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1

TRACALS evaluation report. Radar station evaluation report, duluth IAP, Minnesota  

Microsoft Academic Search

This Radar Traffic Control and Landing Systems (TRACALS) station evaluation report presents data collected to define the capabilities and limitations of the Mobile Radar Approach Control Facility (AN\\/MPN-14) at Duluth International Airport, Minnesota. Included in the report are descriptions of the upper, lower, outer and inner fringes of the useable radar coverage; radar coverage diagrams; ATCRBS coverage and tracking capabilities;

R. L. Cranston

1974-01-01

2

Use of radar and automatic weather stations in avalanche forecasting  

Microsoft Academic Search

The following sources of information have been investigated and their data evaluated in order to issue avalanche warnings in case of catastrophic situations such as in February 1984 in the Swiss Alps: -Daily measurement of snow depth -Data of automatic weather stations. They transmit every 10 minutes precipitation, wind, temperature etc. -Images of 2 radars. Every 10 minutes the user

G. KAPPENBERGER; J. JOSS

3

Four Station Interferometric Radar Observations of Mars  

NASA Technical Reports Server (NTRS)

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

4

Radar cross-section calculation method for antenna of P-18 radar station  

Microsoft Academic Search

The scattered electromagnetic field calculation method for finite cylinder with resonant cross-section is considered. The method is used for calculation of radar cross-section for antenna of P-18 radar station. Also radar cross-sections for perfectly conducting antenna and antenna partially made of perfectly absorbing materials (Macdonald model) are compared.

O. Sukharevsky; Y. Belevshchuk; V. Vasilets; S. Nechitaylo

2010-01-01

5

Tropical rain mapping radar on the Space Station  

NASA Technical Reports Server (NTRS)

The conceptual design for a tropical rain mapping radar for flight on the manned Space Station is discussed. In this design the radar utilizes a narrow, dual-frequency (9.7 GHz and 24.1 GHz) beam, electronically scanned antenna to achieve high spatial (4 km) and vertical (250 m) resolutions and a relatively large (800 km) cross-track swath. An adaptive scan strategy will be used for better utilization of radar energy and dwell time. Such a system can detect precipitation at rates of up to 100 mm/hr with accuracies of roughly 15 percent. With the proposed space-time sampling strategy, the monthly averaged rainfall rate can be estimated to within 8 percent, which is essential for many climatological studies.

Im, Eastwood; Li, Fuk

1989-01-01

6

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

7

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

8

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

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.

1992-05-01

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.

1992-01-01

11

Radar observations of ionospheric irregularities at Syowa Station, Antarctica: a brief overview  

NASA Astrophysics Data System (ADS)

We briefly overview the radar observations that have been made for 30 years at Syowa Station, Antarctica for studying small-scale electron-density irregularities in the southern high-latitude E- and F-region ionosphere. Some observational results (i.e., long-term variations of radio aurora, Doppler spectra with narrow spectral widths and low Doppler velocities, and simultaneous observations of radar and optical auroras) from VHF radars capable of detecting 1.3- to 3-m scale irregularities are presented. A new 50-MHz radar system equipped with phased-antenna arrays began operation in February 1995 to observe two-dimensional behaviours of E-region irregularities. An HF radar experiment also began in February 1995 to explore decameter-scale E- and F-region irregularities in the auroral zone and polar cap. These two radars will contribute to a better understanding of the ionospheric irregularities and ionospheric physics at southern high latitudes. Acknowledgements. This work has been supported by the UK Particle-Physics and Astronomy Research Council. The assistance of the director and staff of the EISCAT Scientific Association, the staff of the Norsk Polarinstitutt and the director and staff of the Swedish Institute of Space Physics is gratefully acknowledged. In addition the authors would like to thank Professor Evgeny Tereshchenko of the Polar Geophysical Institute in Mumansk, Russia and Dr Tuomo Nygrén of the University of Oulu, Finland for provision of data from EISCAT special program time during the November 1995 campaign. Topical Editor D. Alcaydé thanks E. J. Fremouw and another referee for their help in evaluating this paper.--> Correspondence to: I. K. Walker-->

Ogawa, T.

1996-12-01

12

Results of Radar Experiments Performed on-Board the 'Luna-19, 20' Automatic Stations.  

National Technical Information Service (NTIS)

The Luna 19 and Luna 20 automatic stations measured the radiowave reflection characteristics in the 3 cm wavelength range during orbital flight and descent. Procedures used for data processing are outlined, and data pertinent to the specific radar cross s...

N. N. Kroupenio A. G. Balo E. G. Ruzskii V. A. Ladyghin V. V. Cherkasov

1974-01-01

13

Radar interferometer calibration of the EISCAT Svalbard Radar and a additional receiver station  

NASA Astrophysics Data System (ADS)

The EISCAT Svalbard Radar has two parabolic dishes. In order to attempt to implement radar aperture synthesis imaging methods three smaller, passive receive array antennas were built. Several science goals for this new receiver system exist, the primary of which is to study so called naturally enhanced ion acoustic lines. In order to compare radar aperture synthesis imaging results with measurements from optical imagers, calibration of the radar interferometer system is necessary. In this work we present the phase calibration of the EISCAT Svalbard interferometer including one array antenna. The calibration was done using the coherent scatter from satellites passing through the radar beam. Optical signatures of the satellite transits provide accurate position for the satellites. Using transits of a number of satellites sufficient for mapping the radar beam, the interferometric cross-phase was fitted within the radar beam. The calibration technique presented in this work will be applied to all antenna pairs of the antenna configuration for future interferometry studies.

Schlatter, N. M.; Grydeland, T.; Ivchenko, N.; Belyey, V.; Sullivan, J.; La Hoz, C.; Blixt, M.

2013-12-01

14

A signal level simulator for netted radar waveforms evaluation  

Microsoft Academic Search

When evaluating the performances of radar waveforms, it is crucial to understand how the signal is affected by multiple interactions with the environment and the system hardware. Analysis of complex radar systems, such as multistatic and netted designs (see Fig. 1) is often intractable without the application of a dedicated radar simulation system. Recent research into radar simulation has focused

Y. Paichard; M. Brooker; M. Inggs

2009-01-01

15

Signal level Simulator for netted text radar waveforms evaluation  

Microsoft Academic Search

When evaluating the performances of radar waveforms, it is crucial to understand how the signal is affected by multiple interactions with the environment and the system hardware. Analysis of complex radar systems, such as multistatic and netted designs (see Figure 1) is often intractable without the application of a dedicated radar simulation system. Recent research into radar simulation has focused

Yoann Paichard; Marc Brooker; Michael Inggs

2010-01-01

16

Lookout Assist Radar Evaluation Programs.  

National Technical Information Service (NTIS)

The results of this evaluation program demonstrate that the Proximity Warning Principle has considerable utility as both an operational aid to the watch officer and a method of improving the safety of ships at sea. This is particularly true if the device ...

1966-01-01

17

Analysis of estimates of meteor drift obtained with automatic radar stations  

NASA Astrophysics Data System (ADS)

An analysis is made of measurements of meteor wind conducted using two radar stations both located at the Khar'kov facility but with different transmitter powers and somewhat different frequencies (31.1 and 36.9 MHz); measurements were made during December 1978 and March-April 1980. A comparison is made of results of the harmonic analysis of time series of estimates of the meridional component of horizontal wind obtained with these two stations. In most cases estimates of prevailing wind and tides were found to differ only insignificantly. Hourly means of velocity and height and wind profiles are given separately for underdense and overdense trails.

Kashcheev, B. L.; Zhukov, V. V.; Lizogub, V. V.

18

Analysis of estimates of meteor drift obtained with automatic radar stations  

Microsoft Academic Search

An analysis is made of measurements of meteor wind conducted using two radar stations both located at the Khar'kov facility but with different transmitter powers and somewhat different frequencies (31.1 and 36.9 MHz); measurements were made during December 1978 and March-April 1980. A comparison is made of results of the harmonic analysis of time series of estimates of the meridional

B. L. Kashcheev; V. V. Zhukov; V. V. Lizogub

1983-01-01

19

MST radar and radiosonde observations of inertia-gravity wave climatology over tropical stations: Source mechanisms  

Microsoft Academic Search

In this paper, possible source mechanisms for the generation of inertia-gravity wave activity over a tropical station, Gadanki (13.5°N, 79.2°E), are investigated using a long-term data set obtained from Indian mesosphere-stratosphere-troposphere (MST) radar. The gravity wave analysis is carried out in two different height regions, namely, 4-14 and 17-21 km, representing the troposphere and lower stratosphere, respectively. Clear seasonal variation

M. Venkat Ratnam; A. Narendra Babu; V. V. M. Jagannadha Rao; S. Vijaya Bhaskar Rao; D. Narayana Rao

2008-01-01

20

MST radar and radiosonde observations of inertia-gravity wave climatology over tropical stations: Source mechanisms  

Microsoft Academic Search

In this paper, possible source mechanisms for the generation of inertia-gravity wave activity over a tropical station, Gadanki (13.5°N, 79.2°E), are investigated using a long-term data set obtained from Indian mesosphere-stratosphere-troposphere (MST) radar. The gravity wave analysis is carried out in two different height regions, namely, 4–14 and 17–21 km, representing the troposphere and lower stratosphere, respectively. Clear seasonal variation

M. Venkat Ratnam; A. Narendra Babu; V. V. M. Jagannadha Rao; S. Vijaya Bhaskar Rao; D. Narayana Rao

2008-01-01

21

Meteor and MF Radar Observations at Darwin (12S), Adelaide (35S) and Davis Station (68S)  

NASA Astrophysics Data System (ADS)

Meteor radar observations of the Mesosphere Lower Thermosphere region are routinely made at Adelaide (35S), Darwin (12S) and Davis Station (68S). In addition, MF radar observations are made at Adelaide and Davis. Intercomparison of these observations yields insight into the underlying physical processes and into the limitations of the techniques themselves. In this paper, we present observations from these three sites, discuss the underlying dynamics, and consider the implications of differences between the meteor radar, MF radar and satellite observations of winds and temperatures in this region.

Reid, Iain

2012-07-01

22

Evaluation of multiple radar target trackers in stressful environments  

Microsoft Academic Search

This paper evaluates the performance of multiple target tracking (MTT) algorithms in real-life stressful radar tracking environments. Real closely spaced maneuver radar data, generated by six F-18 fighters and other targets, were collected jointly by the defence departments of Canada and United States to support this practical MTT algorithm evaluation study. A set of performance metrics was defined here to

HENRY LEUNG; Zhijian Hu; MARTIN BLANCHETTE

1999-01-01

23

Evaluation of the anti-interception method for MIMO radar  

Microsoft Academic Search

The performance of RF stealth is of significant importance for military radar because of the threat of an electromagnetic interference or an antiradiation missile. What is more, a useful method that can evaluate the RF stealth is needed urgently. In this paper, we proposed a method to evaluate the performance of RF stealth for MIMO radar. We provide a model

Maoxin Cai; Hongming Liu; Jun Li; Zishu He

2012-01-01

24

Digital evaluation of SEASAT-SAR radar image data  

Microsoft Academic Search

The use of spaceborne digital radar image data for small scale topographic and thematic mapping was studied. The information content of digital L-band radar data were analyzed; various evaluation methods of digital image processing for filtering, edge detection, and statistical analysis were employed and tested with regard to their applicability. The tests reveal which surface types and structures can be

Berthold Pfeiffer

1988-01-01

25

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

26

PAVE PAWS Early Warning Radar Operation Cape Cod Air Force Station, MA. Record of Decision.  

National Technical Information Service (NTIS)

This document records the decisions of the United States Air Force with regard to the Supplemental Environmental Impact Statement (SEIS) for the continued operation of the Pave PAWS radar at Cape Cod AFS (December 2008) that was prepared to evaluate poten...

2009-01-01

27

NAVAIDS Station Evaluation Report RAF Alconbury, England.  

National Technical Information Service (NTIS)

The Traffic Control and Landing Systems (TRACALS) station evaluation report presents data collected to define the capabilities and limitations of the Tactical Air Navigation (TACAN) System AN/GRN-20B at RAF Alconbury, England. Included in the report are d...

D. J. Burkard

1975-01-01

28

Step-frequency radar imaging for nondestructive evaluation (NDE) and ground-penetrating radar (GPR) applications  

Microsoft Academic Search

We describe a step-frequency microwave radar imaging system that is suitable for nondestructive evaluation (NDE) and ground-penetrating radar (GPR) applications. The system includes a computer-automated microwave measurement apparatus along with nonlinear inverse scattering imaging algorithms. Through the use of an inverse Fourier transform, the SFR data is transformed into a synthetic time-domain pulse, and imaging algorithms are applied to the

William H. Weedon; Weng C. Chew; Chad A. Ruwe

1994-01-01

29

Step Frequency Ground Penetrating Radar Characterization and Federal Evaluation Tests.  

National Technical Information Service (NTIS)

A step frequency ground penetrating radar (SF GPR) system was characterized and evaluated to determine whether it can be operated safely in a proposed configuration that may include frequency notching in specific frequency bands. This emission testing was...

D. Gibson J. Arnold M. Scott

2010-01-01

30

RAT SCAT Evaluation of Commercially Available Radar Absorbing Materials.  

National Technical Information Service (NTIS)

This report summarizes performance evaluation tests on a variety of commercially available thin flexible sheet type radar absorber materials, including both resonant and non-resonant types. A corner reflector test technique was used which allowed test and...

W. O'Hara

1976-01-01

31

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

32

First observations of ionospheric irregularities and flows over the south geomagnetic pole from the SuperDARN HF radar at McMurdo Station, Antarctica  

Microsoft Academic Search

In February 2010 a new SuperDARN radar began operation at McMurdo Station, Antarctica. The radar's orientation places the south geomagnetic pole near the center of the field of view at about 1200 km range. The radar is the highest latitude radar of the SuperDARN network, both geographically and geomagnetically, and the observations have a different character than those of the

W. A. Bristow; R. T. Parris; J. Spaleta

2010-01-01

33

Evaluation of Radar Reflectivity (Z) for FMCW Millimeter-Wave Cloud Radar “FALCON-I”  

NASA Astrophysics Data System (ADS)

We have developed an FMCW Millimeter-Wave Cloud Radar (MMCR) at 95 GHz named FALCON-I for observations of thin clouds, which are not easily detected with microwave radars. Sensitivities in radar reflectivity Z of FALCON-I are evaluated by comparing simultaneously observed data with the pulse type MMCR named SPIDER of National Institute of Information and Communications Technology (NICT). Evaluated sensitivity of FALCON-I at the height of 5km is more sensitive than -30dBZ in 1 minute resolution, which is comparable to the calculated value from the noise figure of the receiver: -37dBZ. FALCON-I can detect clouds with -30dBZ upto the height of 9km. This is good enough performance for thin cloud observations.

Yamaguchi, Jun; Takano, Toshiaki; Nakanishi, Yuji; Abe, Hideji; Kawamura, Youhei; Yokote, Shinichi; Kumagai, Hiroshi; Ohno, Yuichi; Horie, Hiroaki

34

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

35

MST radar and radiosonde observations of inertia-gravity wave climatology over tropical stations: Source mechanisms  

NASA Astrophysics Data System (ADS)

In this paper, possible source mechanisms for the generation of inertia-gravity wave activity over a tropical station, Gadanki (13.5°N, 79.2°E), are investigated using a long-term data set obtained from Indian mesosphere-stratosphere-troposphere (MST) radar. The gravity wave analysis is carried out in two different height regions, namely, 4-14 and 17-21 km, representing the troposphere and lower stratosphere, respectively. Clear seasonal variation in the wave activity has been noticed in both regions with maximum (minimum) in winter (monsoon) in the troposphere. But it is maximum (minimum) in monsoon (winter) in the lower stratosphere. This kind of winter enhancement in the wave activity is not expected at this tropical site. Interestingly, the contribution of the meridional component to the total kinetic energy (Ek) is found to be dominant rather than zonal in the winter except during 1997-1998. Topography seems to be the likely source for the generation of wave activity during winter in the troposphere. The influence of this topography is also reflected in the nearby radiosonde stations, Chennai (13.0°N, 80.2°E) and Bangalore (12.9°N, 77.6°E), which are located at radial distances of 128 and 190 km from Gadanki, respectively. Although two major sources, that is, strong convection and wind shears, coexist during monsoon season, strong wind shear seems to be the likely source of the wave activity. Large interannual variability in the wave activity is also noticed from 9 years (September 1995 to December 2004) of data. Good consistency is observed between the wave activities observed from nearby (Chennai) radiosonde and Gadanki MST radar data sets. Making use of a network of radiosonde observations operated by India Meteorological Department, we also present the latitudinal variation of wave activity. From the latitudinal variations it is observed that large-scale systems can also influence the generation of the gravity wave activity over larger areas.

Venkat Ratnam, M.; Narendra Babu, A.; Jagannadha Rao, V. V. M.; Vijaya Bhaskar Rao, S.; Narayana Rao, D.

2008-04-01

36

Bridge Deck Evaluation with Ground Penetrating Radar  

Microsoft Academic Search

Ground Penetrating Radar (GPR) uses electromagnetic (EM) waves to identify underlying features in solid structures. The typical technique uses a source antenna to generate EM waves that then interact with and reflect from subsurface features. A receiving antenna measures the reflected waves. The return signals are then analyzed to identify underlying features. This paper describes a study in which the

Dryver Huston; Jing Hu; Noel Pelczarski; Brian Esser

37

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

38

Ground Penetrating Radar (GPR) Analysis: Phase II (2) Field Evaluation.  

National Technical Information Service (NTIS)

The objective of this work was to evaluate the feasibility and value of expanding the MDT's Ground Penetrating Radar (GPR) program to pavement design and rehabilitation, and to network level evaluation. Phase I of this project concluded that in order to i...

A. Carmichael J. Puccinelli K. R. Maser T. Punnackal

2011-01-01

39

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

40

Low-latitude Pi2 Pulsations observed by an FM-CW Radar and CPMN Stations  

NASA Astrophysics Data System (ADS)

At the onset of magnetospheric substorms, impulsive hydromagnetic oscillations occur globally in the magnetosphere with a period range from 40 to 150 seconds [e.g. Saito, 1968]. They are called Pi 2 magnetic pulsations. Pi 2 has been studied with arrays of magnetometers on the ground and with in-situ observation by satellites [e.g. Yumoto, 2001]. However characteristics of Pi 2 electric pulsations in the low-latitude ionosphere have not been clearly identified yet. We have focused on measuring the Pi 2 electric pulsations by an FM-CW (Frequency Modulated Continuous Wave) radar and clarify their characteristics. In order to detect the ionospheric electric fields, we built a FM-CW (HF) radar at Sasaguri (Magnetic Latitude: 23.2 degree, Magnetic Longitude: 199.6 degree), Fukuoka, Japan in 2002. The radar provides the Doppler shift of launched wave frequencies, which corresponds to the height variation of the ionosphere, with a high- time resolution of 3 sec. When the eastward (westward) electric field penetrates into the low-latitude ionosphere, it drifts upward (downward) through the ExB drift. Thus, using the FM-CW radar we can measure east-west electric fields (Ey) in the ionosphere [see Ikeda et al., 2008]. In this study, we also used geomagnetic field data BH at Kujyu (KUJ; M. Lat. 23.6 degree, M. Lon. 203.2 degree), a part of Circum-pan Pacific Magnetic Network (CPMN) stations [cf., Yumoto et al., 2001]. The first Pi 2 event was observed at KUJ and Sasaguri simultaneously at 1332 UT (2232 LT) on 6 November, 2003. Also positive bay was detected in the H-component (BH) at KUJ. The dominant frequencies of the electric field Ey and magnetic field BH were identical. From a cross-correlation analysis between the BH at KUJ and Ey at Sasaguri, we found that the correlation coefficient is 0.80 and phase delay is about -100 degree. Takahashi et al. (JGR, 2001) showed the expected phase relation between magnetic field of cavity- mode Pi 2 and associated electric field. Based on their result, we suggest the phase delay of -100 degree indicates that the first Pi 2 event shows a radial mode structure of cavity-mode Pi 2. The second Pi 2 event was observed at 1415 UT (2315 LT) on the same day 6 November, 2003. The dominant frequency of Ey and BH were the same and phase delay is -148 or 39 degree. Since the phase delay is almost -180 or 0 degree, this Pi 2 event can be described by as a propagating mode. Further we analyzed 26 Pi 2 events that were recorded by a CPMN magnetometer at KUJ or Kagoshima (KAG; Magnetic Latitude: 21.9 degree, Magnetic Longitude: 203.2 degree) and the FM-CW radar simultaneously within a period from Nov. 2003 to Apr. 2004. The criteria of the analyzed Pi 2 events are that Pi 2 magnetic amplitude range of the BH is more than 1 nT at KUJ or KAG. In 12 of all 26 Pi 2 events, the dominant frequency of Ey and BH are identical. Moreover we examined the phase delay of 12 Pi 2 events, and found that the only 3 events in midnight sector show the radial mode structure of cavity-mode Pi 2. Other 9 events show a propagating mode of Pi 2. The observed low-latitude Pi 2s are concluded not to be described as a simple standing or propagating mode.

