground-water system in a quartz diorite rock type. The Langtree Peninsula research station includes 17 monitoring wells and 12 piezometers, including 2 well transects along high to low topographic settings, drilled into separate parts of the ground-water-flow system. The location of the research station is representative of a metaigneous intermediate (composition) regional hydrogeologic unit. The primary rock type is mafic quartz diorite that has steeply dipping foliation. Primary and secondary foliations are present in the quartz diorite at the site, and both have an average strike of about N. 12 degree E. and dip about 60 degree in opposite directions to the southeast (primary) and the northwest (secondary). This rock is cut by granitic dikes (intrusions) ranging in thickness from 2 to 50 feet and having an average strike of N. 20 degree W. and an average dip of 66 degree to the southwest. Depth to consolidated bedrock is considered moderate to deep, ranging from about 24 to 76 feet below land surface. The transition zone was delineated and described in each corehole near the well clusters but had a highly variable thickness ranging from about 1 to 20 feet. Thickness of the regolith (23 to 68 feet) and the transition zone do not appear to be related to topographic setting. Delineated bedrock fractures are dominantly low angle (possibly stress relief), which were observed to be open to partially open at depths of as much as 479 feet below land surface. Well yields ranged from about 3 to 50 gallons per minute. The connection of fracture zones at depth was demonstrated in three bedrock wells during a 48-hour aquifer test, and drawdown curves were similar for all three wells. General findings of this study help characterize ground-water flow in the Piedmont and Mountains ground-water systems. Ground-water flow generally is from high to low topographic settings. Ground-water flow discharges toward a surface-water boundary (Lake Norman), and vertical hydraulic gradients generally are downward in recharge areas and upward in discharge areas. Dominant water types are calcium-bicarbonate and are similar in all three zones (regolith, transition zone, and bedrock) of the ground-water system. Results of continuous ground-water-quality monitoring indicate that ground-water recharge may occur seasonally over a period of several months or after heavy rainfall periods over a shorter period of a few to several weeks.

Microgravity

NASA Image and Video Library

2001-01-24

An artist's concept of the Primary Atomic Clock Reference System (PARCS) plarned to fly on the International Space Station (ISS). PARCS will make even more accurate atomic time available to everyone, from physicists testing Einstein's Theory of Relativity, to hikers using the Global Positioning System to find their way. In ground-based atomic clocks, lasers are used to cool and nearly stop atoms of cesium whose vibrations are used as the time base. The microgravity of space will allow the atoms to be suspended in the clock rather than circulated in an atomic fountain, as required on Earth. PARCS is being developed by the Jet Propulsion Laboratory with principal investigators at the National Institutes of Standards and Technology and the University of Colorado, Boulder. See also No. 0103191

48 CFR 1852.228-76 - Cross-waiver of liability for space station activities.

Code of Federal Regulations, 2010 CFR

2010-10-01

... product or process except when such development is for Space Station-related activities in implementation...) All activities related to ground support, test, training, simulation, or guidance and control...

Ground motion in the presence of complex Topography II: Earthquake sources and 3D simulations

USGS Publications Warehouse

Hartzell, Stephen; Ramirez-Guzman, Leonardo; Meremonte, Mark; Leeds, Alena L.

2017-01-01

Eight seismic stations were placed in a linear array with a topographic relief of 222 m over Mission Peak in the east San Francisco Bay region for a period of one year to study topographic effects. Seventy‐two well‐recorded local earthquakes are used to calculate spectral amplitude ratios relative to a reference site. A well‐defined fundamental resonance peak is observed with individual station amplitudes following the theoretically predicted progression of larger amplitudes in the upslope direction. Favored directions of vibration are also seen that are related to the trapping of shear waves within the primary ridge dimensions. Spectral peaks above the fundamental one are also related to topographic effects but follow a more complex pattern. Theoretical predictions using a 3D velocity model and accurate topography reproduce many of the general frequency and time‐domain features of the data. Shifts in spectral frequencies and amplitude differences, however, are related to deficiencies of the model and point out the importance of contributing factors, including the shear‐wave velocity under the topographic feature, near‐surface velocity gradients, and source parameters.

Psychosocial interactions during ISS missions

NASA Astrophysics Data System (ADS)

Kanas, N. A.; Salnitskiy, V. P.; Ritsher, J. B.; Gushin, V. I.; Weiss, D. S.; Saylor, S. A.; Kozerenko, O. P.; Marmar, C. R.

2007-02-01

Based on anecdotal reports from astronauts and cosmonauts, studies of space analog environments on Earth, and our previous research on the Mir Space Station, a number of psychosocial issues have been identified that can lead to problems during long-duration space expeditions. Several of these issues were studied during a series of missions to the International Space Station. Using a mood and group climate questionnaire that was completed weekly by crewmembers in space and personnel in mission control, we found no evidence to support the presence of predicted decrements in well-being during the second half or in any specific quarter of the missions. The results did support the predicted displacement of negative feelings to outside supervisors among both crew and ground subjects. There were several significant differences in mood and group perceptions between Americans and Russians and between crewmembers and mission control personnel. Crewmembers related cohesion to the support role of their leader, and mission control personnel related cohesion to both the task and support roles of their leader. These findings are discussed with reference to future space missions.

Statistical analysis of electromagnetic radiation measurements in the vicinity of GSM/UMTS base station installed on buildings in Serbia.

PubMed

Koprivica, Mladen; Slavkovic, Vladimir; Neskovic, Natasa; Neskovic, Aleksandar

2016-03-01

As a result of dense deployment of public mobile base stations, additional electromagnetic (EM) radiation occurs in the modern human environment. At the same time, public concern about the exposure to EM radiation emitted by such sources has increased. In order to determine the level of radio frequency radiation generated by base stations, extensive EM field strength measurements were carried out for 664 base station locations, from which 276 locations refer to the case of base stations with antenna system installed on buildings. Having in mind the large percentage (42 %) of locations with installations on buildings, as well as the inevitable presence of people in their vicinity, a detailed analysis of this location category was performed. Measurement results showed that the maximum recorded value of total electric field strength has exceeded International Commission on Non-Ionizing Radiation Protection general public exposure reference levels at 2.5 % of locations and Serbian national reference levels at 15.6 % of locations. It should be emphasised that the values exceeding the reference levels were observed only outdoor, while in indoor total electric field strength in no case exceeded the defined reference levels. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

GPS-Only Terrestrial Reference Frame Based on a Global Reprocessing

NASA Astrophysics Data System (ADS)

Dietrich, R.; Rothacher, M.; Ruelke, A.; Fritsche, M.; Steigenberger, P.

2007-12-01

The realization of the International Terrestrial Reference System (ITRS) with highest accuracy and stability is fundamental and crucial for applications in geodesy, geodynamics, geophysics and global change. In a joint effort TU Dresden and TU Munich/GFZ Potsdam reprocessed a global GPS network of more than 200 stations. As a contribution to an ITRS realization daily normal equations from 1994 to 2005 were rigorously combined in order to determine a global GPS-only reference frame (PDR05/Potsdam-Dresden-Reprocessing Reference Frame). We present a realization of the global terrestrial reference system which follows the center of mass approach in consideration of the load-induced deformation of the Earth's crust due to the redistribution of surface masses. The stability of our reference frame will be evaluated based on the obtained long-term trends of station coordinates, the load-induced deformation estimates and the homogeneous time series of station positions. We will compare our solution with other recent terrestrial reference system realizations and give some conclusions for future realizations of the ITRS.

9 CFR 93.509 - Movement from conveyances to quarantine station.

Code of Federal Regulations, 2014 CFR

2014-01-01

... quarantine station. 93.509 Section 93.509 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION... conveyances to quarantine station. Platforms and chutes used for handling imported swine shall be cleaned and... conveyance to the quarantine grounds in boats, cars, or vehicles approved by the inspector in charge at the...

9 CFR 93.509 - Movement from conveyances to quarantine station.

Code of Federal Regulations, 2012 CFR

2012-01-01

... quarantine station. 93.509 Section 93.509 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION... conveyances to quarantine station. Platforms and chutes used for handling imported swine shall be cleaned and... conveyance to the quarantine grounds in boats, cars, or vehicles approved by the inspector in charge at the...

9 CFR 93.509 - Movement from conveyances to quarantine station.

Code of Federal Regulations, 2011 CFR

2011-01-01

... quarantine station. 93.509 Section 93.509 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION... conveyances to quarantine station. Platforms and chutes used for handling imported swine shall be cleaned and... conveyance to the quarantine grounds in boats, cars, or vehicles approved by the inspector in charge at the...

9 CFR 93.509 - Movement from conveyances to quarantine station.

Code of Federal Regulations, 2013 CFR

2013-01-01

... quarantine station. 93.509 Section 93.509 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION... conveyances to quarantine station. Platforms and chutes used for handling imported swine shall be cleaned and... conveyance to the quarantine grounds in boats, cars, or vehicles approved by the inspector in charge at the...

31. RECORD PLAN, METROPOLITAN SEWER, GENERAL PLAN OF PUMPING STATION ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. RECORD PLAN, METROPOLITAN SEWER, GENERAL PLAN OF PUMPING STATION GROUNDS, DEER ISLAND. METROPOLITAN SEWERAGE COMMISSION, JUNE 1896. Photocopy of image of aperture card 4977-1. Aperture cards and original drawings at Massachusetts Water Resources Authority Archives, Building 39, Charlestown Navy Yard, Boston, MA - Deer Island Pumping Station, Boston, Suffolk County, MA

Orbital ATK's Ground Support Equipment (GSE) Delivery for OA-7

NASA Image and Video Library

2016-12-15

Sealed in its shipping container, the ground support equipment for the Orbital ATK OA-7 commercial resupply services mission has arrived at the Space Station Processing Facility at NASA's Kennedy Space Center in Florida. The container will be moved inside the low bay of the facility. The Orbital ATK CRS-7 with the Cygnus cargo module will lift off atop a United Launch Alliance Atlas V rocket from Space launch Complex 41 at Cape Canaveral Air Force Station. The commercial resupply services mission to the International Space Station will deliver thousands of pounds of supplies, equipment and scientific research materials that improve life on Earth and drive progress toward future space exploration.

