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1

Four Station Interferometric Radar Observations of Mars  

NASA Astrophysics Data System (ADS)

Planetary targets have been observed with radar since the late 1950s when it was first used for ranging experiments with the Moon. As telescope size and power increased, it became possible to observe more distant targets (Venus, Mars, and the outer satellites). Inherent to radar observations is the uncertainty as to the source of the reflection, there being two points where range and Doppler rings intersect on a sphere. The use of interferometric methods, first used on the moon with two stations and later on Venus and Mars, solved this problem. We extend the method through the addition of a fourth receiving telescope (thus doubling the number of projected baselines) and integration of the newly available Mars Orbiter Laser Altimeter (MOLA) topographic datasets.

Larsen, K. W.; Jurgens, R. F.; Arvidson, R. E.; Slade, M. A.; Haldemann, A. F.

2002-01-01

2

Evaluation of performance of Micro Rain Radar over the tropical coastal station Thumba (8.5°N, 76.9°E)  

NASA Astrophysics Data System (ADS)

The vertically pointing Micro Rain Radar (MRR) and disdrometer (RD-80) were installed at a coastal station, Thumba (8.5°N, 76.9°E), to study the characteristics of tropical rains. This paper presents the first results from these observations over Thumba and highlights the impact of Mie-scattering corrections to the MRR data for proper estimation of the rainfall intensity. To evaluate the performance of MRR, a total number of 11 Mesoscale Convective Systems events were considered during the period September 2006 to December 2007. The uncorrected MRR shows an overestimation of rain rate and this is larger during the high rain rates. The Mie scattering corrections lead to a decrease in rain rate of the order 2%-31% and resulted in substantial improvement in the rainfall accumulation (368.69 mm (before) to 302.16 mm (after)). The accumulated rainfall is in good agreement with disdrometer total rainfall of 299.14 mm. For the first time, the impact of Mie scattering for different rain categories has been investigated and study shows the rainfall sum significantly improved (about 22%) during the moderate and heavy rain categories whereas, it shows improvement of 11% during the light rain. These studies may be used to estimate the rain attenuation at Ka band over Indian region for different rain categories.

Kirankumar, N. V. P.; Kunhikrishnan, P. K.

2013-12-01

3

Evaluation of meteorological airborne Doppler radar  

NASA Technical Reports Server (NTRS)

This paper will discuss the capabilities of airborne Doppler radar for atmospheric sciences research. The evaluation is based on airborne and ground based Doppler radar observations of convective storms. The capability of airborne Doppler radar to measure horizontal and vertical air motions is evaluated. Airborne Doppler radar is shown to be a viable tool for atmospheric sciences research.

Hildebrand, P. H.; Mueller, C. K.

1984-01-01

4

Location plan for Signal Corps Radar (S.C.R.) 296 Station 5, ...  

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

Location plan for Signal Corps Radar (S.C.R.) 296 Station 5, October 8, 1943 - Fort Barry, Signal Corps Radar 296, Station 5, Transmitter Building Foundation, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

5

2-D inner-shelf current observations from a single VHF WEllen RAdar (WERA) station  

USGS Publications Warehouse

The majority of High Frequency (HF) radars used worldwide operate at medium to high frequencies (8 to 30 MHz) providing spatial resolutions ranging from 3 to 1.5 km and ranges from 150 to 50 km. This paper presents results from the deployment of a single Very High Frequency (VHF, 48 MHz) WEllen RAdar (WERA) radar with spatial resolution of 150 m and range 10-15 km, used in the nearshore off Cape Hatteras, NC, USA. It consisted of a linear array of 12 antennas operating in beam forming mode. Radial velocities were estimated from radar backscatter for a variety of wind and nearshore wave conditions. A methodology similar to that used for converting acoustically derived beam velocities to an orthogonal system is presented for obtaining 2-D current fields from a single station. The accuracy of the VHF radar-derived radial velocities is examined using a new statistical technique that evaluates the system over the range of measured velocities. The VHF radar velocities showed a bias of 3 to 7 cm/s over the experimental period explainable by the differences in radar penetration and in-situ measurement height. The 2-D current field shows good agreement with the in-situ measurements. Deviations and inaccuracies are well explained by the geometric dilution analysis. ?? 2011 IEEE.

Voulgaris, G.; Kumar, N.; Gurgel, K.-W.; Warner, J.C.; List, J.H.

2011-01-01

6

View of Signal Corps Radar (S.C.R.) 296 Station 5 Transmitter ...  

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

View of Signal Corps Radar (S.C.R.) 296 Station 5 Transmitter Building foundation, showing Fire Control Stations (Buildings 621 and 622) and concrete stairway (top left) camera facing southwest - Fort Barry, Signal Corps Radar 296, Station 5, Transmitter Building Foundation, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

7

View looking down on Signcal Corps Radar (S.C.R.) 296 Station ...  

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

View looking down on Signcal Corps Radar (S.C.R.) 296 Station 5 Transmitter Building foundation from ridge, camera facing south - Fort Barry, Signal Corps Radar 296, Station 5, Transmitter Building Foundation, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

8

Accuracy evaluation of September 2000 Tokai storm radar observation by areal-averaging  

Microsoft Academic Search

The authors studied the observation accuracy of areal rainfall by one of operational radar raingauges, after the appropriate method to evaluate the radar rainfall accuracy was argued. And the authors also verified the accuracy of rainfall forecasting data provided by one organization. As a result of the comparison between the areal rainfalls calculated from the ground rainfall gauging station data

Tadashi MATSUURA; Kazuhiko FUKAMI; Makoto KANEKI; Junichi YOSHITANI

9

Application of ground-penetrating radar at McMurdo Station, Antarctica  

SciTech Connect

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 produced with GPR over most of McMurdo Station.

Stefano, J.E.

1992-01-01

10

Application of ground-penetrating radar at McMurdo Station, Antarctica  

SciTech Connect

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 produced with GPR over most of McMurdo Station.

Stefano, J.E.

1992-05-01

11

Generic evaluation tracker database for OTH radar  

NASA Astrophysics Data System (ADS)

This paper provides a real world target and clutter model for evaluation of radar signal processing algorithms. The procedure is given for target and clutter data collection which is then followed by the equalization and superposition method. We show how the model allows one to vary the target signal to clutter noise ratio so that system performance may be assessed over a wide range of target amplitudes, i.e. detection probability versus target signal to noise ratio. Three candidate pre-track algorithms are evaluated and compared using this model as input in conjunction with an advanced tracker algorithm as a post processor. Data used for the model represents airborne traffic operating over the body of water bounded by North, Central, and South America. The processors relate to the deployment of Over the Horizon Radar for drug interdiction. All the components of this work, model as well as the processors, are in software.

Flanders, Lorraine E.; Hartnett, Michael P.; Vannicola, Vincent C.

1999-10-01

12

Science program for an imaging radar receiving station in Alaska. Report of the science working group  

NASA Technical Reports Server (NTRS)

It is argued that there would be broad scientific benefit in establishing in Alaska an imaging radar receiving station that would collect data from the European Space Agency's Remote Sensing Satellite, ERS-1. This station would acquire imagery of the ice cover from the American territorial waters of the Beaufort, Chukchi, and Bering Seas. This station, in conjunction with similar stations proposed for Kiruna, Sweden, and Prince Albert, Canada would provide synoptic coverage of nearly the entire Arctic. The value of such coverage to aspects of oceanography, geology, glaciology, and botany is considered.

1983-01-01

13

Statistical Analysis for VHF Radar Parameters at SÃO LUÍS, Jicamarca and Christmas Island Equatorial Stations  

NASA Astrophysics Data System (ADS)

Equatorial Spread F (ESF) is a manifestation of ionospheric interchange instabilities in the nighttime equatorial F region. These instabilities generate plasma density irregularities with scale sizes ranging from kilometers to thousands of kilometers. The irregularities can be detected from varieties of instruments such as digisonde, coherent and incoherent scatter radars, in situ space probes, and airglow photometers. In the present study, statistics of various aspects of spread F occurrence are presented from HF/VHF radar and incoherent scatter radar located at three equatorial stations: Christmas Island (2oN, 202.6oE, 2.9oN dip latitude, VHF radar), São Luís (2.59oS, 315.8oE, 0.5oS dip latitude, HF radar) and Jicamarca (12oS, 283.1oE, 0.6oN dip latitude, ISR). The radar parameters presented here are the onset altitude and onset time of the bottom-type and plume, and the peak altitude of the plume which are known to be associated with the spread F occurrence characteristics. The study reveals novel features namely, seasonal and solar flux dependence of spread F occurrence over Christmas island /São Luís, and longitudinal dependence of spread F occurrence characteristics from these three stations based on the chosen parameters. The importance of this work lies in the radar parameter empirical model developed combining statistical analysis of three equatorial and longitudinally separated stations, which is important to study the irregularity generation mechanisms, for space weather forecasting and nowcasting programs, and improving scintillation warning models. These parameters show generally linear correlation with solar flux index (F10.7 cm) and variation with season and magnetic declination angle. The fit correlation with F10.7cm is shown as useful information to implement one spread-F development empirical model based on small scale irregularities detected by VHF radars.

de la cruz cueva, R. Y.; Paula, E. R.; Kherani, E. A.

2013-05-01

14

Evaluation of radar precipitation data in Norway  

Microsoft Academic Search

Radar precipitation data are not put to use in prognosis or simulations in Norway, except for viewing animated maps for the last three hours on the internet. In hydrological models radar precipitation is still not used as a data source for rain, but with higher resolution in both time and space than traditional rain-gauge data, radar should be able to

L. S. Tøfte

2009-01-01

15

PAVEMENT OVERLAY THICKNESS EVALUATION USING GROUND PENTRATING RADAR (GPR)  

E-print Network

PAVEMENT OVERLAY THICKNESS EVALUATION USING GROUND PENTRATING RADAR (GPR) Dwayne Harris, M.Sc., PG deflectometer (FWD), and ground penetrating radar (GPR). Core drilling provides very accurate pin point pavement and affected by the limitations and assumptions the method used to estimate thickness. GPR provides pavement

Shan, Jie

16

Evaluation of photo radar program in British Columbia  

Microsoft Academic Search

This article presents the results of an evaluation of the speed and traffic safety effects of the photo radar program in British Columbia (BC) after 1 year of full operation. Traffic speed data were collected from the photo radar units and from induction loops installed across the province. Traffic collision and injury data were obtained from police investigation reports and

Greg Chen; Jean Wilson; Wayne Meckle; Peter Cooper

2000-01-01

17

Independent evaluation of the ability of spaceborne radar and lidar  

E-print Network

Chapter 1 Independent evaluation of the ability of spaceborne radar and lidar to retrieve the microphysical and radiative properties of ice clouds Summary. The combination of radar and lidar in space offers, that of correcting the lidar signal for extinction. In this chapter "blind tests" of these two algorithms are carried

Hogan, Robin

18

Sandia National Laboratories land use permit for operations at Oliktok Alaska Long Range Radar Station.  

SciTech Connect

The property subject to this Environmental Baseline Survey (EBS) is located at the Oliktok Long Range Radar Station (LRRS). The Oliktok LRRS is located at 70%C2%B0 30' W latitude, 149%C2%B0 53' W longitude. It is situated at Oliktok Point on the shore of the Beaufort Sea, east of the Colville River. The purpose of this EBS is to document the nature, magnitude, and extent of any environmental contamination of the property; identify potential environmental contamination liabilities associated with the property; develop sufficient information to assess the health and safety risks; and ensure adequate protection for human health and the environment related to a specific property.

Catechis, Christopher Spyros

2013-02-01

19

Evaluation of Various Radar Data Quality Control Algorithms Based on Accumulated Radar Rainfall Statistics  

NASA Technical Reports Server (NTRS)

The primary function of the TRMM Ground Validation (GV) Program is to create GV rainfall products that provide basic validation of satellite-derived precipitation measurements for select primary sites. A fundamental and extremely important step in creating high-quality GV products is radar data quality control. Quality control (QC) processing of TRMM GV radar data is based on some automated procedures, but the current QC algorithm is not fully operational and requires significant human interaction to assure satisfactory results. Moreover, the TRMM GV QC algorithm, even with continuous manual tuning, still can not completely remove all types of spurious echoes. In an attempt to improve the current operational radar data QC procedures of the TRMM GV effort, an intercomparison of several QC algorithms has been conducted. This presentation will demonstrate how various radar data QC algorithms affect accumulated radar rainfall products. In all, six different QC algorithms will be applied to two months of WSR-88D radar data from Melbourne, Florida. Daily, five-day, and monthly accumulated radar rainfall maps will be produced for each quality-controlled data set. The QC algorithms will be evaluated and compared based on their ability to remove spurious echoes without removing significant precipitation. Strengths and weaknesses of each algorithm will be assessed based on, their abilit to mitigate both erroneous additions and reductions in rainfall accumulation from spurious echo contamination and true precipitation removal, respectively. Contamination from individual spurious echo categories will be quantified to further diagnose the abilities of each radar QC algorithm. Finally, a cost-benefit analysis will be conducted to determine if a more automated QC algorithm is a viable alternative to the current, labor-intensive QC algorithm employed by TRMM GV.

Robinson, Michael; Steiner, Matthias; Wolff, David B.; Ferrier, Brad S.; Kessinger, Cathy; Einaudi, Franco (Technical Monitor)

2000-01-01

20

Images of Venus by three-station radar interferometry - 1977 results  

NASA Technical Reports Server (NTRS)

During the 1977 inferior conjunction of Venus, radar observations were made using three receiving stations as a multiple interferometer. Maps of surface reflectivity and altimetry were prepared from these observations. The new altimetry maps show considerable improvement in relation to many of the earlier maps made using the two-station interferometer. In particular, there are consistent and explainable correlations between the altimetry and reflectivity maps that did not always exist in the past. The highest-resolution maps (about 8 km) show three isolated mountains having altitudes of approximately 2 km above their environs, a pair of ridges separated by approximately 100 km and extending 800 km, and a few anomalous reflectivity features for which little or no altitude change is observed. Other maps at slightly lower resolution show a bright irregular ringed crater, a few large low-reflectivity regions, a shallow crater 150 km in diameter, a gently sloping mountain, and a short ridge running north-south. Many of the later features have been seen in earlier radar maps and should be useful in refining the spin axis and further characterizing the regolith of certain areas of Venus.

Jurgens, R. F.; Goldstein, R. M.; Rumsey, H. R.; Green, R. R.

1980-01-01

21

Road evaluation with ground penetrating radar  

Microsoft Academic Search

This paper provides a status report of the Ground Penetrating Radar (GPR) highway applications based on studies conducted in both Scandinavia and the USA. After several years of research local transportation agencies are now beginning to implement GPR technology for both network and project level surveys. This paper summarizes the principles of operation of both ground-coupled and air-launched GPR systems

Timo Saarenketo; Tom Scullion

2000-01-01

22

Radar Evaluation of Optical Cloud Constraints to Space Launch Operations  

NASA Technical Reports Server (NTRS)

Weather constraints to launching space vehicles are designed to prevent loss of the vehicle or mission due to weather hazards (See, e.g., Ref 1). Constraints include Lightning Launch Commit Criteria (LLCC) designed to avoid natural and triggered lightning. The LLCC currently in use at most American launch sites including the Eastern Range and Kennedy Space Center require the Launch Weather Officer to determine the height of cloud bases and tops, the location of cloud edges, and cloud transparency. The preferred method of making these determinations is visual observation, but when that isn't possible due to darkness or obscured vision, it is permissible to use radar. This note examines the relationship between visual and radar observations in three ways: A theoretical consideration of the relationship between radar reflectivity and optical transparency. An observational study relating radar reflectivity to cloud edge determined from in-situ measurements of cloud particle concentrations that determine the visible cloud edge. An observational study relating standard radar products to anvil cloud transparency. It is shown that these three approaches yield results consistent with each other and with the radar threshold specified in Reference 2 for LLCC evaluation.

Merceret, Francis J.; Short, David A.; Ward, Jennifer G.

2005-01-01

23

Fiber-distributed Ultra-wideband noise radar with steerable power spectrum and colorless base station.  

PubMed

A fiber-distributed Ultra-wideband (UWB) noise radar was achieved, which consists of a chaotic UWB noise source based on optoelectronic oscillator (OEO), a fiber-distributed transmission link, a colorless base station (BS), and a cross-correlation processing module. Due to a polarization modulation based microwave photonic filter and an electrical UWB pass-band filter embedded in the feedback loop of the OEO, the power spectrum of chaotic UWB signal could be shaped and notch-filtered to avoid the spectrum-overlay-induced interference to the narrow band signals. Meanwhile, the wavelength-reusing could be implemented in the BS by means of the distributed polarization modulation-to-intensity modulation conversion. The experimental comparison for range finding was carried out as the chaotic UWB signal was notch-filtered at 5.2 GHz and 7.8 GHz or not. Measured results indicate that space resolution with cm-level could be realized after 3-km fiber transmission thanks to the excellent self-correlation property of the UWB noise signal provided by the OEO. The performance deterioration of the radar raised by the energy loss of the notch-filtered noise signal was negligible. PMID:24663829

Zheng, Jianyu; Wang, Hui; Fu, Jianbin; Wei, Li; Pan, Shilong; Wang, Lixian; Liu, Jianguo; Zhu, Ninghua

2014-03-10

24

Evaluating roughness models of radar backscatter  

NASA Technical Reports Server (NTRS)

Three radar backscatter roughness models were assessed using soil moisture data collected by the Space Shuttle flight 41G SIR-B SAR in an intensively farmed area. The SIR-B data swath included a large number of bare, dry fields with a large variety of surface roughnesses. The small perturbation model gives the best results, particularly when fields with a definite periodic row structure were omitted. The standard deviation of surface heights appears to be a good measure of relative roughness conditions, but the correlation length is not a good descriptor of the surface, and does not seem to be related in any way to the measured backscatter.

Engman, Edwin T.; Wang, James R.

1987-01-01

25

Evaluating roughness models of radar backscatter  

NASA Technical Reports Server (NTRS)

Three radar backscatter roughness models were assessed using soil moisture data collected by the Space Shuttle flight 41G SIR-B SAR in an intensively farmed area. The SIR-B data swath included a large number of bare, dry fields with a large variety of surface roughnesses. The small perturbation model gives the best results, particularly when fields with a definite periodic row structure were omitted. The standard deviation of surface heights appears to be a good measure of relative roughness conditions, but the correlation length is not a good descriptor of the surface, and does not seem to be related in any way to the measured backscatter.

Engmann, E. T.; Wang, J. R.

1986-01-01

26

Evaluating and managing Cold War era historic properties : the cultural significance of U.S. Air Force defensive radar systems.  

SciTech Connect

Aircraft and later missile radar early warning stations played an important role in the Cold War. They are associated with important technological, social, political, and military themes of the Cold War and are worthy of preservation. The scope and scale of these systems make physical preservation impractical, but the U.S. Air Force program of historical evaluation and documentation of these systems will provide valuable information to future generations studying this historic period.

Whorton, M.

1999-01-20

27

Flight test evaluation of a video tracker for enhanced offshore airborne radar approach capability  

NASA Technical Reports Server (NTRS)

As a part of NASA's Rotorcraft All-Weather Operations Research Program, advanced airborne radar approach (ARA) concepts are being investigated. Since data from previous NASA/FAA flight tests showed significant ARA limitations, a research program was initiated at NASA Ames Research Center to determine the benefit that could be derived by automating certain radar functions and superimposing course display data on the radar display. To evaluate these concepts, a newly developed video tracking system which interfaces with weather radar was acquired. After the pilot designates a destination target, the system tracks the target video as it moves on the radar indicator. Using a small, efficient microprocessor, the autotracker presents valuable approach data on the radar screen and automatically adjusts the radar gain and tilt. Results of a limited flight test evaluation of the autotracker show that the course display concept, combined with automated gain and tilt functions, is effective for improving ARA's and reducing radar operator workload.

Clary, G. R.; Cooper, P. G.

1982-01-01

28

Evaluation of photo radar program in British Columbia.  

PubMed

This article presents the results of an evaluation of the speed and traffic safety effects of the photo radar program in British Columbia (BC) after 1 year of full operation. Traffic speed data were collected from the photo radar units and from induction loops installed across the province. Traffic collision and injury data were obtained from police investigation reports and from BC ambulance services records. The study employed a number of analytical frameworks, including simple before and after comparison, time-series cross-sectional analysis, and interrupted time series analysis. The study revealed a dramatic reduction of speed at photo radar deployment sites. A reduction of 2.4 km/h in mean speed was also observed at selected monitoring sites where enforcement was not likely to be present. The reduction of speed was accompanied by a decrease in collisions, injuries and fatalities. The analysis found a 25% reduction in daytime unsafe speed related collisions, an 11% reduction in daytime traffic collision victims carried by ambulances and a 17%, reduction in daytime traffic collision fatalities. PMID:10868754

Chen, G; Wilson, J; Meckle, W; Cooper, P

2000-07-01

29

Evaluation of TRMM Ground-Validation Radar-Rain Errors Using Rain Gauge Measurements  

NASA Technical Reports Server (NTRS)

Ground-validation (GV) radar-rain products are often utilized for validation of the Tropical Rainfall Measuring Mission (TRMM) spaced-based rain estimates, and hence, quantitative evaluation of the GV radar-rain product error characteristics is vital. This study uses quality-controlled gauge data to compare with TRMM GV radar rain rates in an effort to provide such error characteristics. The results show that significant differences of concurrent radar-gauge rain rates exist at various time scales ranging from 5 min to 1 day, despite lower overall long-term bias. However, the differences between the radar area-averaged rain rates and gauge point rain rates cannot be explained as due to radar error only. The error variance separation method is adapted to partition the variance of radar-gauge differences into the gauge area-point error variance and radar rain estimation error variance. The results provide relatively reliable quantitative uncertainty evaluation of TRMM GV radar rain estimates at various times scales, and are helpful to better understand the differences between measured radar and gauge rain rates. It is envisaged that this study will contribute to better utilization of GV radar rain products to validate versatile spaced-based rain estimates from TRMM, as well as the proposed Global Precipitation Measurement, and other satellites.

Wang, Jianxin; Wolff, David B.

2009-01-01

30

Evaluation of a 35 GHz radar for cloud physics research  

NASA Astrophysics Data System (ADS)

A 35-GHz radar, such as the one that is presently modernized through the incorporation of solid state electronics, Dopplerization, and improved data display capabilities, is useful in observations of the internal structures of clouds and for the detection of low ice particle concentrations in the atmosphere. Simultaneous airborne and radar measurements indicate that the radar reflectivity factors for various water clouds, determined from radar measurements, were generally in good agreement with those derived from in situ measurements of the drop size spectra. The radar can also detect clouds in which droplet diameters do not exceed 27 microns, provided there are sufficient concentrations of 10-15 microns diameter droplets.

Hobbs, P. V.; Locatelli, J. D.; Biswas, K. R.; Funk, N. T.; Weiss, R. R., Sr.

1985-03-01

31

Determination of U, V, and W from single station Doppler radar radial velocities  

NASA Technical Reports Server (NTRS)

The ST/MST (stratosphere troposphere/mesosphere stratosphere troposphere) clear air Doppler radar, or wind profiler, is an important tool in observational meteorology because of its capability to remote observe dynamic parameters of the atmosphere. There are difficulties in transforming the observed radial velocities into meteorological wind components. How this problem has been treated in the past is reviewed, and some of the analysis is recast to a form more suited to the high diagnostic abilities of a number of fixed beam configurations with reference to a linear wind field. The results, in conjunction with other works which treats problems such as the effects of finite sample volumes in the presence of nonhomogeneous atmospheric reflectivity, have implications important to the design of both individual MST/ST radars and MST/ST radar networks. The key parameters to uncoupling terms in the scaling equations are w sub x and w sub y. Whenever the stratiform condition, which states that these two parameters are negligible, is satisfied, a five beam ST radar may determine unbiased values of u, v, and w for sample volumes directly above the radar. The divergence and partial deformation of the flow may also be determined. Three beam systems can determine w and w sub z, but are unable to obtain u and v wind components uncontaminated by vertical sheer terms, even when the stratiform condition is satisfied.

Clark, W. L.; Green, J. L.; Warnock, J. M.

1986-01-01

32

Technology evaluation for space station atmospheric leakage  

SciTech Connect

A concern in operation of a space station is leakage of atmosphere through seal points and through the walls as a result of damage from particle (space debris and micrometeoroid) impacts. This report describes a concept for a monitoring system to detect atmosphere leakage and locate the leak point. The concept is based on analysis and testing of two basic methods selected from an initial technology survey of potential approaches. 18 refs., 58 figs., 5 tabs.

Lemon, D.K.; Friesel, M.A.; Griffin, J.W.; Skorpik, J.R.; Shepard, C.L.; Antoniak, Z.I.; Kurtz, R.J.

1990-02-01

33

High frequency radar stations and moorings to monitor currents and circulation  

NASA Astrophysics Data System (ADS)

The preliminary results of the problem of how to optimize coastal radar observations and moored observations in Alaska are discussed. We analyze dynamically induced correlations in the Kotzebue Sound and conduct their sensitivity analysis to optimize positions of a limited number of radars and moorings. Optimization of the sampling strategy is performed with respect to robustness of the reconstruction of the Kotzebue Sound with a particular emphasis on the accurate monitoring of the currents in several regions. We also present some results of the reconstruction of the circulation during the fall 2008 in the Kotzebue Sound through the variational data assimilation of a SeaSonde high frequency radar, sea surface temperature, sea surface altimetry and atmospheric data into the Semi-Implicit Ocean model (SIOM). Climatological T/S data are used as background fields.

Francis, Oceana; Panteleev, Gleb; Atkinson, David; Weingartner, Tom

2010-05-01

34

Evaluation of space station solar array technology  

NASA Technical Reports Server (NTRS)

The research concerning lightweight solar array assemblies since 1970 is reported. A bibliography of abstracts of documents used for reference during this period is included along with an evaluation of available solar array technology. A list of recommended technology programs is presented.

1972-01-01

35

Angkor site monitoring and evaluation by radar remote sensing  

NASA Astrophysics Data System (ADS)

Angkor, in the northern province of Siem Reap, Cambodia, is one of the most important world heritage sites of Southeast Asia. Seasonal flood and ground sinking are two representative hazards in Angkor site. Synthetic Aperture Radar (SAR) remote sensing has played an important role for the Angkor site monitoring and management. In this study, 46 scenes of TerraSAR data acquired in the span of February, 2011 to December, 2013 were used for the time series analysis and hazard evaluation; that is, two-fold classification for flood area extracting and Multi-Temporal SAR Interferometry (MT-InSAR) for ground subsidence monitoring. For the flood investigation, the original Single Look Complex (SLC) TerraSAR-X data were transferred into amplitude images. Water features in dry and flood seasons were firstly extracted using a proposed mixed-threshold approach based on the backscattering; and then for the correlation analysis between water features and the precipitation in seasonally and annually. Using the MT-InSAR method, the ground subsidence was derived with values ranging from -50 to +12 mm/yr in the observation period of February, 2011 to June, 2013. It is clear that the displacement on the Angkor site was evident, implying the necessity of continuous monitoring.

Chen, Fulong; Jiang, Aihui; Ishwaran, Natarajan

2014-11-01

36

3. VIEW NORTHWEST, height finder radar towers, and radar tower ...  

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

3. VIEW NORTHWEST, height finder radar towers, and radar tower (unknown function) - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

37

Performance evaluation and waveform design for MIMO radar   

E-print Network

Multiple-input multiple-output (MIMO) radar has been receiving increasing attention in recent years due to the dramatic advantages offered by MIMO systems in communications. The amount of energy reflected from a common ...

Du, Chaoran

2010-01-01

38

A Computerized Approach to Substation and Switching Station Reliability Evaluation  

Microsoft Academic Search

This paper presents a new approach for the evaluation of substation and switching station reliability performance in terms of outage frequencies and durations. All realistic component failure modes are included in the reliability predictions. The computer program described in the paper is fairly general. It performs failure modes and effects analysis and provides a concise and orderly description of the

M. S. Grover; R. Billinton

1974-01-01

39

The RADAR Test Methodology: Evaluating a Multi-Task Machine Learning System with Humans in the Loop  

E-print Network

The RADAR Test Methodology: Evaluating a Multi-Task Machine Learning System with Humans in the Loop-HCII-06-102 Abstract The RADAR project involves a collection of machine learning research thrusts the impact of learning when used by a human user. Three conditions (conventional tools, Radar without

40

Photovoltaic-system evaluation at the Northeast Residential Experiment Station  

NASA Astrophysics Data System (ADS)

Five residential photovoltaic systems were tested and the systems' performance and cost was evaluated. The five systems each consist of an unoccupied structure employing a roof mounted photovoltaic array and a utility connected power inverter capable of sending excess PV generated energy to the local utility system. The photovoltaic systems are designed to meet at least 50% of the total annual electrical demand of residences in the cold climate regions of the country. The following specific issues were investigated: photovoltaic array and inverter system power rating and performance characterization, system energy production, reliability and system cost/worth. Summary load data from five houses in the vicinity of the Northeast Residential Experiment Station, and meteorological data from the station's weather station are also presented.

Russell, M. C.

1983-01-01

41

Technology transfer and evaluation for Space Station telerobotics  

NASA Technical Reports Server (NTRS)

The international space station (SS) must take advantage of advanced telerobotics in order to maximize productivity and safety and to reduce maintenance costs. The Automation and Robotics Division at the NASA Lyndon B. Johnson Space Center (JSC) has designed, developed, and constructed the Automated Robotics Maintenance of Space Station (ARMSS) facility for the purpose of transferring and evaluating robotic technology that will reduce SS operation costs. Additionally, JSC had developed a process for expediting the transfer of technology from NASA research centers and evaluating these technologies in SS applications. Software and hardware system developed at the research centers and NASA sponsored universities are currently being transferred to JSC and integrated into the ARMSS for flight crew personnel testing. These technologies will be assessed relative to the SS baseline, and, after refinements, those technologies that provide significant performance improvements will be recommended as upgrades to the SS. Proximity sensors, vision algorithms, and manipulator controllers are among the systems scheduled for evaluation.

Price, Charles R.; Stokes, Lebarian; Diftler, Myron A.

1994-01-01

42

Technical evaluation of the adequacy of station electric distribution system voltages for the Yankee Rowe Nuclear Power Station  

Microsoft Academic Search

This report documents the technical evaluation of the adequacy of the station electric distribution system voltages for the Yankee Rowe Nuclear Power Station. The evaluation is to determine if the onsite distribution system, in conjunction with the offsite power sources, has sufficient capacity to automatically start and operate all Class 1E loads within the equipment voltage ratings under certain conditions

Selan

1981-01-01

43

Technical evaluation of the adequacy of station electric distribution system voltages for the San Onofre Nuclear Generating Station, Unit 1  

Microsoft Academic Search

This report documents the technical evaluation of the adequacy of the station electric distribution system voltages for the San Onofre Nuclear Generating Station, Unit. The evaluation is to determine if the onsite distribution system in conjunction with the offsite power sources has sufficient capacity to automatically start and operate all Class 1E loads within the equipment voltage ratings under certain

Selan

1982-01-01

44

2. VIEW SOUTHWEST, prime search radar tower, height finder radar ...  

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

2. VIEW SOUTHWEST, prime search radar tower, height finder radar towards, height finder radar towers, and radar tower (unknown function) - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

45

Technical evaluation of the station and instrument ground grid systems at the Davis Besse Nuclear Power Station, Unit 1  

SciTech Connect

This report documents the technical evaluation of the station and instrument ground grid systems at the Davis Besse Nuclear Power Station, Unit 1. The evaluation is to determine that there are no inadvertent ties between the instrument and station ground grid systems, that any identified inadvertent ties are corrected, and to assure that the installation meets design criteria. The information submitted by the licensee indicates that there are no inadvertent ties between the station and instrument ground grid systems and that the installation meets design criteria.

Selan, J.C.

1981-06-29

46

A Theoretical Evaluation of Impulse Radar Wave Propagation Through Concrete  

Microsoft Academic Search

It has been shown that one of the most important factors affecting a radar survey of a concrete structure is the operational frequency of the antenna. The operational choice of frequency is difficult as there is always a compromise between signal penetration and resolution. Whilst case histories have proved valuable sources of information, they have not yielded the systematic data

M. C. Forde

1995-01-01

47

Polychlorinated biphenyl profiles in ringed seals (Pusa Hispida) reveal historical contamination by a military radar station in Labrador, Canada.  

PubMed

Significant amounts of soil contaminated with polychlorinated biphenyls (PCBs) were discovered at a military radar station in Saglek Bay, Labrador, Canada, in 1996. Subsequent work showed elevated PCB concentrations in local marine sediments, in the benthic-associated food web, and in some ringed seals (Pusa hispida). The benthic-associated food web clearly reflected local PCB contamination, but the high PCB concentrations found in some ringed seals remained unexplained. In the present study, the authors assess the extent to which this local PCB source at Saglek Bay is contributing to the contamination of ringed seals in northern Labrador. Among 63 ringed seals sampled along the northern Labrador coast, 5 (8%) had PCB levels that were higher than recorded anywhere else in the Canadian Arctic. In addition, compared with seals exhibiting a long-range signal, 45% and 60% of subadults and adult males, respectively, exhibited heavier PCB congener profiles as characterized by principal components analysis, >1.6-fold higher PCB/organochlorine pesticides ratios, and higher PCB concentration-weighted average log octanol-water partition coefficient values, consistent with a local source. Despite the spatially confined nature of contaminated sediments in Saglek Bay, the influence of this PCB source is not inconsequential; PCB concentrations in locally contaminated adult males are 2-fold higher than concentrations in those exposed only to long-range PCB sources and exceed an established threshold of 1.3 mg/kg for adverse health effects in seals. PMID:24273070

Brown, Tanya M; Fisk, Aaron T; Helbing, Caren C; Reimer, Ken J

2014-03-01

48

Shuttle orbiter Ku-band radar/communications system design evaluation. Deliverable test equipment evaluation  

NASA Technical Reports Server (NTRS)

The Ku-band test equipment, known as the Deliverable System Test equipment (DSTE), is reviewed and evaluated. The DSTE is semiautomated and computer programs were generated for 14 communication mode tests and 17 radar mode tests. The 31 test modules provide a good cross section of tests with which to exercise the Ku-band system; however, it is very limited when being used to verify Ku-band system performance. More detailed test descriptions are needed, and a major area of concern is the DSTE sell-off procedure which is inadequate.

Maronde, R. G.

1980-01-01

49

Linking the Annual Variation of Snow Radar-derived Accumulation in West Antarctica to Long-term Automatic Weather Station Measurements  

NASA Astrophysics Data System (ADS)

Understanding the snow accumulation rate on polar ice sheets is important in assessing mass balance and ice sheet contribution to sea level rise. Measuring annual accumulation on a regional scale and extending back in time several decades has been accomplished using the Center for Remote Sensing of Ice Sheets (CReSIS) Snow Radar on the NASA DC-8 that is part of NASA's Ice-Bridge project. The Snow Radar detects and maps near-surface internal layers in polar firn, operating from 2- 6 GHz and providing a depth resolution of ~4 cm. During November 2011, Snow Radar data were obtained for large areas of West Antarctica, including a flight segment that passed within ~70 km of Byrd Station (80°S, 119°W). Byrd Station has a very long automatic weather station (AWS) record, extending from present to 1980, with 3 relatively brief gaps in the record. The AWS data for Byrd Station were obtained from the Antarctic Meteorological Research Center (AMRC) at the University of Wisconsin. The L1B Snow Radar data products, available from the National Snow and Ice Data Center (NSIDC), were analyzed using layer picking software to obtain the depth of reflectors in the firn that are detected by the radar. These reflectors correspond to annual markers in the firn, and allow annual accumulation to be determined. Using the distance between the reflectors and available density profiles from ice cores, water equivalent accumulation for each annual layer back to 1980 is obtained. We are analyzing spatial variations of accumulation along flight lines, as well as variations in the time series of annual accumulation. We are also analyzing links between annual accumulation and surface weather observations from the Byrd Station AWS. Our analyses of surface weather observations have focused on annual temperature, atmospheric pressure and wind extremes (e.g. 5th and 95th percentiles) and links to annual snow accumulation. We are also examining satellite-derived sea ice extent records for the Bellingshausen and Amundsen seas sector (60°W-120°W) over the same 31-year time period and comparing results to annual snow accumulation. Results from this work will be presented at the meeting.

Feng, B.; Braaten, D. A.; Gogineni, P.; Paden, J. D.; Leuschen, C.; Purdon, K.

2013-12-01

50

Evaluating Pseudorange Multipath at CGPS Stations Spanning Mexico  

NASA Astrophysics Data System (ADS)

A research study was conducted in order to quantify and analyze the amount of pseudorange multipath at continuous Global Positioning System (CGPS) stations spanning Mexico. These CGPS stations are administered by a variety of organizations, including government agencies and public universities, and thus serve a wide range of positioning needs. Despite the diversity of the networks and their intended audiences, a core function of all of the networks is to provide a stable framework for high-precision positioning in support of diverse commercial and scientific applications. CGPS data from a large number of publicly available networks located in Mexico were studied. These include the RGNA (National Active Geodetic Network) administered by INEGI (National Institute of Statistics and Geography), the PBO network (Plate Boundary Observatory) funded by the National Science Foundation (NSF) and operated by UNAVCO (University NAVstar Consortium), the Southern California Integrated GPS Network (SCIGN), which is a collaboration effort of the United States Geological Survey (USGS), Scripps Institution of Oceanography and the Jet Propulsion Laboratory (JPL), the UNAM network, operated by the National Seismological System (SSN) and the Institute of Geophysics of the National Autonomous University of Mexico (UNAM), the Suominet Geodetic Network (SNG) and the CORS (Continuously Operating Reference Station) network, operated by the Federal Aviation Administration (FAA). A total of 54 CGPS stations were evaluated, where dual-frequency geodetic-grade receivers collected GPS data continuously during the period from 1994 to 2013. It is usually assumed that despite carefully selected locations, all CGPS stations are to some extent, affected by the presence of signal multipath. In addition, the geographic distribution of stations provides a nation-wide access to the International Terrestrial Reference Frame (ITRF). For real-time kinematic (RTK) and rapid static applications that depend on the pseudo-range observable, the accuracy with which a roaming user may locate their assets with respect to the ITRF may be limited by site-specific multipath. The issue is particularly critical for users depending on pseudorange measurements for 'real-time' (or 'near-real-time') kinematic GPS positioning, where ambiguity resolution is a critical step. Therefore, to identify the most and the least affected GPS stations we analyzed the averaged daily root mean square pseudorange multipath variations (MP1-RMS and MP2-RMS) for all feasible satellites tracked by the CGPS networks. We investigated the sources of multipath, including changes associated with hardware replacement (i.e., receiver and antenna type) and receiver firmware upgrades.

Vazquez, G.; Bennett, R. A.; Spinler, J. C.

2013-12-01

51

Study to investigate and evaluate means of optimizing the radar function for the space shuttle. [(pulse radar)  

NASA Technical Reports Server (NTRS)

Results are discussed of a study to define a radar and antenna system which best suits the space shuttle rendezvous requirements. Topics considered include antenna characteristics and antenna size tradeoffs, fundamental sources of measurement errors inherent in the target itself, backscattering crosssection models of the target and three basic candidate radar types. Antennas up to 1.5 meters in diameter are within specified installation constraints, however, a 1 meter diameter paraboloid and a folding, four slot backfeed on a two gimbal mount implemented for a spiral acquisition scan is recommended. The candidate radar types discussed are: (1) noncoherent pulse radar (2) coherent pulse radar and (3) pulse Doppler radar with linear FM ranging. The radar type recommended is a pulse Doppler with linear FM ranging. Block diagrams of each radar system are shown.

1975-01-01

52

Study to investigate and evaluate means of optimizing the radar function. [systems engineering of pulse radar for the space shuttle  

NASA Technical Reports Server (NTRS)

The investigations for a rendezvous radar system design and an integrated radar/communication system design are presented. Based on these investigations, system block diagrams are given and system parameters are optimized for the noncoherent pulse and coherent pulse Doppler radar modulation types. Both cooperative (transponder) and passive radar operation are examined including the optimization of the corresponding transponder design for the cooperative mode of operation.

1975-01-01

53

Evaluation of three Radar Product Processors Iwan Holleman and Hans Beekhuis  

E-print Network

Evaluation of three Radar Product Processors Iwan Holleman and Hans Beekhuis Internal Report, KNMI IR-2005-03, 2005 #12;2 #12;Contents 1 Introduction 5 2 Set-up of evaluation 9 3 General evaluation 11.3.3 Geographical projection 23 3.3.4 Products 24 3.3.5 File format 25 3.3.6 Documentation 26 4 Evaluation

Stoffelen, Ad

54

Summary of monitoring station component evaluation project 2009-2011.  

SciTech Connect

Sandia National Laboratories (SNL) is regarded as a center for unbiased expertise in testing and evaluation of geophysical sensors and instrumentation for ground-based nuclear explosion monitoring (GNEM) systems. This project will sustain and enhance our component evaluation capabilities. In addition, new sensor technologies that could greatly improve national monitoring system performance will be sought and characterized. This work directly impacts the Ground-based Nuclear Explosion Monitoring mission by verifying that the performance of monitoring station sensors and instrumentation is characterized and suitable to the mission. It enables the operational monitoring agency to deploy instruments of known capability and to have confidence in operational success. This effort will ensure that our evaluation capabilities are maintained for future use.

Hart, Darren M.

2012-02-01

55

Evaluation plan for space station network interface units  

NASA Technical Reports Server (NTRS)

Outlined here is a procedure for evaluating network interface units (NIUs) produced for the Space Station program. The procedures should be equally applicable to the data management system (DMS) testbed NIUs produced by Honeywell and IBM. The evaluation procedures are divided into four areas. Performance measurement tools are hardware and software that must be developed in order to evaluate NIU performance. Performance tests are a series of tests, each of which documents some specific characteristic of NIU and/or network performance. In general, these performance tests quantify the speed, capacity, latency, and reliability of message transmission under a wide variety of conditions. Functionality tests are a series of tests and code inspections that demonstrate the functionality of the particular subset of ISO protocols which have been implemented in a given NIU. Conformance tests are a series of tests which would expose whether or not selected features within the ISO protocols are present and interoperable.

Weaver, Alfred C.

1990-01-01

56

Evaluation of polarimetric through-the-wall radar measurements  

NASA Astrophysics Data System (ADS)

Fully polarimetric through-the-wall radar measurements with high spatial resolution have been attained by using the ISAR (Inverse Synthetic Aperture Radar) technique. Polarimetric methods may reduce the effects of the wall interaction and increase the contrast between humans and the background. The main scene in the measurements was a human sitting in a small wooden cabin. The cabin was placed on a turntable and rotated, to obtain ISAR imaging. By switching the transmitter and receiver antennas between horizontal and vertical polarizations, four polarization combinations were obtained. Phase coherence was maintained through a whole measurement series. This enabled co-processing of the whole collected data set with coherent methods. A statistical description of the measured data was used, with the polarimetric coherency matrix applied to the received signals. ISAR images produced for the TTW scenes show that the human can be discerned from the background. The contrast between the human and the background was found to be greater with vertical polarization at transmit and receive, with less contrast using cross-polarization or horizontal co-polarization, due to the horizontal wall grain orientation. A classification scheme based on the eigenparameters of the coherency matrix (entropy, anisotropy and alpha angle) and the backscatter power has been tested to discriminate between different target objects in the cabin. The method shows some promise, but a reliable classification has not yet been attained.

Johansson, Tommy; Sume, Ain; Rahm, Jonas; Nilsson, Stefan; Örbom, Anders

2012-06-01

57

Implementation and evaluation of the new wind algorithm in NASA's 50 MHz doppler radar wind profiler  

NASA Technical Reports Server (NTRS)

The purpose of this report is to document the Applied Meteorology Unit's implementation and evaluation of the wind algorithm developed by Marshall Space Flight Center (MSFC) on the data analysis processor (DAP) of NASA's 50 MHz doppler radar wind profiler (DRWP). The report also includes a summary of the 50 MHz DRWP characteristics and performance and a proposed concept of operations for the DRWP.

Taylor, Gregory E.; Manobianco, John T.; Schumann, Robin S.; Wheeler, Mark M.; Yersavich, Ann M.

1993-01-01

58

Evaluation of adaptive space-time processing for inclined sideways looking array airborne radars  

Microsoft Academic Search

This paper evaluates the performance of partial adaptive space-time adaptive processing (STAP) approaches based on Doppler prefiltering for inclined sideways looking array (ISLA) airborne radar, in which the angle between the axis of a linear antenna array with that of platform flight is not zero. In ISLA the STAP is more complex than that in a sideways looking array (SLA),

Liao Guisheng; Bao Zheng; Xu Zhiyong

1996-01-01

59

A review of selected ground penetrating radar applications to mineral resource evaluations  

NASA Astrophysics Data System (ADS)

Since the commercialisation of ground penetrating radar (GPR) in the 1970s, the technology has been relegated to niche applications in the mining industry. Advances in radar technology, such as flexible collinear antennas and the integration of live differential GPS positioning, have spurred GPR's acceptance in recent years as a standard exploration method for a number of deposit types. Provided herein is an overview of commercialised GPR applications for surface mineral resource evaluations, covering examples of alluvial channels, nickel and bauxitic laterites, iron ore deposits, mineral sands, coal and kimberlites.

Francke, Jan

2012-06-01

60

Evaluation of synthetic aperture radar for oil-spill response. Final report, June 1992-September 1993  

SciTech Connect

This report provides a detailed evaluation of synthetic aperture radar (SAR) as a potential technology improvement over the Coast Guard's existing side-looking airborne radar (SLAR) for oil-spill surveillance applications. The U.S. Coast Guard Research and Development Center (RD Center), Environmental Safety Branch, sponsored a joint experiment including the U.S. Coast Guard, Sandia National Laboratories, and the National Oceanographic and Atmospheric Administration (NOAA), Hazardous Materials Division. Radar imaging missions were flown on six days over the coastal waters off Santa Barbara, CA, where there are constant natural seeps of oil. Both the Coast Guard SLAR and the Sandia National Laboratories SAR were employed to acquire simultaneous images of oil slicks and other natural sea surface features that impact oil-spill interpretation. Surface truth and other environmental data were also recorded during the experiment. The experiment data were processed at Sandia National Laboratories and delivered to the RD Center on a PC-based computer workstation for analysis by experiment participants. Synthetic aperture radar, Side looking airborne radar, Oil slicks.

Hover, G.L.; Mastin, G.A.; Axline, R.M.; Bradley, J.D.

1993-10-01

61

Shuttle orbiter Ku-band radar/communications system design evaluation  

NASA Technical Reports Server (NTRS)

Tasks performed in an examination and critique of a Ku-band radar communications system for the shuttle orbiter are reported. Topics cover: (1) Ku-band high gain antenna/widebeam horn design evaluation; (2) evaluation of the Ku-band SPA and EA-1 LRU software; (3) system test evaluation; (4) critical design review and development test evaluation; (5) Ku-band bent pipe channel performance evaluation; (6) Ku-band LRU interchangeability analysis; and (7) deliverable test equipment evaluation. Where discrepancies were found, modifications and improvements to the Ku-band system and the associated test procedures are suggested.

Dodds, J.; Holmes, J.; Huth, G. K.; Iwasaki, R.; Maronde, R.; Polydoros, A.; Weber, C.; Broad, P.

1980-01-01

62

5. VIEW EAST, height finder radar towers, radar tower (unknown ...  

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

5. VIEW EAST, height finder radar towers, radar tower (unknown function), prime search radar tower, operations building, and central heating plant - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

63

4. VIEW NORTHEAST, radar tower (unknown function), prime search radar ...  

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

4. VIEW NORTHEAST, radar tower (unknown function), prime search radar tower, emergency power building, and height finder radar tower - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

64

Microbial Diversity Aboard Spacecraft: Evaluation of the International Space Station  

NASA Technical Reports Server (NTRS)

An evaluation of the microbial flora from air, water, and surface samples provided a baseline of microbial diversity onboard the International Space Station (ISS) to gain insight into bacterial and fungal contamination during the initial stages of construction and habitation. Using 16S genetic sequencing and rep-PeR, 63 bacterial strains were isolated for identification and fingerprinted for microbial tracking. The use of these molecular tools allowed for the identification of bacteria not previously identified using automated biochemical analysis and provided a clear indication of the source of several ISS contaminants. Fungal and bacterial data acquired during monitoring do not suggest there is a current microbial hazard to the spacecraft, nor does any trend indicate a potential health risk. Previous spacecraft environmental analysis indicated that microbial contamination will increase with time and require continued surveillance.

Castro, Victoria A.; Thrasher, Adrianna N.; Healy, Mimi; Ott, C. Mark; Pierson, Duane L.