Ikeda, A.; Yumoto, K.; Uozumi, T.; Shinohara, M.; Nozaki, K.; Yoshikawa, A.

2008-12-01

41

Rain Observations with Micro Rain Radar (MRR) over a Tropical Station  

Microsoft Academic Search

The Micro Rain Radar (MRR) a high resolution radar operates at a frequency of 24 GHz installed at Thumba (8.5°N, 76.9°E) under Ka band propagation experiment is used extensively to characterize the tropical rain. This radar measurements of rain were obtained with fine spatial and temporal resolutions like One minute time resolution and 200 m height resolution. With this radar

P. K. Kunhikrishnan; M. R. Sivaraman; N. V. P. Kiran Kumar; Denny Alappatu

2007-01-01

42

Radar  

Microsoft Academic Search

Over 1,000,000 km2 of the equatorial surface of Mars west of the Arsia Mons volcano displays no 3.5-cm radar echo to the very low level of the radar system noise for the Very Large Array; the area displaying this unique property has been terms \\

James R. Zimbelman; Kenneth S. Edgett

1994-01-01

43

A game theory approach to radar ECCM evaluation  

Microsoft Academic Search

The evaluation of candidate ECCM features in a military radar should be an important part of the design process. In spite of its importance, a well-founded quantified methodology has not hitherto been developed. Here, the application of game theory is introduced as a powerful approach to ECCM appraisal. Simplified examples are included to clarify the utility of the technique.

J. Clarke; A. K. Subramanian

1985-01-01

44

A game theory approach to radar ECCM evaluation  

NASA Astrophysics Data System (ADS)

The evaluation of candidate ECCM features in a military radar should be an important part of the design process. In spite of its importance, a well-founded quantified methodology has not hitherto been developed. Here, the application of game theory is introduced as a powerful approach to ECCM appraisal. Simplified examples are included to clarify the utility of the technique.

Clarke, J.; Subramanian, A. K.

45

United States Air Force 611th air support group, 611th Civil Engineer Squadron, Tin City, Long Range Radar Station, Alaska. Final management action plan  

SciTech Connect

The Tin City Long Range Radar Station (LRRS) Management Action Plan (MAP) presents a status summary of environmental restoration and compliance programs, and comprehensive strategies for implementing environmental response actions necessary to protect human health and the environment.

NONE

1996-08-20

46

First observations of ionospheric irregularities and flows over the south geomagnetic pole from the SuperDARN HF radar at McMurdo Station, Antarctica  

NASA Astrophysics Data System (ADS)

In February 2010 a new SuperDARN radar began operation at McMurdo Station, Antarctica. The radar’s orientation places the south geomagnetic pole near the center of the field of view at about 1200 km range. The radar is the highest latitude radar of the SuperDARN network, both geographically and geomagnetically, and the observations have a different character than those of the auroral zone radars. One particular feature of note is the high incidence of observed backscatter. When ionospheric altitudes are above the solar shadow height the incidence of observation is greater than 80% for a large portion of the radar field of view. This is indicative of the near constant presence of field-aligned density irregularities in the polar cap. This paper presents statistics of the observations along with estimates of the convection velocity maps. Prevailing IMF and solar wind velocity were taken from the Omni database and compared to the observed flows.

Bristow, W. A.; Parris, R. T.; Spaleta, J.

2010-12-01

47

Evaluation of textural and multipolarization radar features for crop classification  

Microsoft Academic Search

The aim of this research is to evaluate crop discrimination using airborne radar data based on multipolarization and textural information. Multipolarization data (C-HH, C-VV, and C-HV) were used for discriminating 5 crop types i.e., corn, wheat, soya, pasture, and alfalfa. For the multipolarization evaluation, an unsupervised classification algorithm and a supervised method based on maximum likelihood were used on the

Hassan Anys; Dong-Chen He

1995-01-01

48

Laser radar modeling for simulation and performance evaluation  

NASA Astrophysics Data System (ADS)

Laser radars have the unique capability to give both intensity and full 3-D images of an object or a scene. The latest addition to these capabilities is the possibility to acquire motion. These systems have many civilian and military applications such as terrain modeling, depth sounding, object detection, classification and positioning as well as object tracking. In order to fully understand the performance of laser radars vs experimental data a computer simulation model is of high value. We have developed a modularized computer model capable of modeling performance of a variety of laser radar systems. In order to derive the returned signal waveform from the object one has to account for the laser pulse time characteristics, media effects such as the atmospheric attenuation and scattering as well as object characteristics like shape, BRDF, surface roughness and others. The noise from target speckle and scintillations has to be coupled with detector noise generated by the inherent noise in the detectors and subsequent amplifiers and read out circuitry as well as the noise induced from the optical background. The result can be of help when designing and using new laser radar systems, as well as extending real system parameters and evaluate performance. We will give examples of simulated sensor data in different applications/scenarios together with some real measured data.

Chevalier, Tomas R.; Steinvall, Ove K.

2009-09-01

49

Test and Evaluation of Total Station Instruments.  

National Technical Information Service (NTIS)

Total station instruments, which combine an electronic distance measuring instrument and a theodolite, have been widely accepted by the surveying community to perform geodetic surveys as well as other types of measurements. In response to this new technol...

S. R. DeLoach

1987-01-01

50

Criteria for Evaluating Alternative Transit Station Designs.  

National Technical Information Service (NTIS)

The urban transit interchange facility is described in terms of the important functional facility components and the quality of the station environment. These terminal dimensions are interpreted to establish a list of design objectives which reflect the p...

L. A. Hoel M. J. Demetsky M. R. Virkler

1976-01-01

51

Simultaneous PMC and PMSE observations with a ground-basedlidar and SuperDARN HF radar over Syowa Station, Antarctica  

NASA Astrophysics Data System (ADS)

A Rayleigh-Raman lidar system had been installed by the 52nd JapaneseAntarctic Research Expedition on February, 2011 at Syowa Station Antarctica(69.0°S, 39.5°E). Polar Mesospheric Cloud (PMC) was detected by the lidar at22:30UT (+3hr for LT) on Feb 4th, 2011, the first day of a routineoperation. This event is the first time to detect PMC over Syowa Station bya lidar. In the same night, SuperDARN HF radar with oblique incidence beamsalso detected Polar Mesosphere Summer Echoes (PMSEs) during 21:30UT to23:00UT. Although these signals were detected at different times andlocations, PMC motion estimated using horizontal wind velocities obtained bya collocated MF radar strongly suggests that they have a common origin (i.e.ice particle). We consider that this event occurred in the end of PMCactivity period at Syowa Station in the austral summer season (2010-2011),since the lidar did not detected any PMC signals on other days in February,2011. This is consistent with satellite-born PMC observations by AIM/CIPSand atmospheric temperature observations by AURA/MLS instruments.

Suzuki, Hidehiko; Nakamura, Takuji; Tsutsumi, Masaki; Kawahara, Takuya D.; Ogawa, Tadahiko; Tomikawa, Yoshihiro; Ejiri, Mitsumu K.; Sessai Yukimatu, Akira; Abo, Makoto

2012-07-01

52

Availability & Reliability Evaluation of Dokan Hydro Power Station  

Microsoft Academic Search

This paper introduces a Markov reliability model for Dokan hydro power station by studying the operational data of this station for period 2001-2005. The most important reliability indices are found namely failure rate ? and repair rate mu through data collection and analysis. The availability and reliability of individual units and for the power plant are evaluated by taking into

A. R. Majeed; N. M. Sadiq

2006-01-01

53

Simultaneous PMC and PMSE observations with a ground-based lidar and SuperDARN HF radar at Syowa Station, Antarctica  

NASA Astrophysics Data System (ADS)

A Rayleigh-Raman lidar system was installed in January 2011 at Syowa Station, Antarctica (69.0° S, 39.6° E). Polar mesospheric clouds (PMCs) were detected by lidar at around 22:30 UTC (LT -3 h) on 4 February 2011, which was the first day of observation. This was the first detection of PMCs over Syowa Station by lidar. On the same day, a Super Dual Auroral Radar Network (SuperDARN) HF radar with oblique-incidence beams detected polar mesospheric summer echoes (PMSE) between 21:30 and 23:00 UTC. This event is regarded as the last PMC activity around Syowa Station during the austral summer season (2010-2011), since no other PMC signals were detected by lidar in February 2011. This is consistent with results of PMC and mesopause temperature observations by satellite-born instruments of AIM (Aeronomy of Ice in the Mesosphere)/CIPS (Cloud Imaging and Particle Size) and AURA/MLS (Microwave Limb Sounder) and horizontal wind measurements taken by a separate MF radar. Doppler velocity of PMSE observed by the HF radar showed motion toward Syowa Station (westward). This westward motion is consistent with the wind velocities obtained by the MF radar. However, the PMSE region showed horizontal motion from a north-to-south direction during the PMC event. This event indicates that the apparent horizontal motion of the PMSE region can deviate from neutral wind directions and observed Doppler velocities.

Suzuki, H.; Nakamura, T.; Ejiri, M. K.; Ogawa, T.; Tsutsumi, M.; Abo, M.; Kawahara, T. D.; Tomikawa, Y.; Yukimatu, A. S.; Sato, N.

2013-10-01

54

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

55

Embedded training for the joint surveillance and target attack radar system ground station module  

Microsoft Academic Search

Embedded training is a capability within an actual operational system, which provides sustainment training for system operators. It is invoked and used by the operator without instructor supervision. This paper describes Motorola's prototype embedded training system for the Army's Joint Surveillance and Target Attack Radar System (Joint STARS) groundstation. The embedded training capability is implemented entirely within the operational system

Kathleen M. Mutch; Vincent T. Fox

1995-01-01

56

Performance evaluation of advanced space suit concepts for Space Station  

NASA Technical Reports Server (NTRS)

The requirements for an advanced space suit for Space Station EVA and the methods used to evaluate candidate suit concepts are examined. Two candidate Space Station suits, the AX-5 and the Mk. III, are described and illustrated. The methods to test these suits are discussed, including, tests at the NASA/Johnson Space Center Weightless Environment Training Facility, tests in the microgravity environment of the KC-135 aircraft, CO2 washout evaluations, component torque measurements, environmental hazards protection evaluations, and component cycle life verification.

Klaus, David M.; West, Philip R.

1989-01-01

57

Fabrication of Radar Absorbing Structure and Evaluation of Radar Cross Section: Case Study of Hybrid Shells  

Microsoft Academic Search

Fiber-reinforced composite materials have outstanding mechanical and electrical properties; their applications have been expanded to commercial products as well as military components. Using composite materials, researchers have studied the radar absorbing, or `stealth' technology. In this research, to develop the radar absorbing structure (RAS), hybrid composite materials are fabricated into three-dimensional `C' and `U' shape shells. A series of experiments

Woo-Kyun Jung; Sung-Hoon Ahn; Bierng-Chearl Ahn; Seoung-Bae Park; Myung-Shik Won

2007-01-01

58

Evaluation of the self-consistency principle for calibration of the CASA radar network using properties of the observed medium  

Microsoft Academic Search

The Center for Collaborative and Adaptive Sensing of the Atmosphere (CASA) has deployed a Distributive, Adaptive and Collaborative Sensing (DCAS) network of four radars in central Oklahoma. The radars operate at the X-band frequency and are capable of polarimetric and Doppler measurements. The radar network is being evaluated for Quantitative Precipitation Estimation (QPE). QPE algorithms based on radar power measurements

Jorge M. Trabal; V. Chandrasekar; Eugenio Gorgucci; David J. McLaughlin

2010-01-01

59

Evaluation of Service Station Attendant-Auto Care Project.  

ERIC Educational Resources Information Center

The project described offers an approach to providing occupational skills to socially and educationally handicapped youth, specifically the skills necessary for a service station attendant in driveway salesmanship and auto care. The 10-page evaluation report presents project goals and objectives with evaluation data (represented graphically) and…

Cress, Ronald J.

60

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

61

TRACALS Evaluation Report. Radar Initial Evaluation Report, Incirlik CDI, Turkey, 4 - 15 March 1979.  

National Technical Information Service (NTIS)

This radar initial evaluation report presents data collected from 4-15 March 1979 to define capabilities and limitations of the GCA facility at Incirlik CDI, Turkey. This report includes descriptions of the useable ASR and ATCRBS coverage and tracking cap...

B. J. Merwold

1979-01-01

62

Radiosonde pressure sensor performance - Evaluation using tracking radars  

NASA Technical Reports Server (NTRS)

The standard balloon-borne radiosonde employed for synoptic meteorology provides vertical profiles of temperature, pressure, and humidity as a function of elapsed time. These parameters are used in the hypsometric equation to calculate the geopotential altitude at each sampling point during the balloon's flight. It is important that the vertical location information be accurate. The present investigation was conducted with the objective to evaluate the altitude determination accuracy of the standard radiosonde throughout the entire balloon profile. The tests included two other commercially available pressure sensors to see if they could provide improved accuracy in the stratosphere. The pressure-measuring performance of standard baroswitches, premium baroswitches, and hypsometers in balloon-borne sondes was correlated with tracking radars. It was found that the standard and premium baroswitches perform well up to about 25 km altitude, while hypsometers provide more reliable data above 25 km.

Parsons, C. L.; Norcross, G. A.; Brooks, R. L.

1984-01-01

63

Observations of the ultra-fast Kelvin wave using meteor radar over a Brazilian extra-tropical station  

NASA Astrophysics Data System (ADS)

Characteristics of the equatorial 3.5-day ultra-fast Kelvin (UKF) wave are investigated with four year meteor radar wind observations over Cachoeira Paulista (22.7S, 45W). UFK signature manifests as discrete bursts spanning over various times of the year with generally less amplitude during fall equinox and early winter span. Daily as well as seasonal mean amplitude of the UFK wave is found to be sufficiently smaller than that observed previously from equatorial stations. Estimated vertical wavelength of the UFK wave comes out to be larger than 80 km. Comparison of present results with another Brazilian equatorial station exhibits latitudinal invariance of the wave as well as transient local dynamical influence to its variability. High zonal acceleration caused by momentum flux convergence due to the UFK wave just after equinoxes is supposed to be responsible for driving westerly phase of the mean zonal wind immediately after equinoxes and hence the mesospheric semiannual oscillation. There is a clear signature of modulation of the UFK wave amplitude by various harmonics of the annual oscillation.

Guharay, Amitava; Prado Batista, Paulo; Clemesha, Barclay Robert

2013-04-01

64

Study of the ultra-fast Kelvin wave with meteor radar observations over a Brazilian extra-tropical station  

NASA Astrophysics Data System (ADS)

Characteristics of the 3.5-day ultra-fast Kelvin (UKF) wave are investigated with 4 years of meteor radar wind observations over Cachoeira Paulista (22.7°S, 45°W). The UFK signature manifests itself as discrete bursts spanning over various times of the year with generally less amplitude during fall equinox and early winter. Daily as well as seasonal mean amplitude of the UFK component is found to be considerably smaller than that observed previously from equatorial stations. Estimated vertical wavelengths of the UFK wave come out to be larger than 40 km. Comparison of the present results with another Brazilian equatorial station implies latitudinal invariance of the wave as well as transient local dynamical influence to its variability. High zonal acceleration caused by momentum flux convergence due to the UFK wave just after equinoxes is believed to be responsible for driving the westerly phase of the mean zonal wind immediately after the equinoxes and hence the mesospheric semiannual oscillation to some extent. There is a clear signature of modulation of the UFK wave amplitude by various harmonics of the annual oscillation.

Guharay, A.; Batista, P. P.; Clemesha, B. R.

2013-09-01

65

Frequency estimation algorithm for an extended FMCW radar system with additional phase evaluation  

Microsoft Academic Search

Range detection applications based on radar can be separated into measurements of short distances with high accuracy or large distances with low accuracy. In this paper an approach is investigated to combine the advantages of both principles. Therefore an FMCW radar will be extended with an additional phase evaluation technique. In order to realize this combination an increased range resolution

Serdal Ayhan; Philipp Pahl; Thorsten Kayser; Mario Pauli; Thomas Zwick

2011-01-01

66

RCS evaluation of complex objects coated with radar absorbing materials using the complex ray method  

Microsoft Academic Search

The strategy and results of an RCS (radar cross section) evaluation of a dihedral corner reflector coated with lossy materials using the complex ray method are described. A computer program based on the analysis presented has been developed to perform effective RCS calculations of dihedral corner reflectors having the inner surfaces coated with or without radar adsorbing materials. One of

Y. Z. Ruan; H. P. Du

1992-01-01

67

Experimental evaluation of cursors for B2 Synthetic Aperture Radar (SAR) application  

Microsoft Academic Search

The purpose of the current study was to evaluate the current and two alternative cursors for B-2 Synthetic Aperture Radar (SAR) imagery application and to recommend an alternative design. This study was conducted in response to problems crewmembers are experiencing with the current cursor on the B-2 SAR display. In particular, the design of the current radar cursor (i.e., the

Janet G. Irvin; Jeffrey A. Doyal; Earl D. Sharp; James M. Lasalvia

1993-01-01

68

GROUND PENETRATING RADAR EVALUATION OF RAILWAY TRACK SUBSTRUCTURE CONDITIONS  

Microsoft Academic Search

ABSTRACT Ground penetrating radar has shown ,the ability to map railroad track substructure condition on a continuous top-of- rail nondestructive basis. In this study, 1 GHz radar data were acquired between ,concrete and ,wood ,ties as well ,as from the ballast shoulders beyond the ends of the ties, and with,multiple ,antenna ,orientations ,and ,polarizations. Automatic processing of the data was

G. R. Olhoeft; E. T. Selig

69

PQLX: A Software Tool to Evaluate Seismic Station Performance  

NASA Astrophysics Data System (ADS)

We present a new tool that will allow users to evaluate seismic station performance and characteristics by providing quick and easy transitions between visualizations of the frequency and time domains. The software is based on the probability density functions (PDF) of power spectral densities (PSD) (McNamara and Buland, 2004). The computed PSDs are stored in a MySQL database, allowing a user to access specific time periods of PSDs (PDF subsets) and time series segments through a GUI-driven interface. The power of the method and software lies in the fact that there is no need to screen the data for system transients, earthquakes or general data artifacts since they map into a background probability level. In fact, examination of artifacts related to station operation and episodic cultural noise allow us to estimate both the overall station quality and a baseline level of earth noise at each site. The output of this analysis tool is useful for both operational and scientific applications. Operationally, it is useful for characterizing the current and past performance of existing broadband stations, for conducting tests on potential new seismic station locations, for detecting problems with the recording system or sensors, and for evaluating the overall quality of data and meta-data. Scientifically, the tool allows for mining of PSDs for investigations on the evolution of seismic noise (see Aster et al., Hutt et al., Leeds et al., and Oneel et al., this meeting). The PDF algorithm and initial software were developed by the USGS as a part of the ANSS/GSN data and network QC system. Further development, supported by the IRIS Data Management Center, integrated the PDF algorithm into the IRIS QUACK system. The newest version, PQLX, combines the PDF system with the PQL time series viewing tool developed with support from IRIS PASSCAL. Currently, PQLX is operational at the USGS ANSS NOC and ASL for station performance monitoring.

McNamara, D. E.; Boaz, R. I.

2006-12-01

70

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

71

Evaluation of the Sensitivity of Radar Cross Section Predictions to Uncertainties in Material Characteristics.  

National Technical Information Service (NTIS)

The purpose of this study was to evaluate the effects of material characteristics uncertainties on Radar Cross Section (RCS) predictions. Many methods have been developed to predict the RCS of metal objects, but for material coated objects, these methods ...

G. A. Barnhart

1995-01-01

72

Ground Penetrating Radar for Railroad Track Substructure Evaluation.  

National Technical Information Service (NTIS)

The report presents the results of the first three phases of a multiphase project to adapt Ground Penetrating Radar (GPR) to railroads for use in developing useful indices of substructure condition and performance. Included are brief discussions of some b...