Near-realtime Cosmic Ray measurements for space weather applications

NASA Astrophysics Data System (ADS)

Steigies, C. T.

2013-12-01

In its FP7 program the European Commission has funded the creation of scientific databases. One successful project is the Neutron Monitor database NMDB which provides near-realtime access to ground-based Neutron Monitor measurements. In its beginning NMDB hosted only data from European and Asian participants, but it has recently grown to also include data from North American stations. We are currently working on providing also data from Australian stations. With the increased coverage of stations the accuracy of the NMDB applications to issue an alert of a ground level enhancement (GLE) or to predict the arrival of a coronal mass ejection (CME) is constantly improving. Besides the Cosmic Ray community and Airlines, that want to calculate radiation doses on flight routes, NMDB has also attracted users from outside the core field, for example hydrologists who compare local Neutron measurements with data from NMDB to determine soil humidity. By providing access to data from 50 stations, NMDB includes already data from the majority of the currently operating stations. However, in the future we want to include data from the few remaining stations, as well as historical data from stations that have been shut down.

Quality assessment of DInSAR deformation measurements in volcanic areas by comparing GPS and SBAS results

NASA Astrophysics Data System (ADS)

Bonforte, A.; Casu, F.; de Martino, P.; Guglielmino, F.; Lanari, R.; Manzo, M.; Obrizzo, F.; Puglisi, G.; Sansosti, E.; Tammaro, U.

2009-04-01

Differential Synthetic Aperture Radar Interferometry (DInSAR) is a methodology able to measure ground deformation rates and time series of relatively large areas. Several different approaches have been developed over the past few years: they all have in common the capability to measure deformations on a relatively wide area (say 100 km by 100 km) with a high density of the measuring points. For these reasons, DInSAR represents a very useful tool for investigating geophysical phenomena, with particular reference to volcanic areas. As for any measuring technique, the knowledge of the attainable accuracy is of fundamental importance. In the case of DInSAR technology, we have several error sources, such as orbital inaccuracies, phase unwrapping errors, atmospheric artifacts, effects related to the reference point selection, thus making very difficult to define a theoretical error model. A practical way to obtain assess the accuracy is to compare DInSAR results with independent measurements, such as GPS or levelling. Here we present an in-deep comparison between the deformation measurement obtained by exploiting the DInSAR technique referred to as Small BAseline Subset (SBAS) algorithm and by continuous GPS stations. The selected volcanic test-sites are Etna, Vesuvio and Campi Flegrei, in Italy. From continuous GPS data, solutions are computed at the same days SAR data are acquired for direct comparison. Moreover, three dimensional GPS displacement vectors are projected along the radar line of sight of both ascending and descending acquisition orbits. GPS data are then compared with the coherent DInSAR pixels closest to the GPS station. Relevant statistics of the differences between the two measurements are computed and correlated to some scene parameter that may affect DInSAR accuracy (altitude, terrain slope, etc.).

KSC-00pp1662

NASA Image and Video Library

2000-11-07

The International Space Station ground operations officially turn over the P6 Integrated Truss Structure to the NASA shuttle integration team in a ceremony in the Space Station Processing Facility. A symbolic key is presented to Brent Jett (at left), commander on mission STS-97, which is taking the P6 to the International Space Station. Next to him are (left to right) Bill Dowdell, mission manager; Mark Sorensen, outboard truss cargo element manager for Boeing; and John Elbon, Boeing ISS director of ground operations at KSC. Among the attendees at left watching the ceremony are other STS-97 crew members (in uniform, from left) Mission Specialists Joe Tanner and Carlos Noriega and Pilot Mike Bloomfield. Mission STS-97is the sixth construction flight to the International Space Station. Its payload includes a photovoltaic (PV) module, with giant solar arrays that will provide power to the Station. The mission involves two spacewalks to complete the solar array connections. STS-97 is scheduled to launch Nov. 30 at 10:05 p.m. EST

KSC00pp1662

NASA Image and Video Library

2000-11-07

The International Space Station ground operations officially turn over the P6 Integrated Truss Structure to the NASA shuttle integration team in a ceremony in the Space Station Processing Facility. A symbolic key is presented to Brent Jett (at left), commander on mission STS-97, which is taking the P6 to the International Space Station. Next to him are (left to right) Bill Dowdell, mission manager; Mark Sorensen, outboard truss cargo element manager for Boeing; and John Elbon, Boeing ISS director of ground operations at KSC. Among the attendees at left watching the ceremony are other STS-97 crew members (in uniform, from left) Mission Specialists Joe Tanner and Carlos Noriega and Pilot Mike Bloomfield. Mission STS-97is the sixth construction flight to the International Space Station. Its payload includes a photovoltaic (PV) module, with giant solar arrays that will provide power to the Station. The mission involves two spacewalks to complete the solar array connections. STS-97 is scheduled to launch Nov. 30 at 10:05 p.m. EST

Space Station needs, attributes and architectural options. Volume 2, book 2, part 2, Task 2: Information management system

NASA Technical Reports Server (NTRS)

1983-01-01

Missions to be performed, station operations and functions to be carried out, and technologies anticipated during the time frame of the space station were examined in order to determine the scope of the overall information management system for the space station. This system comprises: (1) the data management system which includes onboard computer related hardware and software required to assume and exercise control of all activities performed on the station; (2) the communication system for both internal and external communications; and (3) the ground segment. Techniques used to examine the information system from a functional and performance point of view are described as well as the analyses performed to derive the architecture of both the onboard data management system and the system for internal and external communications. These architectures are then used to generate a conceptual design of the onboard elements in order to determine the physical parameters (size/weight/power) of the hardware and software. The ground segment elements are summarized.

Space Station needs, attributes and architectural options. Volume 2, book 2, part 2, Task 2: Information management system

NASA Astrophysics Data System (ADS)

1983-04-01

Missions to be performed, station operations and functions to be carried out, and technologies anticipated during the time frame of the space station were examined in order to determine the scope of the overall information management system for the space station. This system comprises: (1) the data management system which includes onboard computer related hardware and software required to assume and exercise control of all activities performed on the station; (2) the communication system for both internal and external communications; and (3) the ground segment. Techniques used to examine the information system from a functional and performance point of view are described as well as the analyses performed to derive the architecture of both the onboard data management system and the system for internal and external communications. These architectures are then used to generate a conceptual design of the onboard elements in order to determine the physical parameters (size/weight/power) of the hardware and software. The ground segment elements are summarized.

The Telecommunications and Data Acquisition Report

NASA Technical Reports Server (NTRS)

Posner, E. C. (Editor)

1987-01-01

Topics addressed include: tracking and ground-based navigation; communications, spacecraft-ground; station control and system technology; capabilities for existing projects; network upgrade and sustaining; mission interface and support; and Ka-band capabilities.

Variability of site response in the Los Angeles urban area

USGS Publications Warehouse

Hartzell, S.; Cranswick, E.; Frankel, A.; Carver, D.; Meremonte, M.

1997-01-01

This article addresses the variability of site response in the Los Angeles area and possible structural causes for the observations. Aftershock records from 231 sites in the San Fernando and Los Angeles basins and the surrounding mountains are used in this study. Spectral ratios, taken with respect to a low-amplitude reference site, are used to document the variation in site amplification in the frequency range 2 to 6 Hz, both spatially and with backazimuth to the source. At higher frequencies (6 to 10 Hz), spectral ratios are shown to have greater spatial variability. Interstation spectral ratios are used to measure the standard deviation among sources as a function of station separation. An increase in the variation in ground motion is shown to take place at a station separation of 1 km. Relative site-response estimates between nearby stations are used to demonstrate that preferred directions of motion can exist even in areas with no surface topographic effects. Significant variations in site response exist over short baselines (up to a factor of 2 over 200 m) that are not explained by differences in surficial geology or shallow shear-wave velocity. A variety of investigative approaches is used, including spectral ratios, arrival-time variations, 1D and 2D waveform modeling, and comparison with seismic reflection lines, to determine the most likely causes of these observations. A correlation is demonstrated between late arrival times of P and S waves and larger site amplification in Sherman Oaks and Northridge. This observation, in conjunction with waveform modeling and seismic reflection profiles, is used to infer that sedimentary structures in the upper 1 to 2 km and topography on the sediment-basement interface play an important role in determining site amplification. These structures, in the form of folds and buried basins, focus energy in spatially restricted areas at the surface. Comparison of displacement waveforms at nearby stations having disparate site amplifications, complemented by known shallow shear-wave velocities at selected sites, is used to support the argument that these structures, in some cases, can be the dominant factor in the modification of local ground motions.

Effects of hydraulic and geologic factors on streamflow of the Yakima River Basin, Washington

USGS Publications Warehouse

Kinnison, Hallard B.; Sceva, Jack E.