2003-01-01

65

Multi-scale evaluation of the IFloodS radar-rainfall products  

NASA Astrophysics Data System (ADS)

Rainfall products estimated using ground-based radars are often used as reference to assess capabilities and limitations of using satellite rainfall estimates in hydrologic modeling and prediction. During the spring of 2013, NASA conducted a hydrology-oriented field campaign called Iowa Flood Studies (IFloodS) in the central and northeastern Iowa in the United States, as a part of the Ground Validation (GV) program for the Global Precipitation Measurement (GPM) mission. The purpose of IFloodS was to enhance the understanding of flood-related rainfall processes and the predictability in flood forecasting. While there are multiple types of rainfall data sets (e.g., satellite, radar, rain gauge, and disdrometer) available as the observational assets of IFloodS, the authors focus on the evaluation of multi-scale rainfall products observed from ground-based radars. The radar-only products used in the evaluation are the NEXRAD single polarization products (i.e., Stage IV, NMQ Q2, and Iowa Flood Center rainfall maps) and products generated using dual-polarization procedures (i.e., the U.S. National Weather Service operational and Colorado State University experimental blended precipitation processing algorithms) with comparable space and time resolution. The NASA NPOL S-band radar products are also evaluated and compared with the aforementioned NEXRAD products. The uncertainty for different temporal and spatial resolution products is characterized using ground reference data of dense rain gauge and disdrometer networks. This multi-scale characterization is required for hydrologic modeling frameworks that assess model predictive abilities as a function of space and time scales.

Seo, Bong-Chul; Krajewski, Witold; Cunha, Luciana; Dolan, Brenda; Smith, James; Rutledge, Steven; Petersen, Walter

2014-05-01

66

Application of 50 MHz doppler radar wind profiler to launch operations at Kennedy Space Center and Cape Canaveral Air Station  

NASA Technical Reports Server (NTRS)

This paper presents a case study where a significant wind shift, not detected by jimspheres, was detected by the 50 MHz DRWP (Doppler Radar Wind Profiler) and evaluated to be acceptable prior to the launch of a Shuttle. This case study illustrates the importance of frequent upper air wind measurements for detecting significant rapidly changing features as well as for providing confidence that the features really exist and are not due to instrumentation error. Had the release of the jimsphere been timed such that it would have detected the entire wind shift, there would not have been sufficient time to release another jimsphere to confirm the existence of the feature prior to the scheduled launch. We found that using a temporal median filter on the one minute spectral estimates coupled with a constraining window about a first guess velocity effectively removes nearly all spurious signals from the velocity profile generated by NASA's 50 MHz DRWP while boosting the temporal resolution to as high as one profile every 3 minutes. The higher temporal resolution of the 50 MHz DRWP using the signal processing algorithm described in this paper ensures the detection of rapidly changing features as well as provides the confidence that the features are genuine. Further benefit is gained when the profiles generated by the DRWP are examined in relation to the profiles measured by jimspheres and/or rawinsondes. The redundancy offered by using two independent measurements can dispel or confirm any suspicion regarding instrumentation error or malfunction and wind profiles can be examined in light of their respective instruments' strengths and weaknesses.

Schumann, Robin S.; Taylor, Gregory E.; Smith, Steve A.; Wilfong, Timothy L.

1994-01-01

67

Evaluation of Raindrop Size Distributions to Improve Radar Rainfall Estimation during the Colorado Flood  

NASA Astrophysics Data System (ADS)

During the period of 9-16 September 2013, a large area of greater than 150 mm of rain, with local amounts of up to 450 mm, fell over a large part of the Colorado Front Range foothills and adjacent plains. This extreme rainfall event caused severe flooding of main river channels and some localized flash flooding which resulted in millions of dollars of damage to private and public properties. The rainfall regime associated with this extreme precipitation event was atypical of storms usually observed in this region. As a result, the radar rainfall algorithms tuned for this region significantly underestimated the total amount of rainfall. In order to quantify the underestimation and provide insight for improving the radar rainfall estimates for this unique precipitation regime, a comparison study has been conducted using data from several disdrometers that were operating throughout the event. Disdrometers observed over 5000 minutes of rainfall during the event. Analysis of the raindrop spectra indicated that most of the rainfall was comprised of a large number of small drops (< 2 mm in diameter). The raindrop spectra have been stratified by the precipitation regime. For these different regimes, new radar rainfall estimators are being derived from the raindrop spectra. The new estimators will be applied to the radar data to provide new rainfall estimates. These estimates will be evaluated using independent rain gauge data. The presentation will provide an overview of the Colorado Flood and a summary of results from the precipitation analysis.

Kucera, Paul; Klepp, Christian

2014-05-01

68

Shuttle imaging radar-A (SIR-A) data analysis. [geology of the Ozark Plateau of southern Missouri, land use in western Illinois, and vegetation types at Koonamore Station, Australia  

NASA Technical Reports Server (NTRS)

The utility of shuttle imaging radar (SIR-A) data was evaluated in several geological and environmental contexts. For the Ozark Plateau of southern Missouri, SIR-A data were of little use in mapping structural features, because of generally uniform returns. For western Illinois, little was to be gained in terms of identifying land use categories by examining differences between overlapping passes. For southern Australia (Koonamore Station), information ion vegetation types that was not obtainable from LANDSAT MSS data alone was obtained. Specifically, high SIR-A returns in the Australian site were found to correlate with locations where shrubs increase surface roughness appreciably. The Australian study site results demonstrate the synergy of acquiring spectral reflectance and radar data over the same location and time. Such data are especially important in that region, since grazing animals have substantially altered and are continuing to alter the distribution of shrublands, grasslands, and soil exposures. Periodic, synoptic acquisition of MSS and SAR data would be of use in monitoring the dynamics of land-cover change in this environment.

Arvidson, R. E.

1983-01-01

69

[Evaluation of medication advertising broadcast on radio stations].  

PubMed

The scope of this paper was to evaluate advertising for medication broadcast on radio stations in Natal, State of Rio Grande do Norte, Brazil, from April to September 2008 and from April to September 2010. The advertising was recorded and transcribed in order to conduct legal analysis and content analysis based on the precepts of Laurence Bardin. Both the advertising recorded during the first stage (regulated by RDC 102/00) and the second stage (regulated by RDC 96/08) contained some form of legal violation. Content analysis detected practically the same violations in both stages, namely the lack of information regarding adverse effects of the medication, appeal to consumption, exaggeration of efficiency/effectiveness and abusive exploitation of illness. Despite the inclusion of more modern and restrictive legislation, radio advertising continues to violate the law blatantly, committing abuse and disrespecting the population's entitlement to good health. The study reveals the need for medication advertising to be dealt with in a broader context, in other words to be treated as a public health concern. It must take into consideration the socio-historical scenario in which it evolved, since the legislation alone is insufficient to combat abuse committed to the detriment of public health. PMID:23358781

Batista, Almária Mariz; Carvalho, Maria Cleide Ribeiro Dantas de

2013-02-01

70

Conceptual design and evaluation of selected Space Station concepts, volume 1  

NASA Technical Reports Server (NTRS)

Space Station configuration concepts are defined to meet the NASA Headquarters Concept Development Group (CDG) requirements. Engineering and programmatic data are produced on these concepts suitable for NASA and industry dissemination. A data base is developed for input to the CDG's evaluation of generic Space Station configurations and for use in the critique of the CDG's generic configuration evaluation process.

1983-01-01

71

Reliability Evaluation of Flood Releasing Structures Power Supply of Hydroelectric Power Station by Fault Tree Analysis  

Microsoft Academic Search

A new approach based on fault tree analysis to evaluate the overall reliability of flood releasing structures power supply system of hydroelectric power station is presented. This paper introduces the fault tree modelling and evaluation methods, and taking one hydroelectric power station in East China for example, a detailed fault tree model for flood releasing structures power supply system is

Zhenjie Li; Yue Yuan; Bowen Wu

2010-01-01

72

Site evaluation for laser satellite-tracking stations  

NASA Technical Reports Server (NTRS)

Twenty-six locations for potential laser satellite-tracking stations, four of them actually already occupied in this role, are reviewed in terms of their known local and regional geology and geophysics. The sites are also considered briefly in terms of weather and operational factors. Fifteen of the sites qualify as suitable for a stable station whose motions are likely to reflect only gross plate motion. The others, including two of the present laser station sites (Arequipa and Athens), fail to qualify unless extra monitoring schemes can be included, such as precise geodetic surveying of ground deformation.

Mao, N. H.; Mohr, P. A.

1976-01-01

73

In-Service Evaluation of the Turbulence Auto-PIREP System and Enhanced Turbulence Radar Technologies  

NASA Technical Reports Server (NTRS)

From August 2003 to December 2006, In-Service Evaluations (ISE) of the Turbulence Auto-PIREP System (TAPS) and Enhanced Turbulence (E-Turb) Radar, technologies developed in NASA's Turbulence Prediction and Warning System (TPAWS) element of its Aviation Safety and Security Program (AvSSP), were conducted. NASA and AeroTech Research established an industry team comprising AeroTech, Delta Air Lines, Rockwell Collins, and ARINC to conduct the ISEs. The technologies were installed on Delta aircraft and their effectiveness was evaluated in day-to-day operations. This report documents the establishment and conduct of the ISEs and presents results and feedback from various users.

Prince, Jason B.; Buck, Bill K.; Robinson, Paul A.; Ryan, Tim

2007-01-01

74

Launch delays in the evaluation of Space Station supportability  

NASA Astrophysics Data System (ADS)

The National Space Transportation System (NSTS) will be the sole provider of assembly items and support resources to Space Station Freedom. Using an operations simulation tool, the consequences of spares provisioning levels and launch schedule perturbations to onorbit systems' effectiveness are explored. The extent of post-Challenger launch delay experiences and how they are modeled are described. By using simulation modeling, the operational availability of space station hardware and distinctions in support requirements are investigated for the Mission Build flights, MB-1 through MB-7.

Dejulio, Edmund; Strickland, Christopher; McCormick, James

1991-11-01

75

Conceptual design and evaluation of selected Space Station concepts: Executive summary  

NASA Technical Reports Server (NTRS)

The results of a space station conceptual design and evaluation study are summarized. The study represented a temporary focusing. Three space station configurations are characterized for user and crew requirements, operation and safety accommodations, engineering considerations including assembly and growth, structural dynamics, communications, thermal control and power systems, as well as system cost.

1983-01-01

76

Evaluation of absorption cycle for space station environmental control system application  

NASA Technical Reports Server (NTRS)

The study to evaluate an absorption cycle refrigeration system to provide environmental control for the space stations is reported. A zero-gravity liquid/vapor separator was designed and tested. The results were used to design a light-weight, efficient generator for the absorption refrigeration system. It is concluded that absorption cycle refrigeration is feasible for providing space station environmental control.

Sims, W. H.; Oneill, M. J.; Reid, H. C.; Bisenius, P. M.

1972-01-01

77

Ranger Station Solar-Energy System Receives Economic Evaluation  

NASA Technical Reports Server (NTRS)

Economic performance of Glendo Reservoir Ranger Station solar-energy system in Wyoming and extrapolated performance in four other locations around the U.S. is reviewed in report. System is a passive drain-down system using water as heat-transfer medium for space and hot-water heating.

1982-01-01

78

Technical-evaluation report on the adequacy of station electric-distribution-system voltages for the San Onofre Nuclear Generating Station, Unit 1. Document No. 50-206  

Microsoft Academic Search

This report documents the technical evaluation of the adequacy of the station electric distribution system voltages for the San Onofre Nuclear Generating Station, Unit 1. The evaluation is to determine if the onsite distribution system in conjunction with the offsite power sources has sufficient capacity to automatically start and operate all Class 1E loads within the equipment voltage ratings under

Selan

1982-01-01

79

The undersea habitat as a space station analog: Evaluation of research and training potential  

NASA Technical Reports Server (NTRS)

An evaluation is given of the utility of undersea habitats for both research and training on behavioral issues relative to the space station. The feasibility of a particular habitat, La Chalupa, is discussed.

Helmreich, Robert L.; Wilhelm, John A.

1985-01-01

80

Evaluation of Space Station Meteoroid/Debris Shielding Materials, Supplement  

NASA Technical Reports Server (NTRS)

The following Lotus 1-2-3 spreadsheets are included. They were converted from Lotus version 2.1 to version 1A, which is more common and can also be read by all subsequent versions. MS-DOS V.3.10 was used to format the diskette. Additional information can be attained by contacting: Eric L. Christiansen, Eagle Engineering, (713)338-2682. 1) IMPACT.WKS Analytical model described in Section 4.2 and Appendix A. 2) HUGONIOT.WKS Calculates peak shock pressure as described in Appendix C. 3) FIGOFMER.WKS Empirical model described in Section 4.1 and Appendix B. 4) DEB_VDIS.WKS Contains orbital debris velocity distribution for typical Space Station orbit. Calculates the fraction of debris below the velocity causing aluminum projectiles to melt as described in Section 3.3. 5) MOD_CRIT.WKS Determines the critical orbital debris and meteoroid size that a Space Station hab or lab module should be designed to protect against based on a 0.9955 probability of no penetration as described in Section 3.3. 6) SSMOD_CE.WKS Determines the number and maximum size of perforations expected in an aluminum bumper of a Space Station common module over its orbital lifetime as discussed in Section 3.3.

1987-01-01

81

1. VIEW NORTHWEST, operations building, height finder radar tower, and ...  

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

1. VIEW NORTHWEST, operations building, height finder radar tower, and radar tower (unknown function) - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

82

Computation of clear-air radar backscatter from numerical simulations of turbulence: 1. Numerical methods and evaluation of biases  

NASA Astrophysics Data System (ADS)

A numerical simulation of secondary instability and turbulence accompanying Kelvin-Helmholtz shear instability and a numerical algorithm computing radar backscatter from these turbulence volumes are employed to examine the validity of routine assumptions employed in radar studies of atmospheric dynamics that rely on backscatter from refractive index fluctuations. The numerical simulation of KH instability describes turbulence dynamics and character from the onset of instability, through fully developed turbulence, to turbulence decay and restratification at late times. Radar backscatter computations employing the Born approximation and the turbulence fields at multiple times are performed for representative radar frequencies, beam widths, and pulse lengths. Vertical velocities obtained from the Doppler spectra are compared with the true velocities evaluated with the same weighting of the true velocity distributions. Results reveal departures of simulated radar velocity estimates that depend on how many scatterers are included in the scattering volume, how their contributions are weighted in space and time, and the morphology of the turbulence field. Biases include underestimates of vertical velocities where velocities and refractive index fluctuations are correlated, apparent velocities due to advection of tilted scatterers, and an inability to define Doppler velocities with precision where turbulence is strong, but backscatter is weak due to mixing and eradication of refractive index gradients. A companion paper employs these procedures to describe the backscatter power and Doppler velocities for two canonical radars throughout the life cycle of the KH instability. Both studies suggest systematic measurement biases that appear to account for a number of reported measurements.

Franke, P. M.; Mahmoud, S.; Raizada, K.; Wan, K.; Fritts, D. C.; Lund, Tom; Werne, J.

2011-11-01

83

FIRE_CI2_ETL_RADAR  

Atmospheric Science Data Center

FIRE_CI2_ETL_RADAR Project Title:  FIRE II CIRRUS Discipline:  ... Platform:  Ground Station Instrument:  Radar Spatial Coverage:  (37.06, -95.34) Spatial ... Order Data Guide Documents:  ETL_RADAR Guide Readme Files:  Readme ETL_RADAR (PS) ...

2014-05-06

84

Evaluation of Single-Doppler Radar Wind Retrievals in Flat and Complex Terrain  

SciTech Connect

The accuracy of winds derived from NEXRAD level II data is assessed by comparison with independent observations from 915 MHz radar wind profilers. The evaluation is carried out at two locations with very different terrain characteristics. One site is located in an area of complex terrain within the State Line Wind Energy Center in northeast Oregon. The other site is located in an area of flat terrain on the east-central Florida coast. The National Severe Storm Laboratory’s 2DVar algorithm is used to retrieve wind fields from the KPDT (Pendleton OR) and KMLB (Melbourne FL) NEXRAD radars. Comparisons between the 2DVar retrievals and the radar profilers were conducted over a period of about 6 months and at multiple height levels at each of the profiler sites. Wind speed correlations at most observation height levels fell in the range from 0.7 to 0.8, indicating that the retrieved winds followed temporal fluctuations in the profiler-observed winds reasonably well. The retrieved winds, however, consistently exhibited slow biases in the range of1 to 2 ms-1. Wind speed difference distributions were broad with standard deviations in the range from 3 to 4 ms-1. Results from the Florida site showed little change in the wind speed correlations and difference standard deviations with altitude between about 300 and 1400 m AGL. Over this same height range, results from the Oregon site showed a monotonic increase in the wind speed correlation and a monotonic decrease in the wind speed difference standard deviation with increasing altitude. The poorest overall agreement occurred at the lowest observable level (~300 m AGL) at the Oregon site, where the effects of the complex terrain were greatest.

Newsom, Rob K.; Berg, Larry K.; Pekour, Mikhail S.; Fast, Jerome D.; Xu, Qin; Zhang, Pengfei; Yang, Qing; Shaw, William J.; Flaherty, Julia E.

2014-08-01

85

An evaluation of oxygen-hydrogen propulsion systems for the Space Station  

NASA Technical Reports Server (NTRS)

Conceptual designs for O2/H2 chemical and resistojet propulsion systems for the space station was developed and evaluated. The evolution of propulsion requirements was considered as the space station configuration and its utilization as a space transportation node change over the first decade of operation. The characteristics of candidate O2/H2 auxiliary propulsion systems are determined, and opportunities for integration with the OTV tank farm and the space station life support, power and thermal control subsystems are investigated. OTV tank farm boiloff can provide a major portion of the growth station impulse requirements and CO2 from the life support system can be a significant propellant resource, provided it is not denied by closure of that subsystem. Waste heat from the thermal control system is sufficient for many propellant conditioning requirements. It is concluded that the optimum level of subsystem integration must be based on higher level space station studies.

Klemetson, R. W.; Garrison, P. W.; Hannum, N. P.

1985-01-01

86

International Space Station Bacteria Filter Element Service Life Evaluation  

NASA Technical Reports Server (NTRS)

The International Space Station (ISS) uses high-efficiency particulate air filters to remove particulate matter from the cabin atmosphere. Known as bacteria filter elements (BFEs), there are 13 elements deployed on board the ISS's U.S. segment in the flight 4R assembly level. The preflight service life prediction of 1 yr for the BFEs is based upon engineering analysis of data collected during developmental testing that used a synthetic dust challenge. While this challenge is considered reasonable and conservative from a design perspective, an understanding of the actual filter loading is required to best manage the critical ISS program resources. Testing was conducted on BFEs returned from the ISS to refine the service life prediction. Results from this testing and implications to ISS resource management are provided.

Perry, J. L.

2005-01-01

87

Experimental Evaluation of Adaptive Beamforming Methods and Interference Models for High Frequency Over-the-Horizon Radar Systems  

Microsoft Academic Search

This paper experimentally evaluates the interference cancellation performance of different adaptive beamforming schemes applicable to high frequency (HF) over-the-horizon (OTH) radar systems. Such systems are known to receive multipath and diffusely scattered radio frequency interference produced as a result of reflection from the stratified, dynamic and spatially inhomogeneous ionospheric propagation medium. Apart from quantifying the effectiveness of operational adaptive beamformers

G. A. Fabrizio; D. A. Gray; M. D. Turley

2003-01-01

88

Evaluation of Terrestrial Laser Scanning and Ground Penetrating Radar for Field-Based High-Throughput Phenotyping in Wheat Breeding  

E-print Network

laser scanning (TLS) and ground penetrating radar (GPR) have the potential to fill this gap by non-invasively estimating biomass and mapping three-dimensional above- and below-ground vegetation. The research objective was to evaluate the use of TLS...

Thompson, Sean M

2014-08-05

89

Tree Roots in Agroforestry: Evaluating Biomass and Distribution with Ground Penetrating Radar  

NASA Astrophysics Data System (ADS)

The root systems of five tree species (Populus deltoides x nigra clone DN-177, Juglans nigra, Quercus rubra, Picea abies, and Thuja occidentalis) are described following non-intrusive imaging using ground penetrating radar (GPR). This research aimed to 1) assess the utility of GPR for in situ root studies and 2) employ GPR to estimate tree root biomass and distribution in an agroforestry system in southern Ontario, Canada. The mean coarse root biomass estimated from GPR analysis was 54.1 +/- 8.7 kg tree-1 (+/- S.E.; n=12), within 1 % of the mean coarse root biomass measured from matched excavations. The vertical distribution of detected roots varied among species, with T. occidentalis and P. abies roots concentrated in the top 20 cm and J. nigra and Q. rubra roots distinctly deeper. I evaluate these root systems based on their C storage potential and complementary root stratification with adjacent crops.

Borden, Kira Alia

90

Evaluation of a new wavelet-based compression algorithm for synthetic aperture radar images  

NASA Astrophysics Data System (ADS)

In this paper we will discuss the performance of a new wavelet based embedded compression algorithm on synthetic aperture radar (SAR) image data. This new algorithm uses index coding on the indices of the discrete wavelet transform of the image data and provides an embedded code to successively approximate it. Results on compressing still images, medical images as well as seismic traces indicate that the new algorithm performs quite competitively with other image compression algorithms. The evaluation for SAR image compression of it will be presented in this paper. One advantage of the new algorithm presented here is that the compressed data is encoded in such a way as to facilitate processing in the compressed wavelet domain, which is a significant aspect considering the rate at which SAR data is collected and the desire to process the data 'near real time'.

Tian, Jun; Guo, Haitao; Wells, Raymond O., Jr.; Burrus, C. Sidney; Odegard, Jan E.

1996-06-01

91

Evaluation of river water quality monitoring stations by principal component analysis  

Microsoft Academic Search

The development of a surface water monitoring network is a critical element in the assessment, restoration, and protection of stream water quality. This study applied principal component analysis (PCA) and principal factor analysis (PFA) techniques to evaluate the effectiveness of the surface water quality-monitoring network in a river where the evaluated variables are monitoring stations. The objective was to identify

Ying Ouyang

2005-01-01

92

Evaluation of the Aquila prototype generic review station (GRS)  

SciTech Connect

The GRS task was envisioned as a means of providing the IAEA with a single instrument with the capability to review a variety of video surveillance systems already in routine use, or contemplated for future deployment. These include the Modular Integrated Video System (MIVS), the Multiplex TV Surveillance System (MUX), the Multi-camera Optical Surveillance System (MOS) and the Compact Surveillance Monitoring System (COSMOS). During 1992, significant efforts were undertaken by IAEA to specify and evaluate commercial or near commercial systems as available from both MIVS and MOS manufacturers. This paper summarizes the design, manufacturing effort and subsequent evaluation of the Aquila review system by IAEA evaluators.

Kadner, S.; Doppke, M. [Aquila Technologies Group, Inc., Albuquerque, NM (United States); Gaertner, K.; Whichello, J. [International Atomic Energy Agency, Vienna (Austria)

1993-12-31

93

Evaluation of active thermal control options for Space Station  

NASA Technical Reports Server (NTRS)

An analysis of various Space Station (MSS) active thermal control systems options under consideration because of their potential low weight, efficiency and reliability is reported. The study addressed ordinary and diode-action body mounted radiators, thermal storage, the area and pumping power requirements for single-phase cooling of cold plates, and single-phase and two-phase active cooling loops. The base configuration considered was a core MSS formed by four habitable modules on which are mounted heat pipe radiators articulated to be always edge-on to the sun. A simulation was performed which accounted for the available heat sinks, several thermal loads and the heat rejection capability. No benefits were found with diode-action radiators if the solar absorption is 0.1 or less, although diode-action heat pipes will maintain a higher level of performance in the presence of coating degradation. Thermal storage becomes important only with radiator coating degradation. Water can be up to three times as efficient as Freon as a heat transfer medium. Finally, single-phase cooling offers a lower system mass than two-phase cooling if varying temperature heat loads can be accommodated.

Schuster, J. R.; Gruszczynski, M. J.; Owen, J. W.

1986-01-01

94

Evaluation of a Spectral-Based Nonlinear Stochastic Nowcasting Model (PhaSt) on Italian radar mosaic  

NASA Astrophysics Data System (ADS)

Evaluation of a Spectral-Based Nonlinear Stochastic Nowcasting Model (PhaSt) on Italian radar mosaic G. Cummings1, N. Rebora2 and F. Silvestro2 1Hydrometeorological Service, Ministry of Agriculture, Georgetown, Guyana 2CIMA research foundation, Savona, Italy The forecasting of precipitation events and flash floods are critical for civil protection. The temporal and spatial resolution of weather radar data as the input for nowcasting models has shown significant promise in improving forecasts in recent years. This work aims to evaluate the performance of a Spectral-Based Nonlinear Stochastic Nowcasting Model (PhaSt) in the Italian radar domain with 76 rainfall events and to assess the hydrological applicability of the forecasts for small to medium size river basins. The results were validated by comparison of the forecasted precipitation fields with the radar observations and by computing simple forecast skill scores. In addition to model evaluation based on seasonal occurrence, the 76 weather events considered were also classified into 2 types: long-lived and spatially distributed (Type I) or brief and localized (Type II). The results showed that PhaSt produced good results for up to 60 minutes for all seasons and event types, and for all the selected model parameter values.

Rhandhir Cummings, Garvin; Rebora, Nicola; Silvestro, Francesco

2014-05-01

95

Study to investigate and evaluate means of optimizing the radar function for the space shuttle  

NASA Technical Reports Server (NTRS)

A detailed analysis of the spiral scan was performed for antenna sizes ranging from 20 inches to 36 inches in diameter and for search angles characteristic of both the radar and the communication acquisition modes. The power budgets for passive target radar detection were calculated for antenna diameters ranging from 20 to 36 inches. Dwell times commensurate with spiral scan were used for these budget calculations. The signal design for the candidate pulse Doppler system is summarized. Ground return analysis carried out for the passive target radar mode is examined, and the details are presented. A concluding description of the proposed candidate radar/communication system configuration is given.

1976-01-01

96

An evaluation of ice formation in large-eddy simulations of supercooled Arctic stratocumulus using ground-based lidar and cloud radar  

Microsoft Academic Search

In order to evaluate possible ice formation processes in mixed phase Arctic stratocumulus, we compare measurements of radar reflectivity and Doppler velocity and lidar backscatter coefficient and circular depolarization ratio with the corresponding quantities computed from large-eddy simulations (LES). The measurements are taken from the Millimeter Cloud Radar and the Arctic High Spectral Resolution Lidar during the Mixed-Phase Arctic Cloud

B. van Diedenhoven; A. M. Fridlind; A. S. Ackerman; E. W. Eloranta; G. M. McFarquhar

2009-01-01

97

Evaluation of pan evaporation modeling with two different neural networks and weather station data  

NASA Astrophysics Data System (ADS)

This study evaluates neural networks models for estimating daily pan evaporation for inland and coastal stations in Republic of Korea. A multilayer perceptron neural networks model (MLP-NNM) and a cascade correlation neural networks model (CCNNM) are developed for local implementation. Five-input models (MLP 5 and CCNNM 5) are generally found to be the best for local implementation. The optimal neural networks models, including MLP 4, MLP 5, CCNNM 4, and CCNNM 5, perform well for homogeneous (cross-stations 1 and 2) and nonhomogeneous (cross-stations 3 and 4) weather stations. Statistical results of CCNNM are better than those of MLP-NNM during the test period for homogeneous and nonhomogeneous weather stations except for MLP 4 being better in BUS-DAE and POH-DAE, and MLP 5 being better in POH-DAE. Applying the conventional models for the test period, it is found that neural networks models perform better than the conventional models for local, homogeneous, and nonhomogeneous weather stations.

Kim, Sungwon; Singh, Vijay P.; Seo, Youngmin

2014-07-01

98

Field evaluation of boric acid and fipronil based bait stations against adult mosquitoes  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effectiveness of boric acid (1%) and fipronil (0.1%) bait stations in reducing the number of laboratory-reared female Aedes aegypti and Ochlerotatus taeniorhynchus mosquitoes released in outdoor screened cages was evaluated. Both toxicants reduced landing rates of the two mosquito species on a ...

99

EVALUATION OF FULL SCALE FABRIC FILTERS ON UTILITY BOILERS: SPS HARRINGTON STATION UNIT 3  

EPA Science Inventory

The report gives results of total mass and fractional size particulate emission tests at Southwestern Public Service's Harrington Station Unit 3 from July 8 to 11, 1981, as part of a program to evaluate and characterize the performance of full-scale fabric filter units installed ...

100

51. View of upper radar scanner switch in radar scanner ...  

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

51. View of upper radar scanner switch in radar scanner building 105 from upper catwalk level showing emanating waveguides from upper switch (upper one-fourth of photograph) and emanating waveguides from lower radar scanner switch in vertical runs. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

101

Evaluation of X-band polarimetric radar estimation of rainfall and rain drop size distribution parameters in West Africa  

NASA Astrophysics Data System (ADS)

As part of the African Monsoon Multidisciplinary Analysis (AMMA) field campaign an X-band dual-polarization Doppler radar was deployed in Benin, West-Africa, in 2006 and 2007, together with a reinforced rain gauge network and several optical disdrometers. Based on this data set, a comparative study of several rainfall estimators that use X-band polarimetric radar data is presented. In tropical convective systems as encountered in Benin, microwave attenuation by rain is significant and quantitative precipitation estimation (QPE) at X-band is a challenge. Here, several algorithms based on the combined use of reflectivity, differential reflectivity and differential phase shift are evaluated against rain gauges and disdrometers. Four rainfall estimators were tested on twelve rainy events: the use of attenuation corrected reflectivity only (estimator R(ZH)), the use of the specific phase shift only R(KDP), the combination of specific phase shift and differential reflectivity R(KDP,ZDR) and an estimator that uses three radar parameters R(ZH,ZDR,KDP). The coefficients of the power law relationships between rain rate and radar variables were adjusted either based on disdrometer data and simulation, or on radar-gauges observations. The three polarimetric based algorithms with coefficients predetermined on observations outperform the R(ZH) estimator for rain rates above 10 mm/h which explain most of the rainfall in the studied region. For the highest rain rates (above 30 mm/h) R(KDP) shows even better scores, and given its performances and its simplicity of implementation, is recommended. The radar based retrieval of two parameters of the rain drop size distribution, the normalized intercept parameter NW and the volumetric median diameter Dm was evaluated on four rainy days thanks to disdrometers. The frequency distributions of the two parameters retrieved by the radar are very close to those observed with the disdrometer. NW retrieval based on a combination of ZH-KDP-ZDR works well whatever the a priori assumption made on the drop shapes. Dm retrieval based on ZDR alone performs well, but if satisfactory ZDR measurements are not available, the combination ZH-KDP provides satisfactory results for both Dm and NW if an appropriate a priori assumption on drop shape is made.

Koffi, A. K.; Gosset, M.; Zahiri, E.-P.; Ochou, A. D.; Kacou, M.; Cazenave, F.; Assamoi, P.

2014-06-01

102

Performance evaluation of the Enraf-Nonius Model 872 radar gage  

SciTech Connect

There are indications that the Enraf-Nonius Radar Gage installed in Tank 241-SY-101 may not be providing an accurate reading of the true surface level in the waste tank. The Pacific Northwest Laboratory (PNL) performed an initial study to determine the effect of the following items on the distance read by the gage: Tank riser; Material permittivity and conductivity Foam; Proportion of supernatant to solid material in the field of view of the instrument; Physical geometry of the supernatant and solid material changing in the field of view with respect to time; and Varying water content in the solid material. The results of the tests indicate that distance measured by the radar gage is affected by the permittivity, conductivity, and angle of the target surface. These parameters affect the complex input impedance of the signal received by the radar gage to measure the distance to the target. In Tank 101-SY, the radar gage is placed on top of a 12 in. diameter riser. The riser affects the field of view of the instrument, and a much smaller target surface is detected when the radar beam propagates through a riser. In addition, the riser acts as a waveguide, and standing waves are enhanced between the target surface and the radar gage. The result is a change in the level measured by the radar gage due to changing properties of the target surface even when the distance to the target does not change. The test results indicate that the radar will not detect dry crust or foam. However, if the crust or foam is stirred so that it becomes wet, then the crust or foam became detectable. The level read using the radar gage decreased as the moisture in the crust or foam evaporated.

Peters, T.J.; Park, W.R.

1992-12-01

103

CETF Space Station payload pointing system design and analysis feasibility study. [Critical Evaluation Task Force  

NASA Technical Reports Server (NTRS)

The expected pointing performance of an attached payload coupled to the Critical Evaluation Task Force Space Station via a payload pointing system (PPS) is determined. The PPS is a 3-axis gimbal which provides the capability for maintaining inertial pointing of a payload in the presence of disturbances associated with the Space Station environment. A system where the axes of rotation were offset from the payload center of mass (CM) by 10 in. in the Z axis was studied as well as a system having the payload CM offset by only 1 inch. There is a significant improvement in pointing performance when going from the 10 in. to the 1 in. gimbal offset.

Smagala, Tom; Mcglew, Dave

1988-01-01

104

Development of a relationship between station and grid-box rainday frequencies for climate model evaluation  

SciTech Connect

The validation of climate model simulations creates substantial demands for comprehensive observed climate datasets. These datasets need not only to be historically and geographically extensive, but need also to be describing areally averaged climate, akin to that generated by climate models. This paper addresses on particular difficulty found when attempting to evaluate the daily precipitation characteristics of a global climate model, namely the problem of aggregating daily precipitation characteristics from station to area. Methodologies are developed for estimating the standard deviation and rainday frequency of grid-box mean daily precipitation time series from relatively few individual station time series.

Osborn, T.J.; Hulme, M. [Univ. of East Anglia (United Kingdom)] [Univ. of East Anglia (United Kingdom)

1997-08-01

105

Microwave emissions from police radar  

E-print Network

The purpose of this study was to evaluate police officers exposures to microwaves emitted by traffic radar units at the ocular and testicular level. Additionally, comparisons were made of the radar manufacturers published maximum power density...

Fink, John Michael

1994-01-01

106

Geostatistical evaluation of satellite radar altimetry for high-resolution mapping of Lambert Glacier, Antarctica  

NASA Technical Reports Server (NTRS)

The potential of satellite radar altimetry for high-resolution mapping of Antarctic ice streams is evaluated, using retracked and slope-corrected data from the Lambert Glacier and Amery Ice Shelf area, East Antarctica, acquired by Geosat during the Exact Repeat Mission (ERM), 1986-89. The map area includes lower Lambert Glacier north of 72.18 deg S, the southern Amery Ice Shelf, and the grounded inland ice sheet on both sides. The Geosat ERM altimetry is found to provide substantially more complete coverage than the 1978 Seasat altimetry, due to improved tracking. Variogram methods are used to estimate the noise levels in the data as a function of position throughout the map area. The spatial structure in the data is quantified by constructing experimental variograms using altimetry from the area of the grounding zone of Lambert Glacier, which is the area chiefly of interest in this topographically complex region. Kriging is employed to invert the along-track height measurements onto a fine-scale 3 km grid. The unsmoothed along-track Geosat ERM altimetry yields spatially continuous maps showing the main topographic features of lower Lambert Glacier, upper Amery Ice Shelf and the adjacent inland ice sheet. The probable position of the grounding line of Lambert Glacier is identified from a break in slope at the grounded ice/floating ice transition. The approximate standard error of the kriged map is inferred from the data noise levels.

Herzfeld, Ute C.; Lingle, Craig S.; Lee, Li-Her

1993-01-01

107

Using COAMPS Microphysics To Model Satellite and Aircraft Radar Data: An Evaluation During Hurricane Dennis  

NASA Astrophysics Data System (ADS)

The field phase of the Tropical Cloud Systems and Processes (TCSP) experiment took place between 1-27 July 2005, based out of San Jose, Costa Rica. Although the focus area for TCSP was planned to be the Eastern Pacific, the unusually early genesis of tropical disturbances in the Eastern Caribbean prompted missions dedicated to the formation and evolution of Hurricane Dennis. The high-altitude (20-km) NASA ER-2 flew 12 missions, including three dates dedicated to Hurricane Dennis. The flights on July 5-6 captured Dennis as it was transitioning from a tropical storm to a hurricane, and July 9 as it was entering a period of rapid intensification. The ER-2 deployed three microwave sensors, the Advanced Microwave Precipitation Radiometer (AMPR), the High Altitude MMIC Sounding Radiometer (HAMSR) and the the ER-2 Doppler Radar (EDOP). The AMPR is the aircraft "simulator" of the TRMM sensor; from 20-km altitude its 85 GHz imagery has an on-Earth resolution of 700-m (2.8-km at 10 GHz) at nadir, nearly 20 times finer than typical TRMM or SSMI satellite imagery. EDOP is an 10 GHz Doppler radar capable of resolving the fine scale vertical reflectivity. Since microwave observations respond to the presence of water vapor, liquid and ice hydrometeors, they are useful for evaluating the capabilities and deficiencies of mesoscale prediction models in representing the spatial evolution of the underlying cloud structure. In this presentation, the microphysical outputs from simulation of Hurricane Dennis using the Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS) were used to forward model observed TRMM and SSMI satellite data, and the AMPR, HAMSR and EDOP data from the ER-2 aircraft overpasses. This allows model-vs- observation diagnostics to be performed in observational space, avoiding usage of retrieved satellite quantities. Statistical intercomparisons show model overpredictions of the reflectivities at upper levels, and an overprediction of the coldest 85 GHz brightness temperatures reflecting excessive graupel. Although the results are limited to a single case, the methodology is potentially adaptable to routine COAMPS model runs for analyzing modifications to microphysical parameterization schemes.

Chen, S.; Turk, J.

2007-12-01

108

Evaluation of WiFi beacon transmissions for wireless based passive radar  

Microsoft Academic Search

Wireless transmissions are a potentially powerful and widely available source of transmissions for passive radar detection. In this work we have carried out a detailed study on the use of IEEE 802.11 (WiFi) transmissions in a passive radar system. The WiFi transmission sequence has been found to be complex and dependent on the user environment but is dominated by direct

H. Guo; K. Woodbridge; C. J. Baker

2008-01-01

109

Radar Scan Strategies for the Patrick Air Force Base Weather Surveillance Radar, Model-74C, Replacement  

NASA Technical Reports Server (NTRS)

The 45th Weather Squadron (45 WS) is replacing the Weather Surveillance Radar, Model 74C (WSR-74C) at Patrick Air Force Base (PAFB), with a Doppler, dual polarization radar, the Radtec 43/250. A new scan strategy is needed for the Radtec 43/250, to provide high vertical resolution data over the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) launch pads, while taking advantage of the new radar's advanced capabilities for detecting severe weather phenomena associated with convection within the 45 WS area of responsibility. The Applied Meteorology Unit (AMU) developed several scan strategies customized for the operational needs of the 45 WS. The AMU also developed a plan for evaluating the scan strategies in the period prior to operational acceptance, currently scheduled for November 2008.

Short, David

2008-01-01

110

Evaluating the use of high-frequency radar coastal currents to correct satellite altimetry  

NASA Astrophysics Data System (ADS)

Coastal altimeter waveforms may differ from the ones in the open ocean, either from rapid changes in the sea state or the presence of land within the satellite altimeter footprint. The optimal retracking method for an individual track may turn out to be a combination of several retrackers and may depend on the sea state. The coastal high-frequency radar (HFR) ocean surface currents, hourly interpolated with a resolution up to 2 km and an offshore range up to 150 km, are evaluated to validate the altimeter sea surface height (SSH) measurements. A method to derive HFR SSH mapped, with a varying spatial-scale optimal interpolation, from the HFR velocities has been implemented. Evaluated mainly in the regions farther than 25 km off the U.S. West Coast, the HFR SSH shows good agreement with Jason-1-2 altimetry products over the years 2008 and 2009. Three Jason-2 PISTACH retrackers and one generic open ocean retracker have been analyzed using the traditional 1 Hz sampling rate. Nearshore, an experimental reprocessing of the 20 Hz range measurements is also tested to check for a gain in along-track spatial resolution. Referencing to the HFR SSH indicate the need to have several retrackers available, even over the continental shelf, with Ice3 fitting better during Bloom events and MLE-4 (or Red3) for high sea states. These studies demonstrate the value of HFR as a potential tool to correct coastal altimeter SSH, refine their spatial resolution and provide some insight into the altimeter behavior as a function of ocean conditions.

Roesler, C. J.; Emery, W. J.; Kim, S. Y.

2013-07-01

111

A volatile organic analyzer for Space Station: Description and evaluation of a gas chromatography/ ion mobility  

NASA Technical Reports Server (NTRS)

A Volatile Organic Analyzer (VOA) is being developed as an essential component of the Space Station's Environmental Health System (EHS) air quality monitoring strategy to provide warning to the crew and ground personnel if volatile organic compounds exceed established exposure limits. The short duration of most Shuttle flights and the relative simplicity of the contaminant removal mechanism have lessened the concern about crew exposure to air contaminants on the Shuttle. However, the longer missions associated with the Space Station, the complex air revitalization system and the proposed number of experiments have led to a desire for real-time monitoring of the contaminants in the Space Station atmosphere. Achieving the performance requirements established for the VOA within the Space Station resource (e.g., power, weight) allocations led to a novel approach that joined a gas chromatograph (GC) to an ion mobility spectrometer (IMS). The authors of this paper will discuss the rational for selecting the GC/IMS technology as opposed to the more established gas chromatography/mass spectrometry (GC/MS) for the foundation of the VOA. The data presented from preliminary evaluations will demonstrate the versatile capability of the GC/IMS to analyze the major contaminants expected in the Space Station atmosphere. The favorable GC/IMS characteristics illustrated in this paper included excellent sensitivity, dual-mode operation for selective detection, and mobility drift times to distinguish co-eluting GC peaks. Preliminary studies have shown that the GC/IMS technology can meet surpass the performance requirements of the Space Station VOA.

Limero, Thomas F.; James, John T.

1994-01-01

112

Evaluation of Two Methods for Determining Surface Soil Moisture from Radar Imagery  

NASA Astrophysics Data System (ADS)

Distributed soil moisture data are useful for determining cross-country mobility, irrigation scheduling, pest management strategy, biomass production and potential for soil erosion and infiltration. Large area monitoring of surface soil moisture (to depths of 5 cm) is possible with radar remote sensing techniques, but accuracy must be assessed before it can be implemented operationally. Two methods for predicting surface soil moisture from radar satellite imagery were tested in sparsely vegetated, semi-arid Arizona rangelands. In the first approach, the Integral Equation Method (IEM) model was run in the forward direction to generate a Look-Up-Table (LUT) of radar backscatter for the expected range of surface roughness and moisture content in the study area. The LUT was used to derive surface soil moisture estimates from radar images acquired at the study site. In the second approach, a difference index was made from time series differences in radar backscatter signals from wet and dry soils. The difference index minimized variations in surface roughness and resulted in a direct relation between difference and surface soil moisture. For both approaches, results were validated against in situ measurements of surface soil moisture at 46 sites with dielectric probes at the time of satellite overpass. The modeling approach requires surface roughness inputs which may be difficult to obtain, whereas the difference technique requires only a dry surface reference backscatter for comparison with wetter surface backscatter to determine moisture content.

Thoma, D.; Moran, M.; Bryant, R.; Holifield, C.; Skirvin, S.; Rahman, M.; Kershner, C.; Watts, J.; Slocum, K.

2003-12-01

113

Radar image interpretability analysis  

Microsoft Academic Search

The utility of radar images with respect to trained image interpreter ability to identify, classify and detect specific terrain features (linear, natural area, complex area features, and individual man-made features) was qualitatively determined. Further, radar images were evaluated with respect to their utility for determining vehicle movement potential and the level of activity within the test areas. Because there are

V. S. Frost; J. A. Stiles; J. C. Holtzman

1981-01-01

114

Noncooperative rendezvous radar system  

NASA Technical Reports Server (NTRS)

A fire control radar system was developed, assembled, and modified. The baseline system and modified angle tracking system are described along with the performance characteristics of the baseline and modified systems. Proposed changes to provide additional techniques for radar evaluation are presented along with flight test data.

1974-01-01

115

Evaluation of wind profiles from the NERC MST radar, Aberystwyth, UK  

NASA Astrophysics Data System (ADS)

This study quantifies the uncertainties in winds measured by the Aberystwyth Mesosphere-Stratosphere-Troposphere (MST) radar (52.4° N, 4.0° W), before and after its renovation in March 2011. A total of 127 radiosondes provide an independent measure of winds. Differences between radiosonde and radar-measured horizontal winds are correlated with long-term averages of vertical velocities, suggesting an influence from local mountain waves. These local influences are an important consideration when using radar winds as a measure of regional conditions, particularly for numerical weather prediction. For those applications, local effects represent a source of sampling error additional to the inherent uncertainties in the measurements themselves. The radar renovation improved the signal-to-noise ratio (SNR) of measurements, with a corresponding improvement in altitude coverage. It also corrected an underestimate of horizontal wind speeds attributed to beam formation problems, due to pre-renovation component failure. The root mean square error (RMSE) in radar-measured horizontal wind components, averaged over half an hour, increases with wind speed and altitude, and is 0.8-2.5 m s-1 (6-12% of wind speed) for post-renovation winds. Pre-renovation values are typically 0.1 m s-1 larger. The RMSE in radial velocities is <0.04 m s-1. Eight weeks of special radar operation are used to investigate the effects of echo power aspect sensitivity. Corrections for echo power aspect sensitivity remove an underestimate of horizontal wind speeds; however aspect sensitivity is azimuthally anisotropic at the scale of routine observations (?1 h). This anisotropy introduces random error into wind profiles. For winds averaged over half an hour, the RMSE is around 3.5% above 8 km, but as large as 4.5% in the mid-troposphere.

Lee, C. F.; Vaughan, G.; Hooper, D. A.

2014-09-01

116

Remote sensing of clouds and evaluation with a 220GHz radar  

NASA Astrophysics Data System (ADS)

A recently developed 220GHz incoherent radar has potential for remote sensing of low reflectivity atmosphere targets in Cloud Chamber. Stepped frequency system is used and bandwidth 10GHz. Preliminary reflectivity measurements of clouds for ranges between 0.2m~4m in narrow Cloud Chamber. The instrument is briefly described. Highlighting uncertainties due to highly variable attenuation and signal interference. Then the results of investigations of the transmitter, receiver, Antennas, as well as the atmospheric Propagation Effects are presented. The results of this effort demonstrate that the radar is a stable, sensitive, system capable of providing accurate power for clouds.

An, Dawei; Shang, Jian; Wu, Qiong; Lu, Feng; Zhang, Peng; Hu, Weidong; Wang, Shitao; Bian, Mingming

2014-11-01

117

Evaluating the use of High-Frequency Radar coastal currents to correct Satellite Altimetry  

NASA Astrophysics Data System (ADS)

Conventional satellite altimetry provides very satisfactory results in open ocean conditions. Yet in coastal zones altimetry faces various problems, including less reliable standard corrections, and altimeter waveform (return echo) degradation arising from the rapid changes in the sea state or land contamination in the altimeter footprint. Different retracking (technique to retrieve geophysical information from the waveforms) methods have been developed, but the optimal method may turn out to be a combination of several retrackers, and may depend on the sea state. The coastal High-Frequency Radar (HFR) ocean surface currents are evaluated to test if they can be exploited to validate the coastal altimeter Sea Surface Height (SSH) measurements. A method to retrieve the geostrophic velocities from the HFR sea surface currents is established in the offshore region where the altimeter data are trusted. At the large mesoscales this method provides HFR SSH that are in very good agreement with altimetry gridded products with correlations larger than 0.8. Along a Jason-1 or Jason-2 altimeter track the agreement depends essentially on the wind history, and a limitation is the smooth field produced by the method. Nevertheless, more than half the cases match with a mean root-mean-square difference of 2.5 cm (6.7 cm/s) in sea level anomaly (across -track geostrophic velocity anomaly). Even without land contamination in the altimeter footprint, the waveforms may be degraded by non-homogeneous ocean dynamics, and during rain or low wind events. The HFR surface currents provide information on the sea surface height, so that various altimetry retrackers are tested under those conditions. Also referencing to the HFR SSH, several coastal retrackers can be evaluated in the near-shore regions. Even though these studies demonstrate the value of HFR as a tool to correct coastal satellite altimetry measurements over a section of an altimeter track, which is an improvement compared to sparse in-situ measurements, caution must be taken when generalizing the methodology since the inferred geostrophic HFR datasets may still be contaminated by ageostrophic components, especially during high wind events.

Roesler, Carolyn J.

118

Shuttle orbiter KU-band radar/communications system design evaluation  

NASA Technical Reports Server (NTRS)

An expanded introduction is presented which addresses the in-depth nature of the tasks and indicates continuity of the reported effort and results with previous work and related contracts, and the two major modes of operation which exist in the Ku-band system, namely, the radar mode and the communication mode, are described. The Ku-band radar system is designed to search for a target in a designated or undesignated mode, then track the detected target, which might be cooperative (active) or passive, providing accurate, estimates of the target range, range rate, angle and angle rate to enable the orbiter to rendezvous with this target. The radar mode is described along with a summary of its predicted performance. The principal sub-unit that implements the radar function is the electronics assembly 2(EA-2). The relationship of EA-2 to the remainder of the Ku-band system is shown. A block diagram of EA-2 is presented including the main command and status signals between EA-2 and the other Ku-band units.