E. T. Selig G. R. Olhoeft J. P. Hyslip S. S. Smith

2005-01-01

73

Evaluating radar detection probabilities by steepest descent integration  

NASA Astrophysics Data System (ADS)

The probability of detection for radars employing noncoherent integration and a fixed threshold or cell-averaging constant false alarm rate (CA-CFAR) processor is computed by numerical contour integration in the complex plane. The technique is applied to both nonfluctuating and chi-squared fluctuating targets. A bound on the truncation error allows for a simple stopping rule for the numerical integration. The method has applicability to many problems in radar detection theory.

Helstrom, C. W.; Ritcey, J. A.

1984-09-01

74

An evaluation of 915-MHz radar wind profiler/RASS by tower and sodar measurements  

NASA Astrophysics Data System (ADS)

The accuracy and precision of the 915-MHz low-atmosphere wind profiler/RASS have been investigated through comparisons with other better-understood instruments such as rawinsonde (Strauch et al., 1987 and May et al., 1989), sodar (Neff and Wilczak, 1993), and tower instruments (Ye et al., 1993). These studies have provided useful information as well as confidence in the performance of this new technology in boundary-layer research and monitoring. However, because the accuracy of the profiler/RASS measurements depends to a large degree on the strength and homogeneity of small-scale turbulence and the amount of moisture in the atmosphere, the performance of the profiler may change significantly from one environment to another. As the radar wind profiler/RASS technology becomes more widely applied to a variety of research applications and moves toward operational wind, temperature, and eventually flux profiling, it is crucial to quantify its performance under different environmental and meteorological conditions. South-central Washington is a semi-arid shrub-steppe environment with an average annual precipitation of only about 15 cm, which is significantly different from the other locations where comparative studies have been conducted. The performance of the RADIAN 915-MHz wind profiler/RASS in such an environment was evaluated using data from standard instruments mounted on a 120-m meteorological tower and a nearby sodar at the Hanford Meteorological Station. The results of this evaluation are presented in this paper.

Zhong, S.; Shaw, W. J.; Hubbe, J. M.

1994-08-01

75

The RADAR Test Methodology: Evaluating a MultiTask Machine Learning System with Humans in the Loop  

Microsoft Academic Search

The RADAR project involves a collection of machine learning research thrusts that are integrated into a cognitive personal assistant. Progress is examined with a test developed to measure the impact of learning when used by a human user. Three conditions (conventional tools, Radar without learning, and Radar with learning) are evaluated in a large-scale, between- subjects study. This paper describes

Aaron Steinfeld; Rachael Bennett; Kyle Cunningham; Matt Lahut; Pablo-Alejandro Quinones; Django Wexler; Dan Siewiorek; Paul Cohen; Julie Fitzgerald; Othar Hansson; Jordan Hayes; Mike Pool; Mark Drummond

76

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

77

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

78

Engineering Evaluation and Calibration of Iowa X-Band Polarimetric Radars  

NASA Astrophysics Data System (ADS)

The detailed knowledge and extensive monitoring of the precipitation structure at smaller temporal and spatial scales are critical to the scientific understanding of the hydrological cycle and associated processes. The hydrometeorological information at smaller scales is usually not available with the current weather radar systems which operate at lower frequencies such as S- and C-bands. This has necessitated the use of higher frequency (X-band) weather radars to obtain rainfall data at improved accuracy and near-ground coverage at shorter ranges. The University of Iowa has acquired four scanning, mobile, X-band polarimetric (XPOL) Doppler weather radars with the objective of accurate quantitative estimation of the rainfall at a high temporal and spatial resolution. These four XPOL radars will be deployed for short-range multiple-view observations of the same weather event thus reducing uncertainties introduced by the signal attenuation and instrument-wide errors. This network of radars is intended to serve multiple areas of hydrological research including uncertainty modelling, urban hydrology, flood and flash-flood prediction, and soil erosion. Compared to the existing networks of X-band weather radars, several features place the XPOL radar systems in a distinctly attractive position for the scientific community. Firstly, the Iowa XPOL radars are mounted on mobile platforms, and consequently, are deployed at any location of interest. Secondly, these systems are capable of acquiring data at a programmable range sampling which can be as low as 30m. Thirdly, the use of dual-polarization provides additional information about the hydrometeors at smaller scales. The radars can operate in staggered PRT and dual-PRF pulsing modes and can process data using either standard pulse-pair or spectral mode techniques. The Iowa XPOL radar systems are currently being evaluated and calibrated to participate in their first field campaigns in the upcoming NASA IFloodS (Iowa Flood Studies) field experiment during Spring-Summer 2013. This paper will present results obtained through extensive system-level tests conducted on the transmitter-receiver unit and carried out largely in conformity with the NASA Global Precipitation Measurement - Ground Validation (GPM-GV) standards. This includes scrutinizing the temporal stability of the some of the performance parameters. The radar systems will also be calibrated against existing standard weather radar systems during the campaign. The experimental observations of the individual XPOL radar units with respect to the reference ground and weather targets will also be analysed. The paper will also present an inter-XPOL comparison of the findings of these experiments.

Vijay Mishra, Kumar; Kruger, Anton; Krajewski, Witold

2013-04-01

79

Reliability evaluation of offsite power supply to generating stations  

SciTech Connect

This paper attempts to promote the understanding of terminology, discusses some of the differences in supply and describes some of the assessment methods associated with the reliability of the offsite power supply. Topics considered include terminology and reliability indices, grid collapse, multiple line outages, loss of switchyard, loss of transformers, and auxiliary bus outage. Minimum requirements for the offsite supply to generating stations must satisfy both economic and safety considerations. Failure mode and effects analysis (FMEA) is discussed. It is concluded that the various requirements of plant loads being supplied and alternative options in the restoration process require that reliability evaluation analyses be tailored to the individual site and load.

Landgren, G.L.; Cole, D.G.

1983-01-01

80

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

81

Laser radar modeling for simulation and performance evaluation  

Microsoft Academic Search

Laser radars have the unique capability to give both intensity and full 3-D images of an object or a scene. The latest addition to these capabilities is the possibility to acquire motion. These systems have many civilian and military applications such as terrain modeling, depth sounding, object detection, classification and positioning as well as object tracking. In order to fully

Tomas R. Chevalier; Ove K. Steinvall

2009-01-01

82

Evaluation Radar Detection Probabilities by Steepest Decent Integration.  

National Technical Information Service (NTIS)

The probability of detection for radars employing noncoherent integration and a fixed threshold or cell-averaging constant false alarm rate (CA-CFAR) processor is computed by nonfluctuating and chi-squared fluctuating targets. A bound on the truncation er...

C. W. Helstrom J. A. Ritcey

1984-01-01

83

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

84

RAT SCAT evaluation of commercially available radar absorbing materials, volume 1  

Microsoft Academic Search

This report summarizes performance evaluation tests on a variety of commercially available thin flexible sheet type radar absorber materials, including both resonant and non-resonant types. A corner reflector test technique was used which allowed test and evaluation of the absorber at both normal incidence and grazing angles out to ninety (90) degrees. Fourteen types of RAM were tested at frequencies

W. Ohara

1976-01-01

85

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

86

Application of geostatistics to evaluate partial weather station networks  

Microsoft Academic Search

Climatic data are an essential input for the determination of crop water requirements. The density and location of weather stations are the important design variables for obtaining the required degree of accuracy of weather data. The planning of weather station networks should include economic considerations, and a mixture of full and partial weather stations could be a cost-effective alternative. A

Muhammad Ashraf; Jim C. Loftis; K. G. Hubbard

1997-01-01

87

Antenna evaluation study for the shuttle multispectral radar, phase 1  

NASA Technical Reports Server (NTRS)

Critical parameters of the shuttle multispectral radar antenna (SMRA) which most affect antenna performance were identified. A preliminary methematical model is presented for describing SMRA performance under the influence of various physical and environmental factors which might degrade performance. Because user groups have not agreed on optimum frequencies best suited for the broadest range of application, the study incorporates frequencies ranging from 1.2 to 14.5 GHz, as well as a consideration of incidence angles from near nadir to nearly 50 deg.

Coffey, E. L., III; Carver, K. R.

1976-01-01

88

Balloon-borne pressure sensor performance evaluation utilizing tracking radars  

NASA Technical Reports Server (NTRS)

The pressure sensors on balloon-borne sondes relate the sonde measurements to height above the Earth's surface through the hypsometric equation. It is crucial that sondes used to explore the vertical structure of the atmosphere do not contribute significant height errors to their measurements of atmospheric constituent concentrations and properties. A series of radiosonde flights was conducted. In most cases, each flight consisted of two sondes attached to a single balloon and each flight was tracked by a highly accurate C-band radar. For the first 19 radiosonde flights, the standard aneroid cell baroswitch assembly used was the pressure sensor. The last 26 radiosondes were equipped with a premium grade aneroid cell baroswitch assembly sensor and with a hypsometer. It is shown that both aneroid cell baroswitch sensors become increasingly inaccurate with altitude. The hypsometer radar differences are not strongly dependent upon altitude and it is found that the standard deviation of the differences at 35 km is 0.179 km.

Norcross, G. A.; Brooks, R. L.

1983-01-01

89

First observations of ionospheric irregularities and flows over the south geomagnetic pole from the Super Dual Auroral Radar Network (SuperDARN) HF radar at McMurdo Station, Antarctica  

NASA Astrophysics Data System (ADS)

Observations from the first 100 days of operation of the Super Dual Auroral Radar Network (SuperDARN) radar at McMurdo Station, Antarctica are presented. The observations are examined for incidence of ionospheric scatter, which is higher than has been found at the auroral zone radars of the SuperDARN network. During some hours of each day, the probability of observing ionospheric scatter exceeded 90%. In the later portion of the period examined, there was a period of time each day during which the scatter incidence dropped significantly. Incidence was as examined versus solar illumination of the ionosphere, and it was found that the decreases coincided with periods when the ionosphere was in darkness. From this, it is concluded that propagation effects were the reason for the decreases. Plasma velocity observations from the period are also presented and compared with the prevailing interplanetary magnetic field (IMF). The observations were averaged over the central polar cap (? > 85°) and were selected for intervals when the radar line of sight was nearly parallel to the Earth-Sun (E-S) line or perpendicular (E-S-perp) to it. A linear relationship was found between the IMF z component and the E-S velocity and similar relationship between the E-S-perp velocity and the IMF y component. There was a significant spread of velocities about the best fit lines. The IMF and average velocity time series were cross-correlated for a number of intervals, and it was found that the average correlation was about 50%, though during some intervals, the correlation exceeds 80%. No explanation is given for the variance of the correlation.

Bristow, W. A.; Spaleta, J.; Parris, R. T.

2011-12-01

90

Evaluation of commercially available SiC MESFETs for phased array radar applications  

Microsoft Academic Search

Silicon carbide MESFETs supplied by a commercial vendor were evaluated for their suitability for phased array radar applications. The results showed superior performance over traditional III-V semiconductors in respect of pulse droop, and demonstrated the increasing maturity of these wide bandgap devices.

M. G. Walden; M. Knight

2002-01-01

91

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

92

Comparative Evaluation of the Subsystem and Nearest-Neighbor Classifiers for Radar Aircraft Identification.  

National Technical Information Service (NTIS)

The purpose of this report is to investigate aspects of design and evaluation of classification algorithms for a type of pattern recognition problem. The problem is one that is encountered in the design of a radar aircraft identification system. This prob...

S. N. ihari

1976-01-01

93

Comparative evaluation of the subsystem and nearest-neighbor classifiers for radar aircraft identification  

Microsoft Academic Search

The purpose of this report is to investigate aspects of design and evaluation of classification algorithms for a type of pattern recognition problem. The problem is one that is encountered in the design of a radar aircraft identification system. This problem differs from the usual situation encountered in statistical pattern recognition theory. Here classes are characterized by labelled training patterns

S. N. Srihari

1976-01-01

94

Application of ground penetrating radar in grouting evaluation for shield tunnel construction  

Microsoft Academic Search

Uniformity and quality of the grout behind the lining segments have a great influence on the long-term settlement in shield tunnel construction in soft soil areas. In order to evaluate the effectiveness of the grouting treatment before the tunnel operation, a nondestructive testing method using ground penetrating radar (GPR) was proposed to detect the grout thickness behind the lining segments

Fengshou Zhang; Xiongyao Xie; Hongwei Huang

2010-01-01

95

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

96

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

97

Borehole Radar Evaluation Program: Antenna designs for optimal directionality  

SciTech Connect

The thrust of this progress report deals with the significant advances we have made in the past few months toward optimal radiating efficiency and optimal directionality from antenna arrays that fit inside a 5.5 in.-OD tool. The reasons spawning this development effort on antennas are the many uses for underground radar systems that can be built around such high-performance antennas. Targets of interest include large man-made voids, natural voids in strata, fractures zones in hard rock, edges and internal faults in salts domes and glaciers, etc. Recent progress includes observation of the radiation patterns of several dipole arrays which we designed to fit within a 5.5-inch OD borehole tool and to radiate efficiently at wavelengths in the band from 0.4 meter to 2 meters with optimal directionality. Front-to-back ratios of 15 dB are consistently observed in the horizontal plane of these arrays. These antennas are observed to radiate with high efficiencies, less than 1 dB loss, into air at 1.3 meter wavelength. 18 figs.

Castle, J.G.; Morris, H.E.

1991-05-01

98

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

99

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

100

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

101

Evaluation of interpolating methods for daily precipitation at various station densities  

NASA Astrophysics Data System (ADS)

Spatial continuous data play a significant role in planning, risk assessment and decision making in climate research and geosciences. It is essential to get accurate grid precipitation data of high resolution in hydrological modeling and water resources management. In recent years, radar and satellite provide an alternative way for spatial precipitation data, but due to technique problems and deficient accuracy, interpolating the observed point data is still the common way to obtain gridding precipitation data for research and management purposes. Many interpolating methods have been proposed and great effort has been made to evaluate and compare them. But by far, no universal method is widely accepted because of the diversity in study regions, difference in climate situations, and differences in data quality and quantity, and selected methods in comparisons. It has been well known that the most paramount factor affecting the performance of interpolating methods is the density of sampling points. However, the performance of different interpolating methods at various sampling densities, which means the performance degradation caused by density changes, has not been deeply examined. This work focuses on the evaluation of interpolating methods in daily precipitation at various station densities and tries to provide guidance on choosing interpolating method under different circumstance. To fill this objective, we choose five commonly used or recommended interpolation methods, i.e. nearest neighbor (NN), inverse distance weighting (IDW), Gradient plus Inverse Distance Squared (GIDS), ordinary kriging (OK) and simple kriging (SK) at five designed sampling densities ranging from 22.6 to 9.8 stations per ten thousand square kilometers at Xiangjiang River basin during 2000 to 2005 when the precipitation data were in the highest density. Four criteria were used for method assessment, i.e., mean error (ME), root mean absolute error (RMSE), model efficient (EF) and index of agreement (IOA) via cross-validation. To further observe their performance in interpolating different precipitation parameters, we also analyzed the changes of performance of the five methods in estimating daily maximum precipitation and precipitation values at different quintiles (5%, 25%, 50%, 75% and 95%) with different sampling densities.

Li, H.; Xu, C.-Y.; Chen, H.; Zhang, Z. X.; Xu, H. L.

2012-04-01

102

Evaluation of MELCOR improvements: Peach Bottom station blackout analyses  

SciTech Connect

Long-term station blackout analyses in Peach Bottom were first carried out using MELCOR 1.8BC, and later with 1.8DN, as part of an overall program between the US Nuclear Regulatory Commission (NRC) and Brookhaven National Laboratory (BNL), to provide independent assessment of MELCOR as a severe accident/source term analysis tool. In addition to the reference MELCOR calculation, several sensitivity calculations were also performed to explore the impact of varying user-input modeling and timestep control parameters on the accident progression and radionuclide releases to the environment calculated by MELCOR. An area of concern that emerged from these studies was the impact of the selection of maximum allowable timestep ({Delta}t{sub max}) on the calculational behavior of MELCOR, where the results showed significant differences in timing of key events, and a lack of convergence of the solution with reduction of {Delta}t{sub max}. These findings were reported to the NRC, SNL, and the MELCOR Peer Review Committee. As a consequence, a significant effort was undertaken to eliminate or mitigate these sensitivities. The latest released version of MELCOR, Version 1.8.2, released in April 1993, contains several new or improved models, and has corrections to mitigate numerical sensitivities. This paper presents the results of updating the earlier sensitivity studies on maximum timestep, to more properly represent the abilities of the improved MELCOR version 1.8.2. Results are presenter in terms of timing of key events, thermal-hydraulic response of the system, and environmental release of radionuclides. The impact of some of the newer models, such as falling debris quench model, and ORNL`s new BH model, is also evaluated.

Madni, I.K.

1993-12-31

103

Design of an orbital debris radar ground demonstration  

NASA Technical Reports Server (NTRS)

A breadboard radar system is being designed and tested at NASA Johnson for dealing with the space debris problem that could present a growing threat to Space Station Freedom. The major design problems are due to the small radar cross section of such debris (below -30 dBm2), the high closing velocities of the particles with respect to the Space Station (10 km/sec and higher), and the stringent weight, power-consumption, maintenance, and reliability constraints on spaceborne systems. Consideration is given to the preliminary implementation of a ground demonstration radar for testing concepts, technologies, and performance envelopes for application to the space-borne debris detection and tracking radar. Simulation results and techniques developed for predicting system performance and for evaluating antenna parameters are given. The design process of the electronically steered phased array antenna is briefly described, and block diagrams for the implementation of the radar system are given.

Paz, I.; Carl, J. R.; Shaw, R. W.; Kovitz, J. K.; Arndt, G. D.

1989-01-01

104

Combined observations of meteors by image-orthicon television camera and multi-station radar. [to compare ionization with luminosity  

NASA Technical Reports Server (NTRS)

Observations from multiple sites of a radar network and by television of 29 individual meteors from February 1969 through June 1970 are reported. Only 12 of the meteors did not appear to fragment over all the observed portion of their trajectories. From these 12, the relation for the radar magnitude to the panchromatic absolute magnitude was found in terms of velocity of the meteor. A very tentative fit to the data on the duration of long enduring echoes versus visual absolute magnitude is made. The exponential decay characteristics of the later parts of several of the light curves are pointed out as possible evidence of mutual coalescence of droplets into which the meteoroid has completely broken.

Cook, A. F.; Forti, G.; Mccrosky, R. E.; Posen, A.; Southworth, R. B.; Williams, J. T.

1973-01-01

105

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

106

Work Plan and Sampling and Analysis Plan for Interim Remedial Actions for Indian Mountain Long Range Radar Station, Elmendorf AFB, Alaska. Addendum to RI/FS Work Plan (July 1994) and Sampling and Analysis Plan (July 1994).  

National Technical Information Service (NTIS)

The purpose of the report is to describe and detail the activities to be conducted as part of the Interim Remedial Action at Indian Mountain Long Range Radar Station, Alaska. Section 1.0 provides introduction and background information, and states the obj...

1995-01-01

107

United States Air Force 611th air support group, 611th Civil Engineer Squadron, Tin City Long Range Radar Station, Alaska final remedial investigation/feasibility study. Volume 1  

SciTech Connect

This Final Remedial Investigation/Feasibility Study describes the work performed; explains project objectives; and presents data collected during project activities, results, and conclusions for the Installation Restoration Program at Tin City Longe Range Radar Station, Alaska. The report describes the risks posed by the site and gives the basis for selecting remedies to mitigate the risks.

NONE

1996-04-30

108

A novel method for evaluating robustness of CFAR radar detectors  

Microsoft Academic Search

A method for evaluating the robustness of constant false alarm rate (CFAR) detectors is presented, which is based on the powerful methodology of influence function (IF) developed in the literature on robust statistics. It can evaluate and compare the robustness of different kinds of CFAR detectors by calculating the first derivative of false alarm probability (FAP) at an underlying distribution,

Meng Huadong; Peng Yingning; Wang Xiqin

2002-01-01

109

Evaluation of RFID tag antenna performance using radar cross sections  

Microsoft Academic Search

Evaluation of a RFID tag antenna performance using RCS is shown to be very effective compared with that based on a detection distance. A tag antenna of which impedance is 35Q at 911MHz is designed and its performances are evaluated by RCS'. The procedures to obtain RCS' by EM simulation are described in detail. How to interpret the tag RCS'

Hongil Kwon; Bomson Lee

2005-01-01

110

TRACALS Evaluation Report. Precision Approach Radar, AN/FPN-62, Initial Evaluation Report, Hill AFB, Utah, 3 - 5 June 1981 and 12 June 1981.  