1963-01-01

The Yakima River basin, in south-central Washington, is the largest single river system entirely within the confines of the State. Its waters are the most extensively utilized of all the rivers in Washington. The river heads high on the eastern slope of the Cascade Mountains, flows for 180 miles in a generally southeast direction, and discharges into the Columbia River. The western part of the basin is a mountainous area formed by sedimentary, volcanic, and metamorphic rocks, which generally have a low capacity for storing and transmitting water. The eastern part of the basin is. formed by a thick sequence of lava flows that have folded into long ridges and troughs. Downwarped structural basins between many of the ridges are partly filled with younger sedimentary deposits, which at some places are many hundreds of feet thick. The Yakima River flows from structural basin to structural basin through narrow water gaps that have been eroded through the anticlinal ridges. Each basin is also a topographic basin and a ground-water subbasin. A gaging station will measure the total outflow of a drainage area only if it is located at the surface outlet of a ground-water subbasin and then only if the stream basin is nearly coextensive with the ground-water subbasin. Many gaging stations in the Yakima basin are so located. The geology, hydrology, size. and location of 25 ground-water subbasins are described. Since the settlement of the valley began, the development of the land and water resources have caused progressive changes in the natural regimen of the basin's runoff. These changes have resulted from diversion of water from the streams, the application of water on the land for irrigation, the storage and release of flood waters, the pumping of ground water, and other factors Irrigation in the Yakima basin is reported 'to have begun about 1864. In 1955 about 425,000 acres were under irrigation. During the past 60-odd years many gaging stations have been operated at different sites within the basin. Only stations in the upper reaches, such as those below Keechelus, Kachess, or Cle Elum Lakes, give discharge records which are an accurate measure of the natural outflow of the drainage area. Farther down, stream, as the utilization of water becomes more extensive, the records at a gaging station show the discharge passing a particular point, but they do not reflect the natural outflow of the basin. Large canals divert water for use on lands above a station or carry it around a station for irrigation downstream. The deep sedimentary deposits within subbasins and the overlying alluvial gravels permit downvalley movement of large subsurface flows which bypass the gaging stations, except in the near vicinity of the water gaps. At the water gaps ground water rises to the surface, becoming streamflow, and can be accurately measured. The location of gaging stations within each subbasin is important, therefore, in determining whether the flow measured represents the total downvalley outflow or whether it is merely the surface-water component. Surface and subsurface factors that may affect the discharge records at each gaging station in the Yakima River basin include a description of upstream diversions, surface return flows, bypass canals, storage reservoirs, subsurface bypass flows, ground-water withdrawals, and other items. The available data are not sufficiently complete to permit a quantitative determination of the total basin yield at most gaging stations. However, data on the existing bypass channels, such as canals and drainage ditches, and on related subsurface movement of water provide valuable information necessary to proper use and interpretation of the streamflow records.

Physical Habitat and Energy Inputs Determine Freshwater Invertebrate Communities in Reference and Cranberry Farm Impacted Northeastern Coastal Zone Streams

NASA Astrophysics Data System (ADS)

Lander, D. M. P.; McCanty, S. T.; Dimino, T. F.; Christian, A. D.

2016-02-01

The River Continuum Concept (RCC) predicts stream biological communities based on dominant physical structures and energy inputs into streams and predicts how these features and corresponding communities change along the stream continuum. Verifying RCC expectations is important for creating valid points of comparison during stream ecosystem evaluation. These reference expectations are critical for restoration projects, such as the restoration of decommissioned cranberry bogs. Our research compares the physical habitat and freshwater invertebrate functional feeding groups (FWIFFG) of reference, active cranberry farming, and cranberry farm passive restoration sites in Northeastern Coastal Zone streams of Massachusetts to the specific RCC FWIFFG predictions. We characterized stream physical habitat using a semi-quantitative habitat characterization protocol and sampled freshwater invertebrates using the U.S. EPA standard 20-jab multi-habitat protocol. We expected that stream habitat would be most homogeneous at active farming stations, intermediate at restoration stations, and most heterogeneous at reference stations. Furthermore, we expected reference stream FWIFFG would be accurately predicted by the RCC and distributions at restoration and active sites would vary significantly. Habitat data was analyzed using a principle component analysis and results confirmed our predictions showing more homogeneous habitat for the active and reference stations, while showing a more heterogeneous habitat at the reference stations. The FWIFFG chi-squared analysis showed significant deviation from our specific RCC FWIFFG predictions. Because published FWIFFG distributions did not match our empirical values for a least disturbed Northeastern Coastal Zone headwater stream, using our data as a community structure template for current and future restoration projects is not recommend without further considerations.

An update to the analysis of the Canadian Spatial Reference System

NASA Astrophysics Data System (ADS)

Ferland, R.; Piraszewski, M.; Craymer, M.

2015-12-01

The primary objective of the Canadian Spatial Reference System (CSRS) is to provide users access to a consistent geo-referencing infrastructure over the Canadian landmass. Global Navigation Satellite System (GNSS) positioning accuracy requirements ranges from meter level to mm level (e.g.: crustal deformation). The highest level of the Canadian infrastructure consist of a network of continually operating GPS and GNSS receivers, referred to as active control stations. The network includes all Canadian public active control stations, some bordering US CORS and Alaska stations, Greenland active control stations, as well as a selection of IGS reference frame stations. The Bernese analysis software is used for the daily processing and the combination into weekly solutions which form the basis for this analysis. IGS weekly final orbit, Earth Rotation parameters (ERP's) and coordinates products are used in the processing. For the more demanding users, the time dependant changes of station coordinates is often more important.All station coordinate estimates and related covariance information is used in this analysis. For each input solution, variance factor, translation, rotation and scale (and if needed their rates) or subsets of these are estimated. In the combination of these weekly solutions, station positions and velocities are estimated. Since the time series from the stations in these networks often experience changes in behavior, new (or reuse of) parameters are generally used in these situations. As is often the case with real data, unrealistic coordinates may occur. Automatic detection and removal of outliers is used in these cases. For the transformation, position and velocity parameters loose apriori estimates and uncertainties are provided. Alignment using the usual Helmert transformation to the latest IGb08 realization of ITRF is also performed during the adjustment.

A SLAM II simulation model for analyzing space station mission processing requirements

NASA Technical Reports Server (NTRS)

Linton, D. G.

1985-01-01

Space station mission processing is modeled via the SLAM 2 simulation language on an IBM 4381 mainframe and an IBM PC microcomputer with 620K RAM, two double-sided disk drives and an 8087 coprocessor chip. Using a time phased mission (payload) schedule and parameters associated with the mission, orbiter (space shuttle) and ground facility databases, estimates for ground facility utilization are computed. Simulation output associated with the science and applications database is used to assess alternative mission schedules.

On increasing the spectral efficiency and transmissivity in the data transmission channel on the spacecraft-ground tracking station line

NASA Astrophysics Data System (ADS)

Andrianov, M. N.; Kostenko, V. I.; Likhachev, S. F.

2018-01-01

The algorithms for achieving a practical increase in the rate of data transmission on the space-craft-ground tracking station line has been considered. This increase is achieved by applying spectral-effective modulation techniques, the technology of orthogonal frequency compression of signals using millimeterrange radio waves. The advantages and disadvantages of each of three algorithms have been revealed. A significant advantage of data transmission in the millimeter range has been indicated.

Laser communication experiment. Volume 1: Design study report: Spacecraft transceiver. Part 3: LCE design specifications

NASA Technical Reports Server (NTRS)

1970-01-01

The requirements for the design, fabrication, performance, and testing of a 10.6 micron optical heterodyne receiver subsystem for use in a laser communication system are presented. The receiver subsystem, as a part of the laser communication experiment operates in the ATS 6 satellite and in a transportable ground station establishing two-way laser communications between the spacecraft and the transportable ground station. The conditions under which environmental tests are conducted are reported.

Ground-based simulation of telepresence for materials science experiments. [remote viewing and control of processes aboard Space Station

NASA Technical Reports Server (NTRS)

Johnston, James C.; Rosenthal, Bruce N.; Bonner, Mary JO; Hahn, Richard C.; Herbach, Bruce

1989-01-01

A series of ground-based telepresence experiments have been performed to determine the minimum video frame rate and resolution required for the successive performance of materials science experiments in space. The approach used is to simulate transmission between earth and space station with transmission between laboratories on earth. The experiments include isothermal dendrite growth, physical vapor transport, and glass melting. Modifications of existing apparatus, software developed, and the establishment of an inhouse network are reviewed.

Space station operations task force. Panel 2 report: Ground operations and support systems

NASA Technical Reports Server (NTRS)

1987-01-01

The Ground Operations Concept embodied in this report provides for safe multi-user utilization of the Space Station, eases user integration, and gives users autonomy and flexibility. It provides for meaningful multi-national participation while protecting U.S. interests. The concept also supports continued space operations technology development by maintaining NASA expertise and enabling technology evolution. Given attention here are pre/post flight operations, logistics, sustaining engineering/configuration management, transportation services/rescue, and information systems and communication.

Preliminary study of GPS orbit determination accuracy achievable from worldwide tracking data

NASA Technical Reports Server (NTRS)

Larden, D. R.; Bender, P. L.

1983-01-01

The improvement in the orbit accuracy if high accuracy tracking data from a substantially larger number of ground stations is available was investigated. Observations from 20 ground stations indicate that 20 cm or better accuracy can be achieved for the horizontal coordinates of the GPS satellites. With this accuracy, the contribution to the error budget for determining 1000 km baselines by GPS geodetic receivers would be only about 1 cm. Previously announced in STAR as N83-14605

A Human-Autonomy Teaming Approach for a Flight-Following Task

NASA Technical Reports Server (NTRS)

Brandt, Summer L.; Russell, Ricky; Lachter, Joel; Shively, Robert

2017-01-01

Managing aircraft is becoming more complex with increasingly sophisticated automation responsible for more flight tasks. With this increased complexity, it is becoming more difficult for operators to understand what the automation is doing and why. Human involvement with increasingly autonomous systems must adjust to allow for a more dynamic relationship involving cooperation and teamwork. As part of an ongoing project to develop a framework for human-autonomy teaming (HAT) in aviation, a part-task study was conducted to demonstrate, evaluate and refine proposed critical aspects of HAT. These features were built into an automated recommender system on a ground station available from previous studies. Participants performed a flight-following task once with the original ground station (i.e., No HAT condition) and once with the HAT features enabled (i.e., HAT condition). Behavioral and subjective measures were collected; subjective measures are presented here. Overall, participants preferred the ground station with HAT features enabled compared to the station without the HAT features. Participants reported that the HAT displays and automation were preferred for keeping up with operationally important issues. Additionally, participants reported that the HAT displays and automation provided enough situation awareness to complete the task and reduced workload relative to the No HAT baseline.

A facility for training Space Station astronauts

NASA Technical Reports Server (NTRS)

Hajare, Ankur R.; Schmidt, James R.

1992-01-01

The Space Station Training Facility (SSTF) will be the primary facility for training the Space Station Freedom astronauts and the Space Station Control Center ground support personnel. Conceptually, the SSTF will consist of two parts: a Student Environment and an Author Environment. The Student Environment will contain trainers, instructor stations, computers and other equipment necessary for training. The Author Environment will contain the systems that will be used to manage, develop, integrate, test and verify, operate and maintain the equipment and software in the Student Environment.