1979-01-01

119

Evaluation of tag entanglement as a factor in harmonic radar studies of insect dispersal  

Technology Transfer Automated Retrieval System (TEKTRAN)

The observation of insects and other small organisms entangled in the habitat after the addition of vertical or trailing electronic tags to their body has generated concerns on the suitability of harmonic radars to track the dispersal of insects. This study compared the walking behavior of adult Co...

120

Performance evaluation of integer to integer wavelet transform for synthetic aperture radar image compression  

Microsoft Academic Search

An efficient and novel imagery compression system for Synthetic Aperture Radar (SAR) which uses integer to integer wavelet transform and Modified Set Partitioning Embedded Block Coder (M-SPECK) has been presented in this paper. The presence of speckle noise, detailed texture, high dynamic range in SAR images, and even its vast data volume show the great differences of SAR imagery. Integer

Wentong Xue; Jianshe Song; Lihai Yuan; Tao Shen

2005-01-01

121

Evaluation of a new wavelet-based compression algorithm for synthetic aperture radar images  

Microsoft Academic Search

In this paper we will discuss the performance of a new wavelet based embedded compression algorithm on synthetic aperture radar (SAR) image data. This new algorithm uses index coding on the indices of the discrete wavelet transform of the image data and provides an embedded code to successively approximate it. Results on compressing still images, medical images as well as

Jun Tian; Haitao Guo; Raymond O. Wells; C. Sidney Burrus; Jan E. Odegard

1996-01-01

122

3. EXTERIOR VIEW OF THE NORTHEAST RADAR DOME COMPLEX, STRUCTURE ...  

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

3. EXTERIOR VIEW OF THE NORTHEAST RADAR DOME COMPLEX, STRUCTURE 411, LOOKING NORTH. - Mill Valley Air Force Station, Radar Domes, East Ridgecrest Boulevard, Mount Tamalpais, Mill Valley, Marin County, CA

123

1. DISTANT VIEW OF RADAR DOMES, STRUCTURE 409 ON THE ...  

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

1. DISTANT VIEW OF RADAR DOMES, STRUCTURE 409 ON THE RIGHT AND 411 ON THE LEFT, LOOKING NORTHEAST. - Mill Valley Air Force Station, Radar Domes, East Ridgecrest Boulevard, Mount Tamalpais, Mill Valley, Marin County, CA

124

Space Radar Image of Star City, Russia  

NASA Technical Reports Server (NTRS)

This radar image shows the Star City cosmonaut training center, east of Moscow, Russia. Four American astronauts are training here for future long-duration flights aboard the Russian Mir space station. These joint flights are giving NASA and the Russian Space Agency experience necessary for the construction of the international Alpha space station, beginning in late 1997. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR), on its 62nd orbit on October 3, 1994. This Star City image is centered at 55.55 degrees north latitude and 38.0 degrees east longitude. The area shown is approximately 32 kilometers by 49 kilometers (20 miles by 30 miles). North is to the top in this image. The radar illumination is from the top of the image. The image was produced using three channels of SIR-C radar data: red indicates L-band (23 cm wavelength, horizontally transmitted and received); green indicates L-band (horizontally transmitted and vertically received); blue indicates C-band (6 cm wavelength, horizontally transmitted and vertically received). In general, dark pink areas are agricultural; pink and light blue areas are urban communities; black areas represent lakes and rivers; dark blue areas are cleared forest; and light green areas are forested. The prominent black runways just right of center are Shchelkovo Airfield, about 4 km long. The textured pale blue-green area east and southeast of Shchelkovo Airfield is forest. Just east of the runways is a thin railroad line running southeast; the Star City compound lies just east of the small bend in the rail line. Star City contains the living quarters and training facilities for Russian cosmonauts and their families. Moscow's inner loop road is visible at the lower left edge of the image. The Kremlin is just off the left edge, on the banks of the meandering Moskva River. The Klyazma River snakes to the southeast from the reservoir in the upper left (shown in bright red), passing just east of Star City and flowing off the lower right edge of the image. The dark blue band of the Vorya River runs north-south in the upper right quadrant, east of Star City. SIR-C/X-SAR radar images are being compared with data from the Russian radar satellite Almaz to evaluate the usefulness of a permanent orbital radar platform in monitoring Earth s environment and ecology.

1994-01-01

125

Efficiency evaluation of ground-penetrating radar by the results of measurement of dielectric properties of soils  

SciTech Connect

The work considers the depth evaluation of ground penetrating radar (GPR) surveys using the attenuation factor of electromagnetic radiation in a medium. A method of determining the attenuation factor of low-conductive non-magnetic soils is developed based on the results of direct measurements of permittivity and conductivity of soils in the range of typical frequencies of GPR. The method relies on measuring the shift and width of the resonance line after a soil sample is being placed into a tunable cavity resonator. The advantage of this method is the preservation of soil structure during the measurement.

Khakiev, Zelimkhan; Kislitsa, Konstantin; Yavna, Victor [Rostov State Transport University, Rostov-on-Don (Russian Federation)

2012-12-15

126

Evaluating storm-scale groundwater recharge dynamics with coupled weather radar data and unsaturated zone modeling  

NASA Astrophysics Data System (ADS)

Groundwater recharge rates through the unsaturated zone emerge from complex interactions within the soil-vegetation-atmosphere system that derive from nonlinear relationships amongst atmospheric boundary conditions, plant water use and soil hydraulic properties. While it is widely recognized that hydrologic models must capture soil water dynamics in order to provide reliable recharge estimates, information on episodic recharge generation remains uncommon, and links between storm-scale weather patterns and their influence on recharge is largely unexplored. In this study, the water balance of a heterogeneous one-dimensional soil domain (3 m deep) beneath a typical rainfed corn agro-ecosystem in eastern Nebraska was numerically simulated in HYDRUS-1D for 12 years (2001-2012) on hourly time steps in order to assess the relationships between weather events and episodic recharge generation. WSR-88D weather radar reflectivity data provided both rainfall forcing data (after estimating rain rates using the z/r ratio method) and a means of storm classification on a scale from convective to stratiform using storm boundary characteristics. Individual storm event importance to cumulative recharge generation was assessed through iterative scenario modeling (773 total simulations). Annual cumulative recharge had a mean value of 9.19 cm/yr (about 12 % of cumulative rainfall) with coefficient of variation of 73%. Simulated recharge generation events occurred only in late winter and spring, with a peak in May (about 35% of total annual recharge). Recharge generation is observed primarily in late spring and early summer because of the combination of high residual soil moisture following a winter replenishment period, heavy convective storms, and low to moderate potential evapotranspiration rates. During the growing season, high rates of root water uptake cause rapid soil water depletion, and the concurrent high potential evapotranspiration and low soil moisture prevented recharge generation until late winter, even when intense convective storms took place. For this reason, about 86% of all precipitation events produce insignificant recharge contributions. Recharge responses to individual storms were nonlinear and did not cluster well with either storm amount or storm classification type. For example, ~7% of rainfall events fall near the 1:1 rainfall/recharge line and these events represent about 37% of cumulative recharge, and individual storms accounted for up to 4% of their annual totals. However, recharge events in late winter are mainly triggered by stratiform precipitation whereas in spring they are generally generated by convective storms. This novel approach to assessing storm-scale recharge may be relevant to several current challenges in the characterization of groundwater recharge processes, including the evaluation of their spatiotemporal distributions and the impacts of climate change on groundwater.

Nasta, P.; Gates, J. B.; Lock, N.; Houston, A. L.

2013-12-01

127

Detail view of southeast corner of Signal Corps Radar (S.C.R.) ...  

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

Detail view of southeast corner of Signal Corps Radar (S.C.R.) 296 Station 5 Transmitter Building foundation, showing Signal Corps Radar (S.C.R.) 296 Station 5 Tower concrete pier in background, camera facing north - Fort Barry, Signal Corps Radar 296, Station 5, Transmitter Building Foundation, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

128

Toxicity evaluation and source apportionment of Polycyclic Aromatic Hydrocarbons (PAHs) at three stations in Istanbul, Turkey.  

PubMed

This paper focuses on the toxicity evaluation and source apportionment of Polycyclic Aromatic Hydrocarbons (PAHs) in three monitoring stations in Istanbul, Turkey. A total of 326 airborne samples were collected and analyzed for 16 PAHs and Total Suspended Particles (TSP) for the period of September 2006-December 2007. The total average PAH concentrations were 100.7±61.3, 84.6±46.7 and 25.1±13.3 ng m(-3) and the TSP concentrations were 101.2±53.2, 152.3±99.1, 49.8±18.6 ?g m(-3) for URB1, URB2 and RUR stations, respectively. Benzo(a)Pyren (BaP) toxic equivalency factors to PAH concentration values were calculated indicating that the health risk of BaP and DiBenz(a,h)Anthracene (markers of traffic emissions) have the highest contribution compared to all of the other species measured at the sampling sites. In order to determine PAH sources, two different source apportionment techniques were applied to the measurements; diagnostic ratios (DR) and Positive Matrix Factorization (PMF). The results of the two applications were compatible indicating the vehicle emissions - especially diesel engines - as the major source for urban stations. PMID:24342492

Hanedar, Asude; Alp, Kadir; Kaynak, Burçak; Av?ar, Edip

2014-08-01

129

Evaluation of genotoxic effects of benzene and its derivatives in workers of gas stations.  

PubMed

The search for reliable biomarkers of human exposure to benzene and its derivatives is still subject of research. Many of the proposed biomarkers have limitations ranging from the low sensitivity to the wide variability of results. Thus, the aim of our study was to assess the frequencies of chromosomal abnormalities (CA) and sister chromatid exchanges (SCE) in workers of gas stations, with (cases, n?=?19) and without (local controls, n?=?6) risk of exposure to benzene and its derivatives, comparing them with the results from the general population (external controls, n?=?38). The blood dosages of benzene, toluene, and xylenes were measured in all participants. Blood solvent levels were compared with the findings obtained in cytogenetic evaluation and a research protocol which included data of the workplace, lifestyle, and health of the individuals. We did not detect the presence of benzene and its derivatives and did not find chromosomal damage that may be associated with the gas station activity in cases. Moreover, although we found an association of increased SCE and the working time in the local controls, the values found for SCE are within normal limits. Thus, our evaluation of SCE and CA reflected the levels of benzene and its derivatives observed in the blood. We believe, therefore, that SCE and CA may actually constitute possible tests for the evaluation of these exposures. However, we believe that further studies, including individuals at risk, are important to confirm this assertion. PMID:24292950

Trevisan, Patrícia; da Silva, Juliane Nascimento; da Silva, Alessandra Pawelec; Rosa, Rafael Fabiano Machado; Paskulin, Giorgio Adriano; Thiesen, Flávia Valladão; de Oliveira, Ceres Andréia Vieira; Zen, Paulo Ricardo Gazzola

2014-04-01

130

Evaluation of the biological effects of police radar RAMER 7F  

Microsoft Academic Search

This paper presents results of experiments on the effects of electromagnetic radiation in the millimeter range (frequency 34.0 [+-] 0.1 GHz, power density 20 [mu]W\\/cm[sup 2]) emitted by a police radar device. Considering the physical properties of the radiation in millimeter range (skin effects), the experiments were carried out on hairless mice. The main physiological parameters tested were body mass,

D. Rotkovska; J. Kautska; A. Bartonickova; J. Keprtova; M. Hofer; J. Moc

1993-01-01

131

Clutter reduction methods in ultra wideband (UWB) radar and time\\/performance evaluation on ARM processors  

Microsoft Academic Search

In this study, principal component analysis (PCA), singular value decomposition (SVD) and independent component analysis (ICA), which are statistical signal processing methods for clutter reduction, are explained in ultra wideband (UWB) radars. In addition, how to use these methods in through wall imaging (TWI) and time\\/performance relationship on ARM Cortex A-8 processors which have floating-point mathematical operation support is examined

E. Ozturk; A. V. Atli; M. S. Mercan; A. Caliskan; I. Y. Erer

2012-01-01

132

Wideband On-ground Monostatic Radar Antenna for Water Content Soil Evaluation: Modeling, Design and Testing  

NASA Astrophysics Data System (ADS)

The knowledge of soil's hydraulic properties spatial distribution is important in agricultural practice optimization and hydrological studies. Non-invasive methods of measurement of the dielectric permittivity such as time domain reflectometry (TDR) and ground penetrating radar (GPR) are increasingly used in order to asses soil water content at the field scale. In order to acquire radar data over a wide frequency range, we designed a simple on-ground radar antenna operating on the frequency range 350 MHz - 2GHz. The antenna was designed using a powerful commercial three dimensional finite-difference time-domain (FDTD) electromagnetic field solver. A prototype of the frequency type radar transmission link was constructed and laboratory measurements were first performed with calibration purpose (the antenna was placed on a 13 cm-thick sand layer of known dielectric permittivity). The antenna is used in monostatic configuration and associated with a vector network analyzer to perform measurements of the antenna-soil reflection coefficients (S11) in the frequency domain. Those measurements are compared to FDTD simulations using the root mean square criterion in order to assess the sand dielectric properties. The use of full-wave FDTD software allows simulation of the whole antenna components, thus all potential influence on the reflection coefficient are recorded. The estimated permittivity with this procedure was close to the real one. In order to test the prototype in real field conditions measurements were performed on a single profile characterized by several agricultural practices (wheat crop, vegetative buffer strip and corn crop). Reflection coefficient (S11) measurements acquired with the prototype are compared to TDR measurements and DC electrical soundings in order to validate the soil apparent dielectric permittivity as well as its apparent electrical conductivity.

Vitale, Q.; Rejiba, F.; Guérin, R.

2012-12-01

133

The Solid Rocket Motor Slag Population: Results of a Radar-based Regressive Statistical Evaluation  

NASA Technical Reports Server (NTRS)

Solid rocket motor (SRM) slag has been identified as a significant source of man-made orbital debris. The propensity of SRMs to generate particles of 100 m and larger has caused concern regarding their contribution to the debris environment. Radar observation, rather than in-situ gathered evidence, is currently the only measurable source for the NASA/ODPO model of the on-orbit slag population. This simulated model includes the time evolution of the resultant orbital populations using a historical database of SRM launches, propellant masses, and estimated locations and times of tail-off. However, due to the small amount of observational evidence, there can be no direct comparison to check the validity of this model. Rather than using the assumed population developed from purely historical and physical assumptions, a regressional approach was used which utilized the populations observed by the Haystack radar from 1996 to present. The estimated trajectories from the historical model of slag sources, and the corresponding plausible detections by the Haystack radar, were identified. Comparisons with observational data from the ensuing years were made, and the SRM model was altered with respect to size and mass production of slag particles to reflect the historical data obtained. The result is a model SRM population that fits within the bounds of the observed environment.

Horstman, Matthew F.; Xu, Yu-Lin

2008-01-01

134

Application of HF radar currents to oil spill modelling.  

PubMed

In this work, the benefits of high-frequency (HF) radar currents for oil spill modeling and trajectory analysis of floating objects are analyzed. The HF radar performance is evaluated by means of comparison between a drifter buoy trajectory and the one simulated using a Lagrangian trajectory model. A methodology to optimize the transport model performance and to calculate the search area of the predicted positions is proposed. This method is applied to data collected during the Galicia HF Radar Experience. This experiment was carried out to explore the capabilities of this technology for operational monitoring along the Spanish coast. Two long-range HF radar stations were installed and operated between November 2005 and February 2006 on the Galician coast. In addition, a drifter buoy was released inside the coverage area of the radar. The HF radar currents, as well as numerical wind data were used to simulate the buoy trajectory using the TESEO oil spill transport model. In order to evaluate the contribution of HF radar currents to trajectory analysis, two simulation alternatives were carried out. In the first one, wind data were used to simulate the motion of the buoy. In the second alternative, surface currents from the HF radar were also taken into account. For each alternative, the model was calibrated by means of the global optimization algorithm SCEM-UA (Shuffled Complex Evolution Metropolis) in order to obtain the probability density function of the model parameters. The buoy trajectory was computed for 24h intervals using a Monte Carlo approach based on the results provided in the calibration process. A bivariate kernel estimator was applied to determine the 95% confidence areas. The analysis performed showed that simulated trajectories integrating HF radar currents are more accurate than those obtained considering only wind numerical data. After a 24h period, the error in the final simulated position improves using HF radar currents. Averaging the information from all the simulated daily periods, the mean search and rescue area calculated using HF radar currents, is reduced by approximately a 62% in comparison with the search area calculated without these data. These results show the positive contribution of HF radar currents for trajectory analysis, and demonstrate that these data combined with atmospheric forecast models, are of value for trajectory analysis of oil spills or floating objects. PMID:18996546

Abascal, Ana J; Castanedo, Sonia; Medina, Raul; Losada, Inigo J; Alvarez-Fanjul, Enrique

2009-02-01

135

Radar Entomology  

NSDL National Science Digital Library

Radar tracking used to profile insect migration, mating and flight patterns. Many links to various pages include current workers in radar entomology, historical uses of the technology, and many images.

0000-00-00

136

Radar principles  

NASA Technical Reports Server (NTRS)

Discussed here is a kind of radar called atmospheric radar, which has as its target clear air echoes from the earth's atmosphere produced by fluctuations of the atmospheric index of refraction. Topics reviewed include the vertical structure of the atmosphere, the radio refractive index and its fluctuations, the radar equation (a relation between transmitted and received power), radar equations for distributed targets and spectral echoes, near field correction, pulsed waveforms, the Doppler principle, and velocity field measurements.

Sato, Toru

1989-01-01

137

The Evaluation of Methicillin Resistance in Staphylococcus aboard the International Space Station  

NASA Technical Reports Server (NTRS)

The International Space Station (ISS) represents a semi-closed environment with a high level of crewmember interaction. As community-acquired methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a health concern in environments with susceptible hosts in close proximity, an evaluation of isolates of clinical and environmental Staphylococcus aureus and coagulase negative Staphylococcus was performed to determine if this trend was also present in astronauts aboard ISS or the space station itself. Rep-PCR fingerprinting analysis of archived ISS isolates confirmed our earlier studies indicating a transfer of S. aureus between crewmembers. In addition, this fingerprinting also indicated a transfer between crewmembers and their environment. While a variety of S. aureus were identified from both the crewmembers and the environment, phenotypic evaluations indicated minimal methicillin resistance. However, positive results for the Penicillin Binding Protein, indicative of the presence of the mecA gene, were detected in multiple isolates of archived Staphylococcus epidermidis and Staphylococcus haemolyticus. Phenotypic analysis of these isolates confirmed their resistance to methicillin. While MRSA has not been isolated aboard ISS, the potential exists for the transfer of the gene, mecA, from coagulase negative environmental Staphylococcus to S. aureus creating MRSA strains. This study suggests the need to expand environmental monitoring aboard long duration exploration spacecraft to include antibiotic resistance profiling.

Ott, C. M.; Bassinger, V. J.; Fontenot, S. L.; Castro, V. A.; Pierson, D. L.

2005-01-01

138

14 CFR Appendix G to Part 121 - Doppler Radar and Inertial Navigation System (INS): Request for Evaluation; Equipment and...  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Doppler Radar and Inertial Navigation System (INS...G Appendix G to Part 121—Doppler Radar and Inertial Navigation System (INS...applicant for authority to use a Doppler Radar or Inertial Navigation System must...

2014-01-01

139

14 CFR Appendix G to Part 121 - Doppler Radar and Inertial Navigation System (INS): Request for Evaluation; Equipment and...  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Doppler Radar and Inertial Navigation System (INS...G Appendix G to Part 121—Doppler Radar and Inertial Navigation System (INS...applicant for authority to use a Doppler Radar or Inertial Navigation System must...

2012-01-01

140

14 CFR Appendix G to Part 121 - Doppler Radar and Inertial Navigation System (INS): Request for Evaluation; Equipment and...  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Doppler Radar and Inertial Navigation System (INS...G Appendix G to Part 121—Doppler Radar and Inertial Navigation System (INS...applicant for authority to use a Doppler Radar or Inertial Navigation System must...

2013-01-01

141

14 CFR Appendix G to Part 121 - Doppler Radar and Inertial Navigation System (INS): Request for Evaluation; Equipment and...  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Doppler Radar and Inertial Navigation System (INS...G Appendix G to Part 121—Doppler Radar and Inertial Navigation System (INS...applicant for authority to use a Doppler Radar or Inertial Navigation System must...

2011-01-01

142

Application of radar observations to the evaluation and improvement of high resolution model simulations of cloud populations in MJO (Invited)  

NASA Astrophysics Data System (ADS)

S-Pol radar data collected during the 2011 AMIE/DYNAMO field campaign is used to evaluate the performance of microphysical schemes in cloud permitting regional model simulations of the Madden-Julian Oscillation (MJO). In general, several of the current state-of-the-art schemes overestimate precipitation from large, deep convective systems. The sensitivity of this bias to various assumptions in microphysics processes of each bulk microphysics scheme is evaluated. Processes that limit the slope of raindrop size distribution for large raindrops, such shattering, are found to be important for realistic simulation of the cloud rain rate statistics. The results of the simulation and field campaign data are used to investigate convective organization, and shallow to deep transition in the context of the November 2011 episode of the MJO.

Hagos, S. M.; Feng, Z.; Long, C. N.; Lim, K.

2013-12-01

143

Evaluation of second-order texture parameters for sea ice classification from radar images  

NASA Astrophysics Data System (ADS)

With the advent of airborne and spaceborne synthetic aperture radar (SAR) systems, sea ice classification from SAR images has become an important research subject. Since gray tone alone has proven to be of limited capability in differentiating ice types, texture has naturally become an attractive avenue to explore. Accordingly, performance of texture quantification parameters as related to their ability to discriminate ice types has to be examined. SAR image appearance depends on radar parameters involved in the image construction procedures from the doppler history record. Therefore the feasibility of using universal texture/ice type relationships that hold for all combinations of radar parameters also has to be investigated. To that end, imagery data from three different SAR systems were used in this study. Five conventional texture parameters, derived from the gray level co-occurrence matrix (GLCM), were examined. Two of them were modified to ensure their invariant character under linear gray tone transformations. Results indicated that all parameters were highly correlated. The parameters did not, in general, vary with the computational variables used in generating co-occurrence matrices. Ice types can be identified uniquely by the mean value of any texture parameter. The relatively high variability of texture parameters, however, confuses ice discrimination, particularly of smoother ice types. Ice classification was conducted using a per-pixel maximum likelihood supervised scheme. When texture was combined with gray tone, the overall average classification accuracy was improved. Texture was successful in improving the classification accuracy of multiyear ice but was less promising in discriminating first-season ice types. The best two GLCM texture parameters, according to the computed overall average classification accuracies, were the inverse difference moment and the entropy. A brief description of GLCM texture parameters as related to ice's physical characteristics is presented.

Shokr, Mohammed E.

1991-06-01

144

The Solid Rocket Motor Slag Population: Results of a Radar-Based Regressive Statistical Evaluation  

NASA Technical Reports Server (NTRS)

Solid rocket motor (SRM) slag has been identified as a potential source of man-made orbital debris. The possibility that SRMs (in addition to generating dust particles in the sub-millimeter range) may generate particles up to centimeters in size has caused concern regarding their contribution to the debris environment. Returned surfaces from space do not have sufficient area or exposure time to provide a clear picture of the SRM millimeter and centimeter debris population. Currently, radar observation is probably the only way to collect data showing the debris contribution from SRMs. Such observation is used to sample the debris environment, but it is difficult to obtain accurate orbital elements for the detected debris objects. NASA has developed several models to describe the different orbital debris populations, based on assumed debris production mechanisms to create clouds of debris objects that can be propagated in time. The NASA model, LEGEND (LEO-to-GEO Environment Debris), functions as a time-tested debris model for most debris sources. However, the current LEGEND model does not include contributions from the SRM population. An SRM model has recently been developed by NASA, based on purely theoretical details of SRM production and known SRM launches, but verification with hard data is needed. Because the detections of individual SRM objects cannot be deterministically separated from the total debris observed by radar, the validation of the SRM model can only be done by combining it with the LEGEND breakup model and comparing it with data. By applying observational constraints, the degree of SRM slag contribution to the environment may be estimated. This serves as an observationally sound method from which to calibrate a purely theoretical model into something more realistic. For this study, we use the populations observed by the Haystack radar from 1996 to present. For the SRM debris, we use a historical database of SRM launches, propellant masses, and estimated locations and times of tailoff to produce and propagate the SRM debris clouds. Comparisons with radar data from the ensuing years were made, and the SRM model was altered with respect to size and mass production of slag particles to reflect the populations estimated from the data. The result is a model SRM population that fits within the bounds of the observed environment and estimates of the production and contribution of SRM debris to the environment.

Horstman, Matthew F.; Xu, Yu-Lin

2008-01-01

145

Evaluation of available analytical techniques for monitoring the quality of space station potable water  

NASA Technical Reports Server (NTRS)

To assure the quality of potable water (PW) on the Space Station (SS) a number of chemical and physical tests must be conducted routinely. After reviewing the requirements for potable water, both direct and indirect analytical methods are evaluated that could make the required tests and improvements compatible with the Space Station operation. A variety of suggestions are made to improve the analytical techniques for SS operation. The most important recommendations are: (1) the silver/silver chloride electrode (SB) method of removing I sub 2/I (-) biocide from the water, since it may interfere with analytical procedures for PW and also its end uses; (2) the orbital reactor (OR) method of carrying out chemistry and electrochemistry in microgravity by using a disk shaped reactor on an orbital table to impart artificial G force to the contents, allowing solution mixing and separation of gases and liquids; and (3) a simple ultra low volume highly sensitive electrochemical/conductivity detector for use with a capillary zone electrophoresis apparatus. It is also recommended, since several different conductivity and resistance measurements are made during the analysis of PW, that the bipolar pulse measuring circuit be used in all these applications for maximum compatibility and redundancy of equipment.

Geer, Richard D.

1989-01-01

146

Evaluation of Cloud-Phase Retrieval Methods for SEVIRI on Meteosat-8 Using Ground-Based Lidar and Cloud Radar Data  

E-print Network

Evaluation of Cloud-Phase Retrieval Methods for SEVIRI on Meteosat-8 Using Ground-Based Lidar and Cloud Radar Data ERWIN L. A. WOLTERS, ROBERT A. ROEBELING, AND ARNOUT J. FEIJT Royal Netherlands 2007) ABSTRACT Three cloud-phase determination algorithms from passive satellite imagers are explored

Stoffelen, Ad

147

47 CFR 80.389 - Frequencies for maritime support stations.  

Code of Federal Regulations, 2013 CFR

...channels assigned to the associated public coast station. (b) Shore radar and radiolocation tests. The following frequency bands are available for assignment to demonstrate radar and radiolocation equipment. The use of frequencies within...

2013-10-01

148

Space Station Freedom coupling tasks: An evaluation of their space operational compatibility  

NASA Technical Reports Server (NTRS)

The development of the Space Station Freedom tasks that are compatible with both telerobotic as well as extravehicular activity is a necessary redundancy in order to insure successful day to day operation. One task to be routinely performed aboard Freedom will be the changeout of various quick disconnect fluid connectors. In an attempt to resolve these potentially contradictory issues of compatibility, mock-ups of couplings suitable to both extravehicular as well as telerobotic activity were designed and built. An evaluation performed at the Remote Operator Interaction Laboratory at NASA's Johnson Space Center is discussed, which assessed the prototype couplings as well as three standard coupling designs. Data collected during manual and telerobotic manipulation of the couplings indicated that the custom coupling was in fact shown to be faster to operate and generally preferred over the standard coupling designs.

Sampaio, Carlos E.; Bierschwale, John M.; Fleming, Terence F.; Stuart, Mark A.

1991-01-01

149

Design and evaluation of FDDI fiber optics networkfor Ethernets, VAX's and Ingraph work stations  

NASA Technical Reports Server (NTRS)

The purpose of this project is to design and evaluate the FDDI Fiber Optics Network for Ethernets, VAX's, and Ingraph work stations. From the KSC Headquarters communication requirement, it would be necessary to develop the FDDI network based on IEEE Standards outlined in the ANSI X3T9.5, Standard 802.3 and 802.5 topology - direct link via intermediate concentrator and bridge/router access. This analysis should examine the major factors that influence the operating conditions of the Headquarters Fiber plant. These factors would include, but are not limited to the interconnecting devices such as repeaters, bridges, routers and many other relevant or significant FDDI characteristics. This analysis is needed to gain a better understanding of overall FDDI performance.

Wernicki, M. Chris

1992-01-01

150

Evaluation of speech recognizers for use in advanced combat helicopter crew station research and development  

NASA Technical Reports Server (NTRS)

The U.S. Army Crew Station Research and Development Facility uses vintage 1984 speech recognizers. An evaluation was performed of newer off-the-shelf speech recognition devices to determine whether newer technology performance and capabilities are substantially better than that of the Army's current speech recognizers. The Phonetic Discrimination (PD-100) Test was used to compare recognizer performance in two ambient noise conditions: quiet office and helicopter noise. Test tokens were spoken by males and females and in isolated-word and connected-work mode. Better overall recognition accuracy was obtained from the newer recognizers. Recognizer capabilities needed to support the development of human factors design requirements for speech command systems in advanced combat helicopters are listed.

Simpson, Carol A.

1990-01-01

151

Evaluation of the biological effects of police radar RAMER 7F  

SciTech Connect

This paper presents results of experiments on the effects of electromagnetic radiation in the millimeter range (frequency 34.0 [+-] 0.1 GHz, power density 20 [mu]W/cm[sup 2]) emitted by a police radar device. Considering the physical properties of the radiation in millimeter range (skin effects), the experiments were carried out on hairless mice. The main physiological parameters tested were body mass, body temperature, peripheral blood, and mass and cellularity of several important organs. Critical organs, the skin, and cornea were examined by electron microscopy. Differentiation ability of hematopoietic cells, progenitors of granulocytes and macrophages, and DNA synthesis in the cornea were compared in irradiated and nonirradiated animals. None of the parameters tested was affected to an extent that would indicate the start of a pathological process or the risk of damage to genetic material.

Rotkovska, D.; Kautska, J.; Bartonickova, A.; Keprtova, J.; Hofer, M. (Institute of biophysics, Brno (Czechoslovakia)); Moc, J. (Military Academy, Brno (Czechoslovakia))

1993-06-01

152

Evaluation of the biological effects of police radar RAMER 7F.  

PubMed

This paper presents results of experiments on the effects of electromagnetic radiation in the millimeter range (frequency 34.0 +/- 0.1 GHz, power density 20 muW/cm2) emitted by a police radar device. Considering the physical properties of the radiation in millimeter range (skin effects), the experiments were carried out on hairless mice. The main physiological parameters tested were body mass, body temperature, peripheral blood, and mass and cellularity of several important organs. Critical organs, the skin, and cornea were examined by electron microscopy. Differentiation ability of hematopoietic cells, progenitors of granulocytes and macrophages, and DNA synthesis in the cornea were compared in irradiated and nonirradiated animals. None of the parameters tested was affected to an extent that would indicate the start of a pathological process or the risk of damage to genetic material. PMID:8354199

Rotkovská, D; Moc, J; Kautská, J; Bartonícková, A; Keprtová, J; Hofer, M

1993-06-01

153

Preliminary geologic evaluation of L-band radar imagery: Arkansas test site  

NASA Technical Reports Server (NTRS)

The relatively small angles of incidence (steep depression angles) of the L-band system provide minimal shadowing on terrain back-slopes and considerable foreshortening on terrain fore-slopes which sacrifice much of the topographic enhancement afforded by a more oblique angle of illumination. In addition, the dynamic range of the return from vegetated surfaces is substantially less for the L-band system, and many surface features defined primarily by subtle changes in vegetation are lost. In areas having terrain conditions similar to those of northern Arkansas, and where LANDSAT and shorter wavelength aircraft radar data are available, the value of the JPL L-band imagery as either a complimentary or supplementary geologic data source is not obvious.

Macdonald, H.; Waite, W. P.

1977-01-01

154

Experimental evaluation of battery cells for space-based radar application  

NASA Technical Reports Server (NTRS)

A test program was conducted to characterize five space-quality nickel-hydrogen (NiH2) battery cells. A subset of those tests was also done on five commercial nickel-cadmium (NiCd) cells, for correlation to the characteristics of an Energy Storage Unit Simulator. The test program implemented the recommendations of a 1991 study, as reported to IECEC-92. The findings of the tests are summarized, and expected impacts on the performance of the electrical power system (EPS) of a large space-based radar (SBR) surveillance satellite are derived. The main characteristics examined and compared were terminal voltage (average and transient) and capacity through discharge, equivalent series resistance, derived inductance and capacitance, charge return efficiency, and inter-pulse charge effectiveness.

Maskell, Craig A.; Metcalfe, John R.

1994-01-01

155

An intercomparison of radar-based liquid cloud microphysics retrievals and implications for model evaluation studies  

NASA Astrophysics Data System (ADS)

This paper presents a statistical comparison of three cloud retrieval products of the Atmospheric Radiation Measurement (ARM) program at the Southern Great Plains (SGP) site from 1998 to 2006: MICROBASE, University of Utah (UU), and University of North Dakota (UND) products. The probability density functions of the various cloud liquid water content (LWC) retrievals appear to be consistent with each other. While the mean MICROBASE and UU cloud LWC retrievals agree well in the middle of cloud, the discrepancy increases to about 0.03 gm-3 at cloud top and cloud base. Alarmingly large differences are found in the droplet effective radius (re) retrievals. The mean MICROBASE re is more than 6 ?m lower than the UU re, whereas the discrepancy is reduced to within 1 ?m if columns containing raining and/or mixed-phase layers are excluded from the comparison. A suite of stratified comparisons and retrieval experiments reveal that the LWC difference stems primarily from rain contamination, partitioning of total liquid later path (LWP) into warm and supercooled liquid, and the input cloud mask and LWP. The large discrepancy among the re retrievals is mainly due to rain contamination and the presence of mixed-phase layers. Since rain or ice particles are likely to dominate radar backscattering over cloud droplets, the large discrepancy found in this paper can be thought of as a physical limitation of single-frequency radar approaches. It is therefore suggested that data users should use the retrievals with caution when rain and/or mixed-phase layers are present in the column.

Huang, D.; Zhao, C.; Dunn, M.; Dong, X.; Mace, G. G.; Jensen, M. P.; Xie, S.; Liu, Y.

2012-06-01

156

Evaluation of SIR-A space radar for geologic interpretation: United States, Panama, Colombia, and New Guinea  

NASA Technical Reports Server (NTRS)

Comparisons between LANDSAT MSS imagery, and aircraft and space radar imagery from different geologic environments in the United States, Panama, Colombia, and New Guinea demonstrate the interdependence of radar system geometry and terrain configuration for optimum retrieval of geologic information. Illustrations suggest that in the case of space radars (SIR-A in particular), the ability to acquire multiple look-angle/look-direction radar images of a given area is more valuable for landform mapping than further improvements in spatial resolution. Radar look-angle is concluded to be one of the most important system parameters of a space radar designed to be used for geologic reconnaissance mapping. The optimum set of system parameters must be determined for imaging different classes of landform features and tailoring the look-angle to local topography.

Macdonald, H.; Waite, W. P.; Kaupp, V. H.; Bridges, L. C.; Storm, M.

1983-01-01

157

Report by the International Space Station (ISS) Management and Cost Evaluation (IMCE) Task Force  

NASA Technical Reports Server (NTRS)

The International Space Station (ISS) Management and Cost Evaluation Task Force (IMCE) was chartered to conduct an independent external review and assessment of the ISS cost, budget, and management. In addition, the Task Force was asked to provide recommendations that could provide maximum benefit to the U.S. taxpayers and the International Partners within the President's budget request. The Task Force has made the following principal findings: (1) The ISS Program's technical achievements to date, as represented by on-orbit capability, are extraordinary; (2) The Existing ISS Program Plan for executing the FY 02-06 budget is not credible; (3) The existing deficiencies in management structure, institutional culture, cost estimating, and program control must be acknowledged and corrected for the Program to move forward in a credible fashion; (4) Additional budget flexibility, from within the Office of Space Flight (OSF) must be provided for a credible core complete program; (5) The research support program is proceeding assuming the budget that was in place before the FY02 budget runout reduction of $1B; (6) There are opportunities to maximize research on the core station program with modest cost impact; (7) The U.S. Core Complete configuration (three person crew) as an end-state will not achieve the unique research potential of the ISS; (8) The cost estimates for the U.S.-funded enhancement options (e.g., permanent seven person crew) are not sufficiently developed to assess credibility. After these findings, the Task Force has formulated several primary recommendations which are published here and include: (1) Major changes must be made in how the ISS program is managed; (2) Additional cost reductions are required within the baseline program; (3) Additional funds must be identified and applied from the Human Space Flight budget; (4) A clearly defined program with a credible end-state, agreed to by all stakeholders, must be developed and implemented.

Young, A. Thomas; Kellogg, Yvonne (Technical Monitor)

2001-01-01

158

Evaluate the Application of TPH test kits to Identify the Potential Contaminants in Gas Stations  

NASA Astrophysics Data System (ADS)

This study is focusing on the utility and applicability of the portable equipments such as, photo ionization detector (PID) and flame ionization detector (FID) for the determination of contaminants during the investigation of various gas stations. According to the onsite screening results, high contaminated soil samples were sent to analytical laboratory for the detection and quantification of the contaminants present therein. However, due to limitations, PID and FID cannot detect the low vapor pressure components. Hence, they cannot reflect the real situation of the contaminated soil samples and areas. This study summarizes the analytical results of total 37 soil samples, collecting from 17 gas stations. Soil samples were not only analyzed according to the standard method of Taiwan EPA in the laboratory, but also tested using the Total Petroleum Hydrocarbon (TPH) test kits, following the USEPA method 9074, to evaluate the TPH concentration in soil samples. With test kits, onsite, first the TPH was extracted from the soil samples using methanol and then mixed with emulsifier to produce turbidity, and finally then measured using the turbidity meter. The TPH test kits method is simple and rapid, and not time consuming like the laboratory method. A positive relationship has been observed (co-efficient of determination, R2 = 0.74) comparing between the results obtained from the laboratory test and kits test methods, especially for the high carbon content oil such as, diesel, but it does not show the obvious relationship with gasoline. Number of advantages has been considered in using the TPH test kits including, easily portable, simple and rapid testing, cost-effective, and onsite quantification. The technique can be applied for high carbon content oil contamination sites during soil sampling, to realize the actual situations and the promoting confirmation efficiency.

Liao, P. Y.; Liu, C. W.; Liu, W. Y.

2012-04-01

159

Evaluating space station applications of automation and robotics technologies from a human productivity point of view  

NASA Technical Reports Server (NTRS)

The role that automation, robotics, and artificial intelligence will play in Space Station operations is now beginning to take shape. Although there is only limited data on the precise nature of the payoffs that these technologies are likely to afford there is a general consensus that, at a minimum, the following benefits will be realized: increased responsiveness to innovation, lower operating costs, and reduction of exposure to hazards. Nevertheless, the question arises as to how much automation can be justified with the technical and economic constraints of the program? The purpose of this paper is to present a methodology which can be used to evaluate and rank different approaches to automating the functions and tasks planned for the Space Station. Special attention is given to the impact of advanced automation on human productivity. The methodology employed is based on the Analytic Hierarchy Process. This permits the introduction of individual judgements to resolve the confict that normally arises when incomparable criteria underly the selection process. Because of the large number of factors involved in the model, the overall problem is decomposed into four subproblems individually focusing on human productivity, economics, design, and operations, respectively. The results from each are then combined to yield the final rankings. To demonstrate the methodology, an example is developed based on the selection of an on-orbit assembly system. Five alternatives for performing this task are identified, ranging from an astronaut working in space, to a dexterous manipulator with sensory feedback. Computational results are presented along with their implications. A final parametric analysis shows that the outcome is locally insensitive to all but complete reversals in preference.

Bard, J. F.

1986-01-01

160

Evaluation of areal precipitation estimates based on downscaled reanalysis and station data by hydrological modelling  

NASA Astrophysics Data System (ADS)

In data sparse regions, as in many mountainous catchments, it is a challenge to generate suitable precipitation input fields for hydrological modelling, as station data do not provide enough information to derive areal precipitation estimates. This study presents a method using the spatial variation of precipitation from downscaled reanalysis data for the interpolation of gauge observations. The second aim of this study is the evaluation of different precipitation estimates by hydrological modelling. Study area is the Karadarya catchment in Central Asia (11 700 km2). ERA-40 reanalysis data are downscaled with the regional climate model Weather Research and Forecasting Model (WRF). Precipitation data from gauge observations are interpolated (i) using monthly accumulated WRF precipitation data, (ii) using monthly fields from multiple linear regression against topographical variables and (iii) with the inverse distance approach. These precipitation data sets are also compared to (iv) the direct use of the precipitation output from the WRF downscaled ERA-40 data and (v) precipitation from the APHRODITE data set. Our study suggests that using monthly fields from downscaled reanalysis data can be a good approach for the interpolation of station data in data sparse mountainous regions. Compared to mean annual precipitation from continental and global scale gridded data sets our precipitation estimates for the study area are considerably higher. The introduction of a calibrated precipitation bias factor for the comparison of different precipitation estimates by hydrological modelling allows for a more informed differentiation with regard to the temporal dynamics, on the one hand, and the overall bias, on the other hand. Uncertainty and sensitivity analyses suggest that our results are robust against uncertainties in the calibration parameters, other model parameters and inputs, and the selected calibration period.

Duethmann, D.; Zimmer, J.; Gafurov, A.; Güntner, A.; Merz, B.; Vorogushyn, S.

2012-09-01

161

Performance Evaluation of the Operational Air Quality Monitor for Water Testing Aboard the International Space Station  

NASA Technical Reports Server (NTRS)

In the history of manned spaceflight, environmental monitoring has relied heavily on archival sampling. For short missions, this type of sample collection was sufficient; returned samples provided a snapshot of the presence of chemical and biological contaminants in the spacecraft air and water. However, with the construction of the International Space Station (ISS) and the subsequent extension of mission durations, soon to be up to one year, the need for enhanced, real-time environmental monitoring became more pressing. The past several years have seen the implementation of several real-time monitors aboard the ISS, complemented with reduced archival sampling. The station air is currently monitored for volatile organic compounds (VOCs) using gas chromatography-differential mobility spectrometry (Air Quality Monitor [AQM]). The water on ISS is analyzed to measure total organic carbon and biocide concentrations using the Total Organic Carbon Analyzer (TOCA) and the Colorimetric Water Quality Monitoring Kit (CWQMK), respectively. The current air and water monitors provide important data, but the number and size of the different instruments makes them impractical for future exploration missions. It is apparent that there is still a need for improvements in environmental monitoring capabilities. One such improvement could be realized by modifying a single instrument to analyze both air and water. As the AQM currently provides quantitative, compound-specific information for target compounds present in air samples, and many of the compounds are also targets for water quality monitoring, this instrument provides a logical starting point to evaluate the feasibility of this approach. In this presentation, we will discuss our recent studies aimed at determining an appropriate method for introducing VOCs from water samples into the gas phase and our current work, in which an electro-thermal vaporization unit has been interfaced with the AQM to analyze target analytes at the relevant concentrations at which they are routinely detected in archival water samples from the ISS.

Wallace, William T.; Limero, Thomas F.; Gazda, Daniel B.; Macatangay, Ariel V.; Dwivedi, Prabha; Fernandez, Facundo M.

2014-01-01

162

Atomic oxygen durability evaluation of the flexible batten for the photovoltaic array mast on Space Station  

NASA Technical Reports Server (NTRS)

A test program was conducted at the National Aeronautics and Space Administration's Lewis Research Center (LeRC) to evaluate the long term low Earth orbital (LEO) atomic oxygen (AO) durability of a flexible (fiberglass-epoxy composite) batten. The flexible batten is a component used to provide structural rigidity in the photovoltaic array mast on Space Station. The mast is used to support and articulate the photovoltaic array, therefore, the flexible batten must be preloaded for the 15 year lifetime of an array blanket. Development hardware and composite materials were evaluated in ground testing facilities for AO durability and dynamic retraction-deployment cyclic loading representative of expected full life in-space application. The CV1144 silicone (AO protective) coating was determined to provide adequate protection against AO degradation of the composite material and provided fiber containment, thus the structural integrity of the flexible batten was maintained. Both silicone coated and uncoated flexible battens maintained load carrying capabilities. Results of the testing did indicate that the CV1144 silicone protective coating was oxidized by AO reactions to form a brittle glassy (SiO2) skin that formed cracking patterns on all sides of the coated samples. The cracking was observed in samples that were mechanically stressed as well as samples in non-stressed conditions. The oxidized silicon was observed to randomly spall in small localized areas, on the flexible battens that underwent retraction-deployment cycling. Some darkening of the silicon, attributed to vacuum ultraviolet (VUV) radiation, was observed.

Stidham, Curtis R.; Rutledge, Sharon K.; Sechkar, Edward A.; Flaherty, David S.; Roig, David M.; Edwards, Jonathan L.

1994-01-01

163

Evaluation of the soil moisture prediction accuracy of a space radar using simulation techniques. [Kansas  

NASA Technical Reports Server (NTRS)

Image simulation techniques were employed to generate synthetic aperture radar images of a 17.7 km x 19.3 km test site located east of Lawrence, Kansas. The simulations were performed for a space SAR at an orbital altitude of 600 km, with the following sensor parameters: frequency = 4.75 GHz, polarization = HH, and angle of incidence range = 7 deg to 22 deg from nadir. Three sets of images were produced corresponding to three different spatial resolutions; 20 m x 20 m with 12 looks, 100 m x 100 m with 23 looks, and 1 km x 1 km with 1000 looks. Each set consisted of images for four different soil moisture distributions across the test site. Results indicate that, for the agricultural portion of the test site, the soil moisture in about 90% of the pixels can be predicted with an accuracy of = + or - 20% of field capacity. Among the three spatial resolutions, the 1 km x 1 km resolution gave the best results for most cases, however, for very dry soil conditions, the 100 m x 100 m resolution was slightly superior.

Ulaby, F. T. (principal investigator); Dobson, M. C.; Stiles, J. A.; Moore, R. K.; Holtzman, J. C.

1981-01-01

164

Performance evaluation of integer to integer wavelet transform for synthetic aperture radar image compression  

NASA Astrophysics Data System (ADS)

An efficient and novel imagery compression system for Synthetic Aperture Radar (SAR) which uses integer to integer wavelet transform and Modified Set Partitioning Embedded Block Coder (M-SPECK) has been presented in this paper. The presence of speckle noise, detailed texture, high dynamic range in SAR images, and even its vast data volume show the great differences of SAR imagery. Integer to integer wavelet transform is invertible in finite precision arithmetic, it maps integers to integers, and approximates linear wavelet transforms from which they are derived. Considering in terms of computational load, compression ratio and subjective visual quality metrics, several filter banks are compared together and some factors affecting the compression performance of the integer to integer wavelet transform are discussed in details. Then the optimal filter banks which are more appropriate for the SAR images compression are given. Information of high frequency has relatively larger proportion in SAR images compared with those of nature images. Measures to modify the quantizing thresholds in traditional SPECK are taken, which could be suitable to the contents of SAR imagery for the purpose of compression. Both the integer to integer wavelet transform and modified SPECK have the desirable feature of low computational complexity. Experimental results show its superiority over the traditional approaches in the condition of tradeoffs between compression efficiency and computational complexity.

Xue, Wentong; Song, Jianshe; Yuan, Lihai; Shen, Tao

2005-11-01

165

EVALUATION OF FULL-SCALE FABRIC FILTERS ON UTILITY BOILERS: PP AND L BRUNNER ISLAND STATION UNIT 1  

EPA Science Inventory

The report gives results of two series of total mass and fractional size particulate emission tests at Pennsylvania Power and Light's Brunner Island Station Unit 1 on August 12-16, 1981, and September 2-4, 1982, as part of a program to evaluate and characterize the performance of...

166

Spaceborne radar  

NASA Technical Reports Server (NTRS)

The spaceborne radar panel considered how radar could be used to measure precipitation from satellites. The emphasis was on how radar could be used with radiometry (at microwave, visible (VIS), and infrared (IR) wavelengths) to reduce the uncertainties of measuring precipitation with radiometry alone. In addition, the fundamental electromagnetic interactions involved in the measurements were discussed to determine the key work areas for research and development to produce effective instruments. Various approaches to implementing radar systems on satellites were considered for both shared and dedicated instruments. Finally, a research and development strategy was proposed for establishing the parametric relations and retrieval algorithms required for extracting precipitation information from the radar and associated radiometric data.

Moore, R. K.; Eckerman, J.; Meneghini, R.; Atlas, D.; Boerner, W. M.; Cherry, S.; Clark, J. F.; Doviak, R. J.; Goldhirsh, J.; Lhermitte, R. M.