National Technical Information Service (NTIS)

This Traffic Control and Landing System (TRACALS) evaluation was performed to define the capabilities and limitations of the AN/FPN-62, Precision Approach Radar (PAR), at Hill AFB, Utah in its installed environment. The evaluation included a comprehensive...

J. C. Caballero K. M. Slater

1981-01-01

111

EVALUATION RESULTS OF SAN FRANCISCO BAY AREA STATION-CAR DEMONSTRATION  

Microsoft Academic Search

Presented is a summary of the evaluation of the first 2.5 years (November 1995-March 1998) of the San Francisco Bay Area Station-Car Demonstration. The 40 station cars were small battery-powered electric cars used for access to and egress from the Bay Area Rapid Transit District stations and for other local trips. The demonstration was a preliminary test of a larger

Victoria Nerenberg; Martin Bernard III; Nancy Collins

1999-01-01

112

Evaluation of Reliable Multicast Delivery in Base Station Diversity Systems  

NASA Astrophysics Data System (ADS)

This paper proposes a multicast delivery system using base station diversity for cellular systems. Conventional works utilize single wireless link communication to achieve reliable multicast. In cellular systems, received signal intensity declines in cell edge areas. Therefore, wireless terminals in cell edge areas suffer from many transmission errors due to low received signal intensity. Additionally, multi-path fading also causes dynamic fluctuation of received signal intensity. Wireless terminals also suffer from transmission errors due to the multi-path fading. The proposed system utilizes multiple wireless link communication to improve transmission performance. Each wireless terminal communicates with some neighbor base stations, and combines frame information which arrives from different base stations. Numerical results demonstrate that the proposed system can achieve multicast data delivery with a short transmission period and can reduce consumed wireless resource due to retransmission.

Naito, Katsuhiro; Mori, Kazuo; Kobayashi, Hideo

113

Next Generation Weather Radar (NEXRAD) Principal User Processor (PUP) Operational Test and Evaluation (OTE) Operational Test Plan.  

National Technical Information Service (NTIS)

The purpose of this plan is to describe and detail the procedural approach, method, and responsibilities to be employed in conducting the Operational Test and Evaluation (OTE) on the Next Generation Weather Radar (NEXRAD) Principal User Processor (PUP) sy...

B. R. Stretcher

1993-01-01

114

Evaluation of a radar-activated, demand-performance bird hazing system  

Microsoft Academic Search

We evaluated a radar-activated integrated hazing system for the protection of waterfowl at large contaminated ponds at a power plant. The hazing devices in the system included acoustic alarm calls, pyrotechnics and chemical repellents dispersed in the form of a bird tear-gas. Unlike, timed interval systems, or systems with random activation sequences, birds did not habituate to the demand-performance system

Gwen R. Stevens; Jamie Rogue; Richard Weber; Larry Clark

2000-01-01

115

A Step-Frequency Radar Imaging System for Microwave Nondestructive Evaluation  

Microsoft Academic Search

We describe a step-frequency radar (SFR) imaging system that is suitable for microwavenondestructive evaluation (NDE) applications. The system includes a computerautomatedmicrowave measurement apparatus, calibration software, and nonlinear inversescattering imaging algorithms. Through the use of an inverse Fourier transform, the rawSFR data is transformed into a synthetic time-domain pulse. A calibration procedure involvingthe use of calibration targets may then be used

W. H. Weedon; W. C. Chew

2000-01-01

116

Evaluation of data association techniques in a real multitarget radar tracking environment  

Microsoft Academic Search

This paper assesses tracking performance of a number of commonly-used data association techniques, including the nearest-neighbor (NN) data association with optimal and sub-optimal assignments, the weighted-average and nearest-neighbor version of the probabilistic data association (PDA), joint probabilistic data association (JPDA), cheap JPDA, and sub-optimal JPDA. The real radar tracking data used for the performance evaluation in this paper contain multiple

Zhijian Hu; Henry Leung; Martin Blanchette

1995-01-01

117

A novel, compact, low-cost, impulse ground-penetrating radar for nondestructive evaluation of pavements  

Microsoft Academic Search

This paper reports on the development of a novel, compact, low-cost, impulse ground-penetrating radar (GPR) and demonstrate its use for nondestructive evaluation of pavement structures. This GPR consists of an ultrashort-monocycle-pulse transmitter (330 ps), an ultrawide-band (UWB) sampling receiver (0-6 GHz), and two UWB antennas (0.2-20 GHz)-completely designed using microwave-integrated circuits with seamless electrical connections between them. An approximate analysis

Jeong Soo Lee; Cam Nguyen; Thomas Scullion

2004-01-01

118

A study of an orbital radar mapping mission to Venus. Volume 2: Configuration comparisons and systems evaluation  

NASA Technical Reports Server (NTRS)

Configuration comparisons and systems evaluation for the orbital radar mapping mission of the planet Venus are discussed. Designs are recommended which best satisfy the science objectives of the Venus radar mapping concept. Attention is given to the interaction and integration of those specific mission-systems recommendations with one another, and the final proposed designs are presented. The feasibility, cost, and scheduling of these configurations are evaluated against assumptions of reasonable state-of-the-art growth and space funding expectations.

1973-01-01

119

Evaluation of MELCOR improvements: Peach Bottom station blackout analyses.  

National Technical Information Service (NTIS)

Long-term station blackout analyses in Peach Bottom were first carried out using MELCOR 1.8BC, and later with 1.8DN, as part of an overall program between the US Nuclear Regulatory Commission (NRC) and Brookhaven National Laboratory (BNL), to provide inde...

I. K. Madni

1993-01-01

120

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

121

International Space Station Bacteria Filter Element Service Life Evaluation.  

National Technical Information Service (NTIS)

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 flig...

J. L. Perry

2005-01-01

122

Performance evaluation of a multi-station shared vehicle system  

Microsoft Academic Search

In recent years, shared vehicle systems have garnered a tremendous amount of interest as an innovative transportation paradigm which can potentially alleviate traffic congestion, improve air quality, and make surface transportation more efficient. In a multi-station configuration however, these systems place an additional burden on both users and system operators to make the system successful. Intelligent transportation technology can play

Matthew Barth; Jing Han; Michael Todd

2001-01-01

123

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

124

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

125

Electromagnetic compatibility (EMC) evaluation of the SELENE spacecraft for the lunar radar sounder (LRS) observations  

NASA Astrophysics Data System (ADS)

In order to achieve the lunar subsurface sounding and planetary radio wave observations by the Lunar Radar Sounder (LRS) onboard the SELENE spacecraft, strict electromagnetic compatibility (EMC) requirements were applied for all instruments and the whole system of the spacecraft. In order to detect the lunar subsurface echoes from a depth of 5 km, the radiated emission (RE) limit was determined to be -10 dB?V/m and the common-mode (CM) current limit to be 20 dB?A. The EMC performance of the spacecraft was finally evaluated in the system EMC test held from Oct. 20 to Oct. 22, 2005. There is no broadband noise but some narrowband noises at a level above the CM-current limit in a frequency range from 4 to 6 MHz, in which radar soundings are operated. Based on the noise spectrum within 4-6 MHz, the noise level of FMCW radar sounder is estimated to be 14~dB lower than the CM-current limit. In the SELENE EMC test, the following new techniques were introduced: (1) systematic control and evaluation of CM-current noises were first performed to improve the spacecraft EMC performance; (2) onboard battery operation was utilized for reduction of ambient broadband noises during EMC measurements.

Kumamoto, A.; Ono, T.; Kasahara, Y.; Goto, Y.; Iijima, Y.; Nakazawa, S.

2008-04-01

126

Evaluation of holographic subsurface radar for NDE of space shuttle thermal protection tiles  

NASA Astrophysics Data System (ADS)

Experiments have been carried out to evaluate holographic subsurface radar (RASCAN) for non-destructive evaluation (NDE) of subnominal bond conditions between the Space Shuttle Thermal Protection System tiles and the aluminum substrate. Initial results have shown detection of small voids and spots of moisture between Space Shuttle thermal protection tiles and underlying aluminum substrate. The characteristic feature of this device is the ability to obtain one-sided radar soundings/images with high sensitivity (detecting of wire of 20 micron and less in diameter), and high resolution (2 cm lateral resolution) in the frequency band of 3.6-4.0 GHz. JPL's advanced high-speed image processing and pattern recognition algorithms can be used to process the data generated by the holographic radar and automatically detect and measure the defects. Combining JPL's technologies with the briefcase size, portable RASCAN system will produce a simple and fully automated scanner capable of inspecting dielectric heat shielding materials or other spacecraft structures for cracks, voids, inclusions, delamination, debonding, etc.. We believe this technology holds promise to significantly enhance the safety of the Space Shuttle and the future CEV and other space exploration missions.

Lu, Thomas; Snapp, Cooper; Chao, Tien-Hsin; Thakoor, Anilkumar; Bechtel, Tim; Ivashov, Sergey; Vasiliev, Igor

2007-05-01

127

An evaluation of the accuracy of some radar wind profiling techniques  

NASA Technical Reports Server (NTRS)

Major advances in Doppler radar measurement in optically clear air have made it feasible to monitor radial velocities in the troposphere and lower stratosphere. For most applications the three dimensional wind vector is monitored rather than the radial velocity. Measurement of the wind vector with a single radar can be made assuming a spatially linear, time invariant wind field. The components and derivatives of the wind are estimated by the parameters of a linear regression of the radial velocities on functions of their spatial locations. The accuracy of the wind measurement thus depends on the locations of the radial velocities. The suitability is evaluated of some of the common retrieval techniques for simultaneous measurement of both the vertical and horizontal wind components. The techniques considered for study are fixed beam, azimuthal scanning (VAD) and elevation scanning (VED).

Koscielny, A. J.; Doviak, R. J.

1983-01-01

128

Evaluation of MELCOR improvements: Peach Bottom station blackout analyses  

Microsoft Academic Search

Long-term station blackout analyses in Peach Bottom were first carried out using MELCOR 1.8BC, and later with 1.8DN, as part of an overall program between the US Nuclear Regulatory Commission (NRC) and Brookhaven National Laboratory (BNL), to provide independent assessment of MELCOR as a severe accident\\/source term analysis tool. In addition to the reference MELCOR calculation, several sensitivity calculations were

Madni

1993-01-01

129

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

130

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

131

Evaluation and Improvements of the Calibration of a TWSTFT Station Using SATSIM.  

National Technical Information Service (NTIS)

As part of the Galileo project of Early Trials on Time Synchronization Techniques and Calibration Issues, the TWSTFT automated station delay calibration system using a special Satellite Simulator developed by VSL (SATSIM) at NMi-VSL was evaluated. This wa...

G. De Jong R. Van Bemmelen

2002-01-01

132

Evaluation of Speech Recognizers for Use in Advanced Combat Helicopter Crew Station Research and Development.  

National Technical Information Service (NTIS)

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 substan...

C. A. Simpson

1990-01-01

133

Evaluation of Moisture Sensors for NGV Fueling Station Applications. Topical Report, November 1994-April 1996.  

National Technical Information Service (NTIS)

Moisture content in natural gas has become an important issue for compressed natural gas (CNG) fueling stations. The objective of this project was to evaluate the performance of four hygrometer technologies and identify the most cost effective designs sui...

P. F. Rowley V. T. Maniquis D. E. Hunecke C. F. Blazek

1996-01-01

134

Results of the Kansas City 1989 Terminal Doppler Weather Radar (TDWR) operational evaluation testing  

NASA Astrophysics Data System (ADS)

The Terminal Doppler Weather Radar (TDWR) testbed was used at the Kansas City International (KCI) airport during the summer of 1989. The objective was to test and refine previous tested techniques for the automatic detection of low-altitude wind shear phenomena (specifically microbursts and gun fronts) and heavy precipitation in a midwest weather environment, as well as to assess possible new products such as storm movement predictions. A successful operation evaluation of the TDWR products took place at the KCI tower and terminal radar control room (TRACON). Several supervisor and controller display refinements were assessed as effective. The system was successful in terms of aircraft at KCI avoiding wind shear encounters during the operational period, and it was assessed as very good in usefulness for continuing operation by the KCI air traffic control (ATC) personnel. The probability of detection for microbursts was substantially better than that in Denver. However, the false-alarm probability was found to be substantially higher in Kansas City due to a combination of weather and clutter phenomena. By optimizing the site-adaptation capabilities of the TDWR meteorological and data quality algorithms, the required false-alarm probability was achieved. The gust front performance was generally poorer than in Denver due to a combination of unfavorable radar-airport-gust front geometry of false alarms induced by low-level jets. Gust front algorithm refinements which should provide improved performance are discussed.

Evans, J. E.

1990-08-01

135

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

136

[Indoor allergens in office. Evaluation of the work station].  

PubMed

House dust mite and other indoor allergens play a prominent role in the pathogenesis of asthma and other allergic diseases. Several studies have shown a close relationship between sensitisation and/or onset of asthmatic symptoms and levels of indoor allergen exposure. Aim of the study was to investigate the concentration of specific markers of the indoor allergenic pollution, such as Der p 1, Der f 1, Mite Group 2, Fel d 1 and Bla g 2. Dust samples were taken using a standard method by means of a 1200 W vacuum cleaner connected with a dust-sampling device (MITEST). A standard A4 size area has been vacuumed four times during 2 min. The concentrations of Der p 1, Der f 1, Mite Group 2, Fel d 1 and Bla g 2 were determined in dust samples from 53 different sources (office chair and carpet) using a commercial kit (DUSTSCREEN). House dust mite allergens were not always detectable in the offices. Indoor allergen concentrations (Der p 1, Der f 1, Mite Group 2, Fel d 1) were significant higher in the work station (chair) than in the carpet (p < 0.0001). Der 1 exceeded the current threshold for sensitization in about 1/4 of the samples. Der f 1 was predominant over Der p 1 according to other studies. A good correlation between the results of Der p 1 and Der f 1 was observed both in carpet and work station. Cat allergen was ubiquitous and predominantly detected in the chairs because of the employees' clothes. No appreciable levels for Mite Gr 2 and Bla g 2 were detected. Such an exposure for 8 hours in every working day may be an important occupational risk for the development of sensitization/elicitation symptoms to house dust mite. To reduce mite allergen levels are necessary preventive measure by means of specific techniques and products as barriers for preventing the direct contact with allergens. PMID:15270436

Marraccini, P; Farioli, L; Pagani, A; Rossi, L; Russignaga, D; Parmiani, S

2004-01-01

137

An Evaluation of the Need for and Desired Location of Additional Meteorological Stations in Southwestern North Dakota.  

National Technical Information Service (NTIS)

The study's objectives are to assess the need and identify the desired locations for additional meteorological monitoring stations in Western North Dakota, and to evaluate the need for augmenting the instrumentation at existing stations to provide adequat...

T. Method D. Nantt J. M. Ramirez

1977-01-01

138

United States Air Force, 611th Air Support Group, 611th Civil Engineer Squadron, Elmendorf AFB, Alaska Final Quality Assurance Project Plan, Installation Restoration Program (IRP) Remedial Investigation/Feasibility Study, Kotzebue Long Range Radar Station, Alaska. Volume 1. QAPP and Appendix A.  

National Technical Information Service (NTIS)

This is the Quality Assurance Project Plan for the Kotzebue Long Range Radar Station (LRRS), Alaska. The Quality Assurance Project Plan (QAPP) describes quality assurance (QA) and quality control (QC) procedures to be used to accomplish the Installation R...

1994-01-01

139

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

140

Remote infrared signage evaluation for transit stations and intersections.  

PubMed

Opportunities for education and employment depend upon effective and independent travel. For mainstream society, this is accomplished to a large extent by printed signs. People who are print disabled, visually impaired, or totally blind are at a disadvantage because they do not have access to signage. Remote infrared signage, such as the Talking Signs (TS) system, provides a solution to this need by labeling the environment for distant viewing. The system uses a transmitting "sign" and a hand-held receiver to tell people about their surroundings. In a seamless infrared signage environment, a visually impaired traveler could: walk safely across an intersection to an ATM or fare machine, from fare machine to bus stop, from bus stop to bus; from bus to building, from building to elevator, from elevator to office, from office to restroom, and so forth. This paper focuses on two problems that are among the most challenging and dangerous faced by blind travelers: negotiating complex transit stations and controlled intersections. We report on human factors studies of TS in these critical tasks, examining such issues as how much training is needed to use the system, its impact on performance and safety, benefits for different population subgroups and user opinions of its value. Results indicate that blind people can quickly and easily learn to use remote infrared signage effectively, and that its use improves travel safety, efficiency, and independence. PMID:10678457

Crandall, W; Brabyn, J; Bentzen, B L; Myers, L

1999-10-01

141

Evaluation of Photovoltaic Panels at the South Pole Station.  

National Technical Information Service (NTIS)

For this study, commercially available photovoltaic (PV) panels of similar mechanical and electrical characteristics were procured from four manufacturers, and their structural survivability and electrical performance were evaluated in the extreme harsh e...

C. R. Williams J. Rand

2000-01-01

142

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

143

EVALUATION AND IMPROVEMENTS OF THE CALIBRATION OF A TWSTFT STATION USING SATSIM  

Microsoft Academic Search

As part of the Galileo project of Early Trials on Time Synchronization Techniques and Calibration Issues, the TWSTFT automated station delay calibration system using a special Satellite Simulator developed by VSL (SATSIM) at NMi-VSL was evaluated. This was done to verify the obtainable uncertainty level with this technique. The results of the evaluation will be presented. The stability of the

Gerrit de Jong; Roland van Bemmelen

144

Evaluation of a Prototype Continuous-Wave, Borehole, Ground-Penetrating Radar  

SciTech Connect

Borehole radar systems can provide essential subsurface structural information for environmental evaluation, geotechnical analysis, or energy exploration. Sandia developed a prototype continuous-wave Borehole Radar (BHR) in 1996, and development of a practical tool has been continuing at a Russian institute under a Sandia contract. The BHR field experiments, which were planned for the summer of 2001 in Russia, provided a unique opportunity to evaluate the latest Sandia algorithms with actual field data. A new three-dimensional code was developed to enable the analysis of BHR data on modest-sized desktop workstations. The code is based on the staggered grid, finite difference technique, and eliminates 55% of the massive storage associated with solving the system of finite-difference linear equations. The code was used to forward-model the Russian site geometry and placement of artificial targets to anticipate any problems that might arise when the data was received. Technical software and equipment problems in the Russian field tests, conducted in August 2001, invalidated all but one of the data sets. However, more field tests with improved equipment and software are planned for 2002, and analysis of that data will be presented in a future report.

WEISS, CHESTER J.; CAFFEY, THURLOW W.H.

2002-07-01

145

Evaluation of U.S. Coast Guard forward-looking airborne radars  

NASA Astrophysics Data System (ADS)

During CY 1983, the U.S. Coast Guard R&D Center conducted field experiments off Fort Pierce, FL and Oregon Inlet, NC to evaluate the small-target detection capabilities of three forward-looking airborne radars (FLARs): the AN/APS-127, the AN/APS-133, and the AN/APN-215. Field data from these experiments and from a West German field test of the AN/APN-134 FLAR were compared to each other and to theoretical detection range predictions promulgated by NADC. These data were used to analyze the potential of each system to fulfill the Coast Guard Search and Rescue (SAR) and Enforcement of Laws and Treaties (ELT) missions. Targets of 1-square meter and 100-square meter radar cross sections were considered in the analysis. The AN/APS-134 was found to be clearly superior to the other three candidate FLAR systems in its capability to fulfill SAR and ELT mission requirements. In sea states 3 and above, the AN/APS-134 is the only FLAR among those evaluated with any significant ability to detect 1-square meter targets. Recommendations are made for conducting FLAR search operations and for future research and development efforts.

Ketchen, H. G.; St. Martin, J.; Hover, G. L.; Mazour, T. J.

1984-03-01

146

A method to evaluate residual phase error for polar formatted synthetic aperture radar systems  

NASA Astrophysics Data System (ADS)

Synthetic aperture radar systems that use the polar format algorithm are subject to a focused scene size limit inherent to the polar format algorithm. The classic focused scene size limit is determined from the dominant residual range phase error term. Given the many sources of phase error in a synthetic aperture radar, a system designer is interested in how much phase error results from the assumptions made with the polar format algorithm. Autofocus algorithms have limits to the amount and type of phase error that can be corrected. Current methods correct only one or a few terms of the residual phase error. A system designer needs to be able to evaluate the contribution of the residual or uncorrected phase error terms to determine the new focused scene size limit. This paper describes a method to estimate the complete residual phase error, not just one or a few of the dominant residual terms. This method is demonstrated with polar format image formation, but is equally applicable to other image formation algorithms. A benefit for the system designer is that additional correction terms can be added or deleted from the analysis as necessary to evaluate the resulting effect upon image quality.