The determination of interseismic, coseismic and postseismic deformations caused by the Gökçeada-Samothraki earthquake (2014, Mw: 6.9) based on GNSS data

NASA Astrophysics Data System (ADS)

Tiryakioglu, Ibrahim; Yigit, Cemal Ozer; Yavasoglu, Hakan; Saka, Mehmet Halis; Alkan, Reha Metin

2017-09-01

Since the 1990s, seismic deformations have been commonly determined using the Global Navigation Satellite System (GNSS). Recently, the GNSS systems have become even more powerful with the use of new technologies in innovative studies. In this study, the GNSS data was used to investigate interseismic, coseismic and postseismic deformation and velocity of the Gökçeada-Samothraki earthquake (Mw = 6.9) that occurred on May 24, 2014. The data was obtained at 30 s (0.033 Hz) and 1 s (1 Hz) intervals from the GNSS receivers in the network of Continuously Operating Reference Stations, Turkey (CORS-TR). For the interseismic period, the daily coordinate time series of 12 stations located within 90-250 km of the earthquake epicenter was evaluated for the displacement of stations over a period of approximately 2000 days prior to the day of the earthquakes, from October 1, 2008 to May 23, 2014. In order to analyze the ground motion displacement during the Gökçeada-Samothraki earthquake, 1 Hz data from 8 continuous GNSS stations was processed using precise point positioning (PPP) and relative positioning methods to estimate the epoch-by-epoch positions of the stations. During the earthquake, coseismic displacements of approximately 7 and 30 mm were detected in the NW direction at the YENC and CANA stations, respectively. However, at the IPSA station, a coseismic deformation of 20 mm was observed in the NE direction. There were no significant changes at the other stations during the earthquake. For the postseismic period, the daily coordinate time series of the 12 stations were evaluated for station displacements for 570 days after the day of the earthquakes, from May 24, 2014 to January 1, 2016. The results demonstrated that no significant postseismic deformation with the exception of the EDIR station. An abnormal deformation caused by local factors was determined at the EDIR station. In this study, the PPP and the relative solution were also compared in terms of capturing the earthquake wave motion. The results demonstrated that the PPP-based solutions showed good agreement with those of relative positioning in terms of the ability to capture coseismic displacement.

Microbial Community Composition, Functions, and Activities in the Gulf of Mexico 1 Year after the Deepwater Horizon Accident

PubMed Central

Yergeau, Etienne; Maynard, Christine; Sanschagrin, Sylvie; Champagne, Julie; Juck, David; Lee, Kenneth

2015-01-01

Several studies have assessed the effects of the released oil on microbes, either during or immediately after the Deepwater Horizon accident. However, little is known about the potential longer-term persistent effects on microbial communities and their functions. In this study, one water column station near the wellhead (3.78 km southwest of the wellhead), one water column reference station outside the affected area (37.77 km southeast of the wellhead), and deep-sea sediments near the wellhead (3.66 km southeast of the wellhead) were sampled 1 year after the capping of the well. In order to analyze microbial community composition, function, and activity, we used metagenomics, metatranscriptomics, and mineralization assays. Mineralization of hexadecane was significantly higher at the wellhead station at a depth of ∼1,200 m than at the reference station. Community composition based on taxonomical or functional data showed that the samples taken at a depth of ∼1,200 m were significantly more dissimilar between the stations than at other depths (surface, 100 m, 750 m, and >1,500 m). Both Bacteria and Archaea showed reduced activity at depths of ∼1,200 m when the wellhead station was compared to the reference station, and their activity was significantly higher in surficial sediments than in 10-cm sediments. Surficial sediments also harbored significantly different active genera than did 5- and 10-cm sediments. For the remaining microbial parameters assessed, no significant differences could be observed between the wellhead and reference stations and between surface and 5- to 10-cm-deep sediments. PMID:26092461

Determination of base-flow characteristics at selected streamflow-gaging stations on the Mad River, Ohio

USGS Publications Warehouse

Koltun, G.F.

1995-01-01

This report describes the results of a study to estimate characteristics of base flow and sustained ground-water discharge at five streamflow-gaging stations on the Mad River in Ohio. The five streamflow-gaging stations are located at Zanesfield, near Urbana, at St. Paris Pike (at Eagle City), near Springfield, and near Dayton. The median of the annual-mean base flows, determined by means of hydrograph separation, ranged from 0.64 (ft3/s)/mi2 (cubic feet per second per square mile) at Zanesfield to 0.74 (ft3/s)/mi2 at St. Paris Pike. The median percentage of annual total streamflow attributed to base flow ranged from 61.8 percent at Zanesfield to 76.1 percent near Urbana. Estimates of an upper limit (or threshold) at which base flows can be considered to be composed predominately of sustained ground-water discharge were made by constructing and analyzing base- flow-duration curves. The sustained ground-water discharges (base flows less than or equal to the estimated sustained ground-water-discharge thresholds) are assumed to originate from ground-water- flow systems that are minimally affected by seasonal climatic changes. The median sustained ground- water discharge ranged from 0.11 (ft3/s)/mi2 at Zanesfield to 0.26 (ft3/s)/mi2 at St. Paris Pike (at Eagle City) and near Springfield. The median sustained ground-water discharge, expressed as a percentage of the median annual-mean base flow, ranged from 17.2 percent at Zanesfield to 38.6 percent near Springfield.

Digital, Satellite-Based Aeronautical Communication

NASA Technical Reports Server (NTRS)

Davarian, F.

1989-01-01

Satellite system relays communication between aircraft and stations on ground. System offers better coverage with direct communication between air and ground, costs less and makes possible new communication services. Carries both voice and data. Because many data exchanged between aircraft and ground contain safety-related information, probability of bit errors essential.

Network command processing system overview

NASA Technical Reports Server (NTRS)

Nam, Yon-Woo; Murphy, Lisa D.

1993-01-01

The Network Command Processing System (NCPS) developed for the National Aeronautics and Space Administration (NASA) Ground Network (GN) stations is a spacecraft command system utilizing a MULTIBUS I/68030 microprocessor. This system was developed and implemented at ground stations worldwide to provide a Project Operations Control Center (POCC) with command capability for support of spacecraft operations such as the LANDSAT, Shuttle, Tracking and Data Relay Satellite, and Nimbus-7. The NCPS consolidates multiple modulation schemes for supporting various manned/unmanned orbital platforms. The NCPS interacts with the POCC and a local operator to process configuration requests, generate modulated uplink sequences, and inform users of the ground command link status. This paper presents the system functional description, hardware description, and the software design.

The Rover Environmental Monitoring Station Ground Temperature Sensor: a pyrometer for measuring ground temperature on Mars.

PubMed

Sebastián, Eduardo; Armiens, Carlos; Gómez-Elvira, Javier; Zorzano, María P; Martinez-Frias, Jesus; Esteban, Blanca; Ramos, Miguel

2010-01-01

We describe the parameters that drive the design and modeling of the Rover Environmental Monitoring Station (REMS) Ground Temperature Sensor (GTS), an instrument aboard NASA's Mars Science Laboratory, and report preliminary test results. REMS GTS is a lightweight, low-power, and low cost pyrometer for measuring the Martian surface kinematic temperature. The sensor's main feature is its innovative design, based on a simple mechanical structure with no moving parts. It includes an in-flight calibration system that permits sensor recalibration when sensor sensitivity has been degraded by deposition of dust over the optics. This paper provides the first results of a GTS engineering model working in a Martian-like, extreme environment.

Water-resources data network evaluation for Monterey County, California; Phase 2, northern and coastal areas of Monterey County

USGS Publications Warehouse

Templin, W.E.; Smith, P.E.; DeBortoli, M.L.; Schluter, R.C.

1995-01-01

This report presents an evaluation of water- resources data-collection networks in the northern and coastal areas of Monterey County, California. This evaluation was done by the U.S. Geological Survey in cooperation with the Monterey County Flood Control and Water Conservation District to evaluate precipitation, surface water, and ground water monitoring networks. This report describes existing monitoring networks in the study areas and areas where possible additional data-collection is needed. During this study, 106 precipitation-quantity gages were identified, of which 84 were active; however, no precipitation-quality gages were identified in the study areas. The precipitaion-quantity gages were concentrated in the Monterey Peninsula and the northern part of the county. If the number of gages in these areas were reduced, coverage would still be adequate to meet most objectives; however, additional gages could improve coverage in the Tularcitos Creek basin and in the coastal areas south of Carmel to the county boundary. If collection of precipitation data were expanded to include monitoring precipitation quality, this expanded monitoring also could include monitoring precipitation for acid rain and pesticides. Eleven continuous streamflow-gaging stations were identified during this study, of which seven were active. To meet the objectives of the streamflow networks outlined in this report, the seven active stations would need to be continued, four stations would need to be reactivated, and an additional six streamflow-gaging stations would need to be added. Eleven stations that routinely were sampled for chemical constituents were identified in the study areas. Surface water in the lower Big Sur River basin was sampled annually for total coli- form and fecal coliform bacteria, and the Big Sur River was sampled monthly at 16 stations for these bacteria. Routine sampling for chemical constituents also was done in the Big Sur River basin. The Monterey County Flood Control and Water Conservation District maintained three networks in the study areas to measure ground-water levels: (1) the summer network, (2) the monthly network, and (3) the annual autumn network. The California American Water Company also did some ground-water-level monitoring in these areas. Well coverage for ground-water monitoring was dense in the seawater-intrusion area north of Moss Landing (possibly because of multiple overlying aquifers), but sparse in other parts of the study areas. During the study, 44 sections were identified as not monitored for ground-water levels. In an ideal ground-water-level network, wells would be evenly spaced, except where local conditions or correlations of wells make monitoring unnecessary. A total of 384 wells that monitor ground-water levels and/or ground-water quality were identified during this study. The Monterey County Flood Control and Water Conservation District sampled ground-water quality monthly during the irrigation season to monitor seawater intrusion. Once each year (during the summer), the wells in this network were monitored for chlorides, specific conductance, and nitrates. Additional samples were collected from each well once every 5 years for complete mineral analysis. The California Department of Health Services, the California American Water Company, the U.S. Army Health Service at Ford Ord, and the Monterey Peninsula Water Management District also monitored ground-water quality in wells in the study areas. Well coverage for the ground-water- quality networks was dense in the seawater- intrusion area north of Moss Landing, but sparse in the rest of the study areas. During this study, 54 sections were identified as not monitored for water quality.