1981-01-01

167

Microwave Emissions from Police Radar  

Microsoft Academic Search

This study evaluated police officers' exposures to microwaves emitted by traffic radar units. Exposure measurements were taken at approximated ocular and testicular levels of officers seated in patrol vehicles. Comparisons were made of the radar manufacturers' published maximum power density specifications and actual measured power densities taken at the antenna faces of those units. Four speed-enforcement agencies and one transportation

J. M. Fink; J. P. Wagner; J. J. Congleton; J. C. Rock

1999-01-01

168

Evaluating PRISM precipitation grid data as possible surrogates for station data at four sites in Oklahoma  

Technology Transfer Automated Retrieval System (TEKTRAN)

The development of climate-sensitive decision support for agriculture or water resource management requires long time series of monthly precipitation for specific locations. Archived station data for many locations is available, but time continuity, quality, and spatial coverage of station data rem...

169

An Evaluation of Technology to Remove Problematic Organic Compounds from the International Space Station Potable Water  

NASA Technical Reports Server (NTRS)

Since activation of the Water Processor Assembly (WPA) on the International Space Station (ISS) in November of 2008, there have been three events in which the TOC (Total Organic Carbon) in the product water has increased to approximately 3 mg/L and has subsequently recovered. Analysis of the product water in 2010 identified the primary component of the TOC as dimethylsilanediol (DMSD). An investigation into the fate of DMSD in the WPA ultimately determined that replacement of both Multifiltration (MF) Beds is the solution to recovering product water quality. The MF Beds were designed to ensure that ionic breakthrough occurs before organic breakthrough. However, DMSD saturated both MF Beds in the series, requiring removal and replacement of both MF Beds with significant life remaining. Analysis of the MF Beds determined that the adsorbent was not effectively removing DMSD, trimethylsilanol, various polydimethylsiloxanes, or dimethylsulfone. Coupled with the fact that the current adsorbent is now obsolete, the authors evaluated various media to identify a replacement adsorbent as well as media with greater capacity for these problematic organic contaminants. This paper provides the results and recommendations of this collaborative study.

Rector, Tony; Metselaar, Carol; Peyton, Barbara; Steele, John; Michalek, William; Bowman, Elizabeth; Wilson, Mark; Gazda, Daniel; Carter, Layne

2014-01-01

170

Structural evaluation of concepts for a solar energy concentrator for Space Station advanced development program  

NASA Technical Reports Server (NTRS)

Solar dynamic power systems have a higher thermodynamic efficiency than conventional photovoltaic systems; therefore they are attractive for long-term space missions with high electrical power demands. In an investigation conducted in support of a preliminary concept for Space Station Freedom, an approach for a solar dynamic power system was developed and a number of the components for the solar concentrator were fabricated for experimental evaluation. The concentrator consists of hexagonal panels comprised of triangular reflective facets which are supported by a truss. Structural analyses of the solar concentrator and the support truss were conducted using finite-element models. A number of potential component failure scenarios were postulated and the resulting structural performance was assessed. The solar concentrator and support truss were found to be adequate to meet a 1.0-Hz structural dynamics design requirement in pristine condition. However, for some of the simulated component failure conditions, the fundamental frequency dropped below the 1.0-Hz design requirement. As a result, two alternative concepts were developed and assessed. One concept incorporated a tetrahedral ring truss support for the hexagonal panels: the second incorporated a full tetrahedral truss support for the panels. The results indicate that significant improvements in stiffness can be obtained by attaching the panels to a tetrahedral truss, and that this concentrator and support truss will meet the 1.0-Hz design requirement with any of the simulated failure conditions.

Kenner, Winfred S.; Rhodes, Marvin D.

1994-01-01

171

Evaluation of the Air Quality Monitor's Performance on the International Space Station  

NASA Technical Reports Server (NTRS)

The Air Quality Monitor (AQM) was flown to the International Space Station (ISS) as an experiment to evaluate its potential to replace the aging Volatile Organic Analyzer (VOA), which ceased operations in August 2009. The AQM (Figure 1) is a small gas chromatography/differential mobility spectrometer (GC/DMS) manufactured by Sionex. Data was presented at last year s ISIMS conference that detailed the preparation of the AQM for flight, including instrument calibration. Furthermore, initial AQM data was compared to VOA results from simultaneous runs of the two instruments. Although comparison with VOA data provided a measure of confidence in the AQM performance, it is the comparison with results from simultaneously acquired air samples (grab sample containers-GSCs) that will define the success (or failure) of the AQM performance. This paper will update the progress in the AQM investigation by comparing AQM data to results from the analyses of GSC samples, returned from ISS. Additionally, a couple of example will illustrate the AQM s ability to detect disruptions in the spacecraft s air quality. Discussion will also focus upon a few unexpected issues that have arisen and how these will be a addressed in the final operational unit now being built.

Limero, Thomas; Reese, Eric; Ballard, Ken; Durham, Tamara

2010-01-01

172

Evaluation of Low-Earth-Orbit Environmental Effects on International Space Station Thermal Control Materials  

NASA Technical Reports Server (NTRS)

Many spacecraft thermal control coatings in low Earth orbit (LEO) can be affected by solar ultraviolet radiation and atomic oxygen. Ultraviolet radiation can darken some polymers and oxides commonly used in thermal control materials. Atomic oxygen can erode polymer materials, but it may reverse the ultraviolet-darkening effect on oxides. Maintaining the desired solar absorptance for thermal control coatings is important to assure the proper operating temperature of the spacecraft. Thermal control coatings to be used on the International Space Station (ISS) were evaluated for their performance after exposure in the NASA Lewis Research Center's Atomic Oxygen-Vacuum Ultraviolet Exposure (AO-VUV) facility. This facility simulated the LEO environments of solar vacuum ultraviolet (VUV) radiation (wavelength range, 115 to 200 nanometers (nm)) and VUV combined with atomic oxygen. Solar absorptance was measured in vacuo to eliminate the "bleaching" effects of ambient oxygen on VUV-induced degradation. The objective of these experiments was to determine solar absorptance increases of various thermal control materials due to exposure to simulated LEO conditions similar to those expected for ISS. Work was done in support of ISS efforts at the requests of Boeing Space and Defense Systems and Lockheed Martin Vought Systems.

Dever, Joyce A.

1998-01-01

173

Shuttle orbiter radar cross-sectional analysis  

NASA Technical Reports Server (NTRS)

Theoretical and model simulation studies on signal to noise levels and shuttle radar cross section are described. Pre-mission system calibrations, system configuration, and postmission system calibration of the tracking radars are described. Conversion of target range, azimuth, and elevation into radar centered east north vertical position coordinates are evaluated. The location of the impinging rf energy with respect to the target vehicles body axis triad is calculated. Cross section correlation between the two radars is presented.

Cooper, D. W.; James, R.

1979-01-01

174

Evaluation of the present theoretical basis for determination of planetary surface properties by earth-based radar  

NASA Technical Reports Server (NTRS)

Spaceflight programs such as the planned Viking landing on Mars require the determination of planetary surface slopes and surface dielectric constants by earth-based methods. Heavy reliance is often placed on radar backscattering data for estimation of these surface properties. An assessment is presented of the basic theory by which the raw radar data are interpreted, and it is shown that serious difficulties and internal inconsistencies are present in the available theoretical formulas. The discussion brings into question the reliability of the presently available results for these surface properties as obtained by earth-based radar methods.

Staton, L. D.

1975-01-01

175

Assessment of FRP-confined concrete : understanding behavior and issues in nondestructive evaluation using radar  

E-print Network

Increase in the use of fiber-reinforced polymer (FRP) composite materials for strengthening and retrofitting of concrete columns and bridge piers has urged the development of' an effective non-destructive evaluation (NDE) ...

Ortega, Jose Alberto, 1978-

2006-01-01

176

Use of radars to monitor stream discharge by noncontact methods  

Microsoft Academic Search

Conventional measurements of river flows are costly, time-consuming, and frequently dangerous. This report evaluates the use of a continuous wave microwave radar, a monostatic UHF Doppler radar, a pulsed Doppler microwave radar, and a ground-penetrating radar to measure river flows continuously over long periods and without touching the water with any instruments. The experiments duplicate the flow records from conventional

J. E. Costa; R. T. Cheng; F. P. Haeni; N. Melcher; K. R. Spicer; E. Hayes; W. Plant; K. Hayes; C. Teague; D. Barrick

2006-01-01

177

Frequency-Modulated Continuous-Wave Fm-Cw Radar for Evaluation of Refractory Structures Used in Glass Manufacturing Furnaces  

NASA Astrophysics Data System (ADS)

A frequency-modulated continuous-wave (FM-CW) handheld radar operating in the frequency range of 8-18 GHz, resulting in a relatively fine range resolution was designed and constructed for on-site inspection of refractory structure thickness. This paper presents the design of the radar and the results of measurements conducted on typical refractory furnace structures assembled in the laboratory.

Carroll, B.; Kharkovsky, S.; Zoughi, R.; Limmer, R.

2009-03-01

178

Automotive radar  

NASA Astrophysics Data System (ADS)

Radar networks for automtovie short-range applications (up to 30m) based on powerful but inexpensive 24GHz high range resolution pulse or FMCW radar systems have been developed at the Technical University of Hamburg-Harburg. The described system has been integrated in to an experimental vehicle and tested in real street environment. This paper considers the general network design, the individual pulse or FMCW radar sensors, the network signal processing scheme, the tracking procedure and possible automotive applications, respectively. Object position estimation is accomplished by the very precise range measurement of each individual sensor and additional trilateration procedures. The paper concludes with some results obtained in realistic traffic conditions with multiple target situations using 24 GHz radar network.

Rohling, Hermann

2004-07-01

179

Evaluation of a redesigned self-checkout station for wheelchair users.  

PubMed

Self-checkout is the emergent/emerging retail technology wherein users (shoppers) check out their own items using an interactive kiosk. A dramatic growth is anticipated in the prevalence of self-checkout systems in retail environments. A study was conducted to develop and evaluate a redesign of a self-checkout system with a focus on issues related to physical accessibility for wheelchair users. Two checkout station prototypes were built: a full-scale model of an existing system and a full-scale model of a system with design modifications (e.g., inclusion of appropriate wheelchair clearance under the workstation, reduced vertical position of the credit card reader, etc.). Five wheelchair users and 10 non-wheelchair users performed simulated self-checkout activities using both workstations. The principal independent variable was workstation type (standard design vs. modified design). The dependent measures were productivity (time to complete a transaction), shoulder flexion angle, torso flexion angle, and the user's subjective assessment of the experience. The results of this study indicate that workstation type did not influence productivity levels in either participant group (wheelchair users or non-wheelchair users). Posture, on the other hand, was significantly improved: the peak shoulder angle was reduced by 64% in wheelchair users and by 69% in the non-wheelchair user group. Peak flexion angle of the torso was also reduced by 67% for wheelchair users. Subjective feedback from the wheelchair user group supported the postural data by showing an overall preference for the redesigned workstation, whereas the non-wheelchair group showed no preference between the two. These results indicate that design for populations with specific limitations does not need to come at a cost of reduced accessibility for persons without these limitations; universal design is achievable. PMID:16796238

Bajaj, Komal; Mirka, Gary A; Sommerich, Carolyn M; Khachatoorian, Haig

2006-01-01

180

Using Radar Charts with Qualitative Evaluation: Techniques to Assess Change in Blended Learning  

ERIC Educational Resources Information Center

When university academics implement changes in learning, such as introducing blended learning, it is conventional practice to examine and evaluate the impact of the resulting curriculum reform. Judging the worth and impact of an educational development is a complex task involving subtle differences in learning. Qualitative methods to explore these…

Kaczynski, Dan; Wood, Leigh; Harding, Ansie

2008-01-01

181

Threat radar system simulations  

NASA Astrophysics Data System (ADS)

The capabilities, requirements, and goals of radar emitter simulators are discussed. Simulators are used to evaluate competing receiver designs, to quantify the performance envelope of a radar system, and to model the characteristics of a transmitted signal waveform. A database of candidate threat systems is developed and, in concert with intelligence data on a given weapons system, permits upgrading simulators to new projected threat capabilities. Four currently available simulation techniques are summarized, noting the usefulness of developing modular software for fast controlled-cost upgrades of simulation capabilities.

Miller, L.

182

Terrestrial ecosystem recovery following removal of a PCB point source at a former pole vault line radar station in Northern Labrador.  

PubMed

Saglek Bay (LAB-2), located on the northeast coast of Labrador is a former Polevault station that was operated by the U.S. Air Force from 1953 to 1971 when it was abandoned. An environmental assessment carried out in 1996 determined that the site was contaminated with polychlorinated biphenyls (PCBs) with concentrations in soils far exceeding the Canadian Environmental Protection Agency (CEPA) regulation of 50 ?g/g in three areas of the site (Beach, Site Summit, Antenna Hill). This led to remediation work carried out between 1999 and 2004 to remove and/or isolate all PCB-contaminated soil exceeding 50 ?g/g and to further remediate parts of the site to <5 ?g/g PCBs. In this study, spatial and temporal trends of PCB concentrations in soil, vegetation (Betula glandulosa and Salix spp.), and deer mice (Peromyscus maniculatus) were investigated over a period of fourteen (1997-2011) years in an effort to track ecosystem recovery following the removal of the PCB point sources. The data collected shows that PCB levels in vegetation samples are approximately four times lower in 2011 than pre-remediation in 1997. Similarly, PCB concentrations in deer mice in 2011 are approximately three times lower than those measured in 1997/98. Spatial trends in vegetation and deer mice continue to demonstrate that areas close to the former point sources of PCBs have higher PCB concentrations than those further away (and higher than background levels) and these residual PCB levels are not likely to decrease in the foreseeable future given the persistent nature of PCBs in general in the environment, and in particular in cold climates. PMID:23712118

Ficko, Sarah A; Luttmer, Carol; Zeeb, Barbara A; Reimer, Kenneth

2013-09-01

183

Evaluation of the neutron radiation environment inside the International Space Station based on the Bonner Ball Neutron Detector experiment  

Microsoft Academic Search

The Bonner Ball Neutron Detector (BBND) experiment was conducted onboard the US Laboratory Module of the International Space Station (ISS) as part of the Human Research Facility project of NASA in order to evaluate the neutron radiation environment in the energy range from thermal up to 15MeV inside the ISS. The BBND experiment was carried out over an eight-month period

H. Koshiishi; H. Matsumoto; A. Chishiki; T. Goka; T. Omodaka

2007-01-01

184

Evaluating a Radar-Based, Non Contact Streamflow Measurement System in the San Joaquin River at Vernalis, California  

USGS Publications Warehouse

Accurate measurement of flow in the San Joaquin River at Vernalis, California, is vital to a wide range of Federal and State agencies, environmental interests, and water contractors. The U.S. Geological Survey uses a conventional stage-discharge rating technique to determine flows at Vernalis. Since the flood of January 1997, the channel has scoured and filled as much as 20 feet in some sections near the measurement site resulting in an unstable stage-discharge rating. In response to recent advances in measurement techniques and the need for more accurate measurement methods, the Geological Survey has undertaken a technology demonstration project to develop and deploy a radar-based streamflow measuring system on the bank of the San Joaquin River at Vernalis, California. The proposed flow-measurement system consists of a ground-penetrating radar system for mapping channel geometries, a microwave radar system for measuring surface velocities, and other necessary infrastructure. Cross-section information derived from ground penetrating radar provided depths similar to those measured by other instruments during the study. Likewise, surface-velocity patterns and magnitudes measured by the pulsed Doppler radar system are consistent with near surface current measurements derived from acoustic velocity instruments. Since the ratio of surface velocity to mean velocity falls to within a small range of theoretical value, using surface velocity as an index velocity to compute river discharge is feasable. Ultimately, the non-contact radar system may be used to make continuous, near-real-time flow measurements during high and medium flows. This report documents the data collected between April 14, 2002 and May 17, 2002 for the purposes of testing this radar based system. Further analyses of the data collected during this field effort will lead to further development and improvement of the system.

Cheng, Ralph T.; Gartner, Jeffrey W.; Mason, Robert R.; Costa, John E.; Plant, William J.; Spicer, Kurt R.; Haeni, F. Peter; Melcher, Nick B.; Keller, William C.; Hayes, Ken

2004-01-01

185

Bistatic and Multistatic Radar: Surveillance, Countermeasures, and Radar Cross Sections. (Latest citations from the Aerospace Database)  

NASA Technical Reports Server (NTRS)

The bibliography contains citations concerning the design, development, testing, and evaluation of bistatic and multistatic radar used in surveillance and countermeasure technology. Citations discuss radar cross sections, target recognition and characteristics, ghost recognition, motion image compensation, and wavelet analysis. Stealth aircraft design, stealth target tracking, synthetic aperture radar, and space applications are examined.

1998-01-01

186

Bistatic and Multistatic Radar: Surveillance, Countermeasures, and Radar Cross Sections. (Latest Citations from the Aerospace Database)  

NASA Technical Reports Server (NTRS)

The bibliography contains citations concerning the design, development, testing, and evaluation of bistatic and multistatic radar used in surveillance and countermeasure technology. Citations discuss radar cross sections, target recognition and characteristics, ghost recognition, motion image compensation, and wavelet analysis. Stealth aircraft design, stealth target tracking, synthetic aperture radar, and space applications are examined.

1997-01-01

187

Survey of Chinese radars  

Microsoft Academic Search

Open information on about 200 Chinese radars including earlier radars is now available. By number of model types China is an important radar country. This Chinese radar survey paper shows that Chinese radars cover a wide spectrum of civilian and military applications. Chinese civilian radars include air-borne weather avoidance\\/navigation, air traffic control (ASR, ARSR, GCA, SSR), harbor surveillance, industrial applications,

S. L. Johnston

1995-01-01

188

Stereo side-looking radar experiments  

NASA Technical Reports Server (NTRS)

The application of side-looking radar images in geoscience fields can be enhanced when using overlapping image strips that are viewed in stereo. A question concerns the quality of stereo radar. This quality is described evaluating stereo viewability and using the concept of vertical exaggeration with sets of actual radar images. A conclusion is that currently available stereo radar data are not optimized, that therefore a better quality can be achieved if data acquisition is appropriately arranged, and that the actual limitations of stereo radar are still unexplored. Previously announced in STAR as N83-29489

Leberl, F.; Raggam, J.; Kobrick, M.

1982-01-01

189

Stereo side-looking radar experiments  

NASA Technical Reports Server (NTRS)

The application of side-looking radar images in geoscience fields can be enhanced when using overlapping image strips that are viewed in stereo. A question concerns the quality of stereo radar. This quality is described evaluating stereo viewability and using the concept of vertical exaggeration with sets of actual radar images. A conclusion is that currently available stereo radar data are not optimized, that therefore a better quality can be achieved if data acquisition is appropriately arranged, and that the actual limitations of stereo radar are still unexplored.

Leberl, F.; Raggam, J.; Kobrick, M.

1980-01-01

190

Radar Performance Improvement. Angle Tracking Modification to Fire Control Radar System for Space Shuttle Rendezvous  

NASA Technical Reports Server (NTRS)

The AN/APQ-153 fire control radar modified to provide angle tracking was evaluated for improved performance. The frequency agile modifications are discussed along with the range-rate improvement modifications, and the radar to computer interface. A parametric design and comparison of noncoherent and coherent radar systems are presented. It is shown that the shuttle rendezvous range and range-rate requirements can be made by a Ku-Band noncoherent pulse radar.

Little, G. R.

1976-01-01

191

Statistical properties of radar backscatter data for imaging applications  

Microsoft Academic Search

Traditionally radar imaging algorithms implement second-order statistics. In this article, the statistical properties, (Gaussianity, linearity, and frequency-reversibility) of measured backscattered radar data are evaluated in order to determine the statistical dependence of radar data. Non-Gaussianity, nonlinearity, or frequency-irreversibility favors the use of higher order statistics, rather than second-order statistics in modeling radar backscatter data for imaging applications. The backscatter radar

J. W. Odendaal; P. Niemand

2003-01-01

192

Using radar and lidar instrument simulators to evaluate moist processes in the Community Atmosphere Model  

NASA Astrophysics Data System (ADS)

Global vertically-profiling active satellite observations and instrument simulator packages enable new exposure of moist processes in global climate models. We evaluate the representation of cloud and precipitation processes within two versions of NCAR’s Community Atmosphere Model (CAM) that will be used for IPCC integrations (CAM3.5, CAM4). The two CAM model versions have large differences in cloud water content, cloud particle size, tropospheric humidity, and precipitation frequency and intensity. CloudSat and CALIOP observations and the COSP simulator package are used to produce “apple-to-apple” comparisons between observed and modeled cloud and precipitation properties. We then assess the fidelity of CAM3.5 and CAM4 cloud and precipitation fields to the CloudSat and CALIOP observations in three areas of climatological interest: the Pacific stratocumulus regions, the Tropical Pacific warm pool, and the North Pacific mid-latitude storm track. In addition to observational comparison, the climate implications of the revealed inter-model and observational differences will be discussed.

Kay, J. E.; Gettelman, A.; Zhang, Y.; Stephens, G. L.

2009-12-01

193

Emission inventory evaluation using observations of regional atmospheric background stations of China.  

PubMed

Any accurate simulation of regional air quality by numerical models entails accurate and up-to-date emissions data for that region. The INTEX-B2006 (I06), one of the newest emission inventories recently popularly used in China and East Asia, has been assessed using the Community Multiscale Air Quality model and observations from regional atmospheric background stations of China. Comparisons of the model results with the observations for the species SO2, NO2, O3 and CO from the three regional atmospheric background stations of Shangdianzi, Longfengshan and Linan show that the model can basically capture the temporal characteristics of observations such as the monthly, seasonal and diurnal variance trends. Compared to the other three species, the simulated CO values were grossly underestimated by about two-third or one-half of the observed values, related to the uncertainty in CO emissions. Compared to the other two stations, Shangdianzi had poorer simulations, especially for SO2 and CO, which partly resulted from the site location close to local emission sources from the Beijing area; and the regional inventory used was not capable of capturing the influencing factors of strong regional sources on stations. Generally, the fact that summer gave poor simulation, especially for SO2 and O3, might partly relate to poor simulations of meteorological fields such as temperature and wind. PMID:23923427

An, Xingqin; Sun, Zhaobin; Lin, Weili; Jin, Min; Li, Nan

2013-03-01

194

Microcomputer Learning Stations and Student Health and Safety: Planning, Evaluation, and Revision of Physical Arrangements.  

ERIC Educational Resources Information Center

Summarizes the National Institute of Occupational Health and Safety's recommendations for computer stations in industrial settings and proposes their adaptation to educational institutions. The human side of computer applications is stressed; solutions to educational problems are described; and a checklist of requirements for student comfort is…

Yeaman, Andrew R. J.

1983-01-01

195

Short-range evaluation of air pollution near bus and railway stations  

Microsoft Academic Search

In the early morning, during workdays, intensive activity is observed at both bus and railway stations. This particular time is critical because of the combination of three factors: (1) simultaneous departure of many buses and trains, (2) cold engines, and, quite frequently, (3) stable meteorological conditions. In our approach, we use ARIA Local™, a simulation package applying CFD tools to

E. Corfa; F. Maury; P. Segers; A. Fresneau; A. Albergel

2004-01-01

196

Evaluation of sensors for NGV and fueling station applications. Topical report, November 1994January 1996  

Microsoft Academic Search

The commercial success of the Natural Gas Vehicles (NGV) requires the availability of sensors to make critical measurements, such as mass flow, gas composition, temperature, pressure, moisture, density, engine load, strain, etc. Engine, engine control, compressor, and dispenser manufacturers and fueling station packagers were surveyed to determine sensor use and needs. Their general comments on needed sensor improvements, detailed sensor

J. E. Huebler; C. F. Blazek

1996-01-01

197

A Special-Purpose Digital Radar Simulation and Performance Prediction Model  

Microsoft Academic Search

A special-purpose radar model has been developed to provide interim capability in the evaluation of Army radar performance. This irterim model is designed to be used pending development of the radar scoring facility and will be replaced by the empirical prediction model developed from the radar scoring facility. The radar model has three basic sections: (1) cross section and signal

Merle E. Parmer

1968-01-01

198

Venus - First Radar Test  

NASA Technical Reports Server (NTRS)

After traveling more than 1.5 billion kilometers (948 million miles), the Magellan spacecraft was inserted into orbit around Venus on Aug. 10, 1990. This mosaic consists of adjacent pieces of two Magellan image strips obtained on Aug. 16 in the first radar test. The radar test was part of a planned In Orbit Checkout sequence designed to prepare the Magellan spacecraft and radar to begin mapping after Aug. 31. The strip on the left was returned to the Goldstone Deep Space Network station in California; the strip to the right was received at the DSN in Canberra, Australia. A third station that will be receiving Magellan data is located near Madrid, Spain. Each image strip is 20 km (12 miles) wide and 16,000 km (10,000 miles) long. This mosaic is a small portion 80 km (50 miles) long. This image is centered at 21 degrees north latitude and 286.8 degrees east longitude, southeast of a volcanic highland region called Beta Regio. The resolution of the image is about 120 meters (400 feet), 10 times better than previous images of the same area of Venus, revealing many new geologic features. The bright line trending northwest southeast across the center of the image is a fracture or fault zone cutting the volcanic plains. In the upper left corner of the image, a multiple ring circular feature of probable volcanic origin can be seen, approximately 4.27 km (2.65 miles) across. The bright and dark variations seen in the plains surrounding these features correspond to volcanic lava flows of varying ages. The volcanic lava flows in the southern half of the image have been cut by north south trending faults. This area is similar geologically to volcanic deposits seen on Earth at Hawaii and the Snake River Plains in Idaho.

1990-01-01

199

Noise level evaluation for a natural gas compressor station driven by gas turbines at the planning stage after four years of operation  

Microsoft Academic Search

For a southern german gas turbine compressor station sound emission levels and noise control thereoff are evaluated based on authority specified emmission levels. Project history, planning and operating experience is shown.

F. Fleischer; H. Hiemer; J. Mann

1987-01-01

200

Spaceborne radar detection of orbital debris  

Microsoft Academic Search

Orbital debris in low-Earth-orbit (LEG) poses an increasing threat to the Space Station Freedom (SSF). A combined ground-based\\/on-orbit radar detection system can provide adequate warning to minimize the collision threat. The paper discusses the unique features on an on-board radar, its contributions to solving the problem, simulation results from modeling of atmospheric effects, and their perturbations upon propagation of debris

J. R. Carl; G. D. Arndt; B. A. Bourgoise; I. Paz

1993-01-01

201

Recent Radar Speckle Observations of Near-Earth Asteroids  

NASA Astrophysics Data System (ADS)

Radar speckle tracking is an observational technique to constrain the spin state of a target object. When illuminated by a monochromatic radar beam, the target scatters light into regions of constructive and destructive interference - a speckle pattern. This pattern moves as the target rotates, with a speed and direction determined by the object’s rotation rate and spin vector. By tracking the motion of a radar speckle pattern between two or more receiving stations, we can constrain the spin state of the target.First applied to measure the spin state of Mercury, since 2008 radar speckle tracking has become one of the standard techniques for radar observations of near-Earth asteroids. We transmit with either of the Arecibo and Goldstone planetary radars, receive with elements of the Very Long Baseline Array or of the Very Large Array, and measure the time lags between the speckle pattern as seen by each station. Starting with the first asteroid observed with speckle observations, 2008 EV5, this technique has allowed us to resolve ambiguities in asteroids’ spin states that delay-Doppler radar imaging and lightcurve observations did not.Recent radar speckle targets have included the near-Earth asteroids 1998 ML14, 2005 WK4, and 2014 HQ124. ML14 was observed with radar shortly after its discovery in 1998, but the earlier radar observations did not yield a unique pole direction constraint. HQ124 is a contact-binary object and was one of the best radar targets of 2014.

Busch, Michael W.; Benner, Lance; Brozovic, Marina; Nolan, Michael C.; Springmann, Alessondra; Taylor, Patrick A.

2014-11-01

202

Evaluations of HRI (heat recovery incinerators) at NS (Naval Station) Mayport and NAS (Naval Air Station) Jacksonville, Florida lessons-learned report. Final report, January-June 1984  

SciTech Connect

The heat recovery incinerators (HRI) at Naval Station Mayport and Naval Air Station Jacksonville, Fla., were studied to determine any lessons that could be learned from the planning, design, construction, operation, and maintenance of these HRIs. The study examined the various problems in these areas, including description of each problem, an analysis of why the problem occurred, and a description of how the problem was alleviated, if it was corrected.

Frounfelker, R.; Belencan, H.

1984-07-01

203

Evaluating the potential use of a high-resolution X-band polarimetric radar observations in Urban Hydrology  

NASA Astrophysics Data System (ADS)

The Mediterranean area concentrates the major natural risks related to the water cycle, including heavy precipitation and flash-flooding during the fall season. Every year in central and south Europe we witness several fatal and economical disasters from severe storm rainfall triggering Flash Floods, and its impacts are increasing worldwide, but remain very difficult to manage. The spatial scale of flash flood occurrence is such that its vulnerability is often focused on dispersed urbanization, transportation and tourism infrastructures (De Marchi and Scolobig 2012). Urbanized and industrialized areas shows peculiar hydrodynamic and meteo-oceanographic features and they concentrate the highest rates of flash floods and fatal disasters. The main causes of disturbance being littoral urban development and harbor activities, the building of littoral rail- and highways, and the presence of several polluted discharges. All the above mentioned characteristics limit our ability to issue timely flood warnings. Precipitation estimates based on raingauge networks are usually associated with low coverage density, particularly at high altitudes. On the other hand, operational weather radar networks may provide valuable information of precipitation at these regimes but reliability of their estimates is often limited due to retrieval (e.g. variability in the reflectivity-to-rainfall relationship) and spatial extent constrains (e.g. blockage issues, overshooting effects). As a result, we currently lack accurate precipitation estimates over urban complex terrain areas, which essentially means that we lack accurate knowledge of the triggering factor for a number of hazards like flash floods and debris flows/landslides occurring in those areas. A potential solution to overcome sampling as well as retrieval uncertainty limitations of current observational networks might be the use of network of low-power dual-polarization X-band radars as complement to raingauges and gap-filling to operational, low-frequency (C-band or S-ban) and high-power weather radars. The above hypothesis is examined using data collected during the HyMEX 2012 Special Observation Period (Nov-Feb) the urban and sub-urban complex terrain area in the Central Italy (CI). The area is densely populated and it includes the high-density populated urban and industrial area of Rome. The orography of CI is quite complex, going from sea level to nearly 3000 m in less than 150 km. The CI area involves many rivers, including two major basins: the Aniene-Tiber basin (1000 km long) and the Aterno-Pescara basin (300 km long), respectively on the west and on the east side of the Apennines ridge. Data include observations from i) the National Observatory of Athens' X-band polarimetric weather radar (XPOL), ii) two X-band miniradars (WR25X located in CNR, WR10X located in Rome Sapienza), iii) a dense network of raingauges and disdrometers (i.e. Parsivel type and 2D-video type). In addition, the experimental area is also covered from the nearby the National Research Council (CNR)'s C-band dual-polarization weather radar (Polar55C), which were involved also in the analysis. A number of storm events are selected and compared with the nearby C-band radar to investigate the potential of using high-resolution and microphysically-derived rainfall based on X-band polarimetric radar observations. Events have been discriminated on the basis of rainfall intensity and hydrological response. Results reveal that in contrast with the other two rainfall sources (in situ and C-band radar), X-band radar rainfall estimates offer an improved representation of the local precipitation variability, which turns to have a significant impact in simulating the peak flows associated with these events.

Anagnostou, Marios N.; Kalogiros, John; Marzano, Frank S.; Anagnostou, Emmanouil N.; Baldini, Luca; Nikolopoulos, EfThymios; Montopoli, Mario; Picciotti, Errico

2014-05-01

204

Interception of LPI radar signals  

NASA Astrophysics Data System (ADS)

Most current radars are designed to transmit short duration pulses with relatively high peak power. These radars can be detected easily by the use of relatively modest EW intercept receivers. Three radar functions (search, anti-ship missile (ASM) seeker, and navigation) are examined to evaluate the effectiveness of potential low probability of intercept (LPI) techniques, such as waveform coding, antenna profile control, and power management that a radar may employ against current Electronic Warfare (EW) receivers. The general conclusion is that it is possible to design a LPI radar which is effective against current intercept EW receivers. LPI operation is most easily achieved at close ranges and against a target with a large radar cross section. The general system sensitivity requirement for the detection of current and projected LPI radars is found to be on the order of -100 dBmi which cannot be met by current EW receivers. Finally, three potential LPI receiver architectures, using channelized, superhet, and acousto-optic receivers with narrow RF and video bandwidths are discussed. They have shown some potential in terms of providing the sensitivity and capability in an environment where both conventional and LPI signals are present.

Lee, Jim P.

1991-11-01

205

Radars in space  

NASA Technical Reports Server (NTRS)

The capabilities of active microwave devices operating from space (typically, radar, scatterometers, interferometers, and altimeters) are discussed. General radar parameters and basic radar principles are explained. Applications of these parameters and principles are also explained. Trends in space radar technology, and where space radars and active microwave sensors in orbit are going are discussed.

Delnore, Victor E.

1990-01-01

206

Flood Monitoring using X-band Dual-polarization Radar Network  

NASA Astrophysics Data System (ADS)

A dense weather radar network is an emerging concept advanced by the Center for Collaborative Adaptive Sensing of the Atmosphere (CASA). Using multiple radars observing over a common will create different data outcomes depending on the characteristics of the radar units employed and the network topology. To define this a general framework is developed to describe the radar network space, and formulations are obtained that can be used for weather radar network characterization. Current weather radar surveillance networks are based upon conventional sensing paradigm of widely-separated, standalone sensing systems using long range radars that operate at wavelengths in 5-10 cm range. Such configuration has limited capability to observe close to the surface of the earth because of the earth's curvature but also has poorer resolution at far ranges. The dense network radar system, observes and measures weather phenomenon such as rainfall and severe weather close to the ground at higher spatial and temporal resolution compared to the current paradigm. In addition the dense network paradigm also is easily adaptable to complex terrain. Flooding is one of the most common natural hazards in the world. Especially, excessive development decreases the response time of urban watersheds and complex terrain to rainfall and increases the chance of localized flooding events over a small spatial domain. Successful monitoring of urban floods requires high spatiotemporal resolution, accurate precipitation estimation because of the rapid flood response as well as the complex hydrologic and hydraulic characteristics in an urban environment. This paper reviews various aspects in radar rainfall mapping in urban coverage using dense X-band dual-polarization radar networks. By reducing the maximum range and operating at X-band, one can ensure good azimuthal resolution with a small-size antenna and keep the radar beam closer to the ground. The networked topology helps to achieve satisfactory sensitivity and fast temporal update across the coverage. Strong clutter is expected from buildings in the neighborhood which act as perfect reflectors. The reduction in radar size enables flexible deployment, such as rooftop installation, with small infrastructure requirement, which is critical in a metropolitan region. Dual-polarization based technologies can be implemented for real-time mitigation of rain attenuations and accurate estimation of rainfall. The NSF Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere (CASA) is developing the technologies and the systems for network centric weather observation. The Differential propagation phase (Kdp) has higher sensitivity at X-band compared to S and C band. It is attractive to use Kdp to derive Quantitative Precipitation Estimation (QPE) because it is immune to rain attenuation, calibration biases, partial beam blockage, and hail contamination. Despite the advantage of Kdp for radar QPE, the estimation of Kdp itself is a challenge as the range derivative of the differential propagation phase profiles. An adaptive Kdp algorithm was implemented in the CASA IP1 testbed that substantially reduces the fluctuation in light rain and the bias at heavy rain. The Kdp estimation also benefits from the higher resolution in the IP1 radar network. The performance of the IP1 QPE product was evaluated for all major rain events against the USDA Agriculture Research Service's gauge network (MicroNet) in the Little Washita watershed, which comprises 20 weather stations in the center of the test bed. The cross-comparison with gauge measurements shows excellent agreement for the storm events during the Spring Experiments of 2007 and 2008. The hourly rainfall estimates compared to the gauge measurements have a very small bias of few percent and a normalized standard error of 21%. The IP1 testbed was designed with overlapping coverage among its radar nodes. The study area is covered by multiple radars and the aspect of network composition is also evaluated. The independence of Kdp on the radar calibration e

Chandrasekar, V.; Wang, Y.; Maki, M.; Nakane, K.

2009-09-01

207

23. SITE BUILDING 002 SCANNER BUILDING RADAR CONTROL ...  

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

23. SITE BUILDING 002 - SCANNER BUILDING - RADAR CONTROL INTERFACE "RCL NO. 2" WITH COMPUTER CONTROL DISC DRIVE UNITS IN FOREGROUND. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

208

9. View southeast corner of perimeter acquisition radar power plant ...  

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

9. View southeast corner of perimeter acquisition radar power plant room #214, control room; showing central monitoring station console in foreground. Well and booster control panel in left background and electric power management panel on far right - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Power Plant, In Limited Access Area, Southwest of PARB at end of Service Road B, Nekoma, Cavalier County, ND

209

50. View of waveguides beginning to move toward two radar ...  

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

50. View of waveguides beginning to move toward two radar scanner switches (two per radar scanner building) by vertical bends; also tuning devices are located here. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

210

9. View toward northeast, southwest oblique of perimeter acquisition radar ...  

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

9. View toward northeast, southwest oblique of perimeter acquisition radar building showing, from left to right, fuel oil pump station, cooling towers, power plant, and diesel intake/exhaust - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

211

The near real time terminal for VLBI radar method  

Microsoft Academic Search

Combination of radar and VLBI allowed obtaining the new scientific instrument for measurement of short-periodic variation of planet proper rotation and determination of the Solar system body orbits in the radio reference frame. Radar, spectral lines, low frequency, spacecraft navigation observations could benefit from this inexpensive solution in those stations where large antennas and sensitive receivers are available and where

A. E. Volvach; G. Tuccari; I. E. Molotov; I. D. Strepka

2005-01-01

212

A methodology for automation and robotics evaluation applied to the space station telerobotic servicer  

NASA Technical Reports Server (NTRS)

The efforts of a recent study aimed at identifying key issues and trade-offs associated with using a Flight Telerobotic Servicer (FTS) to aid in Space Station assembly-phase tasks is described. The use of automation and robotic (A and R) technologies for large space systems would involve a substitution of automation capabilities for human extravehicular or intravehicular activities (EVA, IVA). A methodology is presented that incorporates assessment of candidate assembly-phase tasks, telerobotic performance capabilities, development costs, and effect of operational constraints (space transportation system (STS), attached payload, and proximity operations). Changes in the region of cost-effectiveness are examined under a variety of systems design assumptions. A discussion of issues is presented with focus on three roles the FTS might serve: (1) as a research-oriented testbed to learn more about space usage of telerobotics; (2) as a research based testbed having an experimental demonstration orientation with limited assembly and servicing applications; or (3) as an operational system to augment EVA and to aid the construction of the Space Station and to reduce the programmatic (schedule) risk by increasing the flexibility of mission operations.

Smith, Jeffrey H.; Gyanfi, Max; Volkmer, Kent; Zimmerman, Wayne

1988-01-01

213

An application of multiattribute decision analysis to the Space Station Freedom program. Case study: Automation and robotics technology evaluation  

NASA Technical Reports Server (NTRS)

The results are described of an application of multiattribute analysis to the evaluation of high leverage prototyping technologies in the automation and robotics (A and R) areas that might contribute to the Space Station (SS) Freedom baseline design. An implication is that high leverage prototyping is beneficial to the SS Freedom Program as a means for transferring technology from the advanced development program to the baseline program. The process also highlights the tradeoffs to be made between subsidizing high value, low risk technology development versus high value, high risk technology developments. Twenty one A and R Technology tasks spanning a diverse array of technical concepts were evaluated using multiattribute decision analysis. Because of large uncertainties associated with characterizing the technologies, the methodology was modified to incorporate uncertainty. Eight attributes affected the rankings: initial cost, operation cost, crew productivity, safety, resource requirements, growth potential, and spinoff potential. The four attributes of initial cost, operations cost, crew productivity, and safety affected the rankings the most.

Smith, Jeffrey H.; Levin, Richard R.; Carpenter, Elisabeth J.

1990-01-01

214

Evaluation of the Biolog MicroStation system for yeast identification  

NASA Technical Reports Server (NTRS)

One hundred and fifty-nine isolates representing 16 genera and 53 species of yeasts were processed with the Biolog MicroStation System for yeast identification. Thirteen genera and 38 species were included in the Biolog database. For these 129 isolates, correct identifications to the species level were 13.2, 39.5 and 48.8% after 24, 48 and 72 hours incubation at 30 degrees C, respectively. Three genera and 15 species which were not included in the Biolog database were also tested. Of the 30 isolates studied, 16.7, 53.3 and 56.7% of the isolates were given incorrect names from the system's database after 24,48 and 72 h incubation at 30 degrees C, respectively. The remaining isolates of this group were not identified.

McGinnis, M. R.; Molina, T. C.; Pierson, D. L.; Mishra, S. K.

1996-01-01

215

Evaluation of Pactruss design characteristics critical to space station primary structure  

NASA Technical Reports Server (NTRS)

Several aspects of the possible application of the Pactruss concept to the primary truss structure of the space station are investigated. Estimates are made of the loads and hinge moments in deploying diagonal members as full deployment is approached. Included are the effects of beam columning and compliance of the surrounding structure. Requirements for joint design are suggested and a two-stage mid-diagonal latching hinge concept is described or analyzed. The problems with providing the experimental and theoretical tools needed for assuring reliable synchronous deployment are discussed and a first attempt at high-fidelity analytical simulation with NASTRAN is described. An alternative construction scenario in which the entire dual-keel truss structure is deployed as a single Shuttle payload is suggested.

Hedgepeth, John M.

1987-01-01

216

Weather Radar Fundamentals  

NSDL National Science Digital Library

This 2-hour module presents the fundamental principles of Doppler weather radar operation and how to interpret common weather phenomena using radar imagery. This is accomplished via conceptual animations and many interactive radar examples in which the user can practice interpreting both radar reflectivity and radar velocity imagery. Although intended as an accelerated introduction to understanding and using basic Doppler weather radar products, the module can also serve as an excellent refresher for more experienced users.

2014-09-14

217

An OSSE Framework Based on the Ensemble Square Root Kalman Filter for Evaluating the Impact of Data from Radar Networks on Thunderstorm Analysis and Forecasting  

Microsoft Academic Search

A framework for Observing System Simulation Experiments (OSSEs) based on the ensemble square root Kalman filter (EnSRF) technique for assimilating data from more than one radar network is described. The system is tested by assimilating simulated radial velocity and reflectivity data from a Weather Surveillance Radar-1988 Doppler (WSR-88D) radar and a network of four low-cost radars planned for the Oklahoma

Ming Xue; Mingjing Tong; Kelvin K. Droegemeier

2006-01-01

218

Evaluation of Maximal Oxygen Uptake and Submaximal Estimates of VO2max Before, During, and After Long Duration International Space Station Missions  

NASA Technical Reports Server (NTRS)

Evaluation of Maximal Oxygen Uptake and Submaximal Estimates of VO2max Before, During, and After Long Duration International Space Station Missions (VO2max) will document changes in maximum oxygen uptake for crewmembers onboard the International Space Station (ISS) on long-duration missions, greater than 90 days. This investigation will establish the characteristics of VO2max during flight and assess the validity of the current methods of tracking aerobic capacity change during and following the ISS missions.

2008-01-01

219

Analysis of Borehole-Radar Reflection Data from Machiasport, Maine, December 2003  

USGS Publications Warehouse

In December 2003, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, collected borehole-radar reflection logs in two boreholes in Machiasport, Maine. These bedrock boreholes were drilled as part of a hydrogeologic investigation of the area surrounding the former Air Force Radar Tracking Station site on Howard Mountain near Bucks Harbor. The boreholes, MW09 and MW10, are located approximately 50 meters (m) from, and at the site of, respectively, the locations of former buildings where trichloroethylene was used as part of defense-site operations. These areas are thought to be potential source areas for contamination that has been detected in downgradient bedrock wells. This investigation focused on testing borehole-radar methods at this site. Single-hole radar-reflection surveys were used to identify the depth, orientation, and spatial continuity of reflectors that intersect and surround the boreholes. In addition, the methods were used to (1) identify the radial depth of penetration of the radar waves in the electrically resistive bimodal volcanic formation at the site, (2) provide information for locating additional boreholes at the site, and (3) test the potential applications of borehole-radar methods for further aquifer characterization and (or) evaluation of source-area remediation efforts. Borehole-radar reflection logging uses a pair of downhole transmitting and receiving antennas to record the reflected wave amplitude and transit time of high-frequency electromagnetic waves. For this investigation, 60- and 100-megahertz antennas were used. The electromagnetic waves emitted by the transmitter penetrate into the formation surrounding the borehole and are reflected off of a material with different electromagnetic properties, such as a fracture or change in rock type. Single-hole directional radar surveys indicate the bedrock surrounding these boreholes is highly fractured, because several reflectors were identified in the radar-reflection data. There are several steeply dipping reflectors with orientations similar to the fracture patterns observed with borehole imaging techniques and in outcrops. The radar-reflection data showed that the vitrophyre in borehole MW09 was more highly fractured than the underlying gabbroic unit. The velocities of radar waves in the bedrock surrounding the boreholes were determined using single-hole vertical radar profiling. Velocities of 114 and 125 meters per microsecond were used to determine the distance to reflectors, the radial depth of penetration, and the dip of reflectors. The bimodal volcanic units appear to be ideal for radar-wave propagation. For the radar surveys collected at this site, radar reflections were detected up to 40 m into the rock from the borehole. These results indicate that boreholes could conservatively be spaced about 15-20 m apart for hole-to-hole radar methods to be effective for imaging between the boreholes and monitoring remediation. Integrated analysis of drilling and borehole-geophysical logs indicates the vitrophyric formation is more fractured than the more mafic gabbroic units in these boreholes. There does not, however, appear to be a quantifiable difference in the radar-wave penetration in these two rock units.

Johnson, Carole D.; Joesten, Peter K.

2005-01-01

220

Detail view of northwest side of Signal Corps Radar (S.C.R.) ...  

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

Detail view of northwest side of Signal Corps Radar (S.C.R.) 296 Station 5 Transmitter Building foundation, showing portion of concrete gutter drainage system and asphalt floor tiles, camera facing north - Fort Barry, Signal Corps Radar 296, Station 5, Transmitter Building Foundation, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

221

Advanced ground penetrating radar  

SciTech Connect

An advanced Ground Penetrating Radar (GPR) system has the potential for efficiently and reliably providing high resolution images for inspecting concrete civil structures for defects and damage assessment. To achieve the required performance, improvements in radar hardware, and development and adaptation of advanced 2- and 3-dimensional synthetic aperture imaging techniques are needed. Recent and continuing advancement in computer and computer-related technology areas have made it possible to consider more complex and capable systems for a variety of imaging applications not previously conceived. The authors developed conceptual designs, analyzed system requirements, and performed experiments, modeling, and image reconstructions to study the feasibility of improving GPR technology for non-destructive evaluation of bridge decks and other high-value concrete structures. An overview and summary of practical system concepts and requirements, are presented.

Warhus, J.P.; Mast, J.E.; Johansson, E.M.; Nelson, S.D. [Lawrence Livermore National Lab., CA (United States). Electronics Engineering Dept.

1994-07-26

222

Technical evaluation of the electrical, instrumentation, and control design aspects of the low temperature overpressure protection system for the Beaver Valley Nuclear Power Station, Unit 1  

SciTech Connect

This report documents the technical evaluation of the electrical, instrumentation, and control design aspects for the low temperature overpressure protection system of the Beaver Valley Nuclear Power Station, Unit 1. Design basis criteria used to evaluate the acceptability of the system included operator action, system testability, single failure criterion, and seismic Category I and IEEE Std-279-1971 criteria. 7 refs., 3 figs.

Latorre, V.R.

1980-06-01

223

Multibeam synthetic aperture radar for global oceanography  

NASA Technical Reports Server (NTRS)

A single-frequency multibeam synthetic aperture radar concept for large swath imaging desired for global oceanography is evaluated. Each beam iilluminates a separate range and azimuth interval, and images for different beams may be separated on the basis of the Doppler spectrum of the beams or their spatial azimuth separation in the image plane of the radar processor. The azimuth resolution of the radar system is selected so that the Doppler spectrum of each beam does not interfere with the Doppler foldover due to the finite pulse repetition frequency of the radar system.

Jain, A.

1979-01-01

224

Electrochemical Disinfection Feasibility Assessment Materials Evaluation for the International Space Station  

NASA Technical Reports Server (NTRS)

The International Space Station (ISS) Program recognizes the risk of microbial contamination in their potable and non-potable water sources. The end of the Space Shuttle Program limited the ability to send up shock kits of biocides in the event of an outbreak. Currently, the United States Orbital Segment water system relies primarily on iodine to mitigate contamination concerns, which has been successful in remediating the small cases of contamination documented. However, a secondary method of disinfection is a necessary investment for future space flight. Over the past year, NASA Johnson Space Center has investigated the development of electrochemically generated systems for use on the ISS. These systems include: hydrogen peroxide, ozone, sodium hypochlorite, and peracetic acid. To use these biocides on deployed water systems, NASA must understand of the effect these biocides have on current ISS materials prior to proceeding forward with possible on-orbit applications. This paper will discuss the material testing that was conducted to assess the effects of the biocides on current ISS materials.