Musgrove, Cameron; Naething, Richard

2013-05-01

147

Network planning analysis and data quality evaluation of one way ranging station for irnss  

NASA Astrophysics Data System (ADS)

Indian regional navigation satellite system is an autonomous regional satellite navigation system, developed by Indian Space Research Organisation. IRNSS is under total control of Indian Government. A constellation of seven satellites and a support ground segment is planned under IRNSS. The objective of my project is to design a network for single way ground stations considering the influence of Geometric Dilution of Precision (GDOP), Ionospheric Pierce Points (IPP) and Orbit Determination so that the accuracy of data received from IRNSS satellites is maintained and to evaluate the quality of data from the satellites to ensure its integrity. In GDOP analysis maximum, minimum GDOPS for the constellation are calculated in the service volume that is intended for IRNSS and stations in the region of minimum GDOP could be included in the network of ground stations. In IPP analysis the occurrence of IPP points over the service volume is found and analysis is done to make sure that the entire service volume (divided into grids) has IPP points over it. From the result of this analysis the ground stations that are to be included in the network and also if additional ground stations are required. Also the ground stations must be selected in such a way that the signals received by them have reduced ranging errors. Combining the results of the above said analysis a network of single way ground stations is designed. (Tool used- Matlab, ODTK)

Janani Balasubramaniam, Kirthika

2012-07-01

148

FMCW radar system with additional phase evaluation for high accuracy range detection  

Microsoft Academic Search

A radar based approach of range detection depends mainly on the utilized radar principle which allows either high accuracy or high unambiguous ranges. For the most widely used FMCW radar the entire distance is not restricted in the meter range whereas the achievable accuracy directly depends on the bandwidth. An improvement is only possible if system parameters are changed or

Serdal Ayhan; Mario Pauli; Thorsten Kayser; Steffen Scherr; Thomas Zwick

2011-01-01

149

Evaluation of a high accuracy range detection algorithm for FMCW\\/phase radar systems  

Microsoft Academic Search

The FMCW radar is the most versatile radar principle used today. Depending on the system configuration, it is possible to use an FMCW radar to detect targets in the range from hundreds of kilometers down to a few centimeters. This paper describes an algorithm, which can be applied to improve the FMCW range accuracy down to a few mm. Numerical

Philipp Pahl; Thorsten Kayser; M. Pauli; T. Zwick

2010-01-01

150

Air Route Surveillance Radar Model 4 (ARSR-4) Operational Test and Evaluation (OTE) Final Report.  

National Technical Information Service (NTIS)

The Air Route Surveillance Radar Model 4 (ARSR-4) is a state-of-the- art,three-dimensional, long-range radar. The system is being jointly procured by the Federal Aviation Administration (FAA) and the U.S. military. This radar will replace aging height-fin...

R. F. Pomrink R. K. McDonald T. A. Healy W. P. Conklin

1997-01-01

151

Radar cross section measurements  

Microsoft Academic Search

The present status of radar cross section (RCS) measurements is addressed. The fundamental considerations and definitions associated with RCS measurements are reviewed, including radar waveform, polarization requirements, far-field requirements, and target dimensional scaling. Different types of measurement facilities are examined, including their range geometries, target support systems, calibration standards, and facility evaluation. Instrumentation radar requirements and designs are reviewed, and

Robert B. Dybdal

1987-01-01

152

TACAN and ILS Station Evaluation Report, Loring AFB, Maine.  

National Technical Information Service (NTIS)

The evaluation report presents data collected and analyzed to define the capabilities and limitations of the Loring AFB TACAN (AN/GRN-20B), ILS (AN/MRN-7 and AN/MRN-8), and associated power systems. This report documents the inconsistent width and angle m...

J. N. Raeth

1974-01-01

153

Evaluation of model precipitation analysis using space-borne radar observations  

NASA Astrophysics Data System (ADS)

One of the most challenging aspects of weather prediction is the accurate forecast of precipitation. In recent years, models have been improved to obtain more accurate forecasts and analysis of snow and rain fields. At the same time, high resolution precipitation--sensitive observations have been made available from space--borne platforms and their use represents a great resource both for model evaluation and data assimilation. The Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and Precipitation Radar (PR) are among such currently available satellite instruments. In this study, precipitation profiles obtained at ECMWF using a one--dimensional (1D--var) method applied to TRMM/TMI brightness temperatures (Moreauet al, 2002) are verified against the TRMM PR data. The 1D--var on TMI rainy radiances makes use of a multiple scattering radiative transfer model which can account for the effects of hydrometeors on radiances. From the 1D--var adjusted model fields, radar reflectivity profiles are derived using precomputed look--up tables for a radar frequency of 14 GHz. The model equivalent reflectivities are then compared with the PR data averaged to the model resolution. A first assessment was performed using TRMM data for tropical cyclone MITAG (Philippines, May 5 2002). A qualitative comparison shows that the horizontal structure of the 1D--var model reflectivity field compares well with the observed radar data at low levels, and that the assimilation of TMI improves both the location and the amplitude of the cyclone. The vertical structure, however, is not as well represented. The model reflectivity tends to decrease with height with a steeper gradient than the observations. A proper treatment of snow fall velocity and of the bright band is required to improve the agreement. As further investigation, a statistical comparison deriving probability distribution functions and using a whole month of TRMM data is ongoing. Possible use of PR high resolution data to study the sub--grid structure of rainfall and help develop statistical rainfall down--scaling for the ECMWF model is also currently under investigation.

Benedetti, A.; Bauer, P.; Lopez, P.; Moreau, E.

2003-04-01

154

47 CFR 87.107 - Station identification.  

Code of Federal Regulations, 2013 CFR

...station call sign, its location, its assigned FAA...aeronautical enroute station which is part of a...be identified by the location of its control point. (c) Survival craft station. Identify by...call sign: Airborne weather radar, radio...

2013-10-01

155

47 CFR 87.107 - Station identification.  

Code of Federal Regulations, 2010 CFR

...station call sign, its location, its assigned FAA...aeronautical enroute station which is part of a...be identified by the location of its control point. (c) Survival craft station. Identify by...call sign: Airborne weather radar, radio...

2010-10-01

156

47 CFR 87.107 - Station identification.  

Code of Federal Regulations, 2010 CFR

...station call sign, its location, its assigned FAA...aeronautical enroute station which is part of a...be identified by the location of its control point. (c) Survival craft station. Identify by...call sign: Airborne weather radar, radio...

2009-10-01

157

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

2013-08-01

158

Next Generation Weather Radar (NEXRAD) Principal User Processor (PUP) Operational Test and Evaluation (OT and E) Operational Test Plan.  

National Technical Information Service (NTIS)

The purpose of this plan is to describe and detail the procedural approach, method, and responsibilities to be employed in conducting the Operational Test and Evaluation (OT&E) on the Next Generation Weather Radar (NEXRAD) Principal User Processor (PUP) s...

B. R. Stretcher

1993-01-01

159

Soil surface moisture estimation over a semi-arid region using ENVISAT ASAR radar data for soil evaporation evaluation  

Microsoft Academic Search

The present paper proposes a method for the evaluation of soil evaporation, using soil moisture estimations based on radar satellite measurements. We present firstly an approach for the estimation and monitoring of soil moisture in a semi-arid region in North Africa, using ENVISAT ASAR images, over two types of vegetation covers. The first mapping process is dedicated solely to the

M. Zribi; A. Chahbi; M. Shabou; Z. Lili-Chabaane; B. Duchemin; N. Baghdadi; R. Amri; A. Chehbouni

2011-01-01

160

Evaluation of data association techniques in a real multitarget radar tracking environment  

NASA Astrophysics Data System (ADS)

This paper assesses tracking performance of a number of commonly-used data association techniques, including the nearest-neighbor (NN) data association with optimal and sub-optimal assignments, the weighted-average and nearest-neighbor version of the probabilistic data association (PDA), joint probabilistic data association (JPDA), cheap JPDA, and sub-optimal JPDA. The real radar tracking data used for the performance evaluation in this paper contain multiple maneuvering and non-maneuvering air targets in various clutter conditions. The study shows that all the data association methods perform well when the targets are well separated with near straight-line trajectories. In the case of closely spaced and maneuvering targets, the NN and NN version of JPDA methods are more effective than the weighted-average PDA and JPDA methods.

Hu, Zhijian; Leung, Henry; Blanchette, Martin

1995-09-01

161

Generalized Geologic evaluation of side looking radar imagery of the Teton Range and Jackson Hole, northwestern Wyoming  

NASA Technical Reports Server (NTRS)

A generalized geologic evaluation of lines, localities, and features of various types that are visible on a series of radar image strips covering the Teton Range and Jackson Hole in northwestern Wyoming, is given. No attempt was made to collate a complete geologic map with the radar image at each locality. Formation names, problems of geologic interpretation, and details of stratigraphy and structure that are not directly pertinent to a study of the imagery are omitted, but reference is made to publications that contain this type of supplementary information.

Love, J. D.

1970-01-01

162

Land Suitability Evaluation of Bilverdy Research Station for Wheat, Barley, Alfalfa, Maize and Safflower  

Microsoft Academic Search

In the present study and research work, land suitability evaluation (qualitative classification) was made for the Bilverdy research station of the Islamic Azad University in East Azarbaijan for wheat, barley, alfalfa, maize and safflower. The Simple Limitation Method (SLM), the Limitation Method regarding Number and Intensity (LMNI) and the Parametric Methods (PM) such as the square-root and the Storie methods

Ali Asghar

163

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 ...

164

Clinical evaluation of newly developed CRT viewing station: CT reading and observer's performance  

Microsoft Academic Search

The clinical performance of the new viewing station with six CRT monitors (17-inch, 1,024 × 1,280) was evaluated. In the primary interpretation of CT images, time measurements were carried out for eight radiologists. No significant differences in reading time existed between CRT and film in 3 of 4 readers in head CT series, and in 2 of 6 readers in

Hideki Hirota; Kazuhiro Shimamoto; Kouji Yamakawa; Takeo Ishigaki; Yukio Takahashi; Naoki Sugiyama; Eitaro Nishihara; Yuichiro Tani

1995-01-01

165

Evaluation of the Keyspares Sparing Model Used for the Proposed Space Station.  

National Technical Information Service (NTIS)

The purpose of this study was to evaluate the Keyspares sparing model used to calculate on-orbit spares for the proposed Space Station. The study had five basic objectives: 1. Present and describe the Keyspares' sparing model and its assumptions. 2. Locat...

T. I. Mills

1988-01-01

166

A simulation model for reliability evaluation of space station power systems  

SciTech Connect

This paper presents a detailed simulation model for reliability evaluation of space station electrical power systems. Dependence of reliability and storage characteristics during the sun and eclipse periods is considered. The charging and discharging of energy storage modules is included on a continuous basis. Sample system studies are also presented.

Singh, C.; Patton, A.D.; Kumar, M. (Department of Electrical Engineering, Texas A and M University, College Station, TX (US)); Wagner, H. (National Aeronautics and Space Administration, Houston, TX (US))

1991-03-01

167

Evaluating soil moisture variability using synthetic aperture radar and terrain indices  

NASA Astrophysics Data System (ADS)

The spatial and temporal variability of soil moisture is influenced by precipitation patterns, local topography, soil texture and vegetation. It is likely that on bare agricultural fields of near homogeneous soil texture, soil moisture distribution is primarily controlled by topography. This research examines the relationship between soil moisture maps derived from satellite-based Synthetic Aperture Radar (SAR) sensors and wetness indices calculated from LiDAR digital elevation models (DEMs) under wet, dry and moderate moisture conditions. The radar response (backscatter) from SAR sensors is related to the dielectric constant of the surface, allowing soil moisture values to be retrieved through inversion techniques in backscatter models. Wetness indices model expected moisture patterns through evaluation of the surface slope and the number of upslope moisture-contributing cells (specific catchment area) at any point. Although multiple wetness indices have been developed and assessed, few researchers have evaluated the relationships of these indices in conjunction with high-resolution SAR imagery. For eight dates spanning fall 2009 and spring 2010, fine quad-polarimetric mode RADARSAT-2 imagery and coincident in situ surface parameter data are used to derive soil moisture maps of a small agricultural watershed in southwestern Ontario. Wetness indices are used as surrogates for soil moisture patterns in the same area. High-resolution LiDAR-derived DEMs at resolutions of 1, 4 and 8 m are used to calculate the ln(As/tan?) wetness index where As is the specific catchment area and ? is the surface slope. Multiple flow accumulation algorithms are employed to define As. Statistical analyses quantify the relationships and the described variance among assorted wetness index outputs and satellite-derived soil moisture under changing surface conditions.

Powell, K. A.; Berg, A. A.

2010-12-01

168

Use of radars to monitor stream discharge by noncontact methods  

NASA Astrophysics Data System (ADS)

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 stream gauging stations on the San Joaquin River in California and the Cowlitz River in Washington. The purpose of the experiments was to directly measure the parameters necessary to compute flow: surface velocity (converted to mean velocity) and cross-sectional area, thereby avoiding the uncertainty, complexity, and cost of maintaining rating curves. River channel cross sections were measured by ground-penetrating radar suspended above the river. River surface water velocity was obtained by Bragg scattering of microwave and UHF Doppler radars, and the surface velocity data were converted to mean velocity on the basis of detailed velocity profiles measured by current meters and hydroacoustic instruments. Experiments using these radars to acquire a continuous record of flow were conducted for 4 weeks on the San Joaquin River and for 16 weeks on the Cowlitz River. At the San Joaquin River the radar noncontact measurements produced discharges more than 20% higher than the other independent measurements in the early part of the experiment. After the first 3 days, the noncontact radar discharge measurements were within 5% of the rating values. On the Cowlitz River at Castle Rock, correlation coefficients between the USGS stream gauging station rating curve discharge and discharge computed from three different Doppler radar systems and GPR data over the 16 week experiment were 0.883, 0.969, and 0.992. Noncontact radar results were within a few percent of discharge values obtained by gauging station, current meter, and hydroacoustic methods. Time series of surface velocity obtained by different radars in the Cowlitz River experiment also show small-amplitude pulsations not found in stage records that reflect tidal energy at the gauging station. Noncontact discharge measurements made during a flood on 30 January 2004 agreed with the rated discharge to within 5%. Measurement at both field sites confirm that lognormal velocity profiles exist for a wide range of flows in these rivers, and mean velocity is approximately 0.85 times measured surface velocity. Noncontact methods of flow measurement appear to (1) be as accurate as conventional methods, (2) obtain data when standard contact methods are dangerous or cannot be obtained, and (3) provide insight into flow dynamics not available from detailed stage records alone.

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

2006-07-01

169

Radar principles  

Microsoft Academic Search

The basic operating principles, design, and applications of radars are discussed in an introductory text intended for first-year graduate students. Topics addressed include radar measurements, radar target cross sections, radar detection, ground effects, matched filters, ambiguity functions, coded radar signals, and radar measurement accuracy. Consideration is given to processing coherent pulse trains, moving-target indicators, CFAR, SAR, and monopulse antenna tracking.

Nadav Levanon

1988-01-01

170

Implementation and evaluation of coherent synthetic aperture radar processing for level measurements of bulk goods with an FMCW-system  

NASA Astrophysics Data System (ADS)

In industrial process measurement instrumentation, radar systems are well established for the measurement of filling levels of liquids in tanks. Level measurements of bulk goods in silos, on the other hand, are more challenging because the material is heaped up and its surface has typically a relatively complex shape. In this paper, the application of synthetic aperture radar (SAR) reconstruction with a frequency modulated continuous wave (FMCW) radar system for level measurements of bulk goods is evaluated. In the proposed monostatic setup, echo signals are acquired at discrete antenna positions on top of the silo. Spatially resolved information about the surface contour of a bulk good heap is reconstructed by coherent 'delay and sum' processing. The concept has been experimentally evaluated with a 24 to 26 GHz FMCW radar system mounted on a linear stepping motor positioning unit. Measurements on a thin metal wire at different range and on a curved test-object with a diffusely scattering surface have been performed to analyze the system's point spread function (PSF) and performance. Constant range and azimuth resolutions (-6 dB) of 15 cm and 8 cm, respectively, have been obtained up to a range of 6 m, and results of further evaluations show that the proposed concept allows more accurate and reliable level reconstructions of surface profiles compared to the conventional approach with measurements at a single antenna position.

Vogt, M.; Gerding, M.; Musch, T.

2010-09-01

171

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

172

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

173

Millimeter wave radar evaluation systems setting up at small room by using sliding short terminal at the end of delay line  

Microsoft Academic Search

In this paper, a new simplified radar target simulator (RTS) with no active components used as a millimeter wave radar evaluation system is introduced. The system includes a low-RCS dielectric lens antenna and a dielectric waveguide used as a feed line and also used as a primary radiator of the lens. In a small room environment with a few meter

Hirosuke SUZUKI; Masato INOUE

2005-01-01

174

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

175

Technical evaluation of the proposed technical specification change for the Arkansas Nuclear Power Station, Unit 2  

SciTech Connect

This report documents the technical evaluation of the request for changes in the Technical Specifications for the Arkansas Nuclear Power Station, Unit 2. These changes were proposed by the licensee in a letter dated November 27, 1979. The basis for review included a report entitled Determination of Plant System Trip Setpoints Valves. The requested changes to the Technical Specifications were found to be acceptable based on information submitted by the licensee.

Victor, R.A.

1980-08-01

176

Test and evaluation of the Airport Surveillance Radar (ASR)-8 wind shear detection system (phase 2), revision  

NASA Astrophysics Data System (ADS)

A wind shear detection system developed by the Wave Propagation Laboratory (WPL) to operate with the Federal Aviation Administration (FAA) Airport Surveillance Radar (ASR)-8 was installed and is being tested at the FAA technical Center. Initial efforts, previously reported in Report NA-78-59-LR, were directed toward hardware and software shakedown and feasibility determination. Second phase tests compared radar with aircraft and tower winds, evaluated the wind shear measurement capability under various weather conditions, and investigated the effectiveness of a simple two-azimuth pointing strategy and system capabilities and limitations. Results showed the system to be compatible with and to operate satisfactorily with the ASR-8. The processing and spectral display of clear air and precipitation returns is feasible. The accuracy of agreement between radar-measured winds and components of the aircraft-measured winds in both radially oriented flights and runway offset flights, using a two-azimuth pointing technique, was examined. Radar versus tower wind agreement was also examined. Potentially dangerous wind shears associated with weather during these tests were detectable. Certain system limitations also have been defined and considered. It is recommended that tests continue to complete definition of and demonstrate capabilities in all weather situations, to optimize performance, and to provide information to specify system design for possible development of a prototype model.

Offi, D. L.; Lewis, W.; Lee, T.; Delamarche, A.