Single-Station Sigma for the Iranian Strong Motion Stations

NASA Astrophysics Data System (ADS)

Zafarani, H.; Soghrat, M. R.

2017-11-01

In development of ground motion prediction equations (GMPEs), the residuals are assumed to have a log-normal distribution with a zero mean and a standard deviation, designated as sigma. Sigma has significant effect on evaluation of seismic hazard for designing important infrastructures such as nuclear power plants and dams. Both aleatory and epistemic uncertainties are involved in the sigma parameter. However, ground-motion observations over long time periods are not available at specific sites and the GMPEs have been derived using observed data from multiple sites for a small number of well-recorded earthquakes. Therefore, sigma is dominantly related to the statistics of the spatial variability of ground motion instead of temporal variability at a single point (ergodic assumption). The main purpose of this study is to reduce the variability of the residuals so as to handle it as epistemic uncertainty. In this regard, it is tried to partially apply the non-ergodic assumption by removing repeatable site effects from total variability of six GMPEs driven from the local, Europe-Middle East and worldwide data. For this purpose, we used 1837 acceleration time histories from 374 shallow earthquakes with moment magnitudes ranging from M w 4.0 to 7.3 recorded at 370 stations with at least two recordings per station. According to estimated single-station sigma for the Iranian strong motion stations, the ratio of event-corrected single-station standard deviation ( Φ ss) to within-event standard deviation ( Φ) is about 0.75. In other words, removing the ergodic assumption on site response resulted in 25% reduction of the within-event standard deviation that reduced the total standard deviation by about 15%.

Data Gathering and Energy Transfer Dilemma in UAV-Assisted Flying Access Network for IoT

PubMed Central

Arabi, Sara; Sadik, Mohamed

2018-01-01

Recently, Unmanned Aerial Vehicles (UAVs) have emerged as an alternative solution to assist wireless networks, thanks to numerous advantages they offer in comparison to terrestrial fixed base stations. For instance, a UAV can be used to embed a flying base station providing an on-demand nomadic access to network services. A UAV can also be used to wirelessly recharge out-of-battery ground devices. In this paper, we aim to deal with both data collection and recharging depleted ground Internet-of-Things (IoT) devices through a UAV station used as a flying base station. To extend the network lifetime, we present a novel use of UAV with energy harvesting module and wireless recharging capabilities. However, the UAV is used as an energy source to empower depleted IoT devices. On one hand, the UAV charges depleted ground IoT devices under three policies: (1) low-battery first scheme; (2) high-battery first scheme; and (3) random scheme. On the other hand, the UAV station collects data from IoT devices that have sufficient energy to transmit their packets, and in the same phase, the UAV exploits the Radio Frequency (RF) signals transmitted by IoT devices to extract and harvest energy. Furthermore, and as the UAV station has a limited coverage time due to its energy constraints, we propose and investigate an efficient trade-off between ground users recharging time and data gathering time. Furthermore, we suggest to control and optimize the UAV trajectory in order to complete its travel within a minimum time, while minimizing the energy spent and/or enhancing the network lifetime. Extensive numerical results and simulations show how the system behaves under different scenarios and using various metrics in which we examine the added value of UAV with energy harvesting module. PMID:29751662

US Space VLBI Proposed Outreach Web Site

NASA Technical Reports Server (NTRS)

2000-01-01

The study of how VLBI might be pursued in space began in the late 1970's, when it was realized that the size of the earth was a serious limitation to the study of compact radio sources. By going to space, achieving angular resolution at radio wavelengths that could not be obtained with VLBI systems that were limited by the size of the earth, important tests could not be made of quasar models. The technology appeared to be within reach, and an early space VLBI concept, QUASAT, emerged as a joint project, involving both US and European scientists. In 1984, a workshop was held in Gross Enzerdorf, Austria, under joint sponsorship of NASA and the European Space Agency (ESA). The principal conclusion of the workshop was that a VLBI station in space, telemetering its data to ground data stations, working in connection with ground-based radio telescopes, would give the opportunity to achieve angular resolution of a few tens of micro-arc-seconds, and could develop high-quality radio maps of many classes of radio sources. The ground telemetry stations would also function as the source of a stable local oscillator for the spacecraft, which needs a highly stable frequency reference. The Deep Space Network of NASA could play a vital role in both the frequency-locking system and data acquisition. One outcome of the Gross Enzerdorf workshop was the convening, by COSPAR, of an ad hoc Committee on Space VLBI, to review and recommend procedures by which international collaboration on VLBI in space might be coordinated and promoted. In October 1985, the committee met in Budapest and recommended that the Inter-Agency Consultative Group (IACG) would be an appropriate body to coordinate VLBI activities in space. At the same time ESA convened a committee to explore the technical aspects of coordinating ground and space VLBI activities. At this stage both NASA and ESA were supporting preliminary studies of the QUASAT mission, with effective coordination between the two groups. The Soviet Union had also begun planning a mission with the clear intent to fly it as soon as the could; the mission was designated RadioAstron. In December 1985, the Soviets formed an international study team for the RadioAstron mission, holding the first meeting in Moscow. Subsequent meetings of this international committee were held in Budapest in May 1986 and in Moscow in December 1986. Thus, in 1986 there were three VLBI mission concepts under study: the NASA QUASAT mission, an ESA counterpart, and the Soviet RadioAstron mission.

Influence of strike object grounding on close lightning electric fields

NASA Astrophysics Data System (ADS)

Baba, Yoshihiro; Rakov, Vladimir A.

2008-06-01

Using the finite difference time domain (FDTD) method, we have calculated vertical electric field Ez, horizontal (radial) electric field Eh, and azimuthal magnetic field Hϕ produced on the ground surface by lightning strikes to 160-m- and a 553-m-high conical strike objects representing the Peissenberg tower (Germany) and the CN Tower (Canada), respectively. The fields were computed for a typical subsequent stroke at distances d' from the bottom of the object ranging from 5 to 100 m for the 160-m tower and from 10 to 300 m for the 553-m tower. Grounding of the 160-m object was assumed to be accomplished by its underground basement represented by a 10-m-radius and 8-m-long perfectly conducting cylinder with or without a reference ground plane located 2 m below. The reference ground plane simulates, to some extent, a higher-conducting ground layer that is expected to exist below the water table. The configuration without reference ground plane actually means that this plane is present, but is located at an infinitely large depth. Grounding of the 553-m object was modeled in a similar manner but in the absence of reference ground plane only. In all cases considered, waveforms of Eh and Hϕ are not much influenced by the presence of strike object, while waveforms of Ez are. Waveforms of Ez are essentially unipolar (as they are in the absence of strike object) when the ground conductivity σ is 10 mS/m (the equivalent transient grounding impedance is several ohms) or greater. Thus, for the CN Tower, for which σ ≥ 10 mS/m, the occurrence of Ez polarity change is highly unlikely. For the 160-m tower and for σ = 1 and 0.1 mS/m, waveforms of Ez become bipolar (exhibit polarity change) at d' ≤ 10 m and d' ≤ 50 m, respectively, regardless of the presence of the reference ground plane. The corresponding equivalent transient grounding impedances are about 30 and 50 Ω in the absence of the reference ground plane and smaller than 10 Ω in the presence of the reference ground plane. The source of opposite polarity Ez is the potential rise at the object base (at the air/ground interface) relative to the reference ground plane. For a given grounding electrode geometry, the strength of this source increases with decreasing σ, provided that the grounding impedance is linear. Potential rises at the strike object base for σ = 1 and 0.1 mS/m are some hundreds of kilovolts, which is sufficient to produce electrical breakdown from relatively sharp edges of the basement over a distance of several meters (or more) along the ground surface. The resultant ground surface arcs will serve to reduce the equivalent grounding impedance and, hence, potential rise. Therefore, the polarity change of Ez near the Peissenberg tower, for which σ is probably about 1 mS/m, should be a rare phenomenon, if it occurs at all. The equivalent transient grounding impedance of the cylindrical basement is similar to that of a hemispherical grounding electrode of the same radius. For the 160-m tower and for hemispherical grounding electrode, the transient grounding impedance is higher than its dc grounding resistance for σ = 10 and 1 mS/m, but lower for σ = 0.1 mS/m. For the 553-m tower, the transient grounding impedance of hemispherical electrode is equal to or larger than its dc resistance for all values of σ considered.

A Terrestrial Reference Frame realised on the observation level using a GPS-LEO satellite constellation

NASA Astrophysics Data System (ADS)

Koenig, Daniel

2018-02-01

Applying a one-step integrated process, i.e. by simultaneously processing all data and determining all satellite orbits involved, a Terrestrial Reference Frame (TRF) consisting of a geometric as well as a dynamic part has been determined at the observation level using the EPOS-OC software of Deutsches GeoForschungsZentrum. The satellite systems involved comprise the Global Positioning System (GPS) as well as the twin GRACE spacecrafts. Applying a novel approach, the inherent datum defect has been overcome empirically. In order not to rely on theoretical assumptions this is done by carrying out the TRF estimation based on simulated observations and using the associated satellite orbits as background truth. The datum defect is identified here as the total of all three translations as well as the rotation about the z-axis of the ground station network leading to a rank-deficient estimation problem. To rectify this singularity, datum constraints comprising no-net translation (NNT) conditions in x, y, and z as well as a no-net rotation (NNR) condition about the z-axis are imposed. Thus minimally constrained, the TRF solution covers a time span of roughly a year with daily resolution. For the geometric part the focus is put on Helmert transformations between the a priori and the estimated sets of ground station positions, and the dynamic part is represented by gravity field coefficients of degree one and two. The results of a reference solution reveal the TRF parameters to be estimated reliably with high precision. Moreover, carrying out a comparable two-step approach using the same data and models leads to parameters and observational residuals of worse quality. A validation w.r.t. external sources shows the dynamic origin to coincide at a level of 5 mm or better in x and y, and mostly better than 15 mm in z. Comparing the derived GPS orbits to IGS final orbits as well as analysing the SLR residuals for the GRACE satellites reveals an orbit quality on the few cm level. Additional TRF test solutions demonstrate that K-Band Range-Rate observations between both GRACE spacecrafts are crucial for accurately estimating the dynamic frame's orientation, and reveal the importance of the NNT- and NNR-conditions imposed for estimating the components of the dynamic geocenter.