Rodriquez, Branelle; Shindo, David; Montgomery, Eliza

2013-01-01

225

Evaluation of Electrochemically Generated Potable Water Disinfectants for Use on the International Space Station  

NASA Technical Reports Server (NTRS)

Microbial contamination and subsequent growth in spacecraft water systems are constant concerns for missions involving human crews. The current potable water disinfectant for the International Space Station (ISS) is iodine; however, with the end of the Space Shuttle program, there is a need to develop redundant biocide systems that do not require regular up ]mass dependencies. Throughout the course of a year, four different electrochemical systems were investigated as a possible biocide for potable water on the ISS. Research has indicated that there is a wide variability with regards to efficacy in both concentration and exposure time of these disinfectants, therefore baseline efficacy values were established. This paper describes a series of tests performed in order to establish optimal concentrations and exposure times for four disinfectants against single and mixed species planktonic and biofilm bacteria. Results of the testing determined whether these electrochemical disinfection systems are able to produce a sufficient amount of chemical in both concentration and volume to act as a biocide for potable water on ISS.

Rodriquez, Branelle; Anderson, Molly; Anderson, Molly; Adam, Niklas; Vega, Leticia; Modica, Catherine; Bodkin, Douglas

2012-01-01

226

Evaluation of Electrochemically Generated Potable Water Disinfectants for Use on the International Space Station  

NASA Technical Reports Server (NTRS)

Microbial contamination and subsequent growth in spacecraft water systems are constant concerns for missions involving human crews. The current potable water disinfectant is iodine; however, with the end of the Space Shuttle program, there is a need to develop redundant biocide systems which are less dependent on hardware that would need to be launched on a regular basis. Three systems for electrochemical production of potable water disinfectants are being assessed for use on the International Space Station (ISS). Since there is a wide variability in the literature with regards to efficacy in both concentration and exposure time of these disinfectants, there is a need to establish baseline efficacy values. This paper describes a series of tests performed in order to establish optimal concentrations and exposure times for four disinfectants against single and mixed species planktonic and biofilm bacteria and to determine whether these electrochemical disinfection devices are able to produce a sufficient amount of chemical in both concentration and volume to act as a biocide for potable water on ISS.

Vega, Leticia; Aber, Gregory; Adam, Niklas; Clements, Anna; Modica, Catherine; Younker, Diane

2011-01-01

227

Evaluation of Electrochemically Generated Potable Water Disinfectants for Use on the International Space Station  

NASA Technical Reports Server (NTRS)

Microbial contamination and subsequent growth in spacecraft water systems are constant concerns for missions involving human crews. The current potable water disinfectant for the International Space Station (ISS) is iodine; however, with the end of the Space Shuttle Program, there is a need to develop redundant biocide systems that do not require regular up-mass dependencies. Throughout the course of a year, four different electrochemical systems were investigated as a possible biocide for potable water on the ISS. Research has indicated that a wide variability exists with regards to efficacy in both concentration and exposure time of these disinfectants; therefore, baseline efficacy values were established. This paper describes a series of tests performed to establish optimal concentrations and exposure times for four disinfectants against single and mixed species planktonic and biofilm bacteria. Results of the testing determined whether these electrochemical disinfection systems are able to produce a sufficient amount of chemical in both concentration and volume to act as a biocide for potable water on the ISS.

Rodriquez, Branelle; Anderson, Molly; Adams, Niklas; Vega, Leticia; Botkin, Douglas

2013-01-01

228

Evaluation of Low Earth Orbit Environmental Effects on International Space Station Thermal Control Materials  

NASA Technical Reports Server (NTRS)

Samples of International Space Station (ISS) thermal control coatings were exposed to simulated low Earth orbit (LEO) environmental conditions to determine effects on optical properties. In one test, samples of the white paint coating Z-93P were coated with outgassed products from Tefzel(R) (ethylene tetrafluoroethylene copolymer) power cable insulation as-may occur on ISS. These samples were then exposed, along with an uncontaminated Z-93P witness sample, to vacuum ultraviolet (VUV) radiation to determine solar absorptance degradation. The Z-93P samples coated with Tefzel(R) outgassing products experienced greater increases in solar absorptance than witness samples not coated with Tefzel(R) outgassing products. In another test, samples of second surface silvered Teflon(R) FEP (fluorinated ethylene propylene), SiO. (where x=2)-coated silvered Teflon(R) FEP, and Z-93P witness samples were exposed to the combined environments of atomic oxygen and VLTV radiation to determine optical properties changes due to these simulated ISS environmental effects. This test verified the durability of these materials in the absence of contaminants.

Dever, Joyce A.; Rutledge, Sharon K.; Hasegawa, Mark M.; Reed, Charles K.

1998-01-01

229

Evaluation of the prompt alerting systems at four nuclear power stations  

SciTech Connect

This report presents evaluations of the prompt notification siren systems at the following four US nuclear power facilities: Trojan, Three Mile Island, Indian Point, and Zion. The objective of these evaluations was to provide examples of an analytical procedure for predicting siren-system effectiveness under specific conditions in the 10-mile emergency planning zone (EPZ) surrounding nuclear power plants. This analytical procedure is discussed in report No. PNL-4227.

Towers, D.A.; Anderson, G.S.; Keast, D.N.; Kenoyer, J.L.; Desrosiers, A.E.

1982-09-01

230

Observation of the Earth by radar  

NASA Technical Reports Server (NTRS)

Techniques and applications of radar observation from Earth satellites are discussed. Images processing and analysis of these images are discussed. Also discussed is radar imaging from aircraft. Uses of this data include ocean wave analysis, surface water evaluation, and topographic analysis.

Elachi, C.

1982-01-01

231

HF radar observations of surface circulation off Bodega Bay (northern California, USA)  

Microsoft Academic Search

Two high-frequency radar stations (CODAR) were installed along the northern California coast in May 2001. Comparisons of radar data with acoustic Doppler current profiler (ADCP) current data and near-surface drifter tracks indicate considerable agreement, with minimum RMS differences of order 0.05–0.15 m\\/s and average drifter-HF-radar track separation rates of 5 ± 3 km\\/d. Radar data resolve the three main sources

David M. Kaplan; John Largier; Louis W. Botsford

2005-01-01

232

Satellite Radar Observations of the DeepWater Horizon Oil Spill in the Gulf of Mexico  

Microsoft Academic Search

The University of Miami's satellite ground station located at the Center for Southeastern Tropical Advanced Remote Sensing (CSTARS) collected daily synthetic aperture radar (SAR) images from an extensive set of radar satellites including TerraSAR-X, RadarSat-1 and RadarSat-2, Cosmo-SkyMed constellation, ENVISAT ASAR, ERS-2 and PALSAR. During the 118 days CSTARS collected over 650 SAR image in long strips covering the entire

H. C. Graber; R. E. Turner; M. J. Caruso; P. A. Mallas; K. Polk; R. J. Ramos; G. Samuels

2010-01-01

233

Future Trends in Automotive Radar \\/ Imaging Radar  

Microsoft Academic Search

There is a growing interest of car manufacturers in sensors monitoring the car's surrounding area in order to improve safety systems from mere crash survival to crash prediction or prevention by early detection of hazardous situations. Therefore radar sensors have been intensively investigated for many years. A large variety of radar based vehicular sensors have been developed. Narrow-beam radars are

J. Wenger

1998-01-01

234

SHARAD: The MRO 2005 shallow radar  

Microsoft Academic Search

SHARAD is a subsurface sounding radar provided by the Italian Space Agency (ASI) as a facility instrument to be flown on the NASA mission Mars Reconnaissance Orbiter (MRO). It shall be launched on August 2005 from the Cape Canaveral Air Force Station and shall deliver a payload designed to provide observations from a low Mars orbit with a nominal science

R. Seu; D. Biccari; R. Orosei; L. V. Lorenzoni; R. J. Phillips; L. Marinangeli; G. Picardi; A. Masdea; E. Zampolini

2004-01-01

235

Remote sensing of sea state by radar  

Microsoft Academic Search

In recent years several radar techniques have evolved which allow the remote measurement of certain parameters important in the description of sea state. At MF and HF, monostatic and bistatic configurations employing satellites, ships, islands, and\\/or land based stations can measure the ocean waveheight spectrum with several frequencies via first-order Bragg scatter. At high HF and VHF, the ocean waveheight

D. Barrick

1972-01-01

236

Shuttle orbiter Ku-band radar/communications system design evaluation: High gain antenna/widebeam horn  

NASA Technical Reports Server (NTRS)

The physical characteristics of the high gain antenna reflector and feed elements are described. Deficiencies in the sum feed are discussed, and lack of atmospheric venting is posed as a potential problem area. The measured RF performance of the high gain antenna is examined and the high sidelobe levels measured are related to the physical characteristics of the antenna. An examination of the attributes of the feed which might be influenced by temperature extremes shows that the antenna should be insensitive to temperature variations. Because the feed support bipod structure is considered a significant contributor to the high sidelobe levels measured in the azimuth plane, pod relocation, material changes, and shaping are suggested as improvements. Alternate feed designs are presented to further improve system performance. The widebeam horn and potential temperature effects due to the polarizer are discussed as well as in the effects of linear polarization on TDRS acquisition, and the effects of circular polarization on radar sidelobe avoidance. The radar detection probability is analyzed as a function of scan overlap and target range.

Iwasaki, R.; Dodds, J. G.; Broad, P.

1979-01-01

237

Evaluation of precipitation estimates over CONUS derived from satellite, radar, and rain gauge datasets (2002-2012)  

NASA Astrophysics Data System (ADS)

We use a suite of quantitative precipitation estimates (QPEs) derived from satellite, radar, and surface observations to derive precipitation characteristics over CONUS for the period 2002-2012. This comparison effort includes satellite multi-sensor datasets (bias-adjusted TMPA 3B42, near-real time 3B42RT), radar estimates (NCEP Stage IV), and rain gauge observations. Remotely sensed precipitation datasets are compared with surface observations from the Global Historical Climatology Network (GHCN-Daily) and from the PRISM (Parameter-elevation Regressions on Independent Slopes Model). The comparisons are performed at the annual, seasonal, and daily scales over the River Forecast Centers (RFCs) for CONUS. Annual average rain rates present a satisfying agreement with GHCN-D for all products over CONUS (± 6%). However, differences at the RFC are more important in particular for near-real time 3B42RT precipitation estimates (-33 to +49%). At annual and seasonal scales, the bias-adjusted 3B42 presented important improvement when compared to its near real time counterpart 3B42RT. However, large biases remained for 3B42 over the Western US for higher average accumulation (≥ 5 mm day-1) with respect to GHCN-D surface observations. At the daily scale, 3B42RT performed poorly in capturing extreme daily precipitation (> 4 in day-1) over the Northwest. Furthermore, the conditional analysis and the contingency analysis conducted illustrated the challenge of retrieving extreme precipitation from remote sensing estimates.

Prat, O. P.; Nelson, B. R.

2014-10-01

238

Evaluation on the environmental radioactivity in Shanghai city during the normal operational condition of Qinshan nuclear power station.  

PubMed

The objective of this work was to evaluate the impact of environmental radioactivity in Shanghai from the operation of Qinshan Nuclear Power Station (QNPS). The levels of terrestrial gamma radiation and radioactivities in the drinking water, main food and soils in the Jinshan area where is only 38 km far away from the QNPS were continuously measured in the past 19 y. Both the levels of terrestrial gamma radiation and the radioactivities in the samples were on the normal background levels. No significant changes were found before and after the running of QNPS. The annual public exposure to the terrestrial gamma radiation was estimated to be ?0.1 mSv, and the annual exposure from intakes of (90)Sr and (137)Cs in food was ?0.5 ?Sv. In the past 19 y, no significant impact on the environmental radioactivity in Shanghai was observed due to the operation of QNPS. PMID:23427205

Lu, Heqing; Wang, Qiang

2013-08-01

239

Test and evaluation of the heat recovery incinerator system at Naval Station, Mayport, Florida. Final report, June 1980-April 1981  

SciTech Connect

This report describes test and evaluation of the two-ton/hr heat recovery incinerator (HRI) facility located at Mayport Naval Station, FL, carried out during November and December 1980. The tests included: (1) Solid Waste: characterization, heating value, and ultimate analysis, (2) Ash: moisture, combustibles, and heating values of both bottom and cyclone ashes; Extraction Procedure toxicity tests on leachates from both bottom and cyclone ashes; trace metals in cyclone particulates, (3) Stack Emissions: particulates (quantity and size distribution), chlorides, oxygen, carbon dioxide, carbon monoxide, and trace elements, and (4) Heat and Mass Balance: all measurements required to carry out complete heat and mass balance calculations over the test period. The overall thermal efficiency of the HRI facility while operating at approximately 1.0 ton/hr was found to be 49% when the primary Btu equivalent of the electrical energy consumed during the test program was included.

Not Available

1981-05-01

240

Real-Time Risk and Fault Management in the Mission Evaluation Room for the International Space Station  

SciTech Connect

Effective anomaly resolution in the Mission Evaluation Room (MER) of the International Space Station (ISS) requires consideration of risk in the process of identifying faults and developing corrective actions. Risk models such as fault trees from the ISS Probabilistic Risk Assessment (PRA) can be used to support anomaly resolution, but the functionality required goes significantly beyond what the PRA could provide. Methods and tools are needed that can systematically guide the identification of root causes for on-orbit anomalies, and to develop effective corrective actions that address the event and its consequences without undue risk to the crew or the mission. In addition, an overall information management framework is needed so that risk can be systematically incorporated in the process, and effectively communicated across all the disciplines and levels of management within the space station program. The commercial nuclear power industry developed such a decision making framework, known as the critical safety function approach, to guide emergency response following the accident at Three Mile Island in 1979. This report identifies new methods, tools, and decision processes that can be used to enhance anomaly resolution in the ISS Mission Evaluation Room. Current anomaly resolution processes were reviewed to identify requirements for effective real-time risk and fault management. Experience gained in other domains, especially the commercial nuclear power industry, was reviewed to identify applicable methods and tools. Recommendations were developed for next-generation tools to support MER anomaly resolution, and a plan for implementing the recommendations was formulated. The foundation of the proposed tool set will be a ''Mission Success Framework'' designed to integrate and guide the anomaly resolution process, and to facilitate consistent communication across disciplines while focusing on the overriding importance of mission success.

Nelson, W.R.; Novack, S.D.

2003-05-30

241

Real-Time Risk and Fault Management in the Mission Evaluation Room of the International Space Station  

SciTech Connect

Effective anomaly resolution in the Mission Evaluation Room (MER) of the International Space Station (ISS) requires consideration of risk in the process of identifying faults and developing corrective actions. Risk models such as fault trees from the ISS Probablistic Risk Assessment (PRA) can be used to support anomaly resolution, but the functionality required goes significantly beyond what the PRA could provide. Methods and tools are needed that can systematically guide the identification of root causes for on-orbit anomalies, and to develop effective corrective actions that address the event and its consequences without undue risk to the crew or the mission. In addition, an overall information management framework is needed so that risk can be systematically incorporated in the process, and effectively communicated across all the disciplines and levels of management within the space station program. The commercial nuclear power industry developed such a decision making framework, known as the critical safety function approach, to guide emergency response following the accident at Three Mile Island in 1979. This report identifies new methods, tools, and decision processes that can be used to enhance anomaly resolution in the ISS Mission Evaluation Room. Current anomaly resolution processes were reviewed to identify requirements for effective real-time risk and fault management. Experience gained in other domains, especially the commercial nuclear power industry, was reviewed to identify applicable methods and tools. Recommendations were developed for next-generation tools to support MER anomaly resolution, and a plan for implementing the recommendations was formulated. The foundation of the proposed toolset will be a "Mission Success Framework" designed to integrate and guide the anomaly resolution process, and to facilitate consistent communication across disciplines while focusing on the overriding importance of mission success.

William R. Nelson; Steven D. Novack

2003-05-01

242

Modeling and dosimetric performance evaluation of the RayStation treatment planning system.  

PubMed

The physics modeling, dose calculation accuracy and plan quality assessment of the RayStation (v3.5) treatment planning system (TPS) is presented in this study, with appropriate comparisons to the more established Pinnacle (v9.2) TPS. Modeling and validation for the Elekta MLCi and Agility beam models resulted in a good match to treatment machine-measured data based on tolerances of 3% for in-field and out-of-field regions, 10% for buildup and penumbral regions, and a gamma 2%/2mm dose/distance acceptance criteria. TPS commissioning using a wide range of appropriately selected dosimetry equipment, and following published guidelines, established the MLC modeling and dose calculation accuracy to be within standard tolerances for all tests performed. In both homogeneous and heterogeneous mediums, central axis calculations agreed with measurements within 2% for open fields and 3% for wedged fields, and within 4% off-axis. Treatment plan comparisons for identical clinical goals were made to Pinnacle for the following complex clinical cases: hypofractionated non-small cell lung carcinoma, head and neck, stereotactic spine, as well as for several standard clinical cases comprising of prostate, brain, and breast plans. DVHs, target, and critical organ doses, as well as measured point doses and gamma indices, applying both local and global (Van Dyk) normalization at 2%/2 mm and 3%/3 mm (10% lower threshold) acceptance criteria for these composite plans were assessed. In addition 3DVH was used to compare the perturbed dose distributions to the TPS 3D dose distributions. For all 32 cases, the patients QA checks showed > 95% of pixels passing 3% global/3mm gamma. PMID:25207563

Mzenda, Bongile; Mugabe, Koki V; Sims, Rick; Godwin, Guy; Loria, Dayan

2014-01-01

243

Evaluating the Medical Kit System for the International Space Station(ISS) - A Paradigm Revisited  

NASA Technical Reports Server (NTRS)

Medical capabilities aboard the International Space Station (ISS) have been packaged to help astronaut crew medical officers (CMO) mitigate both urgent and non-urgent medical issues during their 6-month expeditions. Two ISS crewmembers are designated as CMOs for each 3-crewmember mission and are typically not physicians. In addition, the ISS may have communication gaps of up to 45 minutes during each orbit, necessitating medical equipment that can be reliably operated autonomously during flight. The retirement of the space shuttle combined with ten years of manned ISS expeditions led the Space Medicine Division at the NASA Johnson Space Center to reassess the current ISS Medical Kit System. This reassessment led to the system being streamlined to meet future logistical considerations with current Russian space vehicles and future NASA/commercial space vehicle systems. Methods The JSC Space Medicine Division coordinated the development of requirements, fabrication of prototypes, and conducted usability testing for the new ISS Medical Kit System in concert with implementing updated versions of the ISS Medical Check List and associated in-flight software applications. The teams constructed a medical kit system with the flexibility for use on the ISS, and resupply on the Russian Progress space vehicle and future NASA/commercial space vehicles. Results Prototype systems were developed, reviewed, and tested for implementation. Completion of Preliminary and Critical Design Reviews resulted in a streamlined ISS Medical Kit System that is being used for training by ISS crews starting with Expedition 27 (June 2011). Conclusions The team will present the process for designing, developing, , implementing, and training with this new ISS Medical Kit System.

Hailey, Melinda J.; Urbina, Michelle C.; Hughlett, Jessica L.; Gilmore, Stevan; Locke, James; Reyna, Baraquiel; Smith, Gwyn E.

2010-01-01

244

An Evaluation of a Welding Fumes Exhaust System. Agricultural Experiment Station Research Report 284.  

ERIC Educational Resources Information Center

A study evaluated the feasibility of introducing unheated outside air into the airstream of a cross-flow welding exhaust system to reduce heating energy costs of a school welding laboratory. The physical facility used was the agricultural mechanics laboratory at the University of Arizona, which is similar to facilities in which instruction in…

Jacobs, C. O.

245

Using Radar Interferometry (DinSAR) to Evaluate Land Subsidence Caused by Excessive Groundwater Withdrawal in Morocco  

NASA Astrophysics Data System (ADS)

The combination of natural, anthropogenic, and climate change impacts on the water resources of the Middle East and North Africa (MENA) region has devastated its water resources well beyond its current and projected populations. The increased exploitation of groundwater resources in the past half-century coupled with successive droughts has resulted in the acceleration of subsidence rates in the Souss and Massa basins in Morocco. We have completed a preliminary investigation of these impacts on the Souss and Massa basins (~27,000 km2) in the southwestern part of Morocco. This area is characterized by a semi-arid climate (annual precipitation 70-250 mm/year) with agriculture, tourism, and commercial fishing as the primary economic activities, all of which require availability of adequate freshwater resources. Additionally the primary groundwater aquifer (Plio-Quaternary Plain Aquifer), an unconfined aquifer formed mostly of sand and gravel, is being harvested by >20,000 wells at a rate of 650 MCM/yr., exceeding the rate of recharge by 260 MCM/year. Intense development over the past 50 years has exposed the aquifer to a serious risk of groundwater table drawdown (0.5m-2.5m/yr.), land subsidence, loss of artesian pressure, salinization, salt water intrusions along the coast, and deterioration of water quality across the watershed. Differential Interferometry Synthetique Aperture Radar (DInSAR) was utilized to measure ground subsidence induced by groundwater withdrawal. Land subsidence caused by excessive groundwater extraction was determined using a threefold methodology: (1) extraction of subsidence and land deformation patterns using radar interferometry, (2) correlation of the high subsidence areas within the basins to possible natural and anthropogenic factors (e.g. sea level rise, unconsolidated lithological formations distribution, urbanization, excessive groundwater extraction), and (3) forecasting the future of the Souss and Massa basins over the next century if both subsidence and groundwater extraction continue at present rates. Interferometric processing (persistent scatter and small baseline subset) was conducted using ENVI's SARscape program with 168 archived ENVISAT SLC images and 350 ERS1/2 SLC images acquired through the European Space Agency. Radar interferometry results are spatially and temporally consistent with groundwater extraction rates. This analysis has provided insight into the impacts that land subsidence will have on the infrastructure, the population, and the economy of the Souss and Massa basins. Our results could be used to develop management plans for modulating these adverse effects and could be vital to the Moroccan economy and the livelihood of the citizens that inhabit the basins. More broadly, this approach could be applied to other areas within the MENA region facing similar impacts.

Durham, M. C.; Milewski, A.; El Kadiri, R.

2013-12-01

246

Aging of nuclear station diesel generators: Evaluation of operating and expert experience: Phase 1, Study  

SciTech Connect

Pacific Northwest Laboratory evaluated operational and expert experience pertaining to the aging degradation of diesel generators in nuclear service. The research, sponsored by the US Nuclear Regulatory Commission (NRC), identified and characterized the contribution of aging to emergency diesel generator failures. This report, Volume I, reviews diesel-generator experience to identify the systems and components most subject to aging degradation and isolates the major causes of failure that may affect future operational readiness. Evaluations show that as plants age, the percent of aging-related failures increases and failure modes change. A compilation is presented of recommended corrective actions for the failures identified. This study also includes a review of current, relevant industry programs, research, and standards. Volume II reports the results of an industry-wide workshop held on May 28 and 29, 1986 to discuss the technical issues associated with aging of nuclear service emergency diesel generators.

Hoopingarner, K.R.; Vause, J.W.; Dingee, D.A.; Nesbitt, J.F.

1987-08-01

247

Review of reactor pressure vessel evaluation report for Yankee Rowe Nuclear Power Station (YAEC No. 1735)  

Microsoft Academic Search

The Yankee Atomic Electric Company has performed an Integrated Pressurized Thermal Shock (IPTS)-type evaluation of the Yankee Rowe reactor pressure vessel in accordance with the PTS Rule (10 CFR 50. 61) and a US Regulatory Guide 1.154. The Oak Ridge National Laboratory (ORNL) reviewed the YAEC document and performed an independent probabilistic fracture-mechnics analysis. The review included a comparison of

R. D. Cheverton; T. L. Dickson; J. G. Merkle; R. K. Nanstad

1992-01-01

248

Evaluation of 3% hydrogen peroxide for use as an environmental disenfectant aboard the Space Station Freedom  

NASA Technical Reports Server (NTRS)

We evaluate the ability of a 3% (8800 micromolar) solution of hydogen peroxide to kill 12 strains of bacteria and 12 strains of fungi. A 1:4 dilution of 3% H2O2 equivalent to 1100 micromolar, was lethal to all the tested strains. If the situation calls for a nonagressive disinfectant without residue or toxic aftereffects, 3% H2O2 seems an ideal choice.

Lucia, Helen L.; Mishra, S. K.; Gunter, Emelie G.; Pierson, Duane L.

1993-01-01

249

Performance evaluation of lunar penetrating radar onboard the rover of CE-3 probe based on results from ground experiments  

NASA Astrophysics Data System (ADS)

Lunar Penetrating Radar (LPR) onboard the rover that is part of the Chang'e-3 (CE-3) mission was firstly utilized to obtain in situ measurements about geological structure on the lunar surface and the thickness of the lunar regolith, which are key elements for studying the evolutional history of lunar crust. Because penetration depth and resolution of LPR are related to the scientific objectives of this mission, a series of ground-based experiments using LPR was carried out, and results of the experimental data were obtained in a glacial area located in the northwest region of China. The results show that the penetration depth of the first channel antenna used for LPR is over 79 m with a resolution of 2.8 m, and that for the second channel antenna is over 50.8 m with a resolution of 17.1 cm.

Zhang, Hong-Bo; Zheng, Lei; Su, Yan; Fang, Guang-You; Zhou, Bin; Feng, Jian-Qing; Xing, Shu-Guo; Dai, Shun; Li, Jun-Duo; Ji, Yi-Cai; Gao, Yun-Ze; Xiao, Yuan; Li, Chun-Lai

2014-12-01

250

The significance of spatial rainfall representation for flood runoff estimation: a numerical evaluation based on the Lee catchment, UK  

Microsoft Academic Search

The relationship between spatial rainfall and flood runoff production is investigated, based on 15 years of radar data, 16 raingauges and 12 flow stations from the 1400 km2 Lee catchment, UK. Using event-based, semi- distributed rainfall-runoff modelling, alternative rainfall estimators (radar data and raingauge networks of various density) are considered and their effects on simulated runoff evaluated as a function

H. S. Wheater; M. Segond; C. Onof

2006-01-01

251

Evaluation of a Gas Chromatograph-Differential Mobility Spectrometer for Potential Water Monitoring on the International Space Station  

NASA Technical Reports Server (NTRS)

Environmental monitoring for manned spaceflight has long depended on archival sampling, which was sufficient for short missions. However, the longer mission durations aboard the International Space Station (ISS) have shown that enhanced, real-time monitoring capabilities are necessary in order to protect both the crewmembers and the spacecraft systems. Over the past several years, a number of real-time environmental monitors have been deployed on the ISS. Currently, volatile organic compounds (VOCs) in the station air are monitored by the Air Quality Monitor (AQM), a small, lightweight gas chromatograph-differential mobility spectrometer. For water monitoring, real-time monitors are used for total organic carbon (TOC) and biocide analysis. No information on the actual makeup of the TOC is provided presently, however. An improvement to the current state of environmental monitoring could be realized by modifying a single instrument to analyze both air and water. As the AQM currently provides quantitative, compound-specific information for VOCs in air samples, this instrument provides a logical starting point to evaluate the feasibility of this approach. The major hurdle for this effort lies in the liberation of the target analytes from the water matrix. In this presentation, we will discuss our recent studies, in which an electro-thermal vaporization unit has been interfaced with the AQM to analyze target VOCs at the concentrations at which they are routinely detected in archival water samples from the ISS. We will compare the results of these studies with those obtained from the instrumentation routinely used to analyze archival water samples.

Wallace, William T.; Limero, Thomas F.; Gazda, Daniel B.; Macatangay, Ariel V.; Dwivedi, Prabha; Fernandez, Facundo M.

2015-01-01

252

A formative evaluation of the College Station Independent School District's guidance and counseling program  

E-print Network

. Conclusions. 2 21 25 35 42 42 45 47 53 c3 54 63 77 77 88 92 REFERENCES. APPENDIX A: APPENDIX 8: The Guidance and Counseling Activities Instru- ment . The CSISD's Guidance and Counseling Program Guide. 97 105 APPENDIX C: The Outcome... implemented (2) to the proper target population (Christensen, 19BO). This role of evaluation research has also been referred to as monitoring a program (Rossi, Freeman, 5 Wright 1979). Another reason why a program may be ineffective is that the theory...

Conner, Paul William

1981-01-01

253

Study to investigate and evaluate means of optimizing the Ku-band combined radar/communication functions for the space shuttle  

NASA Technical Reports Server (NTRS)

The performance of the space shuttle orbiter's Ku-Band integrated radar and communications equipment is analyzed for the radar mode of operation. The block diagram of the rendezvous radar subsystem is described. Power budgets for passive target detection are calculated, based on the estimated values of system losses. Requirements for processing of radar signals in the search and track modes are examined. Time multiplexed, single-channel, angle tracking of passive scintillating targets is analyzed. Radar performance in the presence of main lobe ground clutter is considered and candidate techniques for clutter suppression are discussed. Principal system parameter drivers are examined for the case of stationkeeping at ranges comparable to target dimension. Candidate ranging waveforms for short range operation are analyzed and compared. The logarithmic error discriminant utilized for range, range rate and angle tracking is formulated and applied to the quantitative analysis of radar subsystem tracking loops.

Weber, C. L.; Udalov, S.; Alem, W.

1977-01-01

254

Health hazard evaluation report HETA 82-093-1453, Southwest Power Station City Utilities, Springfield, Missouri  

SciTech Connect

In response to a request from the Safety Department of City Utilities to evaluate employee exposures to coal and other dusts and fumes at the Southwest Power Facility (SIC-4911), Springfield, Missouri a visit was made to the site. All personal coal dust, fly ash, crystalline silica (14808607), nitrogen-dioxide (10102440), nitric-oxide (10102439), and sulfuric-acid (7664939) samples were below the lowest current criterion level. Four of eight personal sulfur-dioxide (7446095) samples exceeded the NIOSH recommended criterion of 1.3mg/cu m. Medical evaluation resulted in the identification of three workers with chronic bronchitis each of whom smoked cigarettes, eight workers with pulmonary function test abnormalities indicating obstructive airways disease, and two workers with features of restrictive lung disease. One chest X-ray was consistent with pneumoconiosis. The authors conclude that a health hazard existed for employees exposed to sulfur-dioxide and noise. A potential hazard also existed for employee exposure to heat stress in certain locations in the facility. The authors recommend improvements in the respiratory protection program, use of personal protective equipment, and initiation of an employee training program and environmental monitoring by management.

Zey, J.N.; Aw, T.C.

1984-04-01

255

Modified silicon base station chips as biomedical sensors  

Microsoft Academic Search

Subcircuits designed for DCS1800\\/PCS1900 base stations have been reconfigured into single-chip Doppler radar transceivers. Three of these radar chips have been fully integrated in 0.25 ?m silicon CMOS and BiCMOS, and they have been used to remotely monitor heart and respiration activity. These radar chips have detected heartbeat and respiration rate 50 cm from the subject, which may be useful

A. D. Droitcour; O. Boric-Lubecke; V. Lubecke; Jenshan Lin; G. T. A. Kovacsi

2003-01-01

256

Space Station Freedom coupling tasks: An evaluation of their telerobotic and EVA compatibility  

NASA Technical Reports Server (NTRS)

Of the couplings included in this study, several design components were found to be of interest. With respect to the operation of the couplings, the various concepts resulted in differing reactions from the four subjects who participated in this study. The purpose of this study was not to conceive the final coupling design. Rather, it was intended as a step along an interactive process. The newly modified coupling will be included in a series of further controlled, as well as subjective, evaluations. This part of the ongoing work in the Remote Operator Interaction Laboratory (ROIL) designed to enhance the overall interface by improving design at both the teleoperator and telerobot ends of the system.

Sampaio, Carlos E.; Bierschwale, John M.; Fleming, Terence F.; Stuart, Mark A.

1993-01-01

257

Performance evaluation of a pilot-scale permeable reactive barrier at former Naval Air Station Moffett Field, Mountain View, California: Volume 1. Final report, April 1996November 1998  

Microsoft Academic Search

A pilot scale permeable reactive barrier (PRB) or treatment wall demonstration project was initiated by the US Navy EFA West at the former Naval Air Station Moffett Field site in Mountain View, California about 3 years ago. Performance evaluations and cost-benefit analyses were performed by the US Naval Facilities Engineering Service Center (NFESC) and were sponsored by the Department of

C. Reeter; A. Gavaskar; B. Sass; N. Gupta; J. Hicks

1998-01-01

258

Preliminary Results of the Third Test Series of Nonmetal Material Flammability Evaluation In SKOROST Apparatus on the Space Station Mir  

NASA Technical Reports Server (NTRS)

The work has been done according to the US/Russian Joint Project "Experimental Evaluation of the Material Flammability in Microgravity" a continued combustion study in the SKOROST test apparatus on the OS Mir. The objective of the project was to evaluate the flammability and flame-spread rate for the selected polymer materials in low velocity flow in microgravity. Lately, the issue of nonmetal material combustion in microgravity has become of great importance, based on the necessity to develop the fire safety system for the new International Space Station (ISS). Lack of buoyant flow in microgravity reduces oxygen transfer into the combustion zone, which leads to flame extinction when the flow velocity is less than the limiting flow velocity V(sub lim) for the material. The ISS FGB fire-safety system was developed based on this phenomenon. The existence of minimum flow velocity V(sub lim) to sustain fire for the selected materials was determined both theoretically and experimentally. In the latter, it is shown that, even for thermally thin nonmetal materials with a very low oxygen index C(sub lim) of 12.5% (paper sheets with the thickness of 0.1 mm), a limiting flow velocity V(sub lim) exists at oxygen concentration Co(sub OX) = 17-21%, and is about 1.0 - 0.1 cm/sec. This might be explained by the relative increase in thermal losses due to radiation from the surface and from the gaseous phase. In the second series of experiments in Skorost apparatus on Orbital Station Mir the existence of the limiting flow velocity V(sub lim) for combustion was confirmed for PMMA and glass-epoxy composite strip samples 2 mm thick at oxygen concentration C(sub OX) = 21.5%. It was concluded that V(sub lim) depends on C(sub OX) for the PMMA sample with a low oxygen index of 15.5%, the limiting flow velocity V(sub lim) was less than 0.5 cm/sec, and for the glass-epoxy composite sample with a high oxygen index of 19%, the limiting flow velocity V(sub lim) was higher than 15 cm/sec. As of now only those materials that maintain their integrity during combustion were investigated. The materials that disintegrate when burning present more danger for fire safety because the flame can spread farther with the parts of the structure, ejected melt drops, et cetera. Materials such as polyethylene are of great interest since they form a lengthy melt zone during the combustion in normal gravity. This melt zone generates drops of liquids that promote faster flame spread compared to usual combustion. The preliminary results of polyethylene insulation flammability evaluation in microgravity are shown in the NASA Wire Insulation Flammability (WIF) experiment during Space Shuttle flight STS-50. A lot of interesting data was collected during the WIF test program. However, one of the most important results was that, in microgravity, the extinction of the polyethylene occurred almost immediately when the flow of relatively low oxygen concentration (C(sub OX)=21%) was stopped. The purpose of the work reported here is to expand the existing data base on material flammability in microgravity and to conduct the third series of the space experiment using Skorost apparatus on Orbiatl Station Mir with melting polymers, which might increase the probability of fire and its propagation in ventilated microgravity environment of orbiting spacecraft.

Ivanov, A. V.; Alymov, V. F.; Smirnov, A. B.; Shalayev, S. P.; Ye.Belov, D.; Balashov, Ye.V.; Andreeva, T. V.; Semenov, A. V.; Melikhov, A. S.; Bolodyan, I. A.; Potyakin, V. I.

1999-01-01

259

Report on the Radar/PIREP Cloud Top Discrepancy Study  

NASA Technical Reports Server (NTRS)

This report documents the results of the Applied Meteorology Unit's (AMU) investigation of inconsistencies between pilot reported cloud top heights and weather radar indicated echo top heights (assumed to be cloud tops) as identified by the 45 Weather Squadron (45WS). The objective for this study is to document and understand the differences in echo top characteristics as displayed on both the WSR-88D and WSR-74C radars and cloud top heights reported by the contract weather aircraft in support of space launch operations at Cape Canaveral Air Station (CCAS), Florida. These inconsistencies are of operational concern since various Launch Commit Criteria (LCC) and Flight Rules (FR) in part describe safe and unsafe conditions as a function of cloud thickness. Some background radar information was presented. Scan strategies for the WSR-74C and WSR-88D were reviewed along with a description of normal radar beam propagation influenced by the Effective Earth Radius Model. Atmospheric conditions prior to and leading up to both launch operations were detailed. Through the analysis of rawinsonde and radar data, atmospheric refraction or bending of the radar beam was identified as the cause of the discrepancies between reported cloud top heights by the contract weather aircraft and those as identified by both radars. The atmospheric refraction caused the radar beam to be further bent toward the Earth than normal. This radar beam bending causes the radar target to be displayed erroneously, with higher cloud top heights and a very blocky or skewed appearance.

Wheeler, Mark M.

1997-01-01

260

Global radar units on Venus derived from statistical analysis of Pioneer Venus Orbiter radar data  

NASA Technical Reports Server (NTRS)

The classification of surface radar units on Venus using an unsupervised cluster analysis of Pioneer Venus radar reflectivity and root-mean-square (rms)-slope data is described. The advantages of the unsupervised analysis are discussed. F tests are utilized to evaluate the numerical significance of the clusters. The derived rms-slope data and reflectivity for 15 radar units are presented. The relations between radar data bases and elevation are studied. The lowlands, rolling plains, highlands, and mountainous surface of Venus are examined. The geology of Venus landing sites and radar properties, and the surface radar reflectivity images and earth-based images are compared. The spatial relations between classification units are calculated. It is concluded that the unsupervised analysis data correlate well with Head et al. (1985b) data and produce more detailed classification images.

Davis, P. A.; Kozak, R. C.; Schaber, G. G.

1986-01-01

261

Radar electronic warfare  

NASA Astrophysics Data System (ADS)

An overview of radar and electronic warfare is given. Definitions, common terms, and principles of radar and electronic warfare, and simple analyses of interactions between radar systems and electronic countermeasures (ECM) are presented. Electronic counter-countermeasure and electronic support measures are discussed. Background material in mathematics, electromagnetics, and probability necessary for an understanding of radar and electronic warfare is given and radar tracking models are examined. The effects of various ECM emissions on radar systems are analyzed, including discussion of active ECM and angle scanning systems, angle measurement in monopulse, and automatic gain control.

Golden, August, Jr.

262

Airborne derivation of microburst alerts from ground-based Terminal Doppler Weather Radar information: A flight evaluation  

NASA Technical Reports Server (NTRS)

An element of the NASA/FAA windshear program is the integration of ground-based microburst information on the flight deck, to support airborne windshear alerting and microburst avoidance. NASA conducted a windshear flight test program in the summer of 1991 during which airborne processing of Terminal Doppler Weather Radar (TDWR) data was used to derive microburst alerts. Microburst information was extracted from TDWR, transmitted to a NASA Boeing 737 in flight via data link, and processed to estimate the windshear hazard level (F-factor) that would be experienced by the aircraft in each microburst. The microburst location and F-factor were used to derive a situation display and alerts. The situation display was successfully used to maneuver the aircraft for microburst penetrations, during which atmospheric 'truth' measurements were made. A total of 19 penetrations were made of TDWR-reported microburst locations, resulting in 18 airborne microburst alerts from the TDWR data and two microburst alerts from the airborne reactive windshear detection system. The primary factors affecting alerting performance were spatial offset of the flight path from the region of strongest shear, differences in TDWR measurement altitude and airplane penetration altitude, and variations in microburst outflow profiles. Predicted and measured F-factors agreed well in penetrations near microburst cores. Although improvements in airborne and ground processing of the TDWR measurements would be required to support an airborne executive-level alerting protocol, the practicality of airborne utilization of TDWR data link data has been demonstrated.

Hinton, David A.

1993-01-01

263

The Accuracy of Radar Estimates of Ice Terminal Fall Speed from Vertically Pointing Doppler Radar Measurements  

E-print Network

The Accuracy of Radar Estimates of Ice Terminal Fall Speed from Vertically Pointing Doppler Radar and 2835 MHz) are used to characterize the terminal fall speed of hydrometeors and the vertical air motion in tropical ice clouds and to evaluate statistical methods for retrieving these two parameters using a single

Protat, Alain

264

Microwave emissions from police radar.  

PubMed

This study evaluated police officers' exposures to microwaves emitted by traffic radar units. Exposure measurements were taken at approximated ocular and testicular levels of officers seated in patrol vehicles. Comparisons were made of the radar manufacturers' published maximum power density specifications and actual measured power densities taken at the antenna faces of those units. Four speed-enforcement agencies and one transportation research institute provided 54 radar units for evaluation; 17 different models, encompassing 4 frequency bands and 3 antenna configurations, were included. Four of the 986 measurements taken exceeded the 5 mW/cm2 limit accepted by the International Radiation Protection Association and the National Council on Radiation Protection and Measurement, though none exceeded the American Conference of Governmental Industrial Hygienists, American National Standards Institute, Institute of Electrical and Electronic Engineers, or Occupational Safety and Health Administration standard of 10 mW/cm2. The four high measurements were maximum power density readings taken directly in front of the radar. Of the 812 measurements taken at the officers' seated ocular and testicular positions, none exceeded 0.04 mW/cm2; the highest of these (0.034 mW/cm2) was less than 1% of the most conservative current safety standards. High exposures in the limited region directly in front of the radar aperture are easily avoided with proper training. Results of this study indicate that police officer exposure to microwave radiation is apparently minimal. However, because of uncertainty in the medical and scientific communities concerning nonionizing radiation, it is recommended that law enforcement agencies implement a policy of prudent avoidance, including purchasing units with the lowest published maximum power densities, purchasing dash/rear deck-mounted units with antennae mounted outside the patrol vehicle, and training police officers to use the "stand-by" mode when not actually using radar. PMID:10671181

Fink, J M; Wagner, J P; Congleton, J J; Rock, J C

1999-01-01

265

Total SO2 Emissions from Power Stations and Evaluation of their Impact in Kuwait Using a Gaussian Plume Dispersion Model  

Microsoft Academic Search

In Kuwait, most of the power stations use fuel oil as the prime source of energy. The sulphur content (S%) of the fuel used as well as other factors have a direct impact on the ground level concentration of sulphur dioxide (SO2) released by power stations into the atmosphere. The SO2 ground level concentration has to meet the environmental standards

A. A. Ramadan; M. Al-Sudairawi; S. Alhajraf; A. R. Khan

2008-01-01

266

Evaluation of the Moderate Resolution Imaging Spectroradiometer aerosol products at two Aerosol Robotic Network stations in China  

E-print Network

Robotic Network stations in China Wen Mi,1 Zhanqing Li,1,2,3 Xiangao Xia,3 Brent Holben,4 Robert Levy,1 of the Moderate Resolution Imaging Spectroradiometer aerosol products at two Aerosol Robotic Network stations measurements, especially those from the inter- national Aerosol Robotic Network (AERONET) [Holben et al., 1998

Li, Zhanqing

267

Performance and evaluation of gas engine driven rooftop air conditioning equipment at the Willow Grove (PA) Naval Air Station  

SciTech Connect

In a field evaluation conducted for the US Department of Energy (DOE) Office of Federal Energy Management Program (FEMP), the Pacific Northwest Laboratory (PNL) examined the performance of a new US energy-related technology under the FEMP Test Bed Demonstration Program. The technology was a 15-ton natural gas engine driven roof top air conditioning unit. Two such units were installed on a naval retail building to provide space conditioning to the building. Under the Test Bed Demonstration Program, private and public sector interests are focused to support the installation and evaluation of new US technologies in the federal sector. Participating in this effort under a Cooperative Research and Development Agreement (CRADA) with DOE were the American Gas Cooling Center, Philadelphia Electric Company, Thermo King Corporation, and the US Naval Air Station at Willow Grove, Pennsylvania. Equipment operating and service data as well as building interior and exterior conditions were secured for the 1992 cooling season. Based on a computer assessment of the building using standard weather data, a comparison was made with the energy and operating costs associated with the previous space conditioning system. Based on performance during the 1992 cooling season and adjusted to a normal weather year, the technology will save the site $6,000/yr in purchased energy costs. An additional $9,000 in savings due to electricity demand ratchet charge reductions will also be realized. Detailed information on the technology, the installation, and the results of the technology test are provided to illustrate the advantages to the federal sector of using this technology. A history of the CRADA development process is also reported.

Armstrong, P.R.; Conover, D.R.

1993-05-01

268

A Critical Evaluation of Ground-Penetrating Radar Methodology on the Kalavasos and Maroni Built Environments (KAMBE) Project, Cyprus (Invited)  

NASA Astrophysics Data System (ADS)

The Kalavasos and Maroni Built Environments (KAMBE) Project is a multi-year investigation of the urban fabric and architectural organization of two Late Bronze Age (c. 1650-1100 BCE) polities on Cyprus. The Late Bronze Age (known also as the Late Cypriot period on Cyprus) is characterized by the emergence of a number of large, urban settlements on the island. The amalgamation of large populations at centralized sites coincides with contemporary social, economic and political changes, including a growing disparity in funerary goods, an increased emphasis on metallurgy (specifically copper mining and smelting for the production of bronze), and the construction of monumental buildings. The initial phase of the project centered on geophysical survey at two archaeological sites in adjacent river valleys in south-central Cyprus: Kalavasos-Ayios Dhimitrios and the Maroni settlement cluster [1]. These sites are thought to be two of the earliest 'urban' settlements on the island and provide a unique opportunity to explore how urban space was instrumental in the development of social and political complexity during this transformative period. The formation of these Late Bronze Age urban landscapes is, we argue, not simply the result of this emerging social complexity, but is instead an key tool in the creation and maintenance of societal boundaries. Indeed, the process of 'place-making'--the dynamic creation of socially meaningful spaces, likely by elites--may well have been one of the most effective arenas that elites used to re-enforce the growing socio-political disparity. The KAMBE Project investigates the layout and organization of these new 'urban' spaces to better understand how built-space impacted social developments. Geophysical survey methods are ideal for large-scale data collection both to identify potential areas for targeted archaeological excavation, and to provide proxy data for architectural plans that allow us to comment on the nature of the urban fabric at these settlements. Having just completed this first phase of the project, we report on the results of large-scale geophysical survey, including the identification of at least two previously unknown building complexes (one at each site). Here we focus particularly on ground-penetrating radar (GPR) data and survey methodology, in an effort to critically examine the range of approaches applied throughout the project (e.g. various antennae frequencies, data-collection densities, soil moisture/seasonality of survey, and post-collection data processing [2]), and to identify the most effective parameters for archaeological geophysical survey in the region. This paper also advocates for the role of geophysical survey within a multi-component archaeological project, not simply as a prospection tool but as an archaeological data collection method in its own right. 1]Fisher, K. D., J. Leon, S. Manning, M. Rogers, and D. Sewell. In Press. 2011-2012. 'The Kalavasos and Maroni Built Environments Project: Introduction and preliminary report on the 2008 and 2010 seasons. Report of the Department of Antiquities, Cyprus. 2] e.g. Rogers, M., J. F. Leon, K. D. Fisher, S. W. Manning and D. Sewell. 2012. 'Comparing similar ground-penetrating radar surveys under different soil moisture conditions at Kalavasos-Ayios Dhimitrios, Cyprus.' Archaeological Prospection 19 (4): 297-305.

Leon, J.; Urban, T.; Gerard-Little, P.; Kearns, C.; Manning, S. W.; Fisher, K.; Rogers, M.

2013-12-01

269

Station Models  

NSDL National Science Digital Library

This project will allow users to become acquainted with station models that are found on weather maps. Students will study the various atmospheric variables that are depicted on a station model and then practice on an interactive station model program. Part 1 - Being able to read and interpret weather maps is a very important skill in meteorology. One of the most basic skills of predicting the weather is being able to interpret a station model of a given location. A station model is a bundle of information that ...

Mr. Ertl

2007-11-03

270

The Southern Argentine Agile Meteor Radar (SAAMER)  

NASA Astrophysics Data System (ADS)

The Southern Argentina Agile Meteor Radar (SAAMER) is a new generation system deployed in Rio Grande, Tierra del Fuego, Argentina (53 S) in May 2008. SAAMER transmits 10 times more power than regular meteor radars, and uses a newly developed transmitting array, which focuses power upward instead of the traditional single-antenna-all-sky configuration. The system is configured such that the transmitter array can also be utilized as a receiver. The new design greatly increases the sensitivity of the radar enabling the detection of large number of particles at low zenith angles. The more concentrated transmitted power enables additional meteor studies besides those typical of these systems based on the detection of specular reflections, such as routine detections of head echoes and non-specular trails, previously only possible with High Power and Large Aperture radars. In August 2010, SAAMER was upgraded to a system capable to determine meteoroid orbital parameters. This was achieved by adding two remote receiving stations approximately 10 km away from the main site in near perpendicular directions. The upgrade significantly expands the science that is achieved with this new radar enabling us to study the orbital properties of the interplanetary dust environment. Because of the unique geographical location, SAAMER allows for additional inter-hemispheric comparison with measurements from Canadian Meteor Orbit Radar, which is geographically conjugate. Initial surveys show, for example, that SAAMER observes a very strong contribution of the South Toroidal Sporadic meteor source, of which limited observational data is available. In addition, SAAMER offers similar unique capabilities for meteor showers and streams studies given the range of ecliptic latitudes that the system enables detailed study of showers at high southern latitudes (e.g July Phoenicids or Puppids complex). Finally, SAAMER is ideal for the deployment of complementary instrumentation in both, permanent and campaign, operational mode. Results from various radar meteor investigations as well as radar/optical observation campaign will be presented in this paper.