1980-08-01

177

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

178

Array radars solve communication jams  

Microsoft Academic Search

The possibilities of incorporating mobile radar units as slave stations in communications relay applications during times of disrupted communications is examined. The limitations on uses of search, tracking, and multifunction radars are examined, noting that employment of the mobile system entails some tracking by the master phased-arrays to keep the mobile units in focus. The tracking patterns and dwell times

H. D. Lewis

1982-01-01

179

Looking back: some radar recollections  

Microsoft Academic Search

The author reviews the history of military radar and the contributions of pioneers such as Watson Watt and his assistant Arnold Wilkins. By 1938, the design of the first early warning radar, called Chain Home or CH, had been completed. A chain of stations were constructed at intervals along the coast, from Aberdeen southward and around to Dorset. The CH

I. Graham

1999-01-01

180

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

181

Giant Magnetoresistive (GMR) Sensor Microelectromechanical System (MEMS) Device for Nondestructive Evaluation (NDE) Health Monitoring Applications for International Space Station (ISS)  

Microsoft Academic Search

With the imminent launch of the first International Space Station modules, NASA Oflice of Safety and Mission Assurance, specifically the Code Q Nondestructive Evaluation Program, is addressing issues of on-orbit station structural health monitoring. As part of this effort, Jet Propulsion Laboratory is working with NASA's Langley Research Center on development of novel devices and sensors for an NDE tool

R. Ramesham; J. D. Olivas; S. Stokes; W. Wilson; Edward Generazio

182

Processing and evaluation of multichannel airborne radar measurements (MCARM) measured data  

Microsoft Academic Search

Rome Laboratory's (RLs) Multichannel Airborne Radar Measurements (MCARM) program has collected clutter and target data employing an L-band airborne phased array radar testbed. The data collection is at the output of an electronically steered active array mounted on BAC1-11 aircraft. The MCARM array has 16 columns, each consisting of two four-element subarrays. Each subarray has its own output or is

B. N. Suresh Babu; Jose A. Torres; William L. Melvin

1996-01-01

183

Evaluation of Technologies for Inclusion in the US Army Counterfire Radar Program  

SciTech Connect

This paper describes the effort by the Oak Ridge National Laboratory to identify technologies that can be inserted into counterfire radar programs over the next 2 to 20 years. The investigation was funded by the U.S. Army PM (Project Manager) Radars. There are four broad time increments under consideration: (1) incremental improvements to currently fielded systems such as AN/TPQ-36, (2) technologies that can be inserted into near-future systems such as EQ-36, (3) technologies that can be an integral part of conceptual designs of multi-mission radar (MMR) for Future Combat Systems Brigade Combat Team [FCS (BCT)] and (4) technologies that could enable capabilities beyond MMR, such as true on-the-move radar sensors. The science of each technology is described, and how it could add capabilities to counterfire radar is discussed. The approach used for this paper is a combination of a top-down analysis of program requirements and a bottom-up review of potential technologies. An emphasis is placed on reviewing technologies beyond those already planned for ongoing radar upgrades. Drawing on broad areas of expertise such as material sciences and information processing, technologies outside the normal scope of radar designers were identified for analysis. To establish a baseline, current radar systems and lessons learned from deployment of those systems were reviewed, along with requirements, plans, user interviews, and policies regarding future systems. A limited analysis of capability gaps and capability requirements was performed to help prioritize the technologies reviewed. As potential technologies were identified, their utility to address the identified capability needs was analyzed and described.

Kaldenbach, Brian J [ORNL; Killough, Stephen M [ORNL; Moore, Michael Roy [ORNL; Buckner, Mark A [ORNL; Dobies, Stan [PM Radars

2007-01-01

184

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

185

Radar principles  

NASA Astrophysics Data System (ADS)

The basic operating principles, design, and applications of radars are discussed in an introductory text intended for first-year graduate students. Topics addressed include radar measurements, radar target cross sections, radar detection, ground effects, matched filters, ambiguity functions, coded radar signals, and radar measurement accuracy. Consideration is given to processing coherent pulse trains, moving-target indicators, CFAR, SAR, and monopulse antenna tracking. Extensive diagrams and graphs are provided.

Levanon, Nadav

186

Radar Calibration Using a Student-Built Nanosatellite  

Microsoft Academic Search

As a matter of national security, the US military must monitor and calibrate its 80+ C-band radar tracking stations on a consistent basis. These radar stations, which are distributed around the world, currently depend on two calibration satellites: RADCAL and DMSP F-15, launched in 1993 and 1999, respectively. Should either of these two satellites fail, the community of radar calibration

L. Martin; N. Fisher; W. Jones; M. Umeda; J. Furumo; J. Ah Heong; T. Lim; W. Shiroma

2011-01-01

187

Evaluation of two algorithms for a network of coastal HF radars in the Mid-Atlantic Bight  

NASA Astrophysics Data System (ADS)

The National High Frequency (HF) Surface Current Mapping Radar Network is being developed as a backbone system within the U.S. Integrated Ocean Observing System. This paper focuses on the application of HF radar-derived surface current maps to U.S. Coast Guard Search and Rescue operations along the Mid-Atlantic coast of the USA. In that context, we evaluated two algorithms used to combine maps of radial currents into a single map of total vector currents. In situ data provided by seven drifter deployments and four bottom-mounted current meters were used to (1) evaluate the well-established unweighted least squares (UWLS) and the more recently adapted optimal interpolation (OI) algorithms and (2) quantify the sensitivity of the OI algorithm to varying decorrelation scales and error thresholds. Results with both algorithms were shown to depend on the location within the HF radar data footprint. The comparisons near the center of the HF radar coverage showed no significant difference between the two algorithms. The most significant distinction between the two was seen in the drifter trajectories. With these simulations, the weighting of radial velocities by distance in the OI implementation was very effective at reducing both the distance between the actual drifter and the cluster of simulated particles as well as the scale of the search area that encompasses them. In this study, the OI further reduced the already improved UWLS-based search areas by an additional factor of 2. The results also indicated that the OI output was relatively insensitive to the varying decorrelation scales and error thresholds tested.

Kohut, Josh; Roarty, Hugh; Randall-Goodwin, Evan; Glenn, Scott; Lichtenwalner, C. Sage

2012-06-01

188

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±13.3ngm(-3) and the TSP concentrations were 101.2±53.2, 152.3±99.1, 49.8±18.6?gm(-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

189

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

190

Performance evaluation of the retrieval of a two hours rainfall event through microwave tomography applied to a network of radio-base stations  

NASA Astrophysics Data System (ADS)

Critical precipitation events occurred over the Italian territory have been often characterized by high intensity and very fast development, frequently over small catchment areas. The detection of this kind of phenomena is a major issue that poses remarkable problems that cannot be tackled completely only with 'standard' instrumentation (even when available), such as a weather radars or raingauges. Indeed, the rainfall sampling modalities of these instruments may jeopardize the attempts to provide a sufficiently fast risk alert: - the point-like, time-integrated way of sampling of raingauges can completely/partially miss local rainfall cores of high intensity developing in the neighborhoods. Moreover, raingauges provide cumulated rainfall measurements intrinsically affected by a time delay. - In the case of weather radars, several factors may limit the advantages brought by range resolution and instantaneous sampling: precipitation might be sampled at an excessive height due to the distance of the radar site and/or the orography surrounding the valleys/catchments where the aforementioned kind of events is more likely to form up; distance may limit the resolution in the cross-range direction; beam screening due to orography causes a loss of power that is interpreted in the farther range bins as a reduced precipitation intensity. In this context, a positive role for flagging the criticality of a precipitation event can be played by signal attenuation measurements made along microwave links, as available through the infrastructure of a mobile communications network. Three are the interesting features of such networks: 1) the communications among radio-base stations occur where point-to-point electromagnetic visibility is guaranteed, namely along valleys or between tops/flanks of hills or mountains; 2) the extension of these links (few kilometres) is perfectly compatible with the detection of severe but localized precipitation events; 3) measurements can be made on a practically continuous-time basis. In the past years, we showed that new scenarios for tomographic rainfall monitoring have been disclosed by the availability of widespread networks of radio-base stations for mobile communications (i.e., GSM, GPRS, UMTS). Such networks could be employed as the backbone of a low cost system able to provide 2D estimates of rainfall in real time. Monitoring capabilities increase in more populated sites, as urban areas, where such radio links form up a dense network that can be exploited to get detailed information also about structure and evolution of rainfall phenomena. In 2010, we presented a novel tomographic processing method for rainfall rate estimation, specifically adaptable to the dense and asymmetric topologies of urban networks of radio-base stations. In this paper, we show its application to a simulated time sequence of specific attenuation (K) maps, derived from true weather radar data gathered during a rainfall event specifically selected to evaluate the performance of the tomographic retrieval in critical conditions. The event was in fact very localized and intense and lasted two hours. 12 GHz is assumed for the carrier frequency of the radio-base network. We show the reconstruction performance of the 2D K fields achieved resorting first to a symmetric, regular network and then to a couple of totally asymmetric ones.

Facheris, L.; Cuccoli, F.; Baldini, L.

2012-04-01

191

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

NASA Astrophysics Data System (ADS)

To assess if current radar-based liquid cloud microphysical retrievals of the Atmospheric Radiation Measurement (ARM) program can provide useful constraints for modeling studies, this paper presents intercomparison results of three cloud products at the Southern Great Plains (SGP) site: the ARM MICROBASE, University of Utah (UU), and University of North Dakota (UND) products over the nine-year period from 1998 to 2006. The probability density and spatial autocorrelation functions of the three cloud Liquid Water Content (LWC) retrievals appear to be consistent with each other, while large differences are found in the droplet effective radius retrievals. The differences in the vertical distribution of both cloud LWC and droplet effective radius retrievals are found to be alarmingly large, with the relative difference between nine-year mean cloud LWC retrievals ranging from 20% at low altitudes to 100% at high altitudes. Nevertheless, the spread in LWC retrievals is much smaller than that in cloud simulations by climate and cloud resolving models. The MICROBASE effective radius ranges from 2.0 at high altitudes to 6.0 ?m at low altitudes and the UU and UND droplet effective radius is 6 ?m larger. Further analysis through a suite of retrieval experiments shows that the difference between MICROBASE and UU LWC retrievals stems primarily from the partition total Liquid Water path (LWP) into supercooled and warm liquid, and from the input cloud boundaries and LWP. The large differences between MICROBASE and UU droplet effective radius retrievals are mainly due to rain/drizzle contamination and the assumptions of cloud droplet concentration used in the retrieval algorithms. The large discrepancy between different products suggests caution in model evaluation with these observational products, and calls for improved retrievals in general.

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

2011-12-01

192

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

193

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. 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. In those applications, local effects represent a source of sampling error additional to the inherent uncertainties in the measurements themselves. The radar renovation improved the SNR of measurements, with correspondingly improved altitude coverage. It also corrected an under-estimate of horizontal wind speeds attributed to beam formation problems, due to component failure pre-renovation. The standard error in radar-measured winds averaged over half-an-hour increases with wind speed and altitude, and is 0.6-2.5 m s-1 (5-20% of wind speed) for post-renovation horizontal winds. Pre-renovation values are typically 0.4 m s-1 (0.03 m s-1) larger. The standard error 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 additional random error into wind profiles. For winds averaged over half-an-hour, the random error 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.

2014-05-01

194

Evaluation of effective eddy diffusive coefficients using radar observations of turbulence in the stratosphere  

NASA Technical Reports Server (NTRS)

Radar observations show that thin, persistent layers of turbulence occur sporadically in the troposphere and stratosphere. Two probabilistic approaches are used to show that the vertical eddy diffusivity due to such layers is of the order of 0.2-0.3 sq m/sec in the lower stratosphere. An actual realization of turbulent layers, derived from the radar observations at Arecibo, is used in a numerical approach to obtain a profile of eddy diffusivity. It is suggested that turbulence plays a significant role in the vertical transport of trace constituents in the stratosphere.

Woodman, R. F.; Rastogi, P. K.

1984-01-01

195

TRACALS Evaluation Report. ILS Station Evaluation Report, Luke AFB, AZ (1 - 13 December 1976).  

National Technical Information Service (NTIS)

This evaluation report presents data collected and analyzed to define the capabilities and limitations of the Luke AFB ILS (AN/MRN-7/8A) and its associated power system. The ground evaluation phase was conducted 1-9 Dec 1976, and flight evaluation was con...

K. Y. Barnhart

1977-01-01

196

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

197

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

Microsoft Academic Search

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

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

2003-01-01

198

Performance evaluation of conducting polymer paints as radar absorbing materials (RAM)  

Microsoft Academic Search

The efficiency and performance of recently developed RAM (radar absorbing materials) based on conducting polymer paints has been investigated in the range of 8-12 GHz. The used conducting polymer in the paint formulations is the polyaniline doped with two different acids: dodecylbenzene sulfonic acid (DBSA), and camphorsulfonic acid (CSA). In practice, RAM ought to be effective over a range of

R. S. Biscaro; E. L. Nohara; G. G. Peixoto; R. Faez; M. C. Rezende

2003-01-01

199

Description and Initial Evaluation of a Computer-Based Individual Trainer for the Radar Intercept Observer.  

ERIC Educational Resources Information Center

An individual trainer for giving students in the radar intercept observer (RIO) schools concentrated practice in procedures for air-to-air intercepts was designed around a programmable graphics terminal with two integral minicomputers and 8k of core memory. The trainer automatically administers practice in computing values of variables in the…

Rigney, Joseph W.; And Others

200

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

201

Microburst wind structure and evaluation of Doppler radar for airport wind shear detection  

Microsoft Academic Search

The horizontal and vertical structure of airflow within microbursts has been determined using Doppler weather radar data from the Joint Airport Weather Studies (JAWS) Project. It is shown that the downdraft typically associated with microbursts is about 1 km wide and begins to spread horizontally at a height below 1 km. The median time from initial divergence at the surface

J. W. Wilson; R. D. Roberts; C. Kessinger; J. McCarthy

1984-01-01

202

Microburst Wind Structure and Evaluation of Doppler Radar for Airport Wind Shear Detection  

Microsoft Academic Search

Doppler weather radar data from the Joint Airport Weather Studies (JAWS) Project are used to determine the horizontal and vertical structure of airflow within microbursts. Typically, the associated downdraft is about 1 km wide and begins to spread horizontally at a height below 1 km. The median time from initial divergence at the surface to maximum differential wind velocity across

James W. Wilson; Rita D. Roberts; Cathy Kessinger; John McCarthy

1984-01-01

203

Summary Evaluation of the Offshore Target Detection Capabilities of APS-94D and COR Radar Systems.  

National Technical Information Service (NTIS)

Flight test of an APS-94D real aperture and coherent-on-receive (COR) synthetic aperture radar were conducted by the Coast Guard in three locations of southern and central coastal California between May 19-21 1976. The Geography Remote Sensing Unit provid...

J. E. Estes S. P. Kraus

1976-01-01

204

Evaluation of prototype air/fluid separator for Space Station Freedom Health Maintenance Facility  

NASA Technical Reports Server (NTRS)

A prototype air/fluid separator suction apparatus proposed as a possible design for use with the Health Maintenance Facility aboard Space Station Freedom (SSF) was evaluated. A KC-135 parabolic flight test was performed for this purpose. The flights followed the standard 40 parabola profile with 20 to 25 seconds of near-zero gravity in each parabola. A protocol was prepared to evaluate the prototype device in several regulator modes (or suction force), using three fluids of varying viscosity, and using either continuous or intermittent suction. It was felt that a matrixed approach would best approximate the range of utilization anticipated for medical suction on SSF. The protocols were performed in one-gravity in a lab setting to familiarize the team with procedures and techniques. Identical steps were performed aboard the KC-135 during parabolic flight.

Billica, Roger; Smith, Maureen; Murphy, Linda; Kizzee, Victor D.

1991-01-01

205

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

206

TRACALS Evaluation Report. ILS Station Evaluation Report, Luke AFB, AZ, Auxiliary 1.  

National Technical Information Service (NTIS)

This evaluation report presents data collected and analyzed to define the capabilities and limitations of the Luke AFB, Auxiliary 1, ILS (AN/MRN-7/8) and its associated power system. The ground evaluation phase was conducted 4-10 Feb 1977, and the flight ...

K. Y. Barnhart

1977-01-01

207

Adjusting measurement error and dynamic parameters by evaluating real-time experiments with electronically steerable radar (ELRA)  

NASA Astrophysics Data System (ADS)

The correction of errors in the data processing part of a radar system is discussed, with emphasis on the parameters of the target tracking algorithms. From this point of view, one reason for bad performance of the tracking routine is the theoretical assumption of a stochastic Gauss-Markov process describing the target dynamics and a usually assumed Gaussian measurement noise distribution. A functional relation between measurement error variances and the signal-to-noise ratio as well as the target distance is derived from ELRA real-time experiment evaluation. Improvements of the ELRA system by measurement noise parameter adaptation are discussed. Estimates for dynamic parameters are given.

Mieth, H.-J.

208

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

209

Radar wind profilers  

NASA Technical Reports Server (NTRS)

Continuous, automated measurement of tropospheric wind profiles with UHF and VHF Doppler radars has been demonstrated. Ground-based networks of these radars will be available as part of a global wind measurement system, and remote single stations could be built to further complement a spaceborne measurement device. A number of ground-based wind profilers will be in place by the time a space system is tested so the global wind measurement system should be designed with these ground-based profilers providing part of the picture.

Strauch, R. G.

1985-01-01

210

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

211

Evaluation of gridded scanning ARM cloud radar reflectivity observations and vertical doppler velocity retrievals  

NASA Astrophysics Data System (ADS)

The scanning Atmospheric Radiation Measurement (ARM) cloud radars (SACRs) provide continuous atmospheric observations aspiring to capture the 3-D cloud-scale structure. Sampling clouds in 3-D is challenging due to their temporal-spatial scales, the need to sample the sky at high elevations and cloud radar limitations. Thus, a suggested scan strategy is to repetitively slice the atmosphere from horizon to horizon as clouds advect over the radar (Cross-Wind Range-Height Indicator - CW-RHI). Here, the processing and gridding of the SACR CW-RHI scans are presented. First, the SACR sample observations from the ARM Southern Great Plains and Cape Cod sites are post-processed (detection mask, gaseous attenuation correction, insect filtering and velocity de-aliasing). The resulting radial Doppler moment fields are then mapped to Cartesian coordinates with time as one of the dimensions. Next the Cartesian-gridded Doppler velocity fields are decomposed into the horizontal wind velocity contribution and the vertical Doppler velocity component. For validation purposes, all gridded and retrieved fields are compared to collocated zenith-pointing ARM cloud radar measurements. We consider that the SACR sensitivity loss with range, the cloud type observed and the research purpose should be considered in determining the gridded domain size. Our results also demonstrate that the gridded SACR observations resolve the main features of low and high stratiform clouds. It is established that the CW-RHI observations complemented with processing techniques could lead to robust 3-D cloud dynamical representations up to 25-30 degrees off zenith. The proposed gridded products are expected to advance our understanding of 3-D cloud morphology, dynamics and anisotropy and lead to more realistic 3-D radiative transfer calculations.

Lamer, K.; Tatarevic, A.; Jo, I.; Kollias, P.

2014-04-01

212

Evaluation of gridded Scanning ARM Cloud Radar reflectivity observations and vertical Doppler velocity retrievals  

NASA Astrophysics Data System (ADS)

The Scanning ARM Cloud Radars (SACR's) provide continuous atmospheric observations aspiring to capture the 3-D cloud-scale structure. Sampling clouds in 3-D is challenging due to their temporal-spatial scales, the need to sample the sky at high elevations and cloud radar limitations. Thus, a common scan strategy is to repetitively slice the atmosphere from horizon to horizon as clouds advect over the radar (Cross-Wind Range Height Indicator - CWRHI). Here, the processing and gridding of the SACR CW-RHI scans are presented. First, the SACR sample observations from the ARM Oklahoma (SGP) and Cape-Cod (PVC) sites are post-processed (detection mask, velocity de-aliasing and gaseous attenuation correction). The resulting radial Doppler moment fields are then mapped to Cartesian coordinates with time as one of the dimension. The Cartesian-gridded Doppler velocity fields are next decomposed into the horizontal wind velocity contribution and the vertical Doppler velocity component. For validation purposes, all gridded and retrieved fields are compared to collocated zenith pointing ARM cloud radar measurements. We consider that the SACR sensitivity loss with range, the cloud type observed and the research purpose should be considered in determining the gridded domain size. Our results also demonstrate that the gridded SACR observations resolve the main features of low and high stratiform clouds. It is established that the CW-RHI observations complemented with processing techniques could lead to robust 3-D clouds dynamical representations up to 25-30° off zenith. The proposed gridded products are expected to advance our understanding of 3-D cloud morphology, dynamics, anisotropy and lead to more realistic 3-D radiative transfer calculations.

Lamer, K.; Tatarevic, A.; Jo, I.; Kollias, P.