6. VIEW TO THE NORTH NORTHWEST FROM GROUND LEVEL. STRUCTURAL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. VIEW TO THE NORTH NORTHWEST FROM GROUND LEVEL. STRUCTURAL MEMBERS AT INTERSECTION OF RANDOLPH-WELLS STREET. - Union Elevated Railroad, Randolph-Wells Street Station, Randall & Wells Street, Chicago, Cook County, IL

Configurable technology development for reusable control and monitor ground systems

NASA Technical Reports Server (NTRS)

Uhrlaub, David R.

1994-01-01

The control monitor unit (CMU) uses configurable software technology for real-time mission command and control, telemetry processing, simulation, data acquisition, data archiving, and ground operations automation. The base technology is currently planned for the following control and monitor systems: portable Space Station checkout systems; ecological life support systems; Space Station logistics carrier system; and the ground system of the Delta Clipper (SX-2) in the Single-Stage Rocket Technology program. The CMU makes extensive use of commercial technology to increase capability and reduce development and life-cycle costs. The concepts and technology are being developed by McDonnell Douglas Space and Defense Systems for the Real-Time Systems Laboratory at NASA's Kennedy Space Center under the Payload Ground Operations Contract. A second function of the Real-Time Systems Laboratory is development and utilization of advanced software development practices.

Common View Time Transfer Using Worldwide GPS and DMA Monitor Stations

NASA Technical Reports Server (NTRS)

Reid, Wilson G.; McCaskill, Thomas B.; Oaks, Orville J.; Buisson, James A.; Warren, Hugh E.

1996-01-01

Analysis of the on-orbit Navstar clocks and the Global Positioning System (GPS) monitor station reference clocks is performed by the Naval Research Laboratory using both broadcast and postprocessed precise ephemerides. The precise ephemerides are produced by the Defense Mapping Agency (DMA) for each of the GPS space vehicles from pseudo-range measurements collected at five GPS and at five DMA monitor stations spaced around the world. Recently, DMA established an additional site co-located with the US Naval Observatory precise time site. The time reference for the new DMA site is the DoD Master Clock. Now, for the first time, it is possible to transfer time every 15 minutes via common view from the DoD Master Clock to the 11 GPS and DMA monitor stations. The estimated precision of a single common-view time transfer measurement taken over a 15-minute interval was between 1.4 and 2.7 nanoseconds. Using the measurements from all Navstar space vehicles in common view during the 15-minute interval, typically 3-7 space vehicles, improved the estimate of the precision to between 0.65 and 1.13 nanoseconds. The mean phase error obtained from closure of the time transfer around the world using the 11 monitor stations and the 25 space vehicle clocks over a period of 4 months had a magnitude of 31 picoseconds. Analysis of the low noise time transfer from the DoD Master Clock to each of the monitor stations yields not only the bias in the time of the reference clock, but also focuses attention on structure in the behaviour of the reference clock not previously seen. Furthermore, the time transfer provides a a uniformly sampled database of 15-minute measurements that make possible, for the first time, the direct and exhaustive computation of the frequency stability of the monitor station reference clocks. To lend perspective to the analysis, a summary is given of the discontinuities in phase and frequency that occurred in the reference clock at the Master Control Station during the period covered by the analysis.

Modular space station, phase B extension. Program operations plan

NASA Technical Reports Server (NTRS)

1971-01-01

An organized approach is defined for establishing the most significant requirements pertaining to mission operations, information management, and computer program design and development for the modular space station program. The operations plan pertains to the space station and experiment module program elements and to the ground elements required for mission management and mission support operations.

Onboard Short Term Plan Viewer

NASA Technical Reports Server (NTRS)

Hall, Tim; LeBlanc, Troy; Ulman, Brian; McDonald, Aaron; Gramm, Paul; Chang, Li-Min; Keerthi, Suman; Kivlovitz, Dov; Hadlock, Jason

2011-01-01

Onboard Short Term Plan Viewer (OSTPV) is a computer program for electronic display of mission plans and timelines, both aboard the International Space Station (ISS) and in ISS ground control stations located in several countries. OSTPV was specifically designed both (1) for use within the limited ISS computing environment and (2) to be compatible with computers used in ground control stations. OSTPV supplants a prior system in which, aboard the ISS, timelines were printed on paper and incorporated into files that also contained other paper documents. Hence, the introduction of OSTPV has both reduced the consumption of resources and saved time in updating plans and timelines. OSTPV accepts, as input, the mission timeline output of a legacy, print-oriented, UNIX-based program called "Consolidated Planning System" and converts the timeline information for display in an interactive, dynamic, Windows Web-based graphical user interface that is used by both the ISS crew and ground control teams in real time. OSTPV enables the ISS crew to electronically indicate execution of timeline steps, launch electronic procedures, and efficiently report to ground control teams on the statuses of ISS activities, all by use of laptop computers aboard the ISS.

Water Resources Data, New Jersey, Water Year 2005Volume 3 - Water-Quality Data

USGS Publications Warehouse

DeLuca, Michael J.; Heckathorn, Heather A.; Lewis, Jason M.; Gray, Bonnie J.; Feinson, Lawrence S.

2006-01-01

Water-resources data for the 2005 water year for New Jersey are presented in three volumes, and consists of records of stage, discharge, and water-quality of streams; stage and contents of lakes and reservoirs; and water levels and water-quality of ground water. Volume 3 contains a summary of surface- and ground-water hydrologic conditions for the 2005 water year, a listing of current water-resources projects in New Jersey, a bibliography of water-related reports, articles, and fact sheets for New Jersey completed by the Geological Survey in recent years, water-quality records of chemical analyses from 118 continuing-record surface-water stations, 30 ground-water sites, records of daily statistics of temperature and other physical measurements from 9 continuous-recording stations, and 5 special studies that included 89 stream, 11 lake, and 29 ground-water sites. Locations of water-quality stations are shown in figures 23-25. Locations of special-study sites are shown in figures 41-46. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating federal, state, and local agencies in New Jersey.

Second AIAA/NASA USAF Symposium on Automation, Robotics and Advanced Computing for the National Space Program

NASA Technical Reports Server (NTRS)

Myers, Dale

1987-01-01

An introduction is given to NASA goals in the development of automation (expert systems) and robotics technologies in the Space Station program. Artificial intelligence (AI) has been identified as a means to lowering ground support costs. Telerobotics will enhance space assembly, servicing and repair capabilities, and will be used for an estimated half of the necessary EVA tasks. The general principles guiding NASA in the design, development, ground-testing, interactions with industry and construction of the Space Station component systems are summarized. The telerobotics program has progressed to a point where a telerobot servicer is a firm component of the first Space Station element launch, to support assembly, maintenance and servicing of the Station. The University of Wisconsin has been selected for the establishment of a Center for the Commercial Development of Space, specializing in space automation and robotics.

Science in space with the Space Station

NASA Technical Reports Server (NTRS)

Banks, Peter M.

1987-01-01

The potential of the Space Station as a versatile scientific laboratory is discussed, reviewing plans under consideration by the NASA Task Force on Scientific Uses of the Space Station. The special advantages offered by the Station for expanding the scope of 'space science' beyond astrophysics, geophysics, and terrestrial remote sensing are stressed. Topics examined include the advantages of a manned presence, the scientific value and cost effectiveness of smaller, more quickly performable experiments, improved communications for ground control of Station experiments, the international nature of the Station, the need for more scientist astronauts for the Station crew, Station on-orbit maintenance and repair services for coorbiting platforms, and the need for Shuttle testing of proposed Station laboratory equipment and procedures.

Near surface geotechnical and geophysical data cross validated for site characterization applications. The cases of selected accelerometric stations in Crete island (Greece)

NASA Astrophysics Data System (ADS)

Loupasakis, Constantinos; Tsangaratos, Paraskevas; Rozos, Dimitrios; Rondoyianni, Theodora; Vafidis, Antonis; Steiakakis, Emanouil; Agioutantis, Zacharias; Savvaidis, Alexandros; Soupios, Pantelis; Papadopoulos, Ioannis; Papadopoulos, Nikos; Sarris, Apostolos; Mangriotis, Maria-Dafni; Dikmen, Unal

2015-04-01

The near surface ground conditions are highly important for the design of civil constructions. These conditions determine primarily the ability of the foundation formations to bear loads, the stress - strain relations and the corresponding deformations, as well as the soil amplification and corresponding peak ground motion in case of dynamic loading. The static and dynamic geotechnical parameters as well as the ground-type/soil-category can be determined by combining geotechnical and geophysical methods, such as engineering geological surface mapping, geotechnical drilling, in situ and laboratory testing and geophysical investigations. The above mentioned methods were combined for the site characterization in selected sites of the Hellenic Accelerometric Network (HAN) in the area of Crete Island. The combination of the geotechnical and geophysical methods in thirteen (13) sites provided sufficient information about their limitations, setting up the minimum tests requirements in relation to the type of the geological formations. The reduced accuracy of the surface mapping in urban sites, the uncertainties introduced by the geophysical survey in sites with complex geology and the 1-D data provided by the geotechnical drills are some of the causes affecting the right order and the quantity of the necessary investigation methods. Through this study the gradual improvement on the accuracy of the site characterization data in regards to the applied investigation techniques is presented by providing characteristic examples from the total number of thirteen sites. As an example of the gradual improvement of the knowledge about the ground conditions the case of AGN1 strong motion station, located at Agios Nikolaos city (Eastern Crete), is briefly presented. According to the medium scale geological map of IGME the station was supposed to be founded over limestone. The detailed geological mapping reveled that a few meters of loose alluvial deposits occupy the area, expected to lay over the Neogene marly formations and the Mesozoic limestone, identified at the surrounding area. This changes the ground type to E instead of A, based on the EC8 classification. According the geophysical survey the Neogene formations extend down several meters and the mean Vs30 is 476m/s, increasing the rank of the ground type to B. Finally, the geotechnical drill reviled that the loose alluvial deposits extend down 13m containing two clearly identified layers of liquefiable loose sand. Below the alluvial deposits a thin layer (1,5m thick) of Neogene marly formations and the karstified limestone was located, as expected. So finally it was proved that the ground type category at the site is S2, setting up the geotechnical drills as the determinant investigation technique for this site. Besides the above described case, all selected examples present sufficiently the ability, the limitations and the right order of the investigation methods aiming to the site characterization. This research has been co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: THALES. Investing in knowledge society through the European Social Fund.