Janches, Diego

2014-11-01

271

Remorque RADAR Description technique  

E-print Network

ANNEXE: Remorque RADAR Description technique Le but de la remorque est de transporter un RADAR et pour héberger l'électronique radar et son opérateur. Caractéristiques générales de la remorque : · PTC'un côté, une baie de l'autre. Un hublot sur le toit et une baie donnant sur la partie RADAR. Un plafonnier

Heurteaux, Yanick

272

Lunar radar backscatter studies  

NASA Technical Reports Server (NTRS)

The lunar surface material in the Plato area is characterized using Earth based visual, infrared, and radar signatures. Radar scattering in the lunar regolith with an existing optical scattering computer program is modeled. Mapping with 1 to 2 km resolution of the Moon using a 70 cm Arecibo radar is presented.

Thompson, T. W.

1979-01-01

273

Synthetic aperture radar interferometry  

Microsoft Academic Search

Synthetic aperture radar interferometry is an imaging technique for measuring the topography of a surface, its changes over time, and other changes in the detailed characteristic of the surface. By exploiting the phase of the coherent radar signal, interferometry has transformed radar remote sensing from a largely interpretive science to a quantitative tool, with applications in cartography, geodesy, land cover

PAUL A. ROSEN; SCOTT HENSLEY; IAN R. JOUGHIN; FUK K. LI; SØREN N. MADSEN; ERNESTO RODRÍGUEZ; RICHARD M. GOLDSTEIN

2000-01-01

274

The evaluation of 3cm-wavelength radar for mapping surface deposits in the Bristol Lake/Granite Mountain area, Mojave Desert, California  

NASA Technical Reports Server (NTRS)

Surface deposits in the Bristol Lake/Granite Mountains area, Mojave Desert, California were mapped using high resolution 3 cm wavelength radar images. The surface deposits range from silt to boulders in size and were separated into six radar-rock units on the basis of radar return signatures (brightness and texture) and geomorphic expression. Field reconnaissance of the six units showed that the brightness of the radar signatures on the images correlates with the surface roughness of each unit. Two major radar signatures anomalies were noted during the study. A dark radar signature for the large sand ridges in the Kelso Dunes area and a distinct northwest trending contrast boundary between bright and dark radar signatures in the Bristol Dry Lake area. Field reconnaissance of the two areas indicated that near surface moisture may be the cause of dark signatures. Dune areas with little to no vegetation produce a dark signature, whereas areas with sparse to moderate vegetation produce an intermediate to dark signature.

Sugiura, R.; Sabins, F. F., Jr.

1980-01-01

275

Performance evaluation of UHF RFID technologies for real-time bus recognition in the Taipei Bus Station.  

PubMed

Transport stations such as airports, ports, and railways have adopted blocked-type pathway management to process and control travel systems in a one-directional manner. However, this excludes highway transportation where large buses have great variability and mobility; thus, an instant influx of numerous buses increases risks and complicates station management. Focusing on Taipei Bus Station, this study employed RFID technology to develop a system platform integrated with modern information technology that has numerous characteristics. This modern information technology comprised the following systems: ultra-high frequency (UHF) radio-frequency identification (RFID), ultrasound and license number identification, and backstage graphic controls. In conclusion, the system enabled management, bus companies, and passengers to experience the national bus station's new generation technology, which provides diverse information and synchronization functions. Furthermore, this technology reached a new milestone in the energy-saving and efficiency-increasing performance of Taiwan's buses. PMID:23778192

Own, Chung-Ming; Lee, Da-Sheng; Wang, Ti-Ho; Wang, De-Jun; Ting, Yu-Lun

2013-01-01

276

Performance Evaluation of UHF RFID Technologies for Real-Time Bus Recognition in the Taipei Bus Station  

PubMed Central

Transport stations such as airports, ports, and railways have adopted blocked-type pathway management to process and control travel systems in a one-directional manner. However, this excludes highway transportation where large buses have great variability and mobility; thus, an instant influx of numerous buses increases risks and complicates station management. Focusing on Taipei Bus Station, this study employed RFID technology to develop a system platform integrated with modern information technology that has numerous characteristics. This modern information technology comprised the following systems: ultra-high frequency (UHF) radio-frequency identification (RFID), ultrasound and license number identification, and backstage graphic controls. In conclusion, the system enabled management, bus companies, and passengers to experience the national bus station's new generation technology, which provides diverse information and synchronization functions. Furthermore, this technology reached a new milestone in the energy-saving and efficiency-increasing performance of Taiwan's buses. PMID:23778192

Own, Chung-Ming; Lee, Da-Sheng; Wang, Ti-Ho; Wang, De-Jun; Ting, Yu-Lun

2013-01-01

277

On the effects of atmospheric refraction on radar ground patterns  

E-print Network

ON THE EFFECTS OF ATMOSPHERIC REFRACTION ON RADAR GROUND PATTERNS A Thesis by L. GIEN COBB Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree... ABSTRACT Photographs of the PPI of the 3. 2-cm AN/CPS-9 radar located at College Station, Texas, are used to examine ground patterns. A normal pattern is determined and presented for comparison with non-normal patterns, which are divided into groups...

Cobb, Lalovee Glendale

1963-01-01

278

52. View from ground level showing lower radar scanner switch ...  

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

52. View from ground level showing lower radar scanner switch with open port door in radar scanner building 105 showing emanating waveguides from lower switch in vertical run; photograph also shows catwalk to upper scanner switch in upper left side of photograph and structural supports. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

279

High resolution images of Venus from ground-based radar  

NASA Technical Reports Server (NTRS)

The Goldstone Deep Space Station ground-based synthetic aperture radar system has been used to obtain radar images of Venus with resolutions of close to 1.3 km. Observations were made at 12.5 cm wavelength using circular polarization. From 12 days of observations during the 1986 inferior conjunction, three images have been selected for initial processing. The images show remarkable surface features including craters, ridges, and regions of high Fresnel reflectivity in the plains region.

Jurgens, R. F.; Slade, M. A.; Robinett, L.; Brokl, S.; Downs, G. S.

1988-01-01

280

Radar Meteorology Tutorial  

NSDL National Science Digital Library

Brian McNoldy at Multi-community Environmental Storm Observatory (MESO) educates the public about the use of radar in meteorology in this pdf document. After reading about the history of radar, visitors can find out how radar can detect storms by transmitting a high-power beam of radiation. Students can learn how scatter, absorption, frequencies, scan angles, and moments impact the radar display. With the help of many example images, the author also discusses how to interpret the images collected. At the end of the online document, visitors can learn about the characteristics and capabilities of NEXRAD WSR-88D, the radar used throughout the United States.

McNoldy, Brian

281

Using test station and on-farm data for the genetic evaluation of Pietrain boars used on Landrace sows for growth performance.  

PubMed

The aim of this study was to develop a new genetic evaluation model to estimate the genetic merit of boars for growth based on 1) performance of their crossbred progeny fattened in the test station and 2) their own performance or those of relatives from the on-farm testing system. The model was a bivariate random regression animal model with linear splines and was applied to Piétrain boars from the Walloon Region of Belgium mated with Landrace sows. Data contained 1) 12,610 BW records from the test station collected on 1,435 crossbred pigs from Piétrain boars and Landrace sows, and 2) 52,993 BW records from the on-farm testing system collected on 50,670 pigs with a breed composition of at least 40% Piétrain or Landrace. Since 2007, 56 Piétrain boars have been tested in the station. Data used to estimate variance components and breeding values were standardized for the age to take into account heterogeneity of variances and then pre-adjusted at 210 d of age to put all records on the same scale. Body weight records from the test station and from the on-farm testing system were considered as 2 different traits. The heterosis effect was modeled as fixed regression on the heterozygosity coefficient. As all test station animals were similarly crossbred, smaller variation in heterozygosity caused the sampling error of the regression estimate at 210 d to be larger in the test station than in on-farm data with estimates of 28.35 ± 14.55 kg and 9.02 ± 0.67 kg, respectively. Therefore, the most likely reason for the large differences in estimates was sampling. Heritability estimates ranged from 0.37 to 0.60 at 210 and 75 d, respectively, for test station BW and from 0.42 to 0.60 at 210 d and 175 d, respectively, for on-farm BW. Genetic correlation decreased when the age interval between records increased, and were greater between ages for test station than for on-farm data. Genetic correlations between test station and on-farm BW at the same age were high: 0.90 at 175 d and 0.85 at 210 d. For the 56 boars tested in the station, the average reliability of their EBV for ADG between 100 and 210 d was improved from 0.60 using only test station data to 0.69 using jointly test station and on-farm data. Based on these results, the new model developed was considered as a good method of detection of differences in growth potential of Piétrain boars based on test station and on-farm data. PMID:21803975

Dufrasne, M; Rustin, M; Jaspart, V; Wavreile, J; Gengler, N

2011-12-01

282

Radar observations of orbital debris at NASA Johnson Space Center  

NASA Technical Reports Server (NTRS)

This paper describes the original Debris Environment Characterization Radar concept and the design verification experiments developed and carried out with the purpose of establishing methods for assessing the hazards to the Space Station Freedom from radar measurements. Three design verification experiments, utilizing the Arecibo, the Goldstone, and the ALCOR radars were performed. Data obtained from RCS measurements of a representative sample of debris from ground-test hypervelocity impacts and from explosions of simulated satellites will be used to establish a relationship between the physical size of a randomly shaped debris object and its RCS.

Stansbery, E. G.; Stanley, J. F.

1990-01-01

283

The Goldstone solar system radar: A science instrument for planetary research  

NASA Technical Reports Server (NTRS)

The Goldstone Solar System Radar (GSSR) station at NASA's Deep Space Communications Complex in California's Mojave Desert is described. A short chronological account of the GSSR's technical development and scientific discoveries is given. This is followed by a basic discussion of how information is derived from the radar echo and how the raw information can be used to increase understanding of the solar system. A moderately detailed description of the radar system is given, and the engineering performance of the radar is discussed. The operating characteristics of the Arcibo Observatory in Puerto Rico are briefly described and compared with those of the GSSR. Planned and in-process improvements to the existing radar, as well as the performance of a hypothetical 128-m diameter antenna radar station, are described. A comprehensive bibliography of referred scientific and engineering articles presenting results that depended on data gathered by the instrument is provided.

Dvorsky, J. D.; Renzetti, N. A.; Fulton, D. E.

1992-01-01

284

Fuzzy Logic Tornado Detection Using High Resolution Weather Radar  

Microsoft Academic Search

In order to evaluate pulse compression for use in phased array weather radar systems, modifications to a weather radar simulator have been made, which incorporated phase- coding into its functionality. Data derived from Barker-coded pulses with matched and mismatched filters were evaluated against data obtained from uncoded pulses to determine the error performance. The output from the compressed data was

Timothy A. Alberts; Phillip B. Chilson; B. L. Cheong; R. D. Palmer

2007-01-01

285

Computer generation of correlated non-Gaussian radar clutter  

Microsoft Academic Search

We develop computer simulation procedures which enable us to generate any correlated non-Gaussian radar clutter that can be modeled as a spherically invariant random process (SIRP). In most cases, when the clutter is a correlated non-Gaussian random process, performance of the optimal radar signal processor cannot be evaluated analytically. Therefore, in order to evaluate such processors, there is a need

Muralidhar Rangaswamy; Donald Weiner; Aydin Ozturk

1995-01-01

286

17. CAPE COD AIR STATION PAVE PAWS FACILITY AERIAL VIEW ...  

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

17. CAPE COD AIR STATION PAVE PAWS FACILITY AERIAL VIEW WITH PROJECT NEARING COMPLETION. VIEW SHOWS "A" FACE (LEFT) AND "B" FACE OF RADAR ARRAY SYSTEM. NOTE THAT NORTH IS GENERALLY TO RIGHT OF VIEW. - Cape Cod Air Station, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

287

Near-Real Time Quality Control of surface current maps from High-Frequency (HF) radars  

NASA Astrophysics Data System (ADS)

A method for real-time quality control and despiking of sea surface current maps from High-Frequency (HF) SeaSonde radars based on the Signal-to-Noise ratios of the Doppler velocities from individual radar stations is proposed and discussed. Benefits of using a conservative weighted least-squares versus a more traditional least-squares approach for the total vector derivation are demonstrated on a network of radars operating in the Northern Adriatic Sea

Cosoli, S.; Bolzon, G.

2009-04-01

288

Evaluation of station blackout accidents at nuclear power plants: Technical findings related to unresolved safety issue A-44: Final report  

SciTech Connect

''Station Blackout,'' which is the complete loss of alternating current (AC) electrical power in a nuclear power plant, has been designated as Unresolved Safety Issue A-44. Because many safety systems required for reactor core decay heat removal and containment heat removal depend on AC power, the consequences of a station blackout could be severe. This report documents the findings of technical studies performed as part of the program to resolve this issue. The important factors analyzed include: the fequency of loss of offsite power; the probability that emergency or onsite AC power supplies would be unavailable; the capability and reliability of decay heat removal systems independent of AC power; and the likelihood that offsite power would be restored before systems that cannot operate for extended periods without AC power fail, thus resulting in core damage. This report also addresses effects of different designs, locations, and operational features on the estimated frequency of core damage resulting from station blackout events.

Not Available

1988-06-01

289

Radar Imaging Systems Joseph Charpentier  

E-print Network

Radar Imaging Systems Joseph Charpentier Department of Computing Sciences Villanova University types of radar imaging systems; synthetic aperture radar (SAR), through-the-wall radar, and digital holographic near field radar. Each system surveyed experiments that improved the quality of the resulting

290

Evaluation of prototype Advanced Life Support (ALS) pack for use by the Health Maintenance Facility (HMF) on Space Station Freedom (SSF)  

NASA Technical Reports Server (NTRS)

The purpose is to evaluate the prototype Advanced Life Support (ALS) Pack which was developed for the Health Maintenance Facility (HMF). This pack will enable the Crew Medical Officer (CMO) to have ready access to advanced life support supplies and equipment for time critical responses to any situation within the Space Station Freedom. The objectives are: (1) to evaluate the design of the pack; and (2) to collect comments for revision to the design of the pack. The in-flight test procedures and other aspects of the KC-135 parabolic test flight to simulate weightlessness are presented.

Krupa, Debra T.; Gosbee, John; Murphy, Linda; Kizzee, Victor D.

1991-01-01

291

Borehole radar for geothermal applications  

SciTech Connect

An initial evaluation of a continuous wave borehole radar system with steerable antennas has been completed. Candidate antennas have been identified which meet the size requirements for borehole applications. The patterns of these antennas are not dependent on the properties of the surrounding media when the antenna dimensions are less than one-tenth wavelength. The beam patterns can be steered adequately to allow the volume of earth within several meters of a borehole to be investigated. 7 refs., 5 figs.

Scott, M.W.; Caffey, T.W.H.

1991-01-01

292

47 CFR 80.169 - Operators required to adjust transmitters or radar.  

Code of Federal Regulations, 2010 CFR

...or second class radiotelegraph operator certificate must perform such functions at radiotelegraph stations transmitting Morse code. (c) Only persons holding an operator certificate containing a ship radar endorsement must perform such...

2010-10-01

293

47 CFR 80.169 - Operators required to adjust transmitters or radar.  

Code of Federal Regulations, 2012 CFR

...or second class radiotelegraph operator certificate must perform such functions at radiotelegraph stations transmitting Morse code. (c) Only persons holding an operator certificate containing a ship radar endorsement must perform such...

2012-10-01

294

47 CFR 80.169 - Operators required to adjust transmitters or radar.  

Code of Federal Regulations, 2013 CFR

...Operator's Certificate, or Radiotelegraph Operator License must perform such functions at radiotelegraph stations transmitting Morse code. (c) Only persons holding an operator certificate containing a ship radar endorsement must perform such...

2013-10-01

295

47 CFR 80.169 - Operators required to adjust transmitters or radar.  

Code of Federal Regulations, 2011 CFR

...or second class radiotelegraph operator certificate must perform such functions at radiotelegraph stations transmitting Morse code. (c) Only persons holding an operator certificate containing a ship radar endorsement must perform such...

2011-10-01

296

10. Perimeter acquisition radar power plant (upper level) room #219E, ...  

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

10. Perimeter acquisition radar power plant (upper level) room #219E, station services room; showing air compressors which provide diesel generators with internal power kick-on - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Power Plant, In Limited Access Area, Southwest of PARB at end of Service Road B, Nekoma, Cavalier County, ND

297

Results from UHF and HF Radar Studies of Ionospheric Interaction Experiments at HAARP  

Microsoft Academic Search

High power HF radiowave experiments have begun at the HAARP Ionospheric Research Observatory in Gakona, Alaska. The SuperDARN HF radar station in Kodiak, Alaska is now routinely employed to monitor HF backscatter from irregularities formed in the interaction volume over HAARP. A 16-panel prototype of a new UHF incoherent scatter radar facility, AMISR, has recently become operational on the HAARP

J. P. Sheerin; R. Ilie; E. L. Roesler; W. A. Bristow; B. J. Watkins; S. Oyama

2005-01-01

298

Effects of noise, sampling rate and signal sparsity for compressed sensing Synthetic Aperture Radar pulse compression  

Microsoft Academic Search

The traditional radar system needs large bandwidth, and the increasing number of channels brings huge amount of data. These data can easily overflow the memory of the sensor or the bandwidth of the signal which transferred to the ground station. In order to solve this problem, a new method of acquiring Synthetic Aperture Radar (SAR) raw data and compressing pulse

Peng Xiao; Chunsheng Li; Yu Ze

2011-01-01

299

30. Perimeter acquisition radar building room #318, showing radar control. ...  

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

30. Perimeter acquisition radar building room #318, showing radar control. Console and line printers - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

300

Planetary radar studies  

NASA Technical Reports Server (NTRS)

A catalog of lunar and radar anomalies was generated to provide a base for comparison with Venusian radar signatures. The relationships between lunar radar anomalies and regolith processes were investigated, and a consortium was formed to compare lunar and Venusian radar images of craters. Time was scheduled at the Arecibo Observatory to use the 430 MHz radar to obtain high resolution radar maps of six areas of the lunar suface. Data from 1978 observations of Mare Serenitas and Plato are being analyzed on a PDP 11/70 computer to construct the computer program library necessary for the eventual reduction of the May 1981 and subsequent data acquisitions. Papers accepted for publication are presented.

Thompson, T. W.; Cutts, J. A.

1981-01-01

301

Laser radar in robotics  

SciTech Connect

In this paper the authors describe the basic operating principles of laser radar sensors and the typical algorithms used to process laser radar imagery for robotic applications. The authors review 12 laser radar sensors to illustrate the variety of systems that have been applied to robotic applications wherein information extracted from the laser radar data is used to automatically control a mechanism or process. Next, they describe selected robotic applications in seven areas: autonomous vehicle navigation, walking machine foot placement, automated service vehicles, manufacturing and inspection, automotive, military, and agriculture. They conclude with a discussion of the status of laser radar technology and suggest trends seen in the application of laser radar sensors to robotics. Many new applications are expected as the maturity level progresses and system costs are reduced.

Carmer, D.C.; Peterson, L.M. [Environmental Research Inst. of Michigan, Ann Arbor, MI (United States)

1996-02-01

302

CHIRP Doppler radar  

NASA Astrophysics Data System (ADS)

The present investigation is concerned with the concept of a combination of the clinical procedure of reconstruction tomography with the radar processing for linear FM pulse compression. An approach based on such a combination is to be employed to map radar backscatter energy. Radar systems employing pulse compression of linear frequency modulated (CHIRP) pulses are considered along with the inversion formula employed by reconstruction tomography. The conventional system enabling radar backscatter mapping is based on pulse-Doppler radar which basically incorporates range-gated spectrum analysis. CHIRP Doppler radar represents a potential alternative. Advantages are related to an absence of requirements to maintain coherence from pulse to pulse, and the suppression of interference due to second-time-around signals. Raabe (1976) has discussed an application involving the imaging of the wakes of reentering space vehicles.

Bernfeld, M.

1984-04-01

303

MIMO radar, SIMO radar, and IFIR radar: a P. P. Vaidyanathan and Piya Pal  

E-print Network

MIMO radar, SIMO radar, and IFIR radar: a comparison P. P. Vaidyanathan and Piya Pal Dept and SIMO radar systems for the case where the transmitter and receiver are collocated. The simplicity of the application allows one to see clearly where the advantages of MIMO radar come from, and what the tradeoffs are

Vaidyanathan, P. P.

304

Monitoring by holographic radar systems  

NASA Astrophysics Data System (ADS)

Nowadays, radar technology represents a significant opportunity to collect useful information for the monitoring and conservation of critical infrastructures. Radar systems exploit the non-invasive interaction between the matter and the electromagnetic waves at microwave frequencies. Such an interaction allows obtaining images of the region under test from which one can infer the presence of potential anomalies such as deformations, cracks, water infiltrations, etc. This information turns out to be of primary importance in practical scenarios where the probed structure is in a poor state of preservation and renovation works must be planned. In this framework, the aim of this contribution is to describe the potentialities of the holographic radar Rascan 4/4000, a holographic radar developed by Remote Sensing Laboratory of Bauman Moscow State Technical University, as a non-destructive diagnostic tool capable to provide, in real-time, high resolution subsurface images of the sounded structure [1]. This radar provides holograms of hidden anomalies from the amplitude of the interference signal arising between the backscattered signal and a reference signal. The performance of the holographic radar is appraised by means of several experiments. Preliminary tests concerning the imaging below the floor and inside wood structures are carried out in controlled conditions at the Electromagnetic Diagnostic Laboratory of IREA-CNR. After, with reference to bridge monitoring for security aim, the results of a measurement campaign performed on the Musmeci bridge are presented [2]. Acknowledgments This research has been performed in the framework of the "Active and Passive Microwaves for Security and Subsurface imaging (AMISS)" EU 7th Framework Marie Curie Actions IRSES project (PIRSES-GA-2010-269157). REFERENCES [1] S. Ivashov, V. Razevig, I. Vasilyev, A. Zhuravlev, T. Bechtel, L. Capineri, The holographic principle in subsurface radar technology, International Symposium to Commemorate the 60th Anniversary of the Invention of Holography, Springfield, Massachusetts USA, October 27-29, pp. 183-197, 2008. [2] I. Catapano, L. Crocco, A. F. Morabito, F. Soldovieri, "Tomographic imaging of holographic GPR data for non-invasive structural assessment: the Musmeci bridge investigation", Nondestructive testing and evaluation, vol. 27, pp. 229-237, 2012.

Catapano, Ilaria; Crocco, Lorenzo; Affinito, Antonio; Gennarelli, Gianluca; Soldovieri, Francesco

2013-04-01

305

Evaluating Contributions to SKKS Splitting from Lower Mantle Anisotropy: A Case Study from Station DBIC, Cte D'Ivoire  

E-print Network

, 1999; Long and Silver, 2009; Long and Becker, 2010). This interpretation is based on inferences from-azimuthal range; we also identified examples of dis- crepant SKS­SKKS splitting for the same event­station pair on patterns of mantle flow (e.g., Silver, 1996; Savage, 1999; Long and Becker, 2010). Anisotropy is usually

306

An analysis of simulated stereo radar imagery  

NASA Technical Reports Server (NTRS)

Simulated stereo radar imagery is used to investigate parameters for a spaceborne imaging radar. Incidence angles ranging from small to intermediate to large are used with three digital terrain model areas which are representative of relatively flat, moderately rough, and mountainous terrain. The simulated radar imagery was evaluated by interpreters for ease of stereo perception and information content, and rank order within each class of terrain. The interpreter's results are analyzed for trends between the height of a feature and either parallax or vertical exaggeration for a stereo pair. A model is developed which predicts the amount of parallax (or vertical exaggeration) an interpreter would desire for best stereo perception of a feature of a specific height. Results indicate the selection of angle of incidence and stereo intersection angle depend upon the relative relief of the terrain. Examples of the simulated stereo imagery are presented for a candidate spaceborne imaging radar having four selectable angles of incidence.

Pisaruck, M. A.; Kaupp, V. H.; Macdonald, H. C.; Waite, W. P.

1983-01-01

307

Improving on police radar  

Microsoft Academic Search

The use of lasers, cameras, and advanced signal processing to help isolate individual offenders on crowded highways is discussed. The limitations of the predominant radar in use today, namely down-the-road Doppler-radar in which the axis of the antenna is directed along the line of travel of the target vehicle, are described. The potential of video records, across-the-road radar, and both

P. D. Fisher

1992-01-01

308

Caribbean Radar Cases  

NSDL National Science Digital Library

This module presents radar case studies taken from events in the Caribbean that highlight radar signatures of severe weather. These cases include examples of deep convection, squall lines, bow echoes, tornadoes, and heavy rain resulting in flooding. Each case study includes a discussion of the conceptual models of each type of event as a review before showing the radar signatures and allowing the learner to analyze each one.

2014-09-14

309

Evaluation of ground-penetrating radar to detect free-phase hydrocarbons in fractured rocks - Results of numerical modeling and physical experiments  

USGS Publications Warehouse

The suitability of common-offset ground-penetrating radar (GPR) to detect free-phase hydrocarbons in bedrock fractures was evaluated using numerical modeling and physical experiments. The results of one- and two-dimensional numerical modeling at 100 megahertz indicate that GPR reflection amplitudes are relatively insensitive to fracture apertures ranging from 1 to 4 mm. The numerical modeling and physical experiments indicate that differences in the fluids that fill fractures significantly affect the amplitude and the polarity of electromagnetic waves reflected by subhorizontal fractures. Air-filled and hydrocarbon-filled fractures generate low-amplitude reflections that are in-phase with the transmitted pulse. Water-filled fractures create reflections with greater amplitude and opposite polarity than those reflections created by air-filled or hydrocarbon-filled fractures. The results from the numerical modeling and physical experiments demonstrate it is possible to distinguish water-filled fracture reflections from air- or hydrocarbon-filled fracture reflections, nevertheless subsurface heterogeneity, antenna coupling changes, and other sources of noise will likely make it difficult to observe these changes in GPR field data. This indicates that the routine application of common-offset GPR reflection methods for detection of hydrocarbon-filled fractures will be problematic. Ideal cases will require appropriately processed, high-quality GPR data, ground-truth information, and detailed knowledge of subsurface physical properties. Conversely, the sensitivity of GPR methods to changes in subsurface physical properties as demonstrated by the numerical and experimental results suggests the potential of using GPR methods as a monitoring tool. GPR methods may be suited for monitoring pumping and tracer tests, changes in site hydrologic conditions, and remediation activities.The suitability of common-offset ground-penetrating radar (GPR) to detect free-phase hydrocarbons in bedrock fractures was evaluated using numerical modeling and physical experiments. The results of one- and two-dimensional numerical modeling at 100 megahertz indicate that GPR reflection amplitudes are relatively insensitive to fracture apertures ranging from 1 to 4 mm. The numerical modeling and physical experiments indicate that differences in the fluids that fill fractures significantly affect the amplitude and the polarity of electromagnetic waves reflected by subhorizontal fractures. Air-filled and hydrocarbon-filled fractures generate low-amplitude reflections that are in-phase with the transmitted pulse. Water-filled fractures create reflections with greater amplitude and opposite polarity than those reflections created by air-filled or hydrocarbon-filled fractures. The results from the numerical modeling and physical experiments demonstrate it is possible to distinguish water-filled fracture reflections from air- or hydrocarbon-filled fracture reflections, nevertheless subsurface heterogeneity, antenna coupling changes, and other sources of noise will likely make it difficult to observe these changes in GPR field data. This indicates that the routine application of common-offset GPR reflection methods for detection of hydrocarbon-filled fractures will be problematic. Ideal cases will require appropriately processed, high-quality GPR data, ground-truth information, and detailed knowledge of subsurface physical properties. Conversely, the sensitivity of GPR methods to changes in subsurface physical properties as demonstrated by the numerical and experimental results suggests the potential of using GPR methods as a monitoring tool. GPR methods may be suited for monitoring pumping and tracer tests, changes in site hydrologic conditions, and remediation activities.

Lane, J.W., Jr.; Buursink, M.L.; Haeni, F.P.; Versteeg, R.J.

2000-01-01

310

The Invisible Radar Triangle  

NSDL National Science Digital Library

Students learn about radar imaging and its various military and civilian applications that include recognition and detection of human-made targets, and the monitoring of space, deforestation and oil spills. They learn how the concepts of similarity and scaling are used in radar imaging to create three-dimensional models of various targets. Students apply the critical attributes of similar figures to create scale models of a radar imaging scenario using infrared range sensors (to emulate radar functions) and toy airplanes (to emulate targets). They use technology tools to measure angles and distances, and relate the concept of similar figures to real-world applications.

2014-09-18

311

Space station technology  

NASA Astrophysics Data System (ADS)

In an evaluation of the current technological basis for a space station, the Space Station Technology Steering Committee (SSTSC) came to the conclusion that a space station could certainly be made with existing technology. It was, however, found that state-of-the-art technology would not provide for the evolutionary growth aspects of a long life system. In the process of its reviews, the SSTSC identified 10 specific disciplines to categorize the technology which was found to be relevant or potentially applicable to a future space station design. Attention is given to the objectives for the advanced development program, systems and operations, data management, crew and life support, power, thermal management, human capability, auxiliary propulsion, fluid management systems, attitude control and stabilization, structures and mechanisms, and communications.

Tumulty, W. T.

312

Generalized radar/radiometry imaging problems  

E-print Network

Paper Generalized radar/radiometry imaging problems Ivan Prudyus, Sviatoslav Voloshynovskiy, Andriy- ing simulation based on radar, synthetic aperture radar (SAR) and radiometry systems are presented systems, synthetic aperture radar, spatio-temporal imaging. 1. Introduction Resolution of radar

Genève, Université de

313

Alpine radar conversion for LAWR  

NASA Astrophysics Data System (ADS)

The Local Area Weather Radar (LAWR) is a ship-born weather radar system operating in X-band developed by the DHI Group to detect precipitation in urban areas. To date more than thirty units are installed in different settings around the world. A LAWR was also deployed in the Alps, at 3883 m a.s.l. on the Kl. Matterhorn (Valais, Switzerland). This was the highest LAWR of the world and it led to the development of an Alpine LAWR system that, besides featuring important technological improvements needed to withstand the severe Alpine conditions, required the development of a new Alpine Radar COnversion Model (ARCOM), which is the main focus of this contribution. The LAWR system is equipped with the original FURUNO fan-beam slotted antenna and the original logarithmic receiver, which limits the radar observations to the video signal (L) withour providing the reflectivity (Z). The beam is 0.95 deg wide and 20 deg high. It can detect precipitation to a max range of 60 km. In order to account for the limited availability of raw signal and information and the specific mountain set-up, the conversion model had to be developed differently from the state-of-the-art radar conversion technique used for this class of radars. In particular, the ARCOM is based on a model used to simulate a spatial dependent factor, hereafter called ACF, which is in turn function of parameters that take in account climatological conditions, also used in other conversion methods, but additionally accounting for local radar beam features and for orographic forcings such as the effective sampling power (sP), which is modelled by means of antenna pattern, geometric ground clutter and their interaction. The result is a conversion factor formulated to account for a range correction that is based on the increase of the sampling volume, partial beam blocking and local climatological conditions. The importance of the latter in this study is double with respect to the standard conversion technique for this class of radars, because it accounts for the large variability of hydrometeors reflectivity and vertical hydrometeors positioning (echo-top), which is strongly influenced by the high location of the radar. The ARCOM procedure is in addition embedded in a multistep quality control framework, which also includes the calibration on raingauge observations, and can be summarized as follow: 1) correction of both LAWR and raingauge observations for known errors (e.g. magnetron decay and heated-related water loss) 2) evaluation of the local Pearson's correlation coefficient (PCC) as estimator of the linear correlation between raingauge and LAWR observations (logarithmic receiver); 3) computation of the local ACF in the form of the local linear regression coefficient between raingauge and LAWR observations; 4) calibration of the ARCOM, i.e. definition of the parametrization able to reproduce the spatial variability of ACF as function of the local sP, being the PCCs used as weight in the calibration procedure. The resulting calibrated ARCOM finally allows, in any ungauged mountain spot, to convert LAWR observations into precipitation rate. The temporal and the spatial transferability of the ARCOM are evaluated via split-sample and a take-one-out cross validation. The results revealed good spatial transferability and a seasonal bias within 7%, thus opening new opportunities for local range distributed measurements of precipitation in mountain regions.

Savina, M.; Burlando, P.

2012-04-01

314

Health hazard evaluation report HETA 93-1062-2558, Texas Utilities Electric Company, Martin Lake Steam Electric Station, Tatum, Texas  

SciTech Connect

In response to a request from workers at the Texas Utilities Electric Company (SIC-4911), Martin Lake Steam Electric Station in Tatum, Texas, the incidence of neurologic symptoms and exposure to electromagnetic fields and organophosphates were investigated. Workers reported neurological symptoms, including memory loss, dizziness and fatigue. A site visit to the station revealed electromagnetic field levels below the current occupational standard of 10 gauss. The use of an organophosphate containing fire resistant hydraulic fluid, Fyrquel-EH (1330785), was reported by employees. A significant correlation was identified between memory of past symptoms indicative of acute organophosphate exposure after working with Fyrquel-EH and current symptoms; however, blood cholinesterase levels were all within the normal range and no relevant neurologic abnormalities were noted on neurological examinations. The authors conclude that a hazard existed from the use of Fyrquel-EH. The authors recommend measures for the safe handling of organophosphate compounds.

Malkin, R.; Moss, C.E.; Reh, C.M.; Ragab, M.

1996-01-01

315

The use of digital RF memories in radar signal processing  

NASA Astrophysics Data System (ADS)

This paper describes the use that may be made of Digital RF Memories in developing and evaluating new radar systems. It outlines the basic DRFM technology showing how a DRFM works and the sort of performance that may be expected. The application of this technology to radar is then discussed showing the advantages that may be obtained through the use of coherent digital IF processing. Finally some experimental DRFM based radar configurations are described illustrating the results that have been achieved and the implications that these might have on future radar systems.

Clark, D. G. D.; Ingram, P. M.

316

Java Radar Analysis Tool  

NASA Technical Reports Server (NTRS)

Java Radar Analysis Tool (JRAT) is a computer program for analyzing two-dimensional (2D) scatter plots derived from radar returns showing pieces of the disintegrating Space Shuttle Columbia. JRAT can also be applied to similar plots representing radar returns showing aviation accidents, and to scatter plots in general. The 2D scatter plots include overhead map views and side altitude views. The superposition of points in these views makes searching difficult. JRAT enables three-dimensional (3D) viewing: by use of a mouse and keyboard, the user can rotate to any desired viewing angle. The 3D view can include overlaid trajectories and search footprints to enhance situational awareness in searching for pieces. JRAT also enables playback: time-tagged radar-return data can be displayed in time order and an animated 3D model can be moved through the scene to show the locations of the Columbia (or other vehicle) at the times of the corresponding radar events. The combination of overlays and playback enables the user to correlate a radar return with a position of the vehicle to determine whether the return is valid. JRAT can optionally filter single radar returns, enabling the user to selectively hide or highlight a desired radar return.

Zaczek, Mariusz P.

2005-01-01

317

Phased-array radars  

Microsoft Academic Search

The operating principles, technology, and applications of phased-array radars are reviewed and illustrated with diagrams and photographs. Consideration is given to the antenna elements, circuitry for time delays, phase shifters, pulse coding and compression, and hybrid radars combining phased arrays with lenses to alter the beam characteristics. The capabilities and typical hardware of phased arrays are shown using the US

Eli Brookner

1985-01-01

318

Technical evaluation of the noise and isolation testing of the safety features actuation system at the Davis Besse Nuclear Power Station, Unit 1  

SciTech Connect

This report documents the technical evaluation of the noise and isolation testing of the safety features actuation system at the Davis Besse Nuclear Power Station, Unit 1. The tests were to verify that faults on the non-Class 1E circuits would not propagate to the Class 1E circuits and degrade them below acceptable levels. The tests conducted demonstrated that the safety features actuation system did not degrade below acceptable levels nor was the system's ability to perform its protective functions affected.

Selan, J.C.

1981-07-01

319

Looking at Radar Images  

NSDL National Science Digital Library

These activities pertain to the value of the different types of images, including a false color mosaic, a Compressed Stokes image, a vegetation map and key, and various ground photographs. Students are given specific directions on how to decide what features of a radar image indicate such structures as upland forest, clear-cut areas, and roads. In a second activity, students look at the radar images to see if they can produce a vegetation map similar to the one they have been given. The third activity introduces 15 Decade Volcanoes that pose a particular threat to humans. Using the Decade Volcanoes as examples, students view radar images of volcanoes that occur around the world. The final exercise is aimed at helping students distinguish the differences between radar image data and visible photographs. Students will look at radar data and photographs of three sites taken by the astronauts.

320

Monostatic Coherent Radar Sea Clutter Doppler Analysis Matthew Ritchie  

E-print Network

Monostatic Coherent Radar Sea Clutter Doppler Analysis Matthew Ritchie University College London of the variation of sea clutter distribution with Doppler, using monostatic coherent X-band radar data. To evaluate in the Doppler domain. Within coherent monostatic data the research into the variation of Doppler with sea

Haddadi, Hamed

321

Polar mesosphere summer radar echoes: Observations and current theories  

Microsoft Academic Search

In the present article the authors review observations and proposed theories of the strong radar echoes originating from the summer polar mesosphere. The progress that has been made toward understanding this phenomenon is evaluated. The connections of the radar echoes to global climate change, to [open quotes]dusty plasma[close quotes], and to the highest clouds of the atmosphere are discussed. Suggestions

John Y. N. Cho; Michael C. Kelley

1993-01-01

322

Application of HF radar currents to oil spill modelling  

Microsoft Academic Search

In this work, the benefits of high-frequency (HF) radar currents for oil spill modeling and trajectory analysis of floating objects are analyzed. The HF radar performance is evaluated by means of comparison between a drifter buoy trajectory and the one simulated using a Lagrangian trajectory model. A methodology to optimize the transport model performance and to calculate the search area

Ana J. Abascal; Sonia Castanedo; Raul Medina; Inigo J. Losada; Enrique Alvarez-Fanjul

2009-01-01

323

Radar Location Equipment Development Program: Phase I  

SciTech Connect

The work described in this report represents the first phase of a planned three-phase project designed to develop a radar system for monitoring waste canisters stored in a thick layer of bedded salt at the Waste Isolation Pilot Plant near Carlsbad, New Mexico. The canisters will be contained in holes drilled into the floor of the underground waste storage facility. It is hoped that these measurements can be made to accuracies of +-5 cm and +-2/sup 0/, respectively. The initial phase of this project was primarily a feasibility study. Its principal objective was to evaluate the potential effectiveness of the radar method in the planned canister monitoring application. Its scope included an investigation of the characteristics of radar signals backscattered from waste canisters, a test of preliminary data analysis methods, an assessment of the effects of salt and bentonite (a proposed backfill material) on the propagation of the radar signals, and a review of current ground-penetrating radar technology. A laboratory experiment was performed in which radar signals were backscattered from simulated waste canisters. The radar data were recorded by a digital data acquisition system and were subsequently analyzed by three different computer-based methods to extract estimates of canister location and tilt. Each of these methods yielded results that were accurate within a few centimeters in canister location and within 1/sup 0/ in canister tilt. Measurements were also made to determine the signal propagation velocities in salt and bentonite (actually a bentonite/sand mixture) and to estimate the signal attenuation rate in the bentonite. Finally, a product survey and a literature search were made to identify available ground-penetrating radar systems and alternative antenna designs that may be particularly suitable for this unique application. 10 refs., 21 figs., 4 tabs.

Sandness, G.A.; Davis, K.C.

1985-06-01

324

Browse > Conferences> Radar Conference, 2008. RADAR ... INDEX TERMS  

E-print Network

Browse > Conferences> Radar Conference, 2008. RADAR ... INDEX TERMS REFERENCES CITING DOCUMENTS Force, MorphoAnalysis in Signal Process. Lab., Salon-de-Provence This paper appears in: Radar Conference, 2008. RADAR '08. IEEE Issue Date: 26-30 May 2008 On page(s): 1 - 5 Location: Rome ISSN: 1097-5659 Print

Préaux, Jean-Philippe

325

Study to investigate and evaluate means of optimizing the Ku-band combined radar/communication functions for the space shuttle  

NASA Technical Reports Server (NTRS)

The Ku band radar system on the shuttle orbiter operates in both a search and a tracking mode, and its transmitter and antennas share time with the communication mode in the integrated system. The power allocation properties and the Costa subloop subcarrier tracking performance associated with the baseline digital phase shift implementation of the three channel orbiter Ku band modulator are discussed.

Weber, C. L.; Alem, W. K.; Simon, M. K.

1977-01-01

326

Evaluation of the hydrologic measure quality of the Saint Nizier weather radar data on the local urban area of Greater Lyon  

Microsoft Academic Search

The meteorological radar of Saint Nizier d'Azergues, part of Meteo France network Aramis, is situated at only 40 km from the urban community of Greater Lyon, in the north of the Rhône valley, south-east of France. This area gathers many human, environmental and materials stakes and vulnerability. From an operational use, an assessment based on a simulation and analysis of

F. Renard; D. Faure; J. Comby

2009-01-01

327

Radar observations of tornadoes and the field intensity of atmospherics  

Microsoft Academic Search

Radar observations of two pre-monsoon tornadoes as experienced over the Gangetic West Bengal and the integrated field intensity of atmospherics (IFIA) at 30 kHz recorded over the tropical station, Calcutta, have been analysed. The records of IFIA exhibit a pronounced variation in the noise level showing first a sudden enhancement and then a distinct fall which is repetative in nature

A. B. Bhattacharya; R. Bhattacharya

1983-01-01

328

78. View of radar systems technical publication library, transmitter building ...  

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

78. View of radar systems technical publication library, transmitter building no. 102, second floor. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

329

74. Transmitter building no. 102, view of radar digital test ...  

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

74. Transmitter building no. 102, view of radar digital test and maintenance cabinet area control panel and date storage system showing ampex tape storage devices. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

330

37. View of detection radar environmental display (DRED) console for ...  

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

37. View of detection radar environmental display (DRED) console for middle DR 2 (structure no. 736) antenna, located in MWOC facility. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

331

10. View of back side of radar scanner building no. ...  

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

10. View of back side of radar scanner building no. 104 showing passageway links to other building to east and DR 1 antenna in background. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

332

9. View of back side of radar scanner building no. ...  

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

9. View of back side of radar scanner building no. 106 showing passageway links to other buildings east and west, and DR 3 antenna in background. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

333

Facilitating cloud radar and lidar algorithms: the Cloudnet Instrument Synergy/Target Categorization product  

E-print Network

Facilitating cloud radar and lidar algorithms: the Cloudnet Instrument Synergy recognition of the usefulness of cloud radar for evaluating numerous aspects of the representation of clouds.j.hogan@reading.ac.uk. 1http://www.met.rdg.ac.uk/radar/cloudnet/ 2http://www.arm.gov/ are regular 6-hourly radiosonde

Hogan, Robin

334

Facilitating cloud radar and lidar algorithms: the Cloudnet Instrument Synergy/Target Categorization product  

E-print Network

Facilitating cloud radar and lidar algorithms: the Cloudnet Instrument Synergy recognition of the usefulness of cloud radar for evaluating numerous aspects of the representation of clouds, UK. E­mail: r.j.hogan@reading.ac.uk. 1 http://www.met.rdg.ac.uk/radar/cloudnet/ 2 http

Hogan, Robin

335

Evaluating long-term trends in mean- and high- river flows using a network of reference stations in Ireland  

NASA Astrophysics Data System (ADS)

This paper describes the development of a reference hydrometric network for Ireland established primarily for the detection of climate driven trends in mean and high river flows. Thirty-five stations were identified for inclusion in the network plus a further 8 from the UK Benchmark Network. Their average record length is 40 years with a minimum of 28 and maximum of 63 years. Time series were derived for eight river flow indices: annual and seasonal mean flows and the annual maximum 1-, 10- and 30-day flows. Mann Kendall and Theil Sen statistics were applied to all indices using fixed and variable start/end dates. Trends in the winter mean are found to be highly dependent on the chosen period of analysis with the longest records showing increased flows. Contrary to expectations (of regional climate change scenarios), increases are also evident for long-term summer mean flows. High flow metrics exhibit positive and persistent trends that are less affected by inter-annual variability and period of record. Overall, there is strong spatial coherence in these patterns of change, linked to temporal variations in precipitation. Our results highlight the dangers of using conventional fixed periods such as 1961-1990 for trend detection, recognising that there is always a trade-off between record length, density of the network, and geographic coverage. Furthermore, outliers at the beginning of the record can be an artefact of the original motivation for installing the gauging station(s). In this case, water resource concerns during a markedly dry period in the mid-1970s favour positive trends over subsequent decades. Future work will focus on detection times for climate change signals and the identification of sentinel sites for discerning early signs of anthropogenic climate change across Ireland. Broader lessons for monitoring and detection of anthropogenic climate change signals will also be distilled.

Wilby, R. L.; Murphy, C.; Harrigan, S.; Hall, J.

2012-12-01

336

Use and Interpretation of Radar  

NSDL National Science Digital Library

This undergraduate meteorology tutorial from Texas A&M University discusses the basic principles of operation of weather radars, describes how to interpret radar mosaics, and discusses the use of radar in weather forecasting. Students learn the relationship between range and elevation and how to use radar images and mosaics in short-range forecasting.

John Nielsen-Gammon

1996-01-01

337

Ground-penetrating radar methods  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ground-penetrating radar geophysical methods are finding greater and greater use in agriculture. With the ground-penetrating radar (GPR) method, an electromagnetic radio energy (radar) pulse is directed into the subsurface, followed by measurement of the elapsed time taken by the radar signal as it ...

338

Spaceborne meteorological radar studies  

NASA Technical Reports Server (NTRS)

Various radar designs and methods are studied for the estimation of rainfall parameters from space. An immediate goal is to support the development of the spaceborne radar that has been proposed for the Tropical Rain Measuring Mission (TRMM). The effort is divided into two activities: a cooperative airborne rain measuring experiment with the Radio Research Laboratory of Japan (RRL), and the modelling of spaceborne weather radars. An airborne rain measuring experiment was conducted at Wallops Flight Facility in 1985 to 1986 using the dual-wavelength radar/radiometer developed by RRL. The data are presently being used to test a number of methods that are relevant to spaceborne weather radars. An example is shown of path-averaged rain rates as estimated from three methods: the standard reflectivity rain rate method (Z-R), a dual-wavelength method, and a surface reference method. The results from the experiment shows for the first time the feasibility of using attenuation methods from space. The purposes of the modelling are twofold: to understand in a quantitative manner the relationships between a particular radar design and its capability for estimating precipitation parameters and to help devise and test new methods. The models are being used to study the impact of various TRMM radar designs on the accuracy of rain rate estimation as well as to test the performance of range-profiling algorithms, the mirror-image method, and some recently devised graphical methods for the estimation of the drop size distribution.

Meneghini, R.

1988-01-01

339

Earth resources shuttle imaging radar. [systems analysis and design analysis of pulse radar for earth resources information system  

NASA Technical Reports Server (NTRS)

A report is presented on a preliminary design of a Synthetic Array Radar (SAR) intended for experimental use with the space shuttle program. The radar is called Earth Resources Shuttle Imaging Radar (ERSIR). Its primary purpose is to determine the usefulness of SAR in monitoring and managing earth resources. The design of the ERSIR, along with tradeoffs made during its evolution is discussed. The ERSIR consists of a flight sensor for collecting the raw radar data and a ground sensor used both for reducing these radar data to images and for extracting earth resources information from the data. The flight sensor consists of two high powered coherent, pulse radars, one that operates at L and the other at X-band. Radar data, recorded on tape can be either transmitted via a digital data link to a ground terminal or the tape can be delivered to the ground station after the shuttle lands. A description of data processing equipment and display devices is given.