2013-11-01

213

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

214

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

PubMed

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 Colorado potato beetle (Leptinotarsa decemlineata (Say) Chrysomelidae), plum curculio (Conotrachelus nenuphar (Herbst) Curculionidae), and western corn rootworm (Diabrotica virgifera virgifera (LeConte) Chrysomelidae) with and without vertical and or trailing tags in field plots or arenas. The frequency of the larger Colorado potato beetles crossing bare ground or grassy plots was unaffected by the presence of an 8 cm trailing harmonic radar tag. However, plum curculios and western corn rootworms, were either unable to walk with a 4 cm trailing tag (plum curculio) or displayed a reduced ability to successfully cross a bare ground arena. Our results revealed the significant impact of vegetation on successful insect dispersal, whether tagged or not. The vertical movement of these insects on stems, stalks, and tubes was also unaffected by the presence of vertical tags. Trailing tags had a significant negative effect on the vertical movement of the western corn rootworm. Results show that harmonic radar technology is a suitable method for studying the walking paths of the three insects with appropriate tag type and size. The nuisance factor generated by appropriately sized tags was small relative to that of vegetation. PMID:22182617

Boiteau, G; Vincent, C; Meloche, F; Leskey, T C; Colpitts, B G

2011-02-01

215

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

216

Metallurgical evaluation of an 18-inch feedwater line failure at the Surry Unit 2 Power Station  

SciTech Connect

A metallurgical failure analysis was performed on pieces from a catastrophically failed 18-inch diameter feedwater from the Surry Unit 2 Nuclear Power Station. The analysis consisted of optical microscopy, chemical analysis, mechanical and Charpy impact testing and evaluation of the material by scanning electron microscopy. The mechanical tests indicate that the materials of construction met the appropriate specified requirements. The failed elbow had been globally thinned on the inside surface and had a scalloped appearance. The elbow material had been reduced in some areas to below .040 inch (1.02 mm) from an installed thickness of 0.500 inch (12.7 mm). Fractography disclosed a dimpled ruptured (ductile) appearance on all fracture faces and no evidence of coal work on the pipe's inside surface. The conclusion of the investigation is that the Surry failure occurred due to the overall thinning of the pipe (below the design requirements) by a erosion-corrosion mechanism.

Czajkowski, C.J.

1987-03-01

217

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

218

Using ship wake patterns to evaluate SAR (Synthetic Aperture Radar) ocean wave imaging mechanisms. Joint US-Canadian Ocean Wave Investigation Project  

Microsoft Academic Search

The Joint Ocean Wave Investigation Project (JOWIP) was conducted to evaluate the detectability of ocean wave structures on imaging synthetic aperture radar (SAR). This project used Kelvin surface ship wake patterns generated under controlled and well documented surface environmental conditions to isolate SAR image parameters. Use of waves of known wavelength and direction provide the opportunity to evaluate the SAR

R. R. Hammond; R. R. Buntzen; E. E. Floren

1985-01-01

219

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.

0002-11-30

220

Evaluation of temperature differences for paired stations of the U.S. Climate Reference Network  

USGS Publications Warehouse

Adjustments to data observed at pairs of climate stations have been recommended to remove the biases introduced by differences between the stations in time of observation, temperature instrumentatios, latitude, and elevation. A new network of climate stations, located in rural settings, permits comparisons of temperatures for several pairs of stations without two of the biases (time of observation and instrurtientation). The daily, monthly, and annual minimum, maximum, and mean temperatures were compared for five pairs of stations included in the U.S. Climate Reference Network. Significant differences were found between the paired stations in the annual minimum, maximum, and mean temperatures for all five pairs of stations. Adjustments for latitude and elevation differences contributed to greater differences in mean annual temperature for four of the five stations. Lapse rates computed from the mean annual temperature differences between station pairs differed from a constant value, whether or not latitude adjustments were made to the data. The results suggest that microclimate influences on temperatures observed at nearby (horizontally and vertically) stations are potentially much greater than influences that might be due to latitude or elevation differences between the stations. ?? 2005 American Meteorological Society.

Gallo, K. P.

2005-01-01

221

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

222

Automatic Evaluation of Progression Angle and Fetal Head Station through Intrapartum Echographic Monitoring  

PubMed Central

Labor progression is routinely assessed through transvaginal digital inspections, meaning that the clinical decisions taken during the most delicate phase of pregnancy are subjective and scarcely supported by technological devices. In response to such inadequacies, we combined intrapartum echographic acquisitions with advanced tracking algorithms in a new method for noninvasive, quantitative, and automatic monitoring of labor. Aim of this work is the preliminary clinical validation and accuracy evaluation of our automatic algorithm in assessing progression angle (PA) and fetal head station (FHS). A cohort of 10 parturients underwent conventional labor management, with additional translabial echographic examinations after each uterine contraction. PA and FHS were evaluated by our automatic algorithm on the acquired images. Additionally, an experienced clinical sonographer, blinded regarding the algorithm results, quantified on the same acquisitions of the two parameters through manual contouring, which were considered as the standard reference in the evaluation of automatic algorithm and routine method accuracies. The automatic algorithm (mean error ± 2SD) provided a global accuracy of 0.9 ± 4.0?mm for FHS and 4° ± 9° for PA, which is far above the diagnostic ability shown by the routine method, and therefore it resulted in a reliable method for earlier identification of abnormal labor patterns in support of clinical decisions.

Casciaro, Ernesto; Di Renzo, Gian Carlo; Perrone, Antonio

2013-01-01

223

Evaluation of the steady state performance of a DC link built on VSC converter stations using PSCAD\\/EMTDC©  

Microsoft Academic Search

This paper presents a steady state performance analysis carried out to evaluate the operation and behavior of a two VSC-based level-full scale frequency converter working as a HVDC link. The digital model has been implemented and evaluated using PSCAD\\/EMTDCcopy. The emphasis of this work has been put on evaluating the transferred active and reactive power from the rectifying station to

E. Mortera-Vazquez; E. L. Moreno-Goytia; L. E. Ugalde-Caballero

2009-01-01

224

Evaluation of cloud microphysics schemes in simulations of a winter storm using radar and radiometer measurements  

NASA Astrophysics Data System (ADS)

observations from a space-borne radiometer and a ground-based precipitation profiling radar, the impact of cloud microphysics schemes in the WRF model on the simulation of microwave brightness temperature (Tb), radar reflectivity, and Doppler velocity (Vdop) is studied for a winter storm in California. The unique assumptions of particles size distributions, number concentrations, shapes, and fall speeds in different microphysics schemes are implemented into a satellite simulator and customized calculations for the radar are performed to ensure consistent representation of precipitation properties between the microphysics schemes and the radiative transfer models.Simulations with four different schemes in the WRF model, including the Goddard scheme (GSFC), the WRF single-moment 6-class scheme (WSM6), the Thompson scheme (THOM), and the Morrison double-moment scheme (MORR), are compared directly with measurements from the sensors. Results show large variations in the simulated radiative properties. General biases of ~20 K or larger are found in (polarization-corrected) Tb, which is linked to an overestimate of the precipitating ice aloft. The simulated reflectivity with THOM appears to agree well with the observations, while high biases of ~5-10 dBZ are found in GSFC, WSM6 and MORR. Peak reflectivity in MORR exceeds other schemes. These biases are attributable to the snow intercept parameters or the snow number concentrations. Simulated Vdop values based on GSFC agree with the observations well, while other schemes appear to have a ~1 m s-1 high bias in the ice layer. In the rain layer, the model representations of Doppler velocity vary at different sites.

Han, Mei; Braun, Scott A.; Matsui, Toshihisa; Williams, Christopher R.

2013-02-01

225

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

226

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

227

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

228

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

229

Evaluation of station keeping systems for deepwater drilling semi-submersibles  

NASA Astrophysics Data System (ADS)

This paper addresses the need for systematic evaluation of the station keeping systems of deepwater drilling semi-submersibles. Based on the selected drilling semi-submersible configuration, the mooring systems were analyzed and designed for a range of water depths using different mooring line materials. These were steel wire rope, polyester rope and HMPE (high modulus poly ethylene). The mooring analysis was carried out using the advanced fully coupled time domain analysis method in the computer software package HARP. Diffraction analysis was first applied to solve the hydrodynamic properties of the vessel and then the motion equations of the complete dynamic system including the drilling rig, the mooring lines and risers were developed and solved in the time domain. Applying the advanced analysis method, a matrix of mooring systems was developed for operating in water depths of 1 000 m, 1 500 m, and 2 000 m using various mooring materials. The development of mooring systems was conducted in accordance with the commonly adopted mooring design code, API RP 2SK and API RP 2SM. Fresh attempts were then made to comparatively evaluate the mooring system’s characteristics and global performance. Useful results have been obtained in terms of mooring materials, water depths, and key parameters of mooring configurations. The results provide in-depth insight for the design and operation of deepwater mooring systems in the South China Sea environment.

Song, An-Ke; Sun, Li-Ping; Luo, Yong; Wang, Qiang

2010-09-01

230

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

231

High SO(sub 2) removal efficiency testing: Evaluation of high efficiency test results at Hoosier Energy's Merom Station.  

National Technical Information Service (NTIS)

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...

1996-01-01

232

Holographic neural networks versus conventional neural networks: a comparative evaluation for the classification of landmine targets in ground-penetrating radar images  

Microsoft Academic Search

This paper evaluates the performance of a holographic neural network in comparison with a conventional feedforward backpropagation neural network for the classification of landmine targets in ground penetrating radar images. The data used in the study was acquired from four different test sites using the landmine detection system developed by General Dynamics Canada Ltd., in collaboration with the Defense Research

Naga R. Mudigonda; Ray Kacelenga; Mark Edwards

2004-01-01

233

Radar-based hail detection  

NASA Astrophysics Data System (ADS)

Damaging hailstorms are rare but are significant meteorological phenomena from the point of view of economic losses in central Europe. Because of the high spatial and temporal variability of hail, the proper detection of hail occurrences is almost impossible using ground station reports alone. An alternate approach uses information from weather radars. Several algorithms that use single-polarisation radar data have been developed for hail detection. In the present study, seven algorithms were tested on well documented recent hail events from Czechia and southwest Germany from 2002 to 2011. The study aimed to find the optimal threshold values for the applications of these techniques over the Czech territory and for evaluating the climatology of hail events. The results showed that the Waldvogel technique and the NEXRAD severe hail algorithm were the most accurate methods for hail detection over the area of interest. A combined criterion was proposed based on a combination of previously tested techniques. The precision of this “combi-criterion” was demonstrated for a severe hail event. The abilities of the tested criteria to provide information about a hail-fall area distribution and hail damage risk over the Czech territory were shown and discussed.

Skripniková, Kate?ina; ?ezá?ová, Daniela

2014-07-01

234

Local early warning systems with LS-radar  

Microsoft Academic Search

A complement to the local optical early warning system is described. The LS system (LS = optical early warning station) is suggested, using simple marine radars equipped with MTI circuits. It is possible for land based MTI-radar to separate moving target echoes from ground echoes. The LS-radar early warning system gives directly a warning to neighboring local command centers. Advantages

Erik Arvidsson

1988-01-01

235

MER vistas: ground-truth for Earth-based radar  

NASA Technical Reports Server (NTRS)

Earth-based delay-Doppler radar observations of Mars with four receiving stations were carried out during the Mars oppositions of 2001 and 2003 in support of Mars Exploration Rover landing site selection. This interferometric planetary radar technique has demonstrated radar mapping of Mars with a 5 km spatial resolution.

Haldemann, Albert F.; Larsen, Kristopher W.; Jurgens, Raymond F.; Golombek, Matthew P.; Slade, Martin A.

2004-01-01

236

Feasibility analysis of GSM signal for passive radar  

Microsoft Academic Search

Passive radar makes use of an 'illuminator of opportunity' already present in the environment for other purposes (TV transmission, broadcast systems, etc) to detect targets as well as estimating target parameters. This radar has the merit of being a completely covert radar system, which does not advertise the presence of either the receivers or transmitting stations. One such existing radio

Danny K. P. Tan; Hongbo Sun; Yilong Lu; Weixian Liu

2003-01-01

237

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

PubMed Central

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.

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

1993-01-01

238

Evaluation of shoulder integrity in space: first report of musculoskeletal US on the International Space Station  

NASA Technical Reports Server (NTRS)

Investigative procedures were approved by Henry Ford Human Investigation Committee and NASA Johnson Space Center Committee for Protection of Human Subjects. Informed consent was obtained. Authors evaluated ability of nonphysician crewmember to obtain diagnostic-quality musculoskeletal ultrasonographic (US) data of the shoulder by following a just-in-time training algorithm and using real-time remote guidance aboard the International Space Station (ISS). ISS Expedition-9 crewmembers attended a 2.5-hour didactic and hands-on US training session 4 months before launch. Aboard the ISS, they completed a 1-hour computer-based Onboard Proficiency Enhancement program 7 days before examination. Crewmembers did not receive specific training in shoulder anatomy or shoulder US techniques. Evaluation of astronaut shoulder integrity was done by using a Human Research Facility US system. Crew used special positioning techniques for subject and operator to facilitate US in microgravity environment. Common anatomic reference points aided initial probe placement. Real-time US video of shoulder was transmitted to remote experienced sonologists in Telescience Center at Johnson Space Center. Probe manipulation and equipment adjustments were guided with verbal commands from remote sonologists to astronaut operators to complete rotator cuff evaluation. Comprehensive US of crewmember's shoulder included transverse and longitudinal images of biceps and supraspinatus tendons and articular cartilage surface. Total examination time required to guide astronaut operator to acquire necessary images was approximately 15 minutes. Multiple arm and probe positions were used to acquire dynamic video images that were of excellent quality to allow evaluation of shoulder integrity. Postsession download and analysis of high-fidelity US images collected onboard demonstrated additional anatomic detail that could be used to exclude subtle injury. Musculoskeletal US can be performed in space by minimally trained operators by using remote guidance. This technique can be used to evaluate shoulder integrity in symptomatic crewmembers after strenuous extravehicular activities or to monitor microgravity-associated changes in musculoskeletal anatomy. Just-in-time training, combined with remote experienced physician guidance, may provide a useful approach to complex medical tasks performed by nonexperienced personnel in a variety of remote settings, including current and future space programs. (c) RSNA, 2004.

Fincke, E. Michael; Padalka, Gennady; Lee, Doohi; van Holsbeeck, Marnix; Sargsyan, Ashot E.; Hamilton, Douglas R.; Martin, David; Melton, Shannon L.; McFarlin, Kellie; Dulchavsky, Scott A.

2005-01-01

239

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

240

Findings of the Joint Workshop on Evaluation of Impacts of Space Station Freedom Ground Configurations  

NASA Technical Reports Server (NTRS)

At the workshop, experts from the plasma interactions community evaluated the impacts of environmental interactions on the Space Station Freedom (SSF) under each of the proposed grounding schemes. The grounding scheme chosen for the SSF power system was found to have serious implications for SSF design. Interactions of the SSF power system and structure with the low Earth orbit (LEO) plasma differ significantly between different proposed grounding schemes. Environmental constraints will require modification of current SSF designs under any grounding scheme. Maintaining the present negative-grounding scheme compromises SSF safety, structural integrity, and electromagnetic compatibility. It also will increase contamination rates over alternative grounding schemes. One alternative, positive grounding of the array, requires redesign of the primary power system in work package four. Floating the array reduces the number of circuit changes to work package four but adds new hardware. Maintaining the current design will affect all work packages; however, no impacts were identified on work packages one, two, or three by positively grounding or floating the array, with the possible exception of extra corona protection in multi-wire connectors.

Ferguson, Dale C.; Snyder, David B.; Carruth, Ralph

1991-01-01

241

Findings of the Joint Workshop on Evaluation of Impacts of Space Station Freedom Ground Configurations  

NASA Technical Reports Server (NTRS)

A workshop to consider the effects of various proposed Space Station Freedom (SSF) grounding schemes was held. Expert from the plasma interactions community evaluated the impacts of environmental interactions on SSF under each of three proposed grounding schemes. The choice of the grounding scheme for the SSF power system was found to have important implications for SSF design. Interactions of the SSF power system and structure with the low earth orbit (LEO) plasma differ significantly between different grounding schemes. Environmental constraints will require modification of current SSF designs under any grounding scheme. Maintaining the present negative ground scheme may compromise SSF safety, structural integrity, and electromagnetic compatibility, and will increase contamination rates over alternate schemes. Positive grounding of the array requires redesign of the primary power system. Floating the array reduces the number of circuit changes in the primary power system but adds new hardware. Maintaining the present design will affect all parts of SSF. However, no impacts were identified on SSF systems outside of the electrical power system by positively grounding or floating the array.

Ferguson, Dale C.; Snyder, David B.; Carruth, Ralph

1990-01-01

242

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

243

Long life monopropellant hydrazine thruster evaluation for Space Station Freedom application - Test results  

NASA Technical Reports Server (NTRS)

In support of propulsion system thruster development activity for Space Station Freedom (SSF), NASA Johnson Space Center (JSC) conducted a hydrazine thruster technology demonstration program. The goal of this program was to identify impulse life capability of state-of-the-art long life hydrazine thrusters nominally rated for 50 pounds thrust at 300 psia supply pressure. The SSF propulsion system requirement for impulse life of this thruster class is 1.5 million pounds-seconds, corresponding to a throughput of approximately 6400 pounds of propellant. Long life thrusters were procured from The Marquardt Company, Hamilton Standard, and Rocket Research Company, Testing at JSC was completed on the thruster designs to quantify life while simulating expected thruster firing duty cycles and durations for SSF. This paper presents a review of the SSF propulsion system hydrazine thruster requirements, summaries of the three long life thruster designs procured by JSC and acceptance test results for each thruster, the JSC thruster life evaluation test program, and the results of the JSC test program.

Popp, Christopher G.; Cook, Joseph C.; Ragland, Brenda L.; Pate, Leah R.

1992-01-01

244

Invacuo tribological evaluation of coarse-pitch gears for use on the Space Station alpha joint  

NASA Technical Reports Server (NTRS)

Existing invacuo or ambient test data of slow-speed (less than 30 meters/minute pitch line velocity), coarse-pitch gears could not be found suitable for use in evaluating gear materials and surface treatments for the gear-driven bearing race of the Solar Alpha Rotary Joint (SARJ) for Space Station Freedom (SSF). Gear testing was conducted by AEC-Able Engineering Company, Inc. to obtain design data for this critical SSF component. Some bull gear/pinion/lubrication combinations endured over 600,000 cycles (100 SSF years) without measurable wear, while other combinations experienced surface treatment degradation after only 40,000 cycles (seven SSF years). No catastrophic failures, such as seizing or tooth breakage, occurred during any test, all of which were run at least 201,000 cycles (34.5 SSF years). Specific results such as debris characteristics, mechanical efficiencies, effectiveness and degradation of lubrication, and wear data for the various gear combinations tested are described.

Allen, Scotty R.

1992-01-01

245

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

246

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

247

TRACALS Evaluation Report. Airport Surveillance Radar AN/GPN-12. Initial Evaluation Report, Laughlin AFB, Texas, 9-16 January 1981 and 31 January - 1 February 1981.  

National Technical Information Service (NTIS)

This report presents data collected to define the capabilities and limitations of the radar facility at Laughlin AFB, Texas. This report includes descriptions of the useable radar coverage and tracking capabilities, analysis of all flight and equipment pe...

J. C. Caballero G. R. Hurd

1981-01-01

248

Radar - Principles, technology, applications  

NASA Astrophysics Data System (ADS)

An overview of modern radar is presented. The topics addressed include: functions and parameters of the radar system, the radar equation, targets and interfering signals, target echo information extraction, tracking radar, radar transmitters and microwave components, radar antennas, receivers and displays, radar signal processing, high resolution radar.

Edde, Byron

249

Radar observables  

NASA Astrophysics Data System (ADS)

A comprehensive account is given of missile design considerations relevant to the prediction, control, and measurement of airframe radar cross sections (RCSs), with a view to the minimization of missile observability. RCS reduction may proceed through airframe shaping to deflect incident radar emissions, as well as through the use of radar-absorbing surface materials and the devision of active radar signal-cancellation methods; some combination of these is often required, due to the deficiencies of any one method. The interaction of all RCS-reduction methods with airframe aerodynamic-design criteria are stressed.

Knott, Eugene F.

250

TRACALS Evaluation Report. Airport Surveillance Radar AN/GPN-12 and Precision Approach Radar AN/FPN-62 Initial Evaluation Report, Little Rock AFB, Arkansas, 15-24 October 1981.  

National Technical Information Service (NTIS)

This report presents data collected 15-24 October 1981 to define the capabilities and limitations of the TRACALS radar systems (ASR and PAR) at Little Rock AFB, Arkansas. This report includes descriptions of the useable radar coverage and tracking capabil...

J. C. Caballero K. M. Slater

1981-01-01

251

Physical Impact Evaluation of Chalk Point Generating Station's Cooling Water System on the Patuxent River.  

National Technical Information Service (NTIS)

In July and August 1979 a hydrographic survey using fluorescence tracer techniques was conducted to investigate the physical impact of Chalk Point Generating Station's cooling water discharge on the Patuxent River. The objective was to determine the distr...

R. C. Binkerd H. G. Johnston J. K. Comeau

1979-01-01

252

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

National Technical Information Service (NTIS)

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 Sp...