Satellite antenna management system and method

NASA Technical Reports Server (NTRS)

Leath, Timothy T (Inventor); Azzolini, John D (Inventor)

1999-01-01

The antenna management system and method allow a satellite to communicate with a ground station either directly or by an intermediary of a second satellite, thus permitting communication even when the satellite is not within range of the ground station. The system and method employ five major software components, which are the control and initialization module, the command and telemetry handler module, the contact schedule processor module, the contact state machining module, and the telemetry state machine module. The control and initialization module initializes the system and operates the main control cycle, in which the other modules are called. The command and telemetry handler module handles communication to and from the ground station. The contact scheduler processor module handles the contact entry schedules to allow scheduling of contacts with the second satellite. The contact and telemetry state machine modules handle the various states of the satellite in beginning, maintaining and ending contact with the second satellite and in beginning, maintaining and ending communication with the satellite.

Wind Advisory System

NASA Technical Reports Server (NTRS)

Curto, Paul A. (Inventor); Brown, Gerald E. (Inventor); Zysko, Jan A. (Inventor)

2001-01-01

The present invention is a two-part wind advisory system comprising a ground station at an airfield and an airborne unit placed inside an aircraft. The ground station monitors wind conditions (wind speed, wind direction, and wind gust) at the airfield and transmits the wind conditions and an airfield ID to the airborne unit. The airborne unit identifies the airfield by comparing the received airfield ID with airfield IDs stored in a database. The airborne unit also calculates the headwind and crosswind for each runway in both directions at the airfield using the received wind conditions and runway information stored in the database. The airborne unit then determines a recommended runway for takeoff and landing operations of the aircraft based on th runway having the greatest headwind value and displays the airfield ID, wind conditions, and recommended runway to the pilot. Another embodiment of the present invention includes a wireless internet based airborne unit in which the airborne unit can receive the wind conditions from the ground station over the internet.

Autonomous antenna tracking system for mobile symphonie ground stations

NASA Technical Reports Server (NTRS)

Ernsberger, K.; Lorch, G.; Waffenschmidt, E.

1982-01-01

The implementation of a satellite tracking and antenna control system is described. Due to the loss of inclination control for the symphonie satellites, it became necessary to equip the parabolic antennas of the mobile Symphonie ground station with tracking facilities. For the relatively low required tracking accuracy of 0.5 dB, a low cost, step track system was selected. The step track system developed for this purpose and tested over a long period of time in 7 ground stations is based on a search step method with subsequent parabola interpolation. As compared with the real search step method, the system has the advantage of a higher pointing angle resolution, and thus a higher tracking accuracy. When the pilot signal has been switched off for a long period of time, as for instance after the eclipse, the antenna is repointed towards the satellite by an automatically initiated spiral search scan. The function and design of the tracking system are detailed, while easy handling and tracking results.

[Changes of China agricultural climate resources under the background of climate change. II. Spatiotemporal change characteristics of agricultural climate resources in Southwest China].

PubMed

Dai, Shu-Wei; Yang, Xiao-Guang; Zhao, Meng; Li, Yong; Wang, Wen-Feng; Liu, Zhi-Juan

2011-02-01

Based on the 1961-2007 ground observation data from 88 meteorological stations in Southwest China, and by using statistical methods and GIS software, this paper analyzed the spatiotemporal change characteristics of agricultural climate resources in this region in the whole year and during temperature-defined growth period. In 1961-2007, the annual mean temperature in the region showed an increasing trend, with the increment averaged 0.18 degrees C x (10 a)(-1). The > or = 10 degrees C and > or = 15 degrees C accumulated temperature during temperature-defined growth period also showed an increasing trend, with the increment averaged 55.3 degrees C x d x (10 a)(-1) and 37 degrees C x d x (10 a)(-1), respectively. The annual sunshine hours decreased gradually from west to east, and the decreasing trend was more significant in eastern than in western region. The sunshine hours during temperature-defined growth period showed an overall increasing trend, and the spatial difference was great. The precipitation resource had an overall decrease, with the decrement in whole year and during temperature-defined growth period averaged 10 mm x (10 a)(-1) and 8 mm x (10 a)(-1), respectively. The annual reference crop evapotranspiration generally decreased, but the decrement was less than that of annual precipitation. The reference crop evapotranspiration during temperature-defined growth period within about 53% meteorological stations decreased.

Comparing SEBAL and METRIC: Evapotranspiration Models Applied to Paramount Farms Almond Orchards

NASA Astrophysics Data System (ADS)

Furey, B. J.; Kefauver, S. C.

2011-12-01

Two evapotranspiration models were applied to almond and pistachio orchards in California. The SEBAL model, developed by W.G.M. Bastiaanssen, was programmed in MatLab for direct comparison to the METRIC model, developed by R.G. Allen and the IDWR. Remote sensing data from the NASA SARP 2011 Airborne Research Program was used in the application of these models. An evaluation of the models showed that they both followed the same pattern in evapotranspiration (ET) rates for different types of ground cover. The models exhibited a slightly different range of values and appeared to be related (non-linearly). The models both underestimated the actual ET at the CIMIS weather station. However, SEBAL overestimated the ET of the almond orchards by 0.16 mm/hr when applying its crop coefficient to the reference ET. This is compared to METRIC, which underestimated the ET of the almond orchards by only 0.10 mm/hr. Other types of ground cover were similarly compared. Temporal variability in ET rates between the morning and afternoon were also observed.

The Canadian High Arctic Ionospheric Network (CHAIN)

NASA Astrophysics Data System (ADS)

Jayachandran, P. T.; Langley, R. B.; MacDougall, J. W.; Mushini, S. C.; Pokhotelov, D.; Chadwick, R.; Kelly, T.

2009-05-01

Polar cap ionospheric measurements are important for the complete understanding of the various processes in the solar wind - magnetosphere - ionosphere (SW-M-I) system as well as for space weather applications. Currently the polar cap region is lacking high temporal and spatial resolution ionospheric measurements because of the orbit limitations of space-based measurements and the sparse network providing ground- based measurements. Canada has a unique advantage in remedying this shortcoming because it has the most accessible landmass in the high Arctic regions and the Canadian High Arctic Ionospheric Network (CHAIN) is designed to take advantage of Canadian geographic vantage points for a better understanding of the Sun-Earth system. CHAIN is a distributed array of ground-based radio instruments in the Canadian high Arctic. The instruments components of CHAIN are ten high data-rate Global Positioning System ionospheric scintillation and total electron content monitors and six Canadian Advanced Digital Ionosondes. Most of these instruments have been sited within the polar cap region except for two GPS reference stations at lower latitudes. This paper briefly overviews the scientific capabilities, instrument components, and deployment status of CHAIN.

Is popular radio a source of exposure to alcohol references in mid to later life? A content analysis.

PubMed

Haighton, C; Halligan, J; Scott, S

2017-04-20

There is concern around alcohol consumption in mid to later life yet little understanding about what influences this behaviour. No previous research has explored the extent to which adults in mid to later life may be exposed to alcohol references in the media. This project aimed to determine the frequency of alcohol references on radio stations with a high proportion of listeners in mid to later life. Content analysis of alcohol references on four popular UK music-based radio stations with a high proportion of listeners aged 55-64 years over three time points. Alcohol references occur frequently, but vary by time of year and type of radio station. When alcohol is mentioned its consumption is portrayed as the norm, without negative consequences. On three commercial stations, the majority of mentions came from advertising, whereas on BBC Radio 2 nearly all references were talk-based. All adverts for direct promotion of alcohol were by supermarkets. Alcohol was frequently associated with celebrations, socializing or something to consume for its own sake. Adults in the age group 55-64 may be exposed to references to alcohol that could serve to reinforce norms of consumption of alcohol and promote purchases of cheap alcohol. © The Author 2017. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Simulation of Ground-Water Flow and Optimization of Withdrawals from Aquifers at the Naval Air Station Patuxent River, St. Mary's County, Maryland

USGS Publications Warehouse

Dieter, Cheryl A.; Fleck, William B.

2008-01-01

Potentiometric surfaces in the Piney Point-Nanjemoy, Aquia, and Upper Patapsco aquifers have declined from 1950 through 2000 throughout southern Maryland. In the vicinity of Lexington Park, Maryland, the potentiometric surface in the Aquia aquifer in 2000 was as much as 170 feet below sea level, approximately 150 feet lower than estimated pre-pumping levels before 1940. At the present rate, the water levels will have declined to the regulatory allowable maximum of 80 percent of available drawdown in the Aquia aquifer by about 2050. The effect of the withdrawals from these aquifers by the Naval Air Station Patuxent River and surrounding users on the declining potentiometric surface has raised concern for future availability of ground water. Growth at Naval Air Station Patuxent River may increase withdrawals, resulting in further drawdown. A ground-water-flow model, combined with optimization modeling, was used to develop withdrawal scenarios that minimize the effects (drawdown) of hypothetical future withdrawals. A three-dimensional finite-difference ground-water-flow model was developed to simulate the ground-water-flow system in the Piney Point-Nanjemoy, Aquia, and Upper Patapsco aquifers beneath the Naval Air Station Patuxent River. Transient and steady-state conditions were simulated to give water-resource managers additional tools to manage the ground-water resources. The transient simulation, representing 1900 through 2002, showed that the magnitude of withdrawal has increased over that time, causing ground-water flow to change direction in some areas. The steady-state simulation was linked to an optimization model to determine optimal solutions to hypothetical water-management scenarios. Two optimization scenarios were evaluated. The first scenario was designed to determine the optimal pumping rates for wells screened in the Aquia aquifer within three supply groups to meet a 25-percent increase in withdrawal demands, while minimizing the drawdown at a control location. The resulting optimal solution showed that pumping six wells above the rate required for maintenance produced the least amount of drawdown in the local potentiometric surface. The second hypothetical scenario was designed to determine the optimal location for an additional well in the Aquia aquifer in the northeastern part of the main air station. The additional well was needed to meet an increase in withdrawal of 43,000 cubic feet per day. The optimization model determined the optimal location for the new well, out of a possible 10 locations, while minimizing drawdown at control nodes located outside the western boundary of the main air station. The optimal location is about 1,500 feet to the east-northeast of the existing well.