1975-01-01

340

Radar applications overview  

NASA Astrophysics Data System (ADS)

During the fifty years since its initial development as a means of providing early warning of airborne attacks against allied countries during World War II, radar systems have developed to the point of being highly mobile and versatile systems capable of supporting a wide variety of remote sensing applications. Instead of being tied to stationary land-based sites, radar systems have found their way into highly mobile land vehicles as well as into aircraft, missiles, and ships of all sizes. Of all these applications, however, the most exciting revolution has occurred in the airborne platform arena where advanced technology radars can be found in all shapes and sizes...ranging from the large AWACS and Joint STARS long range surveillance and targeting systems to small millimeter wave multi-spectral sensors on smart weapons that can detect and identify their targets through the use of highly sophisticated digital signal processing hardware and software. This paper presents an overview of these radar applications with the emphasis on modern airborne sensors that span the RF spectrum. It will identify and describe the factors that influence the parameters of low frequency and ultra wide band radars designed to penetrate ground and dense foliage environments and locate within them buried mines, enemy armor, and other concealed or camouflaged weapons of war. It will similarly examine the factors that lead to the development of airborne radar systems that support long range extended endurance airborne surveillance platforms designed to detect and precision-located both small high speed airborne threats as well as highly mobile time critical moving and stationary surface vehicles. The mission needs and associated radar design impacts will be contrasted with those of radar systems designed for high maneuverability rapid acquisition tactical strike warfare platforms, and shorter range cued air-to-surface weapons with integral smart radar sensors.

Greenspan, Marshall

1996-06-01

341

Construction and evaluation of an experimental station and reaction apparatus for the chemical reactions of aqueous solution systems with soft x rays from a synchrotron radiation light source  

SciTech Connect

An efficient experimental system for the chemical reactions of various aqueous solutions using soft x rays from synchrotron radiation has been designed, constructed, and evaluated. This system was installed at an end station on a beamline (BL-11) at the Synchrotron Radiation Center of Ritsumeikan University. To protect the storage ring and the beamline from accidental vacuum breaks and contamination caused by unexpected solution leakage in the reaction apparatus, the system has two main protection sections: a differential vacuum pumping section equipped with orifice gaskets of very small aperture and an emergency interlocking system section equipped with a fast closing shutter, etc., in addition to a safety mechanism in the reaction apparatus section. The outline of the system and preliminary experimental data obtained in the evaluation of the system are described.

Shimizu, Yuichi; Koike, Masato; Sano, Kazuo [Kansai Photon Science Institute, Quantum Beam Science Directorate, Japan Atomic, Energy Agency, 8-1 Umemidai, Kizu, Kyoto 619-0215 (Japan); Shimadzu Emit Co. Ltd., 1 Tamachi Nishigosyo Murasakino, Kita Kyoto 603-8165 (Japan)

2006-09-15

342

Radar Remote Sensing  

NASA Technical Reports Server (NTRS)

This lecture was just a taste of radar remote sensing techniques and applications. Other important areas include Stereo radar grammetry. PolInSAR for volumetric structure mapping. Agricultural monitoring, soil moisture, ice-mapping, etc. The broad range of sensor types, frequencies of observation and availability of sensors have enabled radar sensors to make significant contributions in a wide area of earth and planetary remote sensing sciences. The range of applications, both qualitative and quantitative, continue to expand with each new generation of sensors.

Rosen, Paul A.

2012-01-01

343

Space station structures development  

NASA Technical Reports Server (NTRS)

A study of three interrelated tasks focusing on deployable Space Station truss structures is discussed. Task 1, the development of an alternate deployment system for linear truss, resulted in the preliminary design of an in-space reloadable linear motor deployer. Task 2, advanced composites deployable truss development, resulted in the testing and evaluation of composite materials for struts used in a deployable linear truss. Task 3, assembly of structures in space/erectable structures, resulted in the preliminary design of Space Station pressurized module support structures. An independent, redundant support system was developed for the common United States modules.

Teller, V. B.

1986-01-01

344

Redwood Field Station Research  

NSDL National Science Digital Library

This portal provides information on the environmental issues and research projects being conducted in Redwood National and State Parks. The Redwood Field Station, part of the United States Geological Survey's (USGS) Western Ecological Research Center, is involved with restoration of the physical and biological landscapes in the parks, including inventory and monitoring of erosion, sediment transport, and stream temperatures; evaluating the effectiveness of various strategies for watershed restoration; and determining the influence of timber harvest and floods on riparian areas. Users will find links to individual project web pages, as well as a list of Redwood Field Station products and publications.

345

Stage measurement at gaging stations  

USGS Publications Warehouse

Stream and reservoir stage are critical parameters in the computation of stream discharge and reservoir volume, respectively. In addition, a record of stream stage is useful in the design of structures that may be affected by stream elevation, as well as for the planning for various uses of flood plains. This report describes equipment and methodology for the observation, sensing, and recording of stage in streams and reservoirs. Although the U.S. Geological Survey (USGS) still uses the traditional, basic stilling-well float system as a predominant gaging station, modern electronic stage sensors and water-level recorders are now commonly used. Bubble gages coupled with nonsubmersible pressure transducers eliminate the need for stilling wells. Submersible pressure transducers have become common in use for the measurement of stage in both rivers and lakes. Furthermore, noncontact methods, such as radar, acoustic, and laser methods of sensing water levels, are being developed and tested, and in the case of radar, are commonly used for the measurement of stage. This report describes commonly used gaging-station structures, as well as the design and operation of gaging stations. Almost all of the equipment and instruments described in this report will meet the accuracy standard set by the USGS Office of Surface Water (OSW) for the measurement of stage for most applications, which is ?0.01 foot (ft) or 0.2 percent of the effective stage. Several telemetry systems are used to transmit stage data from the gaging station to the office, although satellite telemetry has become the standard. These telemetry systems provide near real-time stage data, as well as other information that alerts the hydrographer to extreme or abnormal events, and instrument malfunctions.

Sauer, Vernon B.; Turnipseed, D. Phil

2010-01-01

346

Evaluation of Manual Ultrasonic Examinations Applied to Detect Flaws in Primary System Dissimilar Metal Welds at North Anna Power Station  

SciTech Connect

During a recent inservice inspection (ISI) of a dissimilar metal weld (DMW) in an inlet (hot leg) steam generator nozzle at North Anna Power Station Unit 1, several axially oriented flaws went undetected by the licensee's manual ultrasonic testing (UT) technique. The flaws were subsequently detected as a result of outside diameter (OD) surface machining in preparation for a full structural weld overlay. The machining operation uncovered the existence of two through-wall flaws, based on the observance of primary water leaking from the DMW. Further ultrasonic tests were then performed, and a total of five axially oriented flaws, classified as primary water stress corrosion cracking (PWSCC), were detected in varied locations around the weld circumference.

Anderson, Michael T.; Diaz, Aaron A.; Doctor, Steven R.

2012-06-01

347

Test and evaluation of load converter topologies used in the Space Station Freedom Power Management and distribution DC test bed  

NASA Technical Reports Server (NTRS)

Power components hardware in support of the Space Station Freedom dc Electrical Power System were tested. One type of breadboard hardware tested is the dc Load Converter Unit, which constitutes the power interface between the electric power system and the actual load. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. Three load converters were tested: a series resonant converter, a series inductor switchmode converter, and a switching full-bridge forward converter. The topology, operation principles, and tests results are described, in general. A comparative analysis of the three units is given with respect to efficiency, regulation, short circuit behavior (protection), and transient characteristics.

Lebron, Ramon C.; Oliver, Angela C.; Bodi, Robert F.

1991-01-01

348

Test and evaluation of load converter topologies used in the Space Station Freedom power management and distribution dc test bed  

NASA Technical Reports Server (NTRS)

Power components hardware in support of the Space Station freedom dc Electric Power System were tested. One type of breadboard hardware tested is the dc Load Converter Unit, which constitutes the power interface between the electric power system and the actual load. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. Three load converters were tested: a series resonant converter, a series inductor switch-mode converter, and a switching full-bridge forward converter. The topology, operation principles, and test results are described, in general. A comparative analysis of the three units is given with respect to efficiency, regulation, short circuit behavior (protection), and transient characteristics.

Lebron, Ramon C.; Oliver, Angela C.; Bodi, Robert F.

1991-01-01

349

An evaluation of the accuracy of geomagnetic data obtained from an unattended, automated, quasi-absolute station  

USGS Publications Warehouse

A comparison is made of geomagnetic calibration data obtained from a high-sensitivity proton magnetometer enclosed within an orthogonal bias coil system, with data obtained from standard procedures at a mid-latitude U.S. Geological Survey magnetic observatory using a quartz horizontal magnetometer, a Ruska magnetometer, and a total field magnetometer. The orthogonal coil arrangement is used with the proton magnetometer to provide Deflected-Inclination-Deflected-Declination (DIDD) data from which quasi-absolute values of declination, horizontal intensity, and vertical intensity can be derived. Vector magnetometers provide the ordinate values to yield baseline calibrations for both the DIDD and standard observatory processes. Results obtained from a prototype system over a period of several months indicate that the DIDD unit can furnish adequate absolute field values for maintaining observatory calibration data, thus providing baseline control for unattended, remote stations. ?? 1990.

Herzog, D.C.

1990-01-01

350

Evaluation of Cloud Microphysics in JMA-NHM Simulations Using Bin or Bulk Microphysical Schemes through Comparison with Cloud Radar Observations  

NASA Technical Reports Server (NTRS)

Numerical weather prediction (NWP) simulations using the Japan Meteorological Agency NonhydrostaticModel (JMA-NHM) are conducted for three precipitation events observed by shipborne or spaceborneW-band cloud radars. Spectral bin and single-moment bulk cloud microphysics schemes are employed separatelyfor an intercomparative study. A radar product simulator that is compatible with both microphysicsschemes is developed to enable a direct comparison between simulation and observation with respect to theequivalent radar reflectivity factor Ze, Doppler velocity (DV), and path-integrated attenuation (PIA). Ingeneral, the bin model simulation shows better agreement with the observed data than the bulk modelsimulation. The correction of the terminal fall velocities of snowflakes using those of hail further improves theresult of the bin model simulation. The results indicate that there are substantial uncertainties in the masssizeand sizeterminal fall velocity relations of snowflakes or in the calculation of terminal fall velocity of snowaloft. For the bulk microphysics, the overestimation of Ze is observed as a result of a significant predominanceof snow over cloud ice due to substantial deposition growth directly to snow. The DV comparison shows thata correction for the fall velocity of hydrometeors considering a change of particle size should be introducedeven in single-moment bulk cloud microphysics.

Iguchi, Takamichi; Nakajima, Teruyuki; Khain, Alexander P.; Saito, Kazuo; Takemura, Toshihiko; Okamoto, Hajime; Nishizawa, Tomoaki; Tao, Wei-Kuo

2012-01-01

351

GMTI MIMO radar  

E-print Network

Multiple-input multiple-output (MIMO) extensions to radar systems enable a number of advantages compared to traditional approaches. These advantages include improved angle estimation and target detection. In this paper, ...

Bliss, Daniel W., Jr.

352

Caribbean Radar Products  

NSDL National Science Digital Library

This module provides examples of radar imagery from various locations in the Caribbean to demonstrate the different types of images available. Also, examples of different meteorological and non meteorological features are presented to show features seen in island locations.

COMET

2013-12-31

353

Imaging with Radar  

NSDL National Science Digital Library

This interactive activity from NOVA features synthetic aperture radar (SAR), which uses radio waves to create high-quality images. Examine SAR images of Washington, D.C., and learn about this technology's unique advantages.

WGBH Educational Foundation

2004-01-29

354

The Implementation and Evaluation of the Emergency Response Dose Assessment System (ERDAS) at Cape Canaveral Air Station/Kennedy Space Center  

NASA Technical Reports Server (NTRS)

The Emergency Response Dose Assessment System (ERDAS) is a system which combines the mesoscale meteorological prediction model RAMS with the diffusion models REEDM and HYPACT. Operators use a graphical user interface to run the models for emergency response and toxic hazard planning at CCAS/KCS. The Applied Meteorology Unit has been evaluating the ERDAS meteorological and diffusion models and obtained the following results: (1) RAMS adequately predicts the occurrence of the daily sea breeze during non-cloudy conditions for several cases. (2) RAMS shows a tendency to predict the sea breeze to occur slightly earlier and to move it further inland than observed. The sea breeze predictions could most likely be improved by better parameterizing the soil moisture and/or sea surface temperatures. (3) The HYPACT/REEDM/RAMS models accurately predict launch plume locations when RAMS winds are accurate and when the correct plume layer is modeled. (4) HYPACT does not adequately handle plume buoyancy for heated plumes since all plumes are presently treated as passive tracers. Enhancements should be incorporated into the ERDAS as it moves toward being a fully operational system and as computer workstations continue to increase in power and decrease in cost. These enhancements include the following: activate RAMS moisture physics; use finer RAMS grid resolution; add RAMS input parameters (e.g. soil moisture, radar, and/or satellite data); automate data quality control; implement four-dimensional data assimilation; modify HYPACT plume rise and deposition physics; and add cumulative dosage calculations in HYPACT.

Evans, Randolph J.; Tremback, Craig J.; Lyons, Walter A.

1996-01-01

355

The Capabilities of Space Stations  

NASA Technical Reports Server (NTRS)

Over the past two years the U.S. space station program has evolved to a three-phased international program, with the first phase consisting of the use of the U.S. Space Shuttle and the upgrading and use of the Russian Mir Space Station, and the second and third phases consisting of the assembly and use of the new International Space Station. Projected capabilities for research, and plans for utilization, have also evolved and it has been difficult for those not directly involved in the design and engineering of these space stations to learn and understand their technical details. The Committee on the Space Station of the National Research Council, with the concurrence of NASA, undertook to write this short report in order to provide concise and objective information on space stations and platforms -- with emphasis on the Mir Space Station and International Space Station -- and to supply a summary of the capabilities of previous, existing, and planned space stations. In keeping with the committee charter and with the task statement for this report, the committee has summarized the research capabilities of five major space platforms: the International Space Station, the Mir Space Station, the Space Shuttle (with a Spacelab or Spacehab module in its cargo bay), the Space Station Freedom (which was redesigned to become the International Space Station in 1993 and 1994), and Skylab. By providing the summary, together with brief descriptions of the platforms, the committee hopes to assist interested readers, including scientists and engineers, government officials, and the general public, in evaluating the utility of each system to meet perceived user needs.

1995-01-01

356

Doppler Radar Technology  

NSDL National Science Digital Library

This resource provides an introduction to the function and uses of the The National Weather Service's (NWS) Weather Surveillance Doppler Radar (WSR-88D). Topics include the components of the system, an overview of the products and overlays the system creates, and some example images with captions explaining what is being shown. There are also links to radar meteorology tutorials and to information on training to use the system and interpret its imagery.

357

Downhole pulse radar  

DOEpatents

A borehole logging tool generates a fast rise-time, short duration, high peak-power radar pulse having broad energy distribution between 30 MHz and 300 MHz through a directional transmitting and receiving antennas having barium titanate in the electromagnetically active region to reduce the wavelength to within an order of magnitude of the diameter of the antenna. Radar returns from geological discontinuities are sampled for transmission uphole. 7 figs.

Chang, Hsi-Tien

1987-09-28

358

Downhole pulse radar  

SciTech Connect

A borehole logging tool generates a fast rise-time, short duration, high peak-power radar pulse having broad energy distribution between 30 MHz and 300 MHz through a directional transmitting and receiving antennas having barium titanate in the electromagnetically active region to reduce the wavelength to within an order of magnitude of the diameter of the antenna. Radar returns from geological discontinuities are sampled for transmission uphole.

Chang, Hsi-Tien (Albuquerque, NM)

1989-01-01

359

Adaptive MIMO radar waveforms  

Microsoft Academic Search

Multiple-Input, Multiple-Output (MIMO) radars enhance performance by transmitting and receiving coded waveforms from multiple locations. To date, the theoretical literature on MIMO radar has focused largely on the use of ldquoorthogonal waveforms.rdquo Practical approaches to approximate orthogonality (e.g., via waveforms characterized by low cross-correlation and low autocorrelation sidelobe levels) have also started to emerge. We show, however, that such waveforms

Daniel J. Rabideau; Lexington MA

2008-01-01

360

Technical evaluation of the susceptibility of safety-related systems to flooding caused by the failure of non-category 1 systems for the Yankee Rowe Nuclear Power Station  

Microsoft Academic Search

This report documents the technical evaluation of the Maine Yankee Atomic Power Station. The purpose of this evaluation was to determine whether the failure of any non-Class I (seismic) equipment could result in a condition, such as flooding, that might adversely affect the performance of the safety-related equipment required for the safe shutdown of the facility, or to mitigate the

Epps

1980-01-01

361

Pulse Doppler radar simulation study  

NASA Astrophysics Data System (ADS)

In the past several years two different models have been produced for predicting detection performance of space-based and airborne coherent pulsed radars. The present work describes enhancements incorporated in the software including: (1) conversion of the code to ANSI standard FORTRAN-77; (2) development and implementation of a suitable algorithm for the evaluation of the clutter covariance matrix of an array processor; (3) derivation and coding of the linear frequency modulated (LFM) waveform simulation capability for radar system performance evaluation; and (4) implementation of a Monte Carlo code to study receiver imperfections for the non-frequency modulated (NFM) waveform as well as the derivation of analytical expressions describing the effects of linear receiver imperfections on this waveform. Single precision accuracy was found to be close to that of double precision. The looping of the clutter patches was found to be the time limiting process in the clutter calculations and hence little run time was gained by use of single precision. Evaluation of the LFM waveform showed range velocity coupling and a nonstationary behaviour or the return signal. Detection performance of the LFM waveform is consistently better than that of the NFM waveform.

Gibb, Murray; Lightstone, Leonard; Saper, Ronald H.

1988-10-01

362

On wave radar measurement  

NASA Astrophysics Data System (ADS)

The SAAB REX WaveRadar sensor is widely used for platform-based wave measurement systems by the offshore oil and gas industry. It offers in situ surface elevation wave measurements at relatively low operational costs. Furthermore, there is adequate flexibility in sampling rates, allowing in principle sampling frequencies from 1 to 10 Hz, but with an angular microwave beam width of 10° and an implied ocean surface footprint in the order of metres, significant limitations on the spatial and temporal resolution might be expected. Indeed there are reports that the accuracy of the measurements from wave radars may not be as good as expected. We review the functionality of a WaveRadar using numerical simulations to better understand how WaveRadar estimates compare with known surface elevations. In addition, we review recent field measurements made with a WaveRadar set at the maximum sampling frequency, in the light of the expected functionality and the numerical simulations, and we include inter-comparisons between SAAB radars and buoy measurements for locations in the North Sea.

Ewans, Kevin; Feld, Graham; Jonathan, Philip

2014-08-01

363

On wave radar measurement  

NASA Astrophysics Data System (ADS)

The SAAB REX WaveRadar sensor is widely used for platform-based wave measurement systems by the offshore oil and gas industry. It offers in situ surface elevation wave measurements at relatively low operational costs. Furthermore, there is adequate flexibility in sampling rates, allowing in principle sampling frequencies from 1 to 10 Hz, but with an angular microwave beam width of 10° and an implied ocean surface footprint in the order of metres, significant limitations on the spatial and temporal resolution might be expected. Indeed there are reports that the accuracy of the measurements from wave radars may not be as good as expected. We review the functionality of a WaveRadar using numerical simulations to better understand how WaveRadar estimates compare with known surface elevations. In addition, we review recent field measurements made with a WaveRadar set at the maximum sampling frequency, in the light of the expected functionality and the numerical simulations, and we include inter-comparisons between SAAB radars and buoy measurements for locations in the North Sea.

Ewans, Kevin; Feld, Graham; Jonathan, Philip

2014-09-01

364

Developing Lightning Prediction Tools for the CCAFS Dual-Polarimetric Radar  

NASA Technical Reports Server (NTRS)

NASA Marshall Space Flight Center and the University of Alabama Huntsville are collaborating with the 45th Weather Squadron (45WS) to develop improved lightning prediction capabilities for the new C-band dual-polarimetric weather radar being acquired for use by 45WS and launch weather forecasters at Cape Canaveral Air Force Station (CCAFS). In particular, these algorithms will focus on lightning onset, cessation and combined lightning-radar applications for convective winds assessment. Research using radar reflectivity (Z) data for prediction of lightning onset has been extensively discussed in the literature and subsequently applied by launch weather forecasters as it pertains to lightning nowcasting. Currently the forecasters apply a relatively straight forward but effective temperature-Z threshold algorithm for assessing the likelihood of lightning onset in a given storm. In addition, a layered VIL above the freezing level product is used as automated guidance for the onset of lightning. Only limited research and field work has been conducted on lightning cessation using Z and vertically-integrated Z for determining cessation. Though not used operationally vertically-integrated Z (basis for VIL) has recently shown promise as a tool for use in nowcasting lightning cessation. The work discussed herein leverages and expands upon these and similar reflectivity-threshold approaches via the application/addition of over two decades of polarimetric radar research focused on distinct multi-parameter radar signatures of ice/mixed-phase initiation and ice-crystal orientation in highly electrified convective clouds. Specifically, our approach is based on numerous previous studies that have observed repeatable patterns in the behavior of the vertical hydrometeor column as it relates to the temporal evolution of differential reflectivity and depolarization (manifested in either LDR or p(sub hv)), development of in-situ mixed and ice phase microphysics, electric fields, and ensuing lightning in the sub-tropical/tropical convection typical of the southeastern U.S., Maritime Continent, and southwestern Amazon. The polarimetric signatures detected in this setting provide a basis for automated 3-D detection of hydrometeor types in fuzzy logic hydrometeor identification algorithms (HID). Our working hypothesis is that improvement in lightning onset warning lead time and specificity for a given storm, relative to application of a Z-threshold algorithm, should arise as a consequence of the ability of dual-polarimetric radar to unambiguously detect and identify (through HID algorithms) the updraft elevation of rain-water cores above the freezing level and subsequent onset of drop freezing, riming, and robust mixed phase processes leading to significant charge separation and lightning. This type of algorithm, though dependent on the quality of the polarimetric data should be less susceptible to variable Z-calibration that can impact a given Z-threshold approach. To facilitate development of the algorithm while the 45WS dual-pol radar is in its current test stages and to evaluate the impact of polarimetric data quality (e.g., modified scan parameters and sampling) on the ensuing algorithms, we are using the ARMOR C-band dual-pol radar in Huntsville combined with N. Alabama LMA data and ARMOR HID algorithms [NCAR algorithm modified for application at C-band] in a testbed fashion. For lightning cessation we are revisiting the application of differential propagation phase variables for the monitoring of ice crystal alignment driven by in-cloud electric fields combined with metrics of ice water path (i.e., vertically integrated reflectivity). Importantly it should be noted that this approach is still very much a research topic and as such, we will explore operational applications that involve radar frequencies other than C-Band by using the UAH MAX X-band dual-pol radar in slow staring modes.

Petersen, W. A.; Carey, L. D.; Deierling, W.; Johnson, E.; Bateman, M.

2009-01-01

365

Development of Ku-band rendezvous radar tracking and acquisition simulation programs  

NASA Technical Reports Server (NTRS)

The fidelity of the Space Shuttle Radar tracking simulation model was improved. The data from the Shuttle Orbiter Radar Test and Evaluation (SORTE) program experiments performed at the White Sands Missile Range (WSMR) were reviewed and analyzed. The selected flight rendezvous radar data was evaluated. Problems with the Inertial Line-of-Sight (ILOS) angle rate tracker were evaluated using the improved fidelity angle rate tracker simulation model.

1986-01-01

366

Language Learning Stations.  

ERIC Educational Resources Information Center

Describes use of learning stations at elementary and secondary levels. Explains vocabulary, grammar, conversation, listening, reading and culture stations; materials and equipment for stations; management concerns. (BK)

Strauber, Sandra K.

1981-01-01

367

Venus Orbital Imaging Radar mission analysis  

NASA Technical Reports Server (NTRS)

Mission objectives for the Venus Orbital Imaging Radar (VOIR) project are outlined with attention to its scientific instrumentation. Design parameters of the SAR (Synthetic Aperture Radar) are described, including a high resolution capability of 200 m from a circular orbit of 375 km, which will be able to map the entire surface of the planet. Nineteen atmospheric experiments are foreseen, among them: CO2 stability assays, measurements of vertical mass transfer rates, observations of cloud circulation and composition, and an evaluation of solar wind effects on atmospheric dynamics. Navigation and orbital injection plans are reviewed, noting that the 1983 launch window (using STS) is optimum.

Nock, K. T.; Bender, D. F.

1977-01-01

368

Urban Flood Warning Systems using Radar Technologies  

NASA Astrophysics Data System (ADS)

There have been an increasing number of urban areas that rely on weather radars to provide accurate precipitation information for flood warning purposes. As non-structural tools, radar-based flood warning systems can provide accurate and timely warnings to the public and private entities in urban areas that are prone to flash floods. The wider spatial and temporal coverage from radar increases flood warning lead-time when compared to rain and stream gages alone. The Third Generation Rice and Texas Medical Center (TMC) Flood Alert System (FAS3) has been delivering warning information with 2 to 3 hours of lead time and a R2 value of 93% to facility personnel in a readily understood format for more than 50 events in the past 15 years. The current FAS utilizes NEXRAD Level II radar rainfall data coupled with a real-time hydrologic model (RTHEC-1) to deliver warning information. The system has a user-friendly dashboard to provide rainfall maps, Google Maps based inundation maps, hydrologic predictions, and real-time monitoring at the bayou. This paper will evaluate its reliable performance during the recent events occurring in 2012 and 2013 and the development of a similar radar-based flood warning system for the City of Sugar Land, Texas. Having a significant role in the communication of flood information, FAS marks an important step towards the establishment of an operational and reliable flood warning system for flood-prone urban areas.

Fang, N.; Bedient, P. B.

2013-12-01

369

MPLNET lidar data assimilation in the ECMWF MACC-II Aerosol system: evaluation of model performances at NCU lidar station  

NASA Astrophysics Data System (ADS)

Atmospheric profiles of the optical aerosol properties through the retrieved backscattering or extinction coefficients by lidar measurements can improve drastically the MACC-II aerosol model performances on vertical dimension. Currently the MODIS Aerosol Optical Depth data (both from Terra and Aqua) are assimilated into the model. Being a columnintegrated quantity, these data do not modify the model aerosol vertical profile, especially if the aerosols are not interactive with the meteorology. Since 1999, the MPLNET lidar network provides continuously lidar data measurements from worldwide permanent stations (currently 21), deployed from the Arctic to the Antarctic regions and in tropical and equatorial zones. The purpose of this study is to show the first preliminary results of the intercomparison of MPLNET lidar data against the ECWMF MACC-II aerosol model, for a selected MPLNET permanent observational site at National Central University of Taiwan. Assessing the model performances it is the first step for future near-real time lidar data assimilation into MACC-II aerosol model forecast.

Lolli, Simone; Welton, Ellsworth J.; Benedetti, Angela; Jones, Luke; Suttie, Martin; Wang, Sheng-Hsiang

2014-10-01

370

Evaluation of an 8 hour versus a 12 hour shift roster on employees at a power station.  

PubMed

Several studies exist that have conducted research into the effects of different shiftwork patterns on the individual, especially regarding 8 and 12 h rosters. The findings of these studies have been largely supportive of longer shifts, however, the effects on work performance are not as clear cut. This study aimed to examine the changeover from an 8 h roster to a 12 h roster in a power station via monitoring on-shift performance, general health and well-being, sleep and mood behaviour, as well as absence and accident data. Results suggest that the domestic and social life of workers was markedly improved under the 12 h roster. Improvements in physical health, sleeping behaviour and mood state of employees were also documented. On-shift performance measures showed an increase in error rates at the end of a 12 h shift. Ways of reducing the risk of error towards the end of a 12 h shift should be explored. The results of this study suggest that 12 h shifts are a valid alternative to 8 h shifts in this particular workplace, although tasks that require error-free activities should not be performed towards the end of a 12 h shift. PMID:10709754

Mitchell, R J; Williamson, A M

2000-02-01

371

Bats avoid radar installations: could electromagnetic fields deter bats from colliding with wind turbines?  

PubMed

Large numbers of bats are killed by collisions with wind turbines, and there is at present no direct method of reducing or preventing this mortality. We therefore determine whether the electromagnetic radiation associated with radar installations can elicit an aversive behavioural response in foraging bats. Four civil air traffic control (ATC) radar stations, three military ATC radars and three weather radars were selected, each surrounded by heterogeneous habitat. Three sampling points matched for habitat type and structure, dominant vegetation species, altitude and surrounding land class were located at increasing distances from each station. A portable electromagnetic field meter measured the field strength of the radar at three distances from the source: in close proximity (<200 m) with a high electromagnetic field (EMF) strength >2 volts/metre, an intermediate point within line of sight of the radar (200-400 m) and with an EMF strength <2 v/m, and a control site out of sight of the radar (>400 m) and registering an EMF of zero v/m. At each radar station bat activity was recorded three times with three independent sampling points monitored on each occasion, resulting in a total of 90 samples, 30 of which were obtained within each field strength category. At these sampling points, bat activity was recorded using an automatic bat recording station, operated from sunset to sunrise. Bat activity was significantly reduced in habitats exposed to an EMF strength of greater than 2 v/m when compared to matched sites registering EMF levels of zero. The reduction in bat activity was not significantly different at lower levels of EMF strength within 400 m of the radar. We predict that the reduction in bat activity within habitats exposed to electromagnetic radiation may be a result of thermal induction and an increased risk of hyperthermia. PMID:17372629

Nicholls, Barry; Racey, Paul A

2007-01-01

372

Radar MeteorologyRadar Meteorology Feb 20, 1941 10 cm (S-band) radar used to track rain showers (Ligda)  

E-print Network

Radar MeteorologyRadar Meteorology Feb 20, 1941 10 cm (S-band) radar used to track rain showers similar observations in the early 1940's (U.S. Air Corps meteorologists receiving "radar" training at MIT in 1943 First operational weather radar, Panama, 1943 Science of radar meteorology born from WWII research

Rutledge, Steven

373

1. View of three detection radar (DR) antennas. DR 1 ...  

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

1. View of three detection radar (DR) antennas. DR 1 (structure no. 735) on left, DR 2 (structure no. 736) in center, and DR 3 (structure no. 737) looking north 30 degrees west, with tracking radar (large radome) and satcom (satellite communication) system in small radome in view between DR 2 and DR 3 antennae. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

374

High SO{sub 2} removal efficiency testing: Evaluation of high efficiency test results at Hoosier Energy`s Merom Station  

SciTech Connect

Tests were conducted at Hoosier Energy`s Merom Station 535-MW Units 1 and 2 wet limestone flue gas desulfurization (FGD) systems to evaluate options for achieving high SO{sub 2} removal efficiency. The options tested included use of dibasic acid (DBA) and sodium formate additives as well as operation at higher reagent ratios (higher pH set points). In addition to the tested options, the effectiveness of other potential options was simulated using the Electric Power Research Institute`s FGD Process Integration and Simulation Model (FGDPRISM) after it was calibrated to the system. An economic analysis was done to determine the cost effectiveness of each option. A summary of results is given on the following: SO{sub 2} removal performance; additive consumption; and SO{sub 2} removal upgrade economics.

NONE

1996-04-22

375

Evaluation of zeolite mixtures for decontaminating high-activity-level water at the Three Mile Island Unit 2 Nuclear Power Station  

SciTech Connect

Mixtures of Linde Ionsiv IE-96 and Ionsiv A-51 were evaluated for use in the Submerged Demineralizer System (SDS) that was installed at the Three Mile Island Unit 2 Nuclear Power Station to decontaminate approx. 2780 m/sup 3/ of high-activity-level water. The original SDS flowsheet was conservatively designed for removal of cesium and strontium and would have required the use of approx. 60 SDS columns. Mixed zeolite tests were made on a 10/sup -5/ scale and indicated that the appropriate ratio of IE-96/A-51 was 3/2. A mathematical model was used to predict the performance of the mixed zeolite columns in the SDS configuration and with the intended method of operation. Actual loading results were similar to those predicted for strontium and better than those predicted for cesium. The number of SDS columns needed to process the HALW was reduced to approx. 10. 6 references, 4 figures, 2 tables.

Collins, E.D.; Campbell, D.O.; King, L.J.; Knauer, J.B.; Wallace, R.M.

1984-05-01

376

A solid state low pulse power ground surveillance radar  

NASA Astrophysics Data System (ADS)

The use of high-duty-ratio transmissions improves the efficiency and economy of solid state transmitter power amplifiers, while simultaneously reducing the detectability of a radar by conventional electronic surveillance receivers. A composite waveform, consisting of two orthogonally coded pulses radiated within the same pulse repetition interval, offers a combination of high transmission duty ratio and a pulse repetition rate low enough to avoid range ambiguity. Used with solid-state-transmitters, low-sidelobe antennas, and modern signal-processing techniques, this waveform provides the basis for a class of short-to-medium-range radars that combine good clutter discrimination with high survivability in a radar countermeasures environment. Following a short discussion of radar detectability and a description of the orthogonally coded pulse waveform, this paper outlines the design features of a practical ground surveillance radar that is being developed to evaluate these concepts.

McKillop, A.

377

Mapping diverse forest cover with multipolarization airborne radar  

NASA Technical Reports Server (NTRS)

Imaging radar backscatter in continuously forested areas contains information about the forest canopy; it also contains data about topography, landforms, and terrain texture. For purposes of radar image interpretation and geologic mapping researchers were interested in identifying and separating forest canopy effects from geologic or geomorphic effects on radar images. The objectives of this investigation was to evaluate forest canopy variables in multipolarization radar images under conditions where geologic and topographic variables are at a minimum. A subsidiary objective was to compare the discriminatory capabilities of the radar images with corresponding optical images of similar spatial resolution. It appears that the multipolarization images discriminate variation in tree density, but no evidence was found for discrimination between evergreen and deciduous forest types.

Ford, J. P.; Wickland, D. E.; Sharitz, R. R.

1985-01-01

378

66. VIEW SHOWING HOLD FOR RADAR CABLES AT RADAR SITE, ...  

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

66. VIEW SHOWING HOLD FOR RADAR CABLES AT RADAR SITE, LOOKING NORTH Everett Weinreb, photographer, March 1988 - Mount Gleason Nike Missile Site, Angeles National Forest, South of Soledad Canyon, Sylmar, Los Angeles County, CA

379

Investigation of Advanced Radar Techniques for Atmospheric Hazard Detection with Airborne Weather Radar  

NASA Technical Reports Server (NTRS)

In 2013 ProSensing Inc. conducted a study to investigate the hazard detection potential of aircraft weather radars with new measurement capabilities, such as multi-frequency, polarimetric and radiometric modes. Various radar designs and features were evaluated for sensitivity, measurement range and for detecting and quantifying atmospheric hazards in wide range of weather conditions. Projected size, weight, power consumption and cost of the various designs were also considered. Various cloud and precipitation conditions were modeled and used to conduct an analytic evaluation of the design options. This report provides an overview of the study and summarizes the conclusions and recommendations.

Pazmany, Andrew L.

2014-01-01

380

Community Radio Stations as Community Technology Centers: An Evaluation of the Development Impact of Technological Hybridization on Stakeholder Communities in South Africa  

Microsoft Academic Search

This study investigated the impact of using community radio stations to extend information and communication technology (ICT) benefits to poor communities in South Africa. Six community radio stations in six rural South African communities were studied, using face-to-face interviews, community conversations, and observation method. The study found these radio stations have ICT presence, but because of a lack of resources

Eronini R. Megwa

2007-01-01

381

Evaluation of geophysical logs, Phase II, at Willow Grove Naval Air Station Joint Reserve Base, Montgomery County, Pennsylvania  

USGS Publications Warehouse

Between March and April 1998, the U.S. Navy contracted Tetra Tech NUS Inc., to drill two monitor wells in the Stockton Formation at the Willow Grove Naval Air Station Joint Reserve Base, Horsham Township, Montgomery County, Pa. The wells MG-1634 and MG-1635 were installed to monitor water levels and sample contaminants in the shallow, intermediate, and deep water-producing zones of the fractured bedrock. Chemical analyses of the samples will help determine the horizontal and vertical distribution of any contaminated ground water migrating from known contaminant sources. Wells were drilled near the Fire Training Area (Site 5). Depths of all boreholes range from 69 to 149 feet below land surface. The U.S. Geological Survey conducted borehole geophysical logging and video surveys to identify water-producing zones in newly drilled monitor wells MG-1634 and MG-1635 and in wells MG-1675 and MG-1676. The logging was conducted from March 5, 1998, to April 16, 1998. This work is a continuation of the Phase I work. Caliper logs and video surveys were used to locate fractures; inflections on fluid-temperature and fluid-resistivity logs were used to locate possible water-producing fractures. Heatpulse-flowmeter measurements were used to verify the locations of water-producing or water-receiving zones and to measure rates of flow between water-bearing fractures. Single-point-resistance and natural-gamma logs provided information on stratigraphy. After interpretation of geophysical logs, video surveys, and driller's notes, wells MG-1634 and MG-1635 were screened such that water-levels fluctuations could be monitored and discrete water samples collected from one or more water-producing zones in each borehole.

Conger, Randall W.

1999-01-01

382

An Independent Human Factors Analysis and Evaluation of the Emergency Medical Protocol Checklist for the International Space Station  

NASA Technical Reports Server (NTRS)

Emergency medical capabilities aboard the ISS include a Crew Medical Officer (CMO) (not necessarily a physician), and back-up, resuscitation equipment, and a medical checklist. It is essential that CMOs have reliable, usable and informative medical protocols that can be carried out independently in flight. The study evaluates the existing ISS Medical Checklist layout against a checklist updated to reflect a human factors approach to structure and organization. Method: The ISS Medical checklist was divided into non-emergency and emergency sections, and re-organized based on alphabetical and a body systems approach. A desk-top evaluation examined the ability of subjects to navigate to specific medical problems identified as representative of likely non-emergency events. A second evaluation aims to focus on the emergency section of the Medical Checklist, based on the preliminary findings of the first. The final evaluation will use Astronaut CMOs as subjects comparing the original checklist against the updated layout in the task of caring for a "downed crewmember" using a Human Patient Simulator [Medical Education Technologies, Inc.]. Results: Initial results have demonstrated a clear improvement of the re-organized sections to determine the solution to the medical problems. There was no distinct advantage for either alternative, although subjects stated having a preference for the body systems approach. In the second evaluation, subjects will be asked to identify emergency medical conditions, with measures including correct diagnosis, time to completion and solution strategy. The third evaluation will compare the original and fully updated checklists in clinical situations. Conclusions: Initial findings indicate that the ISS Medical Checklist will benefit from a reorganization. The present structure of the checklist has evolved over recent years without systematic testing of crewmember ability to diagnose medical problems. The improvements are expected to enable ISS Crewmembers to more speedily and accurately respond to medical situations on the ISS.

Marshburn, Thomas; Whitmore, Mihriban; Ortiz, Rosie; Segal, Michele; Smart, Kieran; Hughes, Catherine

2003-01-01

383

Sky Station  

NSDL National Science Digital Library

While satellites are the current backbone of telecommunications and wireless infrastructure, the company that maintains this Web site envisions a completely new technology. The Stratospheric Telecommunications Service (STS) relies on "lighter-than-air platforms which are held in a geo-stationary position in the stratosphere (approximately 21Km) over a major metropolitan area." The Sky Station company documents much of the STS theory online, as well as maintaining news and information articles about the progress of the system's development. US and international organizations have already reserved some of the radio frequency spectrum for stratospheric platforms, and it seems to have considerable support from important agencies.

384

Weather Radar and Instrumentation: Laboratory Modules  

NSDL National Science Digital Library

These 16 radar education modules, developed for the Weather Radar and Instrumentation Curriculum at the University of Oklahoma, provide hands-on instruction for beginning, intermediate, or advanced students to learn about radar systems, especially weather radar. Topics include hardware, weather radar, adaptive systems, advanced hydrometeors, applications of weather radar, and atmospheric interpretations. The modules may be downloaded.

385

Mapping Wintering Waterfowl Distributions Using Weather Surveillance Radar  

PubMed Central

The current network of weather surveillance radars within the United States readily detects flying birds and has proven to be a useful remote-sensing tool for ornithological study. Radar reflectivity measures serve as an index to bird density and have been used to quantitatively map landbird distributions during migratory stopover by sampling birds aloft at the onset of nocturnal migratory flights. Our objective was to further develop and validate a similar approach for mapping wintering waterfowl distributions using weather surveillance radar observations at the onset of evening flights. We evaluated data from the Sacramento, CA radar (KDAX) during winters 1998–1999 and 1999–2000. We determined an optimal sampling time by evaluating the accuracy and precision of radar observations at different times during the onset of evening flight relative to observed diurnal distributions of radio-marked birds on the ground. The mean time of evening flight initiation occurred 23 min after sunset with the strongest correlations between reflectivity and waterfowl density on the ground occurring almost immediately after flight initiation. Radar measures became more spatially homogeneous as evening flight progressed because birds dispersed from their departure locations. Radars effectively detected birds to a mean maximum range of 83 km during the first 20 min of evening flight. Using a sun elevation angle of ?5° (28 min after sunset) as our optimal sampling time, we validated our approach using KDAX data and additional data from the Beale Air Force Base, CA (KBBX) radar during winter 1998–1999. Bias-adjusted radar reflectivity of waterfowl aloft was positively related to the observed diurnal density of radio-marked waterfowl locations on the ground. Thus, weather radars provide accurate measures of relative wintering waterfowl density that can be used to comprehensively map their distributions over large spatial extents. PMID:22911816

Buler, Jeffrey J.; Randall, Lori A.; Fleskes, Joseph P.; Barrow, Wylie C.; Bogart, Tianna; Kluver, Daria

2012-01-01

386

Radar studies related to the earth resources program. [remote sensing programs  

NASA Technical Reports Server (NTRS)

The radar systems research discussed is directed toward achieving successful application of radar to remote sensing problems in such areas as geology, hydrology, agriculture, geography, forestry, and oceanography. Topics discussed include imaging radar and evaluation of its modification, study of digital processing for synthetic aperture system, digital simulation of synthetic aperture system, averaging techniques studies, ultrasonic modeling of panchromatic system, panchromatic radar/radar spectrometer development, measuring octave-bandwidth response of selected targets, scatterometer system analysis, and a model Fresnel-zone processor for synthetic aperture imagery.

Holtzman, J.

1972-01-01

387

Radar-cross-section reduction of wind turbines. part 1.  

SciTech Connect

In recent years, increasing deployment of large wind-turbine farms has become an issue of growing concern for the radar community. The large radar cross section (RCS) presented by wind turbines interferes with radar operation, and the Doppler shift caused by blade rotation causes problems identifying and tracking moving targets. Each new wind-turbine farm installation must be carefully evaluated for potential disruption of radar operation for air defense, air traffic control, weather sensing, and other applications. Several approaches currently exist to minimize conflict between wind-turbine farms and radar installations, including procedural adjustments, radar upgrades, and proper choice of low-impact wind-farm sites, but each has problems with limited effectiveness or prohibitive cost. An alternative approach, heretofore not technically feasible, is to reduce the RCS of wind turbines to the extent that they can be installed near existing radar installations. This report summarizes efforts to reduce wind-turbine RCS, with a particular emphasis on the blades. The report begins with a survey of the wind-turbine RCS-reduction literature to establish a baseline for comparison. The following topics are then addressed: electromagnetic model development and validation, novel material development, integration into wind-turbine fabrication processes, integrated-absorber design, and wind-turbine RCS modeling. Related topics of interest, including alternative mitigation techniques (procedural, at-the-radar, etc.), an introduction to RCS and electromagnetic scattering, and RCS-reduction modeling techniques, can be found in a previous report.

Brock, Billy C.; Loui, Hung; McDonald, Jacob J.; Paquette, Joshua A.; Calkins, David A.; Miller, William K.; Allen, Steven E.; Clem, Paul Gilbert; Patitz, Ward E.

2012-03-05

388

33. Perimeter acquisition radar building room #320, perimeter acquisition radar ...  

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

33. Perimeter acquisition radar building room #320, perimeter acquisition radar operations center (PAROC), contains the tactical command and control group equipment required to control the par site. Showing spacetrack monitor console - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

389

Synthetic Aperture Radar Simulation On Radar Terrain Clutter  

Microsoft Academic Search

The subject of this paper is related to a new method of Synthetic Aperture Radar (i.e., SAR) simulation on radar terrain clutter. Usually, images are simulated at pixel level after Doppler compression. In this case this study deals with the simulation of the raw signal at the output of the antenna i.e. for each pulse emitted by the radar during

ARMAND Pierre; VIDAL-MADJAR Daniel

1992-01-01

390

Systems and Methods for Radar Data Communication  

NASA Technical Reports Server (NTRS)

A radar information processing system is operable to process high bandwidth radar information received from a radar system into low bandwidth radar information that may be communicated to a low bandwidth connection coupled to an electronic flight bag (EFB). An exemplary embodiment receives radar information from a radar system, the radar information communicated from the radar system at a first bandwidth; processes the received radar information into processed radar information, the processed radar information configured for communication over a connection operable at a second bandwidth, the second bandwidth lower than the first bandwidth; and communicates the radar information from a radar system, the radar information communicated from the radar system at a first bandwidth.

Bunch, Brian (Inventor); Szeto, Roland (Inventor); Miller, Brad (Inventor)

2013-01-01

391

Radar data smoothing filter study  

NASA Technical Reports Server (NTRS)

The accuracy of the current Wallops Flight Facility (WFF) data smoothing techniques for a variety of radars and payloads is examined. Alternative data reduction techniques are given and recommendations are made for improving radar data processing at WFF. A data adaptive algorithm, based on Kalman filtering and smoothing techniques, is also developed for estimating payload trajectories above the atmosphere from noisy time varying radar data. This algorithm is tested and verified using radar tracking data from WFF.

White, J. V.

1984-01-01

392

The Southern Argentina Agile Meteor Radar (SAAMER): Platform for comprehensive meteor radar observations and studies  

NASA Astrophysics Data System (ADS)

The Southern Argentina Agile Meteor Radar (SAAMER) is a new generation system deployed in Rio Grande, Tierra del Fuego, Argentina (53^oS) in May 2008 (Janches et al., 2013,2014). SAAMER transmits 10 times more power than regular meteor radars, and uses a newly developed transmitting array, which focuses power upward instead of the traditional single-antenna-all-sky configuration. The system is configured such that the transmitter array can also be utilized as a receiver. The new design greatly increases the sensitivity of the radar enabling the detection of large numbers of particles at low zenith angles. The more concentrated transmitted power enables additional meteor studies besides those typical of these systems based on the detection of specular reflections, such as routine detections of head echoes and non-specular trails, previously only possible with High Power and Large Aperture radars (Janches et al., 2014). In August 2010, SAAMER was upgraded to a system capable to determine meteoroid orbital parameters. This was achieved by adding two remote receiving stations approximately 10 km away from the main site in near perpendicular directions (Pifko et al., 2014). The upgrade significantly expands the science that is achieved with this new radar enabling us to study the orbital properties of the interplanetary dust environment. Because of the unique geographical location, the SAAMER allows for additional inter-hemispheric comparison with measurements from Canadian Meteor Orbit Radar, which is geographically conjugate. Initial surveys show, for example, that SAAMER observes a very strong contribution of the South Toroidal Sporadic meteor source (Pifko et al., 2014), of which limited observational data is available. In addition, SAAMER offers similar unique capabilities for meteor showers and streams studies given the range of ecliptic latitudes that the system enables to survey (Janches et al., 2013). It can effectively observe radiants from the ecliptic south pole to approximately 30°N, and thus enable a detailed study of showers at high southern latitudes (e.g., July Phoenicids or Puppids complex), which are unobservable from the CMOR's location. Finally, SAAMER is ideal for the deployment of complementary instrumentation in both permanent and campaign operational modes. Results from various radar meteor investigations as well as radar/optical observation campaigns will be presented in this paper.

Janches, D.; Hormaechea, J.; Pifko, S.; Hocking, W.; Fritts, D.; Brunini, C.; Close, S.; Michell, R.; Samara, M.

2014-07-01

393

Evaluation of severe accident risks and the potential for risk reduction: Surry Power Station, Unit 1: Draft report for comment  

SciTech Connect

The Severe Accident Risk Reduction Program (SARRP) has completed a rebaselining of the risks to the public from a particular pressurized water reactor with a subatmospheric containment (Surry, Unit 1). Emphasis was placed on determining the magnitude and character of the uncertainties, rather than focusing on a point estimate. The risk-reduction potential of a set of proposed safety option backfits was also studied, and their costs and benefits were also evaluated. It was found that the risks from internal events are generally lower than previously evaluated in the Reactor Safety Study (RSS). However, certain unresolved issues (such as direct containment heating) caused the top of the uncertainty band to appear at a level that is comparable with the RSS point estimate. None of the postulated safety options appears to be cost effective for the Surry power plant. This work supports the Nuclear Regulatory Commission's assessment of severe accidents in NUREG-1150.

Benjamin, A.S.; Boyd, G.J.; Kunsman, D.M.; Murfin, W.B.; Williams, D.C.