B. Rodriquez D. Botkin L. Vega M. Anderson N. Adams

2013-01-01

253

Program of the Antarctic Syowa MST\\/IS radar (PANSY)  

Microsoft Academic Search

We have been promoting a project to introduce the first MST Mesosphere-Stratosphere-Troposphere IS Incoherent Scatter radar which is a VHF pulse Doppler radar in the Antarctic to Syowa Station 39E 69S Program of the Antarctic Syowa MST IS Radar PANSY as an important station observing the earth s environment with the aim to catch the climate change signals that the

K. Sato; M. Tsutsumi; T. Sato; A. Saito; Y. Tomikawa; T. Aso; T. Yamanouchi; M. Ejiri

2006-01-01

254

A simulator for the Seasat-A synthetic aperture radar ground support network  

Microsoft Academic Search

The characteristics and capabilities of link measurement and simulation equipment for the NASA ground stations supporting the Seasat-A synthetic aperture radar (SAR) are described. The Spaceflight Tracking and Data Network (STDN) Seasat-A SAR Simulator generates SAR radar and data link signals, including chirp, radar return, pilot, PRN radar timing, and noise components. After injection into and passage through the STDN

S. C. Jones; J. D. Colson; P. J. Grunberger

1978-01-01

255

Fire Station Location Package.  

National Technical Information Service (NTIS)

Using the PTI Fire Station Package, local administrators and fire officials evaluate adequacy of station locations - present and planned - on response time rather than arbitrary distance requirements to get the most protection for the least investment. A ...

1975-01-01

256

Oconee Nuclear Power Station Main Steam Line Break Analysis for Steam Generator Tube Stress Evaluation  

SciTech Connect

For certain steam line break (SLB) analyses, the RETRAN-3D Oconee model predicts water carryout through the break. The amount of liquid carried from the system is dependent on the assumed break size, feedwater boundary conditions, and initial conditions. Although liquid carryout is potentially realistic during this scenario, there are no plant or test facility data on which to validate the amount of water carryout.Because the steam generator tube stress evaluation is a safety related analysis, a conservative approach is required. Overcooling effects for an SLB transient are maximized by retaining as much steam generator liquid as possible to remove energy from the reactor coolant system. Because water carryout is nonconservative, and due to the lack of data, the analysis is performed assuming no liquid is carried from the break. This boundary condition is difficult to impose on a RETRAN-3D analysis since the amount of liquid entrained in the break flow is determined by internal code models, which the analyst cannot control directly.This paper presents the methodology used to eliminate water carryout for these types of calculations. The methodology consists of a combination of special RETRAN-3D code modifications and model input changes.In the second part of the paper, the results of an SLB analysis for the Oconee Nuclear Station employing the above methodology are presented. These analyses are done to compute the temperature differences between the steam generator tubes and the shell of the once-through steam generator. The temperature of the thin tubes decreases much faster than the temperature of the shell during an overcooling transient such as an SLB, resulting in tensile stresses that might lead to tube failures.A number of break sizes were analyzed starting with a double-ended main SLB down to a small break of 0.0372 m{sup 2} (0.4 ft{sup 2}). The sensitivity of the tube tensile stress to the assumed break size is presented.

Muransky, Jan S.; Shatford, John G.; Peterson, Craig E.; Swindlehurst, Gregg B

2004-10-15

257

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

258

Evaluation of the attenuation provided by a radar absorbing material (RAM) coating on an HF wire rope antenna  

Microsoft Academic Search

A shipboard electromagnetic interference (EMI) problem is considered. The use of radar absorbent material (RAM) to reduce unintentional X-band (8-12 GHz) radar reflections from HF wire rope antennas is analyzed. An exact series solution for a lossy-coated circular cylinder was developed and used to determine the effectiveness of the various RAM coatings

Griffin K. Gothard; Broun Hall

1991-01-01

259

Application of impulse radar to continuous profiling of tephra-bearing lake sediments and peats: An initial evaluation  

Microsoft Academic Search

Subsurface interface radar (SIR), or impulse radar, uses electromagnetic pulses for continuous stratigraphic profiling. It has been applied to lake sediments (dy-gyttja) and peat deposits containing a sequence of thin, late Quaternary, ashgrade tephras at Lake Maratoto, North Island, New Zealand. The SIR system is very rapid, precise, and reasonably accurate compared with conventional coring and probing methods, but still

David J. Lowe

1985-01-01

260

Radar Astronomy.  

National Technical Information Service (NTIS)

A general review of radar astronomy is given. Typical radar systems are described and results cited. Methods of determining elements of orbits and rotation rates of planets are discussed. A proposed test of the Einstein theory of general relativity is des...

G. H. Pettengill I. I. Shapiro

1965-01-01

261

Radar astronomy  

Microsoft Academic Search

Radar Astronomy is a new and growing branch of Astronomy. Although it seems that radio echo studies must be confined to the solar system, they can play an important part in developing our understanding of the Sun and the planets. At the present time these objects are barely detectable by radar techniques and much of the work has been concerned

J. V. Evans

1960-01-01

262

Evaluation of the 29-km Eta Model. Part 1; Objective Verification at Three Selected Stations  

NASA Technical Reports Server (NTRS)

This paper describes an objective verification of the National Centers for Environmental Prediction (NCEP) 29-km eta model from May 1996 through January 1998. The evaluation was designed to assess the model's surface and upper-air point forecast accuracy at three selected locations during separate warm (May - August) and cool (October - January) season periods. In order to enhance sample sizes available for statistical calculations, the objective verification includes two consecutive warm and cool season periods. Systematic model deficiencies comprise the larger portion of the total error in most of the surface forecast variables that were evaluated. The error characteristics for both surface and upper-air forecasts vary widely by parameter, season, and station location. At upper levels, a few characteristic biases are identified. Overall however, the upper-level errors are more nonsystematic in nature and could be explained partly by observational measurement uncertainty. With a few exceptions, the upper-air results also indicate that 24-h model error growth is not statistically significant. In February and August 1997, NCEP implemented upgrades to the eta model's physical parameterizations that were designed to change some of the model's error characteristics near the surface. The results shown in this paper indicate that these upgrades led to identifiable and statistically significant changes in forecast accuracy for selected surface parameters. While some of the changes were expected, others were not consistent with the intent of the model updates and further emphasize the need for ongoing sensitivity studies and localized statistical verification efforts. Objective verification of point forecasts is a stringent measure of model performance, but when used alone, is not enough to quantify the overall value that model guidance may add to the forecast process. Therefore, results from a subjective verification of the meso-eta model over the Florida peninsula are discussed in the companion paper by Manobianco and Nutter. Overall verification results presented here and in part two should establish a reasonable benchmark from which model users and developers may pursue the ongoing eta model verification strategies in the future.

Nutter, Paul A.; Manobianco, John; Merceret, Francis J. (Technical Monitor)

1998-01-01

263

Performance evaluation and analysis of a novel 300-mm combination bake-chill station  

NASA Astrophysics Data System (ADS)

DUV resists are extremely sensitive to temperature variations on the wafer during bake and chill cycles. In resist-processing tracks today, the wafer is moved by a robot or transfer arm, from the bake to chill plate. During this move, since the resist is still above the activation temperature, the wafer temperature is uncontrolled until it is placed on a chill plate. In the new station design presented here, the wafer is heated to the desired bake temperature and chilled back to room temperature before being moved by the robot, resulting in a tight temperature control of the wafer, throughout the process. Two models, axi-symmetric and three-dimensional (geometrically similar to the new station), are generated for analyzing the thermal performance of the above station. The numerical simulations, solving the momentum and energy equations in the computational domain, are performed using the commercial CFD software Fluent. The simulated temporal evolution of temperature from the beginning to the end of the bake-chill process is verified with the experimental data as measured by a 42-point OnWafer temperature sensor wafer on the new station. Methods to improve wafer surface temperature uniformity, in light of bake-chill-station mechanical and thermal design losses are discussed. Higher throughput of the cluster, a major productivity improvement contribution of this new design, is also highlighted.

Narasimhan, Arunn; Ramanan, Natarajan R.; Williams, Daniel J.

2003-06-01

264

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

265

Evaluating Snowfall Detectability of NASA CloudSat with NOAA/NSSL Ground Radar-Based National Multi-sensor Mosaic QPE (NMQ)  

NASA Astrophysics Data System (ADS)

NASA CloudSat, carrying the first space-borne Cloud Profiling Radar (CPR), is the first satellite that provides scientific communities with global snowfall observations. The accuracy of snowfall observation and quantification at middle and high latitude area is directly correlated with the liability of satellite-based precipitation estimates. However, up-to-date there is not systematic evaluation of its snowfall detectability at regional and global scale. Validation and evaluation of CPR's capability of snowfall detection is still needed in satellite precipitation communities. The NOAA/NSSL ground radar-based National Mosaic and multi-sensor Quantitative Precipitation Estimates (QPE) (NMQ or Q2) provides the high spatiotemporal resolution (1km/5min) 2-dimensional (2D) multi-suites precipitation products as well as 3-dimensional (3D) products. Such high-resolution QPE products offer an ideal alternate to evaluate satellite-based observations and products. In this paper, the CloudSat-CPR's detectability of falling snow is systematically evaluated using NMQ-Q2 snowfall products (i.e., solid snowfall precipitation identification) over the CONUS from January 2009 to December 2012. Spatial and temporal matching is applied to obtain the most matched dataset from both observations considering their differences in spatiotemporal resolution. The evaluation results offer the insights into the performance of CPR in detecting falling snow and also demonstrate its great potential in improving the solid precipitation (snowfall) in the mid-high latitude area and high-altitude area (e.g. the Tibetan plateau). A synthetic approach of incorporating the ground-radar-based NMQ products for evaluating and integrating into spaceborne radar observations will be highly expected with the launch of Global Precipitation Measurement in 2014.

Chen, S.; Cao, Q.; Hong, Y.; Gourley, J. J.; Hu, J.

2013-12-01

266

Metallurgical Evaluation of an 18-Inch Feedwater Line Failure at the Surry Unit 2 Power Station.  

National Technical Information Service (NTIS)

A metallurgical failure analysis was performed on pieces from a catastrophically failed 18-inch diameter feedwater line from the Surry Unit 2 Nuclear Power Station. The failed pipe had been globally thinned and had a scalloped appearance on the inside sur...

C. J. Czajkowski

1987-01-01

267

Evaluation of the Productivities of Maure and Peul Cattle Breeds at the Sahelian Station, Niono, Mali.  

National Technical Information Service (NTIS)

From 1966 to 1975, the Sahelian Station at Niono, Mali, maintained substantial herds of two typical African breeds of Zebu cattle, the Maure and the Peul, together with their crosses, in order to collect comparative data in the areas noted below. This rep...

1978-01-01

268

Decision Analysis Methodology to Evaluate Integrated Solid Waste Management Alternatives for a Remote Alaskan Air Station.  

National Technical Information Service (NTIS)

Eareckson Air Station (AS), a remote U.S. Air Force installation, faces the complex decision of selecting a new municipal solid waste (MSW) management strategy to replace its current non-compliant system. This research effort applies value-focused thinkin...

M. J. Shoviak

2001-01-01

269

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

270

Evaluation of the Present Theoretical Basis for Determination of Planetary Surface Properties by Earth-Based Radar.  

National Technical Information Service (NTIS)

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 th...

L. D. Staton

1975-01-01

271

Evaluation of an HF-radar ship detection and tracking algorithm by comparison to AIS and SAR data  

Microsoft Academic Search

Since several years, High Frequency (HF) Over-The-Horizon (OTH) radar is used to measure oce?anographie parameters, such as currents, waves, and wind direction over large areas up to 200 km off the coast. Cost effective low power systems transmitting less than 50 Watts have been developed, e.g. the WERA (WEUen RAdar), and are now commercially available. Besides their applications in oceanography

Klaus-Werner Gurgel; Thomas Schlick; Jochen Horstmann; Salvatore Maresca

2010-01-01

272

Evaluation of Diablo Canyon Nuclear Power Station Unit 2 Technical Specifications  

SciTech Connect

This document was prepared for the Nuclear Regulatory Commission (NRC) to assist them in determining whether the Diablo Canyon Nuclear Power Station Unit 2 Technical Specifications (T/S), which govern plant systems configurations and operations, are in conformance with the requirements of the Final Safety Analysis report (FSAR) as amended, and the requirements of the Safety Evaluaton Report (SER) as supplemented. A comparative audit of the FSAR as amended, and the SER as supplemented was performed with the Diablo Canyon T/S. Several discrepancies were identified and subsequently resolved by the cognizant NRC reviewer. Pending completion of the resolutions noted in Section 3 of this report, the Diablo Canyon Nuclear Power Station Unit 2 T/S, to the extent reviewed, are in conformance with the FSAR and SER.

Baxter, D.E.; Bruske, S.J.

1985-08-01

273

UV variability and climatology from the re-evaluated spectral records of seven European stations  

Microsoft Academic Search

For the annual course of the long-term monthly means of the daily integrals of irradiance at 305 nm and 324 nm, and of the CIE-weighted and UV-B integrals, Thessaloniki has by far the highest values, while the Scandinavian stations of Sodankyla, Jokioinen and Norrkoping the lowest. The same pattern appears also for the maximum values (Figure 1). At 324 nm

A. F Bais; C. Meleti; S. Kazadzis; K. Garane Lakkal; C. Topaloglou; H. Slaper; J. Kaurola; W. Josefsson; U. Feister; M. Janouch

274

Evaluating the thermodynamic efficiency of hydrogen cycles at wet-steam nuclear power stations  

NASA Astrophysics Data System (ADS)

Various schematic solutions for implementing a hydrogen cycle on the basis of thermal and nuclear power stations are discussed. Different approaches to construction of cooling systems for the combustion chambers used in hydrogen-oxygen steam generators are described. An example of solution is given in which the combustion chamber is cooled by steam, which is the most efficient one in the thermodynamic respect. Results from an assessment of the thermodynamic efficiency of hydrogen cycles organized on the basis of the power unit of a wet-steam nuclear power station equipped with a K-1000-60/1500 turbine are presented. The thermodynamic efficiency of different schematic and parametric versions of implementing a hydrogen cycle, including those with a satellite turbine operating on displaced steam, is carried out. It is shown that the use of satellite turbines allows the power output and efficiency of the power unit of a wet-steam nuclear power station to be upgraded in a reliable and effective manner.

Aminov, R. Z.; Egorov, A. N.

2013-04-01

275

A reflectivity climatology algorithm for hybrid scans and its application to radar coverage over the Tibetan Plateau  

NASA Astrophysics Data System (ADS)

The traditional algorithm for hybrid radar scans uses standard terrain digital elevation model (DEM) data and the latitudes, longitudes and altitudes of contributing radar stations. While radar station location information is often inaccurate, signal blockages due to trees, buildings, and other surface objects are not included in the DEM data. Accordingly, hybrid scan elevations derived using this traditional algorithm are prone to errors. Here, reflectivity climatology data (the frequency of occurrence of reflectivity) are used to improve the algorithm for hybrid scans. Three parameters are introduced, then applied to evaluation of signal blockage for every radar bin using a fuzzy logic technique. This new algorithm provides an improved determination of the lowest unblocked elevation for hybrid scans. The new algorithm is validated by examining the scope and continuity of the calculated hybrid scan reflectivity in a case study, and the performance of this climatology-based algorithm is evaluated relative to the traditional terrain-based algorithm. The climatology-based hybrid scans are then used to examine the spatial coverage provided by the operational weather radar network over the Tibetan Plateau. The results indicate that the terrain-based hybrid scan algorithm introduced errors that caused obvious V-shaped gaps in hybrid scan reflectivity. By contrast, the climatology-based hybrid scan algorithm more accurately determined the lowest unblocked elevation and reduced the impacts of blockage. The coverage map illustrates the limitations of the weather radar network over the Tibetan Plateau. These limitations inhibit the usefulness of the radar data. Additional radar or observational data are needed to fill these gaps and minimize the impacts of signal blockage.

Zhuang, Wei; Liu, Liping

2012-12-01

276

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

277

Meander line RFID tag at UHF band evaluated with radar cross sections  

Microsoft Academic Search

This paper presents a meander line RFID tag antenna operating at UHF band. The proposed inductively-coupled tag can be easily designed to have a specific antenna impedance. The designed antenna impedance is 77+j100? at 911 MHz. The performance of the antenna is evaluated by monitoring RCS' corresponding to varied chip impedances. The procedures to determine RCS by EM simulation are

Hongil Kwon; Bomson Lee

2005-01-01

278

Safety Evaluation Report Related to the Operation of Clinton Power Station, Unit No. 1, Docket No. 50-461, Illinois Power Company, et al. Supplement No. 5.  

National Technical Information Service (NTIS)

Supplement No. 5 to the Safety Evaluation Report on the application filed by Illinois Power Company, Soyland Power Cooperative, Inc., and Western Illinois Power Cooperative, Inc. as applicants and owners, for a license to operate the Clinton Power Station...

1986-01-01

279

Safety Evaluation Report: Related to the License Renewal of Kewaunee Power Station, Docket No. 50-305, Dominion Energy Kewaunee, Inc.  

National Technical Information Service (NTIS)

This safety evaluation report (SER) documents the technical review of the Kewaunee Power Station (KPS) license renewal application (LRA) by the U.S. Nuclear Regulatory Commission (NRC) staff (the staff). By letter dated August 12, 2008, Dominion Energy Ke...

2011-01-01

280

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

281

Borehole radar for geothermal applications.  

National Technical Information Service (NTIS)

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 depende...

M. W. Scott T. W. H. Caffey

1991-01-01

282

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., Jr.; Costa, John E.; Plant, William J.; Spicer, Kurt R.; Haeni, F. Peter; Melcher, Nick B.; Keller, William C.; Hayes, Ken

2004-01-01

283

Shuttle Imaging Radar - Geologic applications  

NASA Technical Reports Server (NTRS)

The Space Shuttle, on its second flight (November 12, 1981), carried the first science and applications payload which provided an early demonstration of Shuttle's research capabilities. One of the experiments, the Shuttle Imaging Radar-A (SIR-A), had as a prime objective to evaluate the capability of spaceborne imaging radars as a tool for geologic exploration. The results of the experiment will help determine the value of using the combination of space radar and Landsat imagery for improved geologic analysis and mapping. Preliminary analysis of the Shuttle radar imagery with Seasat and Landsat imagery from similar areas provides evidence that spaceborne radars can significantly complement Landsat interpretation, and vastly improve geologic reconnaissance mapping in those areas of the world that are relatively unmapped because of perpetual cloud cover.

Macdonald, H.; Bridges, L.; Waite, W.; Kaupp, V.

1982-01-01

284

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

285

Evaluation of Preproduction Hardware Components for IMS Station Upgrades to Reduce Manufacturers Development Time  

NASA Astrophysics Data System (ADS)

Since the Comprehensive Nuclear-Test-Ban Treaty was opened for signature in 1996, nearly 80% of the network has been certified as operational, and those stations are sending data to the International Data Centre (IDC) in Vienna. Several International Monitoring System (IMS) monitoring facilities have been in operation for close to 15 years, and several certified stations are facing equipment obsolescence issues. The search for engineering solutions to replace obsolete hardware components is guided by two primary goals: 1) be compliant with IMS minimum technical requirements and 2) be able to be integrated with the existing system. To reduce the development and verification time necessary to address obsolescence in equipment, the PTS has requested the preproduction testing of the recently revised Guralp CMG-DM24AM digitizer. Performing preproduction testing has helped in identifying issues, which Guralp Systems has resolved. In our poster, we will review the reasons for the digitizer updates, present results of the preproduction testing of the Guralp digitizer, and comment on the value this process has provided to the IMS operation.

Hart, Darren; Pearce, Nathan; Starovoit, Yuri; Guralp, Cansun

2014-05-01

286

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

287

Safety Evaluation of the Byron Station, Units 1 and 2, and the Braidwood Station, Units 1 and 2. Docket Nos. STN 50-454, STN 50-455, STN 50-456, STN 50-457.  

National Technical Information Service (NTIS)

A safety evaluation of the Commonwealth Edison Company's application for licenses to construct and operate its proposed Byron Station, Units 1 and 2 (Docket Nos. STN-50-454 and STN-50-455), located in Rockvale Township, Ogle County, Illinois, and its prop...

1975-01-01

288

Test and Evaluation Software for a Prototype Network of Water Level Measurement Stations  

Microsoft Academic Search

The National Ocean Service is replacing its National Water Level Observation Network with the Next Generation Water Level Measurement System. A prototype network of 20 field units will be used to test and evaluate the initial design concept and to define final technical specification. Special Test and Evaluation