High performance VLSI telemetry data systems

NASA Technical Reports Server (NTRS)

Chesney, J.; Speciale, N.; Horner, W.; Sabia, S.

1990-01-01

NASA's deployment of major space complexes such as Space Station Freedom (SSF) and the Earth Observing System (EOS) will demand increased functionality and performance from ground based telemetry acquisition systems well above current system capabilities. Adaptation of space telemetry data transport and processing standards such as those specified by the Consultative Committee for Space Data Systems (CCSDS) standards and those required for commercial ground distribution of telemetry data, will drive these functional and performance requirements. In addition, budget limitations will force the requirement for higher modularity, flexibility, and interchangeability at lower cost in new ground telemetry data system elements. At NASA's Goddard Space Flight Center (GSFC), the design and development of generic ground telemetry data system elements, over the last five years, has resulted in significant solutions to these problems. This solution, referred to as the functional components approach includes both hardware and software components ready for end user application. The hardware functional components consist of modern data flow architectures utilizing Application Specific Integrated Circuits (ASIC's) developed specifically to support NASA's telemetry data systems needs and designed to meet a range of data rate requirements up to 300 Mbps. Real-time operating system software components support both embedded local software intelligence, and overall system control, status, processing, and interface requirements. These components, hardware and software, form the superstructure upon which project specific elements are added to complete a telemetry ground data system installation. This paper describes the functional components approach, some specific component examples, and a project example of the evolution from VLSI component, to basic board level functional component, to integrated telemetry data system.

Wyoming Water Resources Data, Water Year 2002, Volume 2. Ground Water

USGS Publications Warehouse

Swanson, R.B.; Blajszczak, E.J.; Roberts, S.C.; Watson, K.R.; Mason, J.P.

2003-01-01

Water resources data for the 2002 water year for Wyoming consists of records of stage, discharge and water quality of streams; stage and contents of lakes and reservoirs, and water levels and water quality of ground water. Volume 1 of this report contains discharge records for 156 gaging stations; water quality for 33 gaging stations and 34 ungaged stations, and stage and contents for one reservoir. Additional water data were collected at various sites, not part of the systematic data collection program, and are published as miscellaneous measurements. These data together with the data in Volume 2 represent part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Wyoming.

Wyoming Water Resources Data, Water Year 2003, Volume 2. Ground Water

USGS Publications Warehouse

Swanson, R.B.; Blajszczak, E.J.; Roberts, S.C.; Watson, K.R.; Mason, J.P.

2004-01-01

Water resources data for the 2003 water year for Wyoming consists of records of stage, discharge and water quality of streams; stage and contents of lakes and reservoirs, and water levels and water quality of ground water. Volume 1 of this report contains discharge records for 160 gaging stations; water quality for 42 gaged stations and 28 ungaged stations, and stage and contents for one reservoir. Additional water data were collected at various sites, not part of the systematic data collection program, and are published as miscellaneous measurements. These data together with the data in Volume 2 represent part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Wyoming.

Wyoming Water Resources Data, Water Year 2000, Volume 2. Ground Water

USGS Publications Warehouse

Mason, J.P.; Swanson, R.B.; Roberts, S.C.

2001-01-01

Water resources data for the 2000 water year for Wyoming consists of records of stage, discharge and water quality of streams; stage and contents of lakes and reservoirs, and water levels and water quality of ground water. Volume 1 of this report contains discharge records for 141 gaging stations; stage and contents for 15 lakes and reservoirs; and water quality for 22 gaging stations and 21 ungaged stations. Additional water data were collected at various sites, not part of the systematic data collection program, and are published as miscellaneous measurements. These data together with the data in Volume 2 represent part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Wyoming.

The ESA-NASA 'CHOICE' Study: Winterover at Concordia Station, Interior Antarctica, as an Analog for Spaceflight-Associated Immune Dysregu1ation

NASA Technical Reports Server (NTRS)

Crucian, Brian E,; Feuerecker, M.; Salam, A. P.; Rybka, A.; Stowe, R. P.; Morrels, M.; Mehta, S. K.; Quiriarte, H.; Quintens, Roel; Thieme, U.;

Video requirements for materials processing experiments in the space station US laboratory

NASA Technical Reports Server (NTRS)

Baugher, Charles R.

1989-01-01

Full utilization of the potential of the materials research on the Space Station can be achieved only if adequate means are available for interactive experimentation between the science facilities and ground-based investigators. Extensive video interfaces linking these three elements are the only alternative for establishing a viable relation. Because of the limit in the downlink capability, a comprehensive complement of on-board video processing, and video compression is needed. The application of video compression will be an absolute necessity since it's effectiveness will directly impact the quantity of data which will be available to ground investigator teams, and their ability to review the effects of process changes and the experiment progress. Video data compression utilization on the Space Station is discussed.

Space-to-Ground: Kilauea Volcano: 05/18/2018

NASA Image and Video Library

2018-05-17

NASA astronauts completed another successful spacewalk, and had an opportunity to photograph a major event happening on the planet. NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station.

Satellite Weather Watch.

ERIC Educational Resources Information Center

Summers, R. Joe

1982-01-01

Describes an inexpensive (about $1,500) direct-readout ground station for use in secondary school science/mathematics programs. Includes suggested activities including, among others, developing map overlays, operating station equipment, interpreting satellite data, developing weather forecasts, and using microcomputers for data storage, orbit…

A stochastic estimate of ground motion at Oceano, California, for the M 6.5 22 December 2003 San Simeon earthquake, derived from aftershock recordings

USGS Publications Warehouse

Di, Alessandro C.; Boatwright, J.

2006-01-01

The U.S. Geological Survey deployed a digital seismic station in Oceano, California, in February 2004, to investigate the cause of damage and liquefaction from the 22 December 2003 M 6.5 San Simeon earthquake. This station recorded 11 M > 2.8 aftershocks in almost 8 weeks. We analyze these recordings, together with recordings of the mainshock and the same aftershocks obtained from nearby stations in Park Hill and San Luis Obispo, to estimate the mainshock ground motion in Oceano. We estimate the Fourier amplitude spectrum using generalized spectral ratio analysis. We test a set of aftershocks as Green's functions by comparing simulated and recorded acceleration amplitude spectra for the mainshock at San Luis Obispo and Park Hill. We convolve the aftershock accelerograms with a stochastic operator to simulate the duration and phase of the mainshock accelerograms. This approximation allows us to extend the range of aftershocks that can be used as Green's functions to events nearly three magnitude units smaller than the mainshock. Our realizations for the mainshock accelerogram at Oceano yield peak ground accelerations distributed as 28% ?? 4%g. We interpret these realizations as upper bounds for the actual ground motion, because our analysis assumes a linear response, whereas the presence of liquefaction indicates that the ground behaved nonlinearly in Oceano.

Robust method to detect and locate local earthquakes by means of amplitude measurements.

NASA Astrophysics Data System (ADS)

del Puy Papí Isaba, María; Brückl, Ewald

2016-04-01

In this study we present a robust new method to detect and locate medium and low magnitude local earthquakes. This method is based on an empirical model of the ground motion obtained from amplitude data of earthquakes in the area of interest, which were located using traditional methods. The first step of our method is the computation of maximum resultant ground velocities in sliding time windows covering the whole period of interest. In the second step, these maximum resultant ground velocities are back-projected to every point of a grid covering the whole area of interest while applying the empirical amplitude - distance relations. We refer to these back-projected ground velocities as pseudo-magnitudes. The number of operating seismic stations in the local network equals the number of pseudo-magnitudes at each grid-point. Our method introduces the new idea of selecting the minimum pseudo-magnitude at each grid-point for further analysis instead of searching for a minimum of the L2 or L1 norm. In case no detectable earthquake occurred, the spatial distribution of the minimum pseudo-magnitudes constrains the magnitude of weak earthquakes hidden in the ambient noise. In the case of a detectable local earthquake, the spatial distribution of the minimum pseudo-magnitudes shows a significant maximum at the grid-point nearest to the actual epicenter. The application of our method is restricted to the area confined by the convex hull of the seismic station network. Additionally, one must ensure that there are no dead traces involved in the processing. Compared to methods based on L2 and even L1 norms, our new method is almost wholly insensitive to outliers (data from locally disturbed seismic stations). A further advantage is the fast determination of the epicenter and magnitude of a seismic event located within a seismic network. This is possible due to the method of obtaining and storing a back-projected matrix, independent of the registered amplitude, for each seismic station. As a direct consequence, we are able to save computing time for the calculation of the final back-projected maximum resultant amplitude at every grid-point. The capability of the method was demonstrated firstly using synthetic data. In the next step, this method was applied to data of 43 local earthquakes of low and medium magnitude (1.7 < magnitude scale < 4.3). These earthquakes were recorded and detected by the seismic network ALPAACT (seismological and geodetic monitoring of Alpine PAnnonian ACtive Tectonics) in the period 2010/06/11 to 2013/09/20. Data provided by the ALPAACT network is used in order to understand seismic activity in the Mürz Valley - Semmering - Vienna Basin transfer fault system in Austria and what makes it such a relatively high earthquake hazard and risk area. The method will substantially support our efforts to involve scholars from polytechnic schools in seismological work within the Sparkling Science project Schools & Quakes.