1987-02-01

394

Radar image San Francisco Bay Area, California  

NASA Technical Reports Server (NTRS)

The San Francisco Bay Area in California and its surroundings are shown in this radar image from the Shuttle Radar Topography Mission (SRTM). On this image, smooth areas, such as the bay, lakes, roads and airport runways appear dark, while areas with buildings and trees appear bright. Downtown San Francisco is at the center and the city of Oakland is at the right across the San Francisco Bay. Some city areas, such as the South of Market district in San Francisco, appear bright due to the alignment of streets and buildings with respect to the incoming radar beam. Three of the bridges spanning the Bay are seen in this image. The Bay Bridge is in the center and extends from the city of San Francisco to Yerba Buena and Treasure Islands, and from there to Oakland. The Golden Gate Bridge is to the left and extends from San Francisco to Sausalito. The Richmond-San Rafael Bridge is in the upper right and extends from San Rafael to Richmond. Angel Island is the large island east of the Golden Gate Bridge, and lies north of the much smaller Alcatraz Island. The Alameda Naval Air Station is seen just below the Bay Bridge at the center of the image. Two major faults bounding the San Francisco-Oakland urban areas are visible on this image. The San Andreas fault, on the San Francisco peninsula, is seen on the left side of the image. The fault trace is the straight feature filled with linear reservoirs, which appear dark. The Hayward fault is the straight feature on the right side of the image between the urban areas and the hillier terrain to the east.

This radar image was acquired by just one of SRTM's two antennas and, consequently, does not show topographic data, but only the strength of the radar signal reflected from the ground. This signal, known as radar backscatter, provides insight into the nature of the surface, including its roughness, vegetation cover and urbanization. The overall faint striping pattern in the images is a data processing artifact due to the preliminary nature of this image product. These artifacts will be removed after further data processing.

This image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11,2000. SRTM uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian Space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

Size: 38 km (24 miles) by 71 km (44 miles) Location: 37.7 deg. North lat., 122.2 deg. West lon. Orientation: North to the upper right Original Data Resolution: 30 meters (99 feet) Date Acquired: February 16, 2000

2000-01-01

395

Kiowa Creek Switching Station  

SciTech Connect

The Western Area Power Administration (Western) proposes to construct, operate, and maintain a new Kiowa Creek Switching Station near Orchard in Morgan County, Colorado. Kiowa Creek Switching Station would consist of a fenced area of approximately 300 by 300 feet and contain various electrical equipment typical for a switching station. As part of this new construction, approximately one mile of an existing 115-kilovolt (kV) transmission line will be removed and replaced with a double circuit overhead line. The project will also include a short (one-third mile) realignment of an existing line to permit connection with the new switching station. In accordance with the Council on Environmental Quality (CEQ) regulations for implementing the procedural provisions of the National Environmental Policy Act of 1969 (NEPA), 40 CFR Parts 1500--1508, the Department of Energy (DOE) has determined that an environmental impact statement (EIS) is not required for the proposed project. This determination is based on the information contained in this environmental assessment (EA) prepared by Western. The EA identifies and evaluates the environmental and socioeconomic effects of the proposed action, and concludes that the advance impacts on the human environment resulting from the proposed project would not be significant. 8 refs., 3 figs., 1 tab.

Not Available

1990-03-01

396

The Shuttle Radar Topography Mission  

Microsoft Academic Search

The Shuttle Radar Topography Mission produced the most complete, highest-resolution digital elevation model of the Earth. The project was a joint endeavor of NASA, the National Geospatial-Intelligence Agency, and the German and Italian Space Agencies and flew in February 2000. It used dual radar antennas to acquire interferometric radar data, processed to digital topographic data at 1 arc sec resolution.

Tom G. Farr; Paul A. Rosen; Edward Caro; Robert Crippen; Riley Duren; Scott Hensley; Michael Kobrick; Mimi Paller; Ernesto Rodriguez; Ladislav Roth; David Seal; Scott Shaffer; Joanne Shimada; Jeffrey Umland; Marian Werner; Michael Oskin; Douglas Burbank; Douglas Alsdorf

2007-01-01

397

Spaceborne Imaging Radar Symposium  

NASA Technical Reports Server (NTRS)

An overview of the present state of the art in the different scientific and technological fields related to spaceborne imaging radars was presented. The data acquired with the SEASAT SAR (1978) and Shuttle Imaging Radar, SIR-A (1981) clearly demonstrated the important emphasis in the 80's is going to be on in-depth research investigations conducted with the more flexible and sophisticated SIR series instruments and on long term monitoring of geophysical phenomena conducted from free-flying platforms such as ERS-1 and RADARSAT.

Elachi, C.

1983-01-01

398

Radar Investigations of Asteroids  

NASA Technical Reports Server (NTRS)

Radar investigations of asteroids, including observations during 1984 to 1985 of at least 8 potential targets and continued analyses of radar data obtained during 1980 to 1984 for 30 other asteroids is proposed. The primary scientific objectives include estimation of echo strength, polarization, spectral shape, spectral bandwidth, and Doppler shift. These measurements yield estimates of target size, shape, and spin vector; place constraints on topography, morphology, density, and composition of the planetary surface; yield refined estimates of target orbital parameters; and reveals the presence of asteroidal satellites.

Ostro, S. J.

1984-01-01

399

Radar detection of phobos.  

PubMed

Radar echoes from the martian satellite Phobos provide information about that object's surface properties at scales near the 3.5-cm observing wavelength. Phobos appears less rough than the moon at centimeter-to-decimeter scales. The uppermost few decimeters of the satellite's regolith have a mean bulk density within 20% of 2.0 g cm(-3). The radar signature of Phobos (albedo, polarization ratio, and echo spectral shape) differs from signatures measured for small, Earth-approaching objects, but resembles those of large (>/=100-km), C-class, mainbelt asteroids. PMID:17847261

Ostro, S J; Jurgens, R F; Yeomans, D K; Standish, E M; Greiner, W

1989-03-24

400

Microwave radar oceanographic investigations  

NASA Technical Reports Server (NTRS)

The Radar Ocean Wave Spectrometer (ROWS) technique was developed and demonstrated for measuring ocean wave directional spectra from air and space platforms. The measurement technique was well demonstrated with data collected in a number of flight experiments involving wave spectral comparisons with wave buoys and the Surface Contour Radar (SCR). Recent missions include the SIR-B underflight experiment (1984), FASINEX (1986), and LEWEX (1987). ROWS related activity is presently concentrating on using the aircraft instrument for wave-processes investigations and obtaining the necessary support (consensus) for a satellite instrument development program. Prospective platforms include EOS and the Canadian RADARSAT.

Jackson, F. C.

1988-01-01

401

Evaluation of a Human Modeling Software Tool in the Prediction of Extra Vehicular Activity Tasks for an International Space Station Assembly Mission  

NASA Technical Reports Server (NTRS)

The difficulty of accomplishing work in extravehicular activity (EVA) is well documented. It arises as a result of motion constraints imposed by a pressurized spacesuit in a near-vacuum and of the frictionless environment induced in microgravity. The appropriate placement of foot restraints is crucial to ensuring that astronauts can remove and drive bolts, mate and demate connectors, and actuate levers. The location on structural members of the foot restraint sockets, to which the portable foot restraint is attached, must provide for an orientation of the restraint that affords the astronaut adequate visual and reach envelopes. Previously, the initial location of these sockets was dependent upon the experienced designer's ability to estimate placement. The design was tested in a simulated zero-gravity environment; spacesuited astronauts performed the tasks with mockups while submerged in water. Crew evaluation of the tasks based on these designs often indicated the bolt or other structure to which force needed to be applied was not within an acceptable work envelope, resulting in redesign. The development of improved methods for location of crew aids prior to testing would result in savings to the design effort for EVA hardware. Such an effort to streamline EVA design is especially relevant to International Space Station construction and maintenance. Assembly operations alone are expected to require in excess of four hundred hours of EVA. Thus, techniques which conserve design resources for assembly missions can have significant impact. We describe an effort to implement a human modelling application in the design effort for an International Space Station Assembly Mission. On Assembly Flight 6A, the Canadian-built Space Station Remote Manipulator System will be delivered to the U.S. Laboratory. It will be released from its launch restraints by astronauts in EVA. The design of the placement of foot restraint sockets was carried out using the human model Jack, and the modelling results were compared with actual underwater test results. The predicted locations of the sockets was found to be acceptable for 94% of the tasks attempted by the astronauts, This effort provides confidence in the capabilities of this package to accurately model tasks. It therefore increases assurance that the tool maybe used early in the design process.

Dischinger, H. Charles; Loughead, Tomas E.

1997-01-01

402

Near Surface Accumulation Patterns in the Recovery Lakes Area as Revealed by AN Ultra-Wideband Ground Based Radar  

NASA Astrophysics Data System (ADS)

High-frequency radar data were collected on the second leg of the Norwegian-US traverse from South Pole to Troll Station in 2008/09. The traverse route went directly over all four Recovery Lakes, which have been identified previously from remote sensing data. We used a ground-based high-frequency FMCW radar with a center frequency of 1.75 GHz. The radar data covering the uppermost 100 m of the firn pack are used to examine subsurface structures at the proposed lake margins. We combine radar and dated firn core data to determine local accumulation anomalies and areas of different flow velocities.

Sinisalo, A. K.; Müller, K.; Langley, K.; Anschütz, H.; Hamran, S.; Øyan, M.; Hagen, J. M.; Kohler, J.; Melland, G.; McConnell, J. R.

2010-12-01

403

47 CFR 87.171 - Class of station symbols.  

Code of Federal Regulations, 2014 CFR

... RLS—Surveillance radar RLT—Radionavigation land test RLW—Microwave landing system RNV—Radio Navigation Land/DME RPC—Ramp Control TJ—Aircraft earth station in the Aeronautical Mobile-Satellite Service UAT—Universal Access...

2014-10-01

404

Experimental phased array radar ELRA with extended flexibility  

NASA Astrophysics Data System (ADS)

An update of a phased array radar research project with the experimental system ELRA (electronic steerable radar) is given with respect to the extended and improved possibilities for performing measurements and evaluations for different types of radar operation. The variability of waveforms for solid-state transmitters is described. Flexible control of multifunction operation with various search and localization tasks is achieved with a network of microcomputers. Different means of signal processing are used for target detection and estimation. The active receiving array is divided into subarrays, and offers digital beamforming for pattern shaping and adaptive jammer suppression. Experimental results are presented.

Groeger, I.; Sander, W.; Wirth, W.-D.

1990-11-01

405

RADAR: An In-Building RF-based User Location and Tracking System  

Microsoft Academic Search

The proliferation of mobile computing devices and local-area wireless networks has fostered a growing interest in location-aware systems and services. In this paper we present RADAR, a radio-frequency (RF) based system for locating and tracking users inside buildings. RADAR operates by recording and processing signal strength information at multiple base stations positioned to provide overlapping coverage in the area of

Paramvir Bahl; Venkata N. Padmanabhan

2000-01-01

406

HF radar observations of small-scale surface current variability in the Straits of Florida  

Microsoft Academic Search

A dual-station high-frequency Wellen radar (WERA), transmitting at 16.045 MHz, was deployed along the eastern Florida Shelf and operated and maintained by the University of Miami's Rosenstiel School of Marine and Atmospheric Science. From September 2004 to June 2005, a moored acoustic Doppler current profiler (ADCP) acquired subsurface current measurements within the radar footprint along the shelf break at 86-m

A. B. Parks; L. K. Shay; W. E. Johns; J. Martinez-Pedraja; K.-W. Gurgel

2009-01-01

407

Mapping bathymetry using X-band marine radar data recorded from a moving vessel  

Microsoft Academic Search

Marine radars mounted on ships can provide remarkable insights into ocean behaviour from distances of several kilometres,\\u000a placing other in situ observations and the environment around a ship into a wider oceanographic context. It has been known\\u000a for some time that it is possible to map shallow water bathymetry and currents using radar image sequences recorded from shore\\u000a based stations.

Paul S. Bell; John C. Osler

408

Current Structure Variations Detected by High-Frequency Radar and Vector-Measuring Current Meters  

Microsoft Academic Search

Ocean surface current measurements from high-frequency (HF) radar are assessed by comparing these data to near-surface current observations from 1 to 30 October 1994 at two moored subsurface current meter arrays (20 and 25 m) instrumented with vector-measuring current meters (VMCMs) and Seacat sensors during the Duck94 experiment. A dual-station ocean surface current radar (OSCR) mapped the current fields at

Lynn K. Shay; Steven J. Lentz; Hans C. Graber; Brian K. Haus

1998-01-01

409

MTE ground station testbed-a battlefield awareness asset for GMTI exploitation  

Microsoft Academic Search

The focus of this paper is to describe the moving target exploitation (MTE) ground station testbed-a battlefield awareness asset based on the Army's common ground station (CGS) whose primary capability is the exploitation of ground moving target indicator (GMTI) radar data. In this paper, we describe the core GMTI and high range resolution (HRR) exploitation capabilities to be integrated into

Robert L. Popp; Nils R. Sandell; Bruce L. Johnson

1999-01-01

410

28. Site Plan: AF Station P67, Fort Custer, Michigan, Plot ...  

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

28. Site Plan: AF Station P-67, Fort Custer, Michigan, Plot Plan (to accompany FY 1956 project planning report), USACOE, 22 July 1954. - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

411

Space Radar Image of Orange County, California (annotated version)  

NASA Technical Reports Server (NTRS)

This spaceborne radar image of Orange County, Calif., shows the massive urbanization of this rapidly growing region located just south of Los Angeles. Orange County, sandwiched between rugged mountains and the Pacific Ocean, includes the communities of Anaheim, Santa Ana and Huntington Beach. Anaheim Stadium can be seen in the upper center of the image, as a small white ring to the right of a major freeway intersection. The large dark blue rectangular area in the upper left is the Seal Beach Naval Weapons Station and adjacent wildlife refuge. Runways of the El Toro Marine Air Station appear as a black 'x' near the center of the image. The large purple area to the left of the the Air Station and extending to the coast is the scar left by the Laguna wildfire of October 1993. The sparse vegetation left in the wake of the fire provides a weak source of radar echoes, making the burn areas distinctively dark in the image. Another large burn area, from the Ortega fire of 1993, is seen in the mountains in the lower right of the image. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on October 3, 1994. The image is centered at 33.7 degrees north latitude and 117.7 degrees west longitude. North is toward the upper right. The image shows an area 66.2 kilometers by 44.2 kilometers (41.0 miles by 27.4 miles). The colors are assigned todifferent frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted, horizontally received; green is L-band, horizontally transmitted, vertically received; blue is C-band, horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

1994-01-01

412

Space station tracking requirements feasibility study, volume 2  

NASA Technical Reports Server (NTRS)

The objective of this feasibility study is to determine analytically the accuracies of various sensors being considered as candidates for Space Station use. Specifically, the studies were performed whether or not the candidate sensors are capable of providing the required accuracy, or if alternate sensor approaches should be investigated. Other topics related to operation in the Space Station environment were considered as directed by NASA-JSC. The following topics are addressed: (1) Space Station GPS; (2) Space Station Radar; (3) Docking Sensors; (4) Space Station Link Analysis; (5) Antenna Switching, Power Control, and AGC Functions for Multiple Access; (6) Multichannel Modems; (7) FTS/EVA Emergency Shutdown; (8) Space Station Information Systems Coding; (9) Wanderer Study; and (10) Optical Communications System Analysis. Brief overviews of the abovementioned topics are given. Wherever applicable, the appropriate appendices provide detailed technical analysis. The report is presented in two volumes. This is Volume 2, containing Appendices K through U.

Udalov, Sergei; Dodds, James

1988-01-01

413

Space station tracking requirements feasibility study, volume 1  

NASA Technical Reports Server (NTRS)

The objective of this feasibility study is to determine analytically the accuracies of various sensors being considered as candidates for Space Station use. Specifically, the studies were performed whether or not the candidate sensors are capable of providing the required accuracy, or if alternate sensor approaches be investigated. Other topics related to operation in the Space Station environment were considered as directed by NASA-JCS. The following topics are addressed: (1) Space Station GPS; (2) Space Station Radar; (3) Docking Sensors; (4) Space Station Link Analysis; (5) Antenna Switching, Power Control, and AGC Functions for Multiple Access; (6) Multichannel Modems; (7) FTS/EVA Emergency Shutdown; (8) Space Station Information Systems Coding; (9) Wanderer Study; and (10) Optical Communications System Analysis. Brief overviews of the abovementioned topics are given. Wherever applicable, the appropriate appendices provide detailed technical analysis. The report is presented in two volumes. This is Volume 1, containing the main body and Appendices A through J.

Udalov, Sergei; Dodds, James

1988-01-01

414

Multiline radar scan  

NASA Technical Reports Server (NTRS)

Scanning scheme is more efficient than conventional scanning. Originally designed for optical radar in space vehicles, scheme may also find uses in site-surveillance security systems and in other industrial applications. It should be particularly useful when system must run on battery energy, as would be case in power outages.

Levinson, S.

1977-01-01

415

Airborne firefinder radar concept  

Microsoft Academic Search

An airborne firefinder radar (AFFR) is suggested for an upgraded version of the forthcoming Global Hawk Unmanned Aerial Vehicle (UAV). The AFFR could detect an artillery shell within 1 second of firing and, within a few seconds, determine its trajectory origin location (position of the gun) to a circular error probable (CEP) of less than 50 meters. The AFFR could

R. J. Sullivan; J. F. Nicoll; J. M. Ralston

1998-01-01

416

Impulse radar studfinder  

DOEpatents

An impulse radar studfinder propagates electromagnetic pulses and detects reflected pulses from a fixed range. Unmodulated pulses, about 200 ps wide, are emitted. A large number of reflected pulses are sampled and averaged. Background reflections are subtracted. Reflections from wall studs or other hidden objects are detected and displayed using light emitting diodes.

McEwan, Thomas E. (Livermore, CA)

1995-01-01

417

Impulse radar studfinder  

DOEpatents

An impulse radar studfinder propagates electromagnetic pulses and detects reflected pulses from a fixed range. Unmodulated pulses, about 200 ps wide, are emitted. A large number of reflected pulses are sampled and averaged. Background reflections are subtracted. Reflections from wall studs or other hidden objects are detected and displayed using light emitting diodes. 9 figs.

McEwan, T.E.

1995-10-10

418

High resolution radar imaging  

NASA Astrophysics Data System (ADS)

The goal of this project is to formulate and investigate new approaches for forming images of radar targets from spotlight-mode, delay-doppler measurements. These measurements could be acquired with a high-resolution radar-imaging system operating with an optical-or radio-frequency carrier. Two approaches are under study. The first is motivated by an image-reconstruction algorithm used in radionuclide imaging called the confidence-weighted algorithm; here, we will refer to this approach as the chirp-rate modulation approach. The second approach is based on more fundamental principles which starts with a mathematical model that accurately describes the physics of an imaging radar-system and then uses statistical-estimation theory with this model to derive processing algorithms; we will refer to this as the estimation-theory approach. Progress during this reporting period has been made on: (1) extending the estimation-theory approach to include a constraint on input signal-to-noise ratio; (2) extending the estimation-theory approach to include a sieve constraint for stabilizing image estimates, (3) extending the estimation-theory approach to include a specular or glint component in the radar-echo data; (4) analyzing the performance of the estimation-theory approach through computer simulations; and (5) modifying the chirp-rate modulation approach through the introduction of the Wigner-Ville distribution. A patent was awarded associated with the chirp-rate modulation approach.

Snyder, Donald L.

1988-11-01

419

Compressed Synthetic Aperture Radar  

Microsoft Academic Search

In this paper, we introduce a new synthetic aperture radar (SAR) imaging modality which can provide a high-resolution map of the spatial distribution of targets and terrain using a significantly reduced number of needed transmitted and\\/or received electromagnetic waveforms. This new imaging scheme, requires no new hardware components and allows the aperture to be compressed. It also presents many new

Vishal M. Patel; Glenn R. Easley; Dennis M. Healy; Jr.

2010-01-01

420

Vision requirements for Space Station applications  

NASA Technical Reports Server (NTRS)

Problems which will be encountered by computer vision systems in Space Station operations are discussed, along with solutions be examined at Johnson Space Station. Lighting cannot be controlled in space, nor can the random presence of reflective surfaces. Task-oriented capabilities are to include docking to moving objects, identification of unexpected objects during autonomous flights to different orbits, and diagnoses of damage and repair requirements for autonomous Space Station inspection robots. The approaches being examined to provide these and other capabilities are television IR sensors, advanced pattern recognition programs feeding on data from laser probes, laser radar for robot eyesight and arrays of SMART sensors for automated location and tracking of target objects. Attention is also being given to liquid crystal light valves for optical processing of images for comparisons with on-board electronic libraries of images.

Crouse, K. R.

1985-01-01

421

Adaptive airborne radar simulation with equalization filter taps  

Microsoft Academic Search

Space-time processing (STP) provides an adaptive filter for an airborne phased-array radar to detect targets in clutter and jamming that have spatial and Doppler spread. We developed a flexible airborne radar simulation to identify limitations in the techniques and to evaluate the capabilities of different STP designs. One of the space-time architectures, jointly adaptive STP in the element space, employs

B. N. Babu; J. A. Torres

1993-01-01

422

Space Station propulsion system  

NASA Technical Reports Server (NTRS)

Viewgraphs on space station propulsion systems are presented. Topics covered include: space station propulsion system requirements; space station propulsion system design; space station propulsion system drivers; hydrazine technology development; waste fluid disposal system; space station propulsion system evolution; propellant selection trade study; technology needs to water electrolysis/oxygen-hydrogen propulsion system; and technology needs for bipropellant systems.

Henderson, J.

1990-01-01

423

Ground-penetrating radar monitoring of a controlled DNAPL release: 200 MHz radar  

SciTech Connect

A controlled release of tetrachloroethylene was performed in a saturated, natural sandy aquifer to evaluate the effectiveness of various geophysical techniques for detecting and monitoring dense nonaqueous phase liquids (DNAPLs) in the subsurface. Tetrachloroethylene, typical of most DNAPLs, has a low relative dielectric permittivity (2.3), which contrasts with the high relative permittivity (80) of the pore water it displaces, making it a potential target for detection by ground-penetrating radar (GPR). GPR data were acquired using 200 MHz antennas. Radar sections collected at different times over the same spatial location clearly show the changes induced by the movement of DNAPL in the subsurface. Temporal changes can be examined through the evolution of a radar data trace collected at a single spatial location. Normal moveout analysis of common-midpoint (CMP) data demonstrates induced changes in electromagnetic (EM) wave velocities of up to 30% caused by the presence of DNAPL. The distribution of DNAPL can be mapped in three dimensions at different times using a network of 16 radar lines. The 200 MHz GPR proved to be an effective technique for monitoring the movement of DNAPL in the subsurface. Direct detection of DNAPLs by radar is also feasible in this simple environment.

Brewster, M.L. (Komex International Ltd., Calgary, Alberta (Canada) Univ. of Waterloo, Ontario (Canada). Waterloo Centre for Groundwater Research); Annan, A.P. (Sensors and Software, Inc., Mississauga, Ontario (Canada) Univ. of Waterloo, Ontario (Canada). Waterloo Centre for Groundwater Research)

1994-08-01

424

Mathematical analysis study for radar data processing and enhancement. Part 1: Radar data analysis  

NASA Technical Reports Server (NTRS)

A study is performed under NASA contract to evaluate data from an AN/FPS-16 radar installed for support of flight programs at Dryden Flight Research Facility of NASA Ames Research Center. The purpose of this study is to provide information necessary for improving post-flight data reduction and knowledge of accuracy of derived radar quantities. Tracking data from six flights are analyzed. Noise and bias errors in raw tracking data are determined for each of the flights. A discussion of an altiude bias error during all of the tracking missions is included. This bias error is defined by utilizing pressure altitude measurements made during survey flights. Four separate filtering methods, representative of the most widely used optimal estimation techniques for enhancement of radar tracking data, are analyzed for suitability in processing both real-time and post-mission data. Additional information regarding the radar and its measurements, including typical noise and bias errors in the range and angle measurements, is also presented. This is in two parts. This is part 1, an analysis of radar data.

James, R.; Brownlow, J. D.

1985-01-01

425

High-Frequency Radar Mapping of Surface Currents Using WERA  

Microsoft Academic Search

A dual-station high-frequency Wellen Radar (WERA), transmitting at 16.045 MHz, was deployed along the west Florida shelf in phased array mode during the summer of 2003. A 33-day, continuous time series of radial and vector surface current fields was acquired starting on 23 August ending 25 September 2003. Over a 30-min sample interval, WERA mapped coastal ocean currents over an

Lynn K. Shay; Jorge Martinez-Pedraja; Thomas M. Cook; Brian K. Haus; Robert H. Weisberg

2007-01-01

426

Space station group activities habitability module study  

NASA Technical Reports Server (NTRS)

This study explores and analyzes architectural design approaches for the interior of the Space Station Habitability Module (originally defined as Habitability Module 1 in Space Station Reference Configuration Decription, JSC-19989, August 1984). In the Research Phase, architectural program and habitability design guidelines are specified. In the Schematic Design Phase, a range of alternative concepts is described and illustrated with drawings, scale-model photographs and design analysis evaluations. Recommendations are presented on the internal architectural, configuration of the Space Station Habitability Module for such functions as the wardroom, galley, exercise facility, library and station control work station. The models show full design configurations for on-orbit performance.

Nixon, David

1986-01-01

427

Evaluation of trends in some temperature series at some Italian stations and their modelling by means of spectral methods: first results in the Latium coastal area  

NASA Astrophysics Data System (ADS)

The investigation of the presence of signals indicating possible climatic changes in progress during the second half of the last century in the coastal area of the central Tyrrhenian sea has been carried out within the context of a research programme promoted by the Italian Science Academy (alias "the Academy of the XL") and financed by the Presidential Bureau. Our goal has been a better understanding of the behaviour of the minimum and maximum temperature variations in the period 1951-1999 and the modelling of their stochastic residuals through spectral analysis and the optimized construction of suitable autoregressive one-parameter processes. The meteorological data source for this research was the Italian "Agrometeorological National DataBase" (BDAN) of the Agrometeorological Informatics National System (SIAN). The spectral and stochastic analysis of meteorological data usually require full data sets without gaps, but, in BDAN, numerous data sets taken at stations located in the investigated area were incomplete. Thus, after the selection of an adequate number of stations, both representative of the region under study and characterized by a low number of data gaps, the first step was to fill all the gaps in the daily series using specific statistical techniques. After this preliminary treatment, we were left with seven temperature series that showed enough good characteristics in order to carry out an efficient modelling. Spectral analysis of minimum and maximum temperature series permitted to identify an auto-regressive one-parameter model well representing the stochastic residual of each series. With the aid of the complete model, consisting of a deterministic component (a linear trend plus two seasonal oscillations) and a stochastic residual, one can satisfactorily reconstruct the data in the past (climatic historical analysis) and to try a prediction of future values (forecasting). Thus the proposed model appears to represent a valid method to evaluate the whole variability of each climatic series in a multi-decadal time scale. As for the deterministic component, the Fourier analysis of minimum and maximum temperatures series showed for each station the existence, beside the secular linear trend, of a first oscillation (annual), and a secondary oscillation (half-yearly), each characterized by an amplitude and a phase. On the other hand, the stochastic residual can always be regarded as the superposition of an AR(1) process and a residual white noise. The lower half-yearly seasonal component, although small, can produce an amplitude attenuation or enhancement, and a phase advance or delay, among the climatic expected values and the standard meteorological sequences. The results of the stochastic analysis showed the presence during the period 1951-1999 of a discrete variability in the minimum and maximum temperature series along the Tyrrhenian coastal area, more intense for minimum temperatures. This behaviour can have direct and indirect consequences on natural vegetation and on the planning of agricultural activity, in particular for what concerns the evaluation of the quantity of the "available energy" for plant development and the assessment of "production sustainability" for the agricultural crops in terms of quantity, cost and quality of the agro products.

Beltrano, M. C.; Testa, O.; Malvestuto, V.; Esposito, S.

2010-09-01

428

Structural investigation of the Canadian Shield by orbital radar and LANDSAT  

NASA Technical Reports Server (NTRS)

Canadian Shield were studied by orbital radar. The primary objective of the study is scientific: to investigate and clarify the tectonic relationships of the Churchill, Superior, and Grenville Provinces, concentrating on their geologic boundaries, the Nelson and Grenvill Fronts. Theories about its origin range from in-situ regional metamorphism to tectonic sutures resulting from terrain accretion. The SIR-B investigation clarifies this problem. Secondary objectives are technique development, and include: (1) evaluation of the use of orbital radar in high altitude Precambrian terrains; (2) evaluation of look-azimuth biasing in radar and LANDSAT imagery; and (3) investigation of the synergistic use of radar, LANDSAT, and geophysical data in Precambrian studies.

Lowman, P. D., Jr.; Blodget, H. W.; Webster, W. J., Jr.; Paia, S.; Singhroy, V. H.; Slaney, V. R.

1984-01-01

429

UAV-based Radar Sounding of Antarctic Ice  

NASA Astrophysics Data System (ADS)

We developed a compact radar for use on a small UAV to conduct measurements over the ice sheets in Greenland and Antarctica. It operates at center frequencies of 14 and 35 MHz with bandwidths of 1 MHz and 4 MHz, respectively. The radar weighs about 2 kgs and is housed in a box with dimensions of 20.3 cm x 15.2 cm x 13.2 cm. It transmits a signal power of 100 W at a pulse repletion frequency of 10 kHz and requires average power of about 20 W. The antennas for operating the radar are integrated into the wings and airframe of a small UAV with a wingspan of 5.3 m. We selected the frequencies of 14 and 35 MHz based on previous successful soundings of temperate ice in Alaska with a 12.5 MHz impulse radar [Arcone, 2002] and temperate glaciers in Patagonia with a 30 MHz monocycle radar [Blindow et al., 2012]. We developed the radar-equipped UAV to perform surveys over a 2-D grid, which allows us to synthesize a large two-dimensional aperture and obtain fine resolution in both the along- and cross-track directions. Low-frequency, high-sensitivity radars with 2-D aperture synthesis capability are needed to overcome the surface and volume scatter that masks weak echoes from the ice-bed interface of fast-flowing glaciers. We collected data with the radar-equipped UAV on sub-glacial ice near Lake Whillans at both 14 and 35 MHz. We acquired data to evaluate the concept of 2-D aperture synthesis and successfully demonstrated the first successful sounding of ice with a radar on an UAV. We are planning to build multiple radar-equipped UAVs for collecting fine-resolution data near the grounding lines of fast-flowing glaciers. In this presentation we will provide a brief overview of the radar and UAV, as well as present results obtained at both 14 and 35 MHz. Arcone, S. 2002. Airborne-radar stratigraphy and electrical structure of temperate firn: Bagley Ice Field, Alaska, U.S.A. Journal of Glaciology, 48, 317-334. Blindow, N., C. Salat, and G. Casassa. 2012. Airborne GPR sounding of deep temperate glaciers—examples from the Northern Patagonian Icefield, 14th International Conference on Ground Penetrating Radar (GPR) June 4-8, 2012, Shanghai, China, ISBN 978-1-4673-2663-6.

Leuschen, Carl; Yan, Jie-Bang; Mahmood, Ali; Rodriguez-Morales, Fernando; Hale, Rick; Camps-Raga, Bruno; Metz, Lynsey; Wang, Zongbo; Paden, John; Bowman, Alec; Keshmiri, Shahriar; Gogineni, Sivaprasad

2014-05-01

430

Intelligent Virtual Station (IVS)  

NASA Technical Reports Server (NTRS)

The Intelligent Virtual Station (IVS) is enabling the integration of design, training, and operations capabilities into an intelligent virtual station for the International Space Station (ISS). A viewgraph of the IVS Remote Server is presented.

2002-01-01

431

MIMO Radar with Widely Separated Antennas  

Microsoft Academic Search

MIMO (multiple-input multiple-output) radar refers to an architecture that employs multiple, spatially distributed transmitters and receivers. While, in a general sense, MIMO radar can be viewed as a type of multistatic radar, the separate nomenclature suggests unique features that set MIMO radar apart from the multistatic radar literature and that have a close relation to MIMO communications. This article reviews

Alexander Haimovich; Rick Blum; Leonard Cimini

2008-01-01

432

METR 4624--Radar Meteorology SPRING 2014  

E-print Network

METR 4624--Radar Meteorology SPRING 2014 Dr. Michael I. Biggerstaff; drdoppler@ou.edu (best method Principles of weather radar and storm observations including: radar system design, em wave propagation, radar&Q, moments of the power spectrum, ground clutter, attenuation, rainfall measurements using radar reflectivity

Droegemeier, Kelvin K.

433

METR 4624--Radar Meteorology SPRING 2012  

E-print Network

METR 4624--Radar Meteorology SPRING 2012 Dr. Michael I. Biggerstaff; drdoppler@ou.edu (best method Principles of weather radar and storm observations including: radar system design, em wave propagation, radar&Q, moments of the power spectrum, ground clutter, attenuation, rainfall measurements using radar reflectivity

Droegemeier, Kelvin K.

434

An MSK Radar Waveform  

NASA Technical Reports Server (NTRS)

The minimum-shift-keying (MSK) radar waveform is formed by periodically extending a waveform that separately modulates the in-phase and quadrature- phase components of the carrier with offset pulse-shaped pseudo noise (PN) sequences. To generate this waveform, a pair of periodic PN sequences is each passed through a pulse-shaping filter with a half sinusoid impulse response. These shaped PN waveforms are then offset by half a chip time and are separately modulated on the in-phase and quadrature phase components of an RF carrier. This new radar waveform allows an increase in radar resolution without the need for additional spectrum. In addition, it provides self-interference suppression and configurable peak sidelobes. Compared strictly on the basis of the expressions for delay resolution, main-lobe bandwidth, effective Doppler bandwidth, and peak ambiguity sidelobe, it appears that bi-phase coded (BPC) outperforms the new MSK waveform. However, a radar waveform must meet certain constraints imposed by the transmission and reception of the modulation, as well as criteria dictated by the observation. In particular, the phase discontinuity of the BPC waveform presents a significant impediment to the achievement of finer resolutions in radar measurements a limitation that is overcome by using the continuous phase MSK waveform. The phase continuity, and the lower fractional out-of-band power of MSK, increases the allowable bandwidth compared with BPC, resulting in a factor of two increase in the range resolution of the radar. The MSK waveform also has been demonstrated to have an ambiguity sidelobe structure very similar to BPC, where the sidelobe levels can be decreased by increasing the length of the m-sequence used in its generation. This ability to set the peak sidelobe level is advantageous as it allows the system to be configured to a variety of targets, including those with a larger dynamic range. Other conventionally used waveforms that possess an even greater spectral efficiency than the MSK waveform, such as linear frequency modulation (LFM) and Costas frequency hopping, have a fixed peak sidelobe level that is therefore not configurable, and can be exceeded by high contrast targets. Furthermore, in the case of a multistatic experiment observing a target in motion, self-interference from the transmitter to the receiver is mitigated by the MSK waveform. Waveforms that have delay Doppler coupling, such as LFM, provide no such protection.

Quirk, Kevin J.; Srinivasan, Meera

2012-01-01

435

Studies of ground penetrating radar antennas  

Microsoft Academic Search

Virtually all systems that have been developed in recent years to detect landmines and buried unexploded ordinance (UXO), have included the ground-penetrating radar (GPR) as one of the principal subsystems. Much of the effort reported to date in evaluating these GPRs has focused on obtaining overall end-to-end detection performance metrics (Pd, Pfa). These studies have been useful but they provide

P. R. Lacko; William W. Clark; Kelly Sherbondy; James M. Ralston; Elvis Dieguez

2003-01-01

436

Compression of Polarimetric Synthetic Aperture Radar Data  

Microsoft Academic Search

Abstract—The paper deals with proposition and evaluation of new and specific methods,to represent vector radar data acquired by means a side-looking measurement in order to use compression pro- cess of Lind, Buzo, Gray (LBG), and Kohonen’s self organizing feature maps of topology. The aim is to enable after coding, transmission, and decoding a high-resolution reconstruction image using the Synthetic Aperture

S. El Assad; X. Morin; D. Barba; V. Slavova

2003-01-01

437

Performance and evaluation of gas engine driven rooftop air conditioning equipment at the Willow Grove (PA) Naval Air Station. Interim report, 1992 cooling season  

SciTech Connect

In a field evaluation conducted for the US Department of Energy (DOE) Office of Federal Energy Management Program (FEMP), the Pacific Northwest Laboratory (PNL) examined the performance of a new US energy-related technology under the FEMP Test Bed Demonstration Program. The technology was a 15-ton natural gas engine driven roof top air conditioning unit. Two such units were installed on a naval retail building to provide space conditioning to the building. Under the Test Bed Demonstration Program, private and public sector interests are focused to support the installation and evaluation of new US technologies in the federal sector. Participating in this effort under a Cooperative Research and Development Agreement (CRADA) with DOE were the American Gas Cooling Center, Philadelphia Electric Company, Thermo King Corporation, and the US Naval Air Station at Willow Grove, Pennsylvania. Equipment operating and service data as well as building interior and exterior conditions were secured for the 1992 cooling season. Based on a computer assessment of the building using standard weather data, a comparison was made with the energy and operating costs associated with the previous space conditioning system. Based on performance during the 1992 cooling season and adjusted to a normal weather year, the technology will save the site $6,000/yr in purchased energy costs. An additional $9,000 in savings due to electricity demand ratchet charge reductions will also be realized. Detailed information on the technology, the installation, and the results of the technology test are provided to illustrate the advantages to the federal sector of using this technology. A history of the CRADA development process is also reported.

Armstrong, P.R.; Conover, D.R.

1993-05-01

438

Evaluation of machine learning tools as a statistical downscaling tool: temperatures projections for multi-stations for Thames River Basin, Canada  

NASA Astrophysics Data System (ADS)

Many impact studies require climate change information at a finer resolution than that provided by global climate models (GCMs). This paper investigates the performances of existing state-of-the-art rule induction and tree algorithms, namely single conjunctive rule learner, decision table, M5 model tree, and REPTree, and explores the impact of climate change on maximum and minimum temperatures (i.e., predictands) of 14 meteorological stations in the Upper Thames River Basin, Ontario, Canada. The data used for evaluation were large-scale predictor variables, extracted from National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis dataset and the simulations from third generation Canadian coupled global climate model. Data for four grid points covering the study region were used for developing the downscaling model. M5 model tree algorithm was found to yield better performance among all other learning techniques explored in the present study. Hence, this technique was applied to project predictands generated from GCM using three scenarios (A1B, A2, and B1) for the periods (2046-2065 and 2081-2100). A simple multiplicative shift was used for correcting predictand values. The potential of the downscaling models in simulating predictands was evaluated, and downscaling results reveal that the proposed downscaling model can reproduce local daily predictands from large-scale weather variables. Trend of projected maximum and minimum temperatures was studied for historical as well as downscaled values using GCM and scenario uncertainty. There is likely an increasing trend for T max and T min for A1B, A2, and B1 scenarios while decreasing trend has been observed for B1 scenarios during 2081-2100.

Goyal, Manish Kumar; Burn, Donald H.; Ojha, C. S. P.

2012-05-01

439

41. Perimeter acquisition radar building radar element and coaxial display, ...  

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

41. Perimeter acquisition radar building radar element and coaxial display, with drawing of typical antenna section. Drawing, from left to right, shows element, aluminum ground plane, cable connectors and hardware, cable, and back-up ring. Grey area is the concrete wall - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

440

Kuiper Belt Mapping Radar  

NASA Technical Reports Server (NTRS)

Since their initial discovery in 1992, to date only a relatively small number of Kuiper Belt Objects (KBO's) have been discovered. Current detection techniques rely on frame-to-frame comparisons of images collected by optical telescopes such as Hubble, to detect KBO's as they move against the background stellar field. Another technique involving studies of KBO's through occultation of known stars has been proposed. Such techniques are serendipitous, not systematic, and may lead to an inadequate understanding of the size, range, and distribution of KBO's. In this paper, a future Kuiper Belt Mapping Radar is proposed as a solution to the problem of mapping the size distribution, extent, and range of KBO's. This approach can also be used to recover radar albedo and object rotation rates. Additional information is contained in the original extended abstract.

Freeman, A.; Nilsen, E.

2001-01-01

441

RADAR Reveals Titan Topography  

NASA Technical Reports Server (NTRS)

The Cassini Titan RADAR Mapper is a K(sub u)-band (13.78 GHz, lambda = 2.17 cm) linear polarized RADAR instrument capable of operating in synthetic aperture (SAR), scatterometer, altimeter and radiometer modes. During the first targeted flyby of Titan on 26 October, 2004 (referred to as Ta) observations were made in all modes. Evidence for topographic relief based on the Ta altimetry and SAR data are presented here. Additional SAR and altimetry observations are planned for the T3 encounter on 15 February, 2005, but have not been carried out at this writing. Results from the T3 encounter relevant to topography will be included in our presentation. Data obtained in the Ta encounter include a SAR image swath

Kirk, R. L.; Callahan, P.; Seu, R.; Lorenz, R. D.; Paganelli, F.; Lopes, R.; Elachi, C.

2005-01-01

442

Floor-plan radar  

NASA Astrophysics Data System (ADS)

Urban-warfare specialists, law-enforcement officers, counter-drug agents, and counter-terrorism experts encounter operational situations where they must assault a target building and capture or rescue its occupants. To minimize potential casualties, the assault team needs a picture of the building's interior and a copy of its floor plan. With this need in mind, we constructed a scale model of a single- story house and imaged its interior using synthetic-aperture techniques. The interior and exterior walls nearest the radar set were imaged with good fidelity, but the distal ones appear poorly defined and surrounded by ghosts and artifacts. The latter defects are traceable to beam attenuation, wavefront distortion, multiple scattering, traveling waves, resonance phenomena, and other effects not accounted for in the traditional (noninteracting, isotropic point scatterer) model for radar imaging.

Falconer, David G.; Ueberschaer, Ronald M.

2000-07-01

443

Radar response to vegetation  

Microsoft Academic Search

Active microwave measurements of vegetation backscatter were conducted to determine the utility of radar in 1) mapping soil moisture through vegetation and 2) mapping crop types. Using a truck-mounted boom, spectral response data were obtained for four crop types (corn, milo, soybeans, and alfalfa) over the 4-8 GHz frequency band, at incidence angles of0deg-70degin10degsteps, and for all four linear polarization

F. Ulaby

1975-01-01

444

Imaging synthetic aperture radar  

DOEpatents

A linear-FM SAR imaging radar method and apparatus to produce a real-time image by first arranging the returned signals into a plurality of subaperture arrays, the columns of each subaperture array having samples of dechirped baseband pulses, and further including a processing of each subaperture array to obtain coarse-resolution in azimuth, then fine-resolution in range, and lastly, to combine the processed subapertures to obtain the final fine-resolution in azimuth. Greater efficiency is achieved because both the transmitted signal and a local oscillator signal mixed with the returned signal can be varied on a pulse-to-pulse basis as a function of radar motion. Moreover, a novel circuit can adjust the sampling location and the A/D sample rate of the combined dechirped baseband signal which greatly reduces processing time and hardware. The processing steps include implementing a window function, stabilizing either a central reference point and/or all other points of a subaperture with respect to doppler frequency and/or range as a function of radar motion, sorting and compressing the signals using a standard fourier transforms. The stabilization of each processing part is accomplished with vector multiplication using waveforms generated as a function of radar motion wherein these waveforms may be synthesized in integrated circuits. Stabilization of range migration as a function of doppler frequency by simple vector multiplication is a particularly useful feature of the invention; as is stabilization of azimuth migration by correcting for spatially varying phase errors prior to the application of an autofocus process.

Burns, Bryan L. (Tijeras, NM); Cordaro, J. Thomas (Albuquerque, NM)

1997-01-01

445

Dual scan rate radar  

Microsoft Academic Search

A dual scan rate radar system (DSR) includes a phased array antenna, a transmitter, a receiver and a control unit. Each rf pulse from the transmitter includes contiguous long-range and short-range pulses. The control unit adjusts the antenna so that the long-range pulse is transmitted into a slow beam at theta s and the short-range pulse is transmitted into a

W. M. Waters

1986-01-01

446

Space Radar Image of Manaus, Brazil  

NASA Technical Reports Server (NTRS)

These two images were created using data from the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR). On the left is a false-color image of Manaus, Brazil acquired April 12, 1994, onboard space shuttle Endeavour. In the center of this image is the Solimoes River just west of Manaus before it combines with the Rio Negro to form the Amazon River. The scene is around 8 by 8 kilometers (5 by 5 miles) with north toward the top. The radar image was produced in L-band where red areas correspond to high backscatter at HH polarization, while green areas exhibit high backscatter at HV polarization. Blue areas show low backscatter at VV polarization. The image on the right is a classification map showing the extent of flooding beneath the forest canopy. The classification map was developed by SIR-C/X-SAR science team members at the University of California,Santa Barbara. The map uses the L-HH, L-HV, and L-VV images to classify the radar image into six categories: Red flooded forest Green unflooded tropical rain forest Blue open water, Amazon river Yellow unflooded fields, some floating grasses Gray flooded shrubs Black floating and flooded grasses Data like these help scientists evaluate flood damage on a global scale. Floods are highly episodic and much of the area inundated is often tree-covered. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.v. (DLR), the major partner in science, operations and data processing of X-SAR.

1999-01-01

447

Radar gun hazards  

SciTech Connect

Radar guns - hand-held units used by the law to nail speeders - have been in use since the early '60s. Now they've been accused of causing cancer. Police officers in several states have so far filed eight suits against the manufacturer, claiming that they have contracted rare forms of cancer, such as of the eyelid and the testicle, from frequent proximity to the devices. Spurred by concerns expressed by police groups, researchers at the Rochester Institute of Technology are conducting what they believe to be the first research of its kind in the nation. Last month psychologist John Violanti, an expert in policy psychology and health, sent out a one-page survey to 6,000 active and retired police officers in New York State, asking them about their health and their use of radar guns. Violanti says melanoma, leukemia, and lymph node cancer may be linked to these as well as other electromagnetic devices. The Food and Drug Administration earlier this year issued a warning about radar guns, telling users not to operate them closer than 6 inches from the body. But this may not be a sufficient safeguard since the instruments can give off crisscrossing wave emissions within a police vehicle. The survey will be used to help determine if it would be safer to mount the guns, which are currently either hand-held or mounted on dashboards, outside troopers' cars.

Not Available

1991-12-20

448

Spaceborne Imaging Radar Project  

NASA Technical Reports Server (NTRS)

In June of 1985 the Project Initiation Agreement was signed by the Jet Propulsion Laboratory and the NASA Office of Space Science and Applications for the Spaceborne Imaging Radar Project (SIR). The thrust of the Spaceborne Imaging Radar Project is to continue the evolution of synthetic aperture radar (SAR) science and technology developed during SEASAT, SIR-A and SIR-B missions to meet the needs of the Earth Observing System (EOS) in the mid 1990's. As originally formulated, the Project plans were for a reflight of the SIR-B in 1987, the development of a new SAR, SIR-C, for missions in mid 1989 and early 1990, and the upgrade of SIR-C to EOS configuration with a qualification flight aboard the shuttle in the 1993 time frame (SIR-D). However, the loss of the shuttle Challenger has delayed the first manifest for SIR to early 1990. This delay prompted the decision to drop SIR-B reflight plans and move ahead with SIR-C to more effectively utilize this first mission opportunity. The planning for this project is discussed.

Herman, Neil

1986-01-01

449

Model for optimal parallax in stereo radar imagery  

NASA Technical Reports Server (NTRS)

Simulated stereo radar imagery is used to investigate parameters for a spaceborne imaging radar. Incidence angles ranging from small to intermediate to large are used with three digital terrain model areas which are representative of relatively flat, moderately rough, and mountaneous terrain. The simulated radar imagery was evaluated by interpreters for ease of stereo perception and information content, and rank ordered within each class of terrain. The interpreter's results are analyzed for trends between the height of a feature and either parallax or vertical exaggeration for a stereo pair. A model is developed which predicts the amount of parallax (or vertical exaggeration) an interpreter would desire for best stereo perception of a feature of a specific height. Results indicate the selection of angle of incidence and stereo intersection angle depend upon the relief of the terrain. Examples of the simulated stereo imagery are presented for a candidate spaceborne imaging radar having four selectable angles of incidence.

Pisaruck, M. A.; Kaupp, V. H.; Macdonald, H. C.; Waite, W. P.

1984-01-01

450

Radar studies of bird migration  

NASA Technical Reports Server (NTRS)

Observations of bird migration with NASA radars were made at Wallops Island, Va. Simultaneous observations were made at a number of radar sites in the North Atlantic Ocean in an effort to discover what happened to those birds that were observed leaving the coast of North America headed toward Bermuda, the Caribbean and South America. Transatlantic migration, utilizing observations from a large number of radars is discussed. Detailed studies of bird movements at Wallops Island are presented.

Williams, T. C.; Williams, J. M.

1974-01-01

451

Radar-aeolian roughness project  

NASA Technical Reports Server (NTRS)

The objective is to establish an empirical relationship between measurements of radar, aeolian, and surface roughness on a variety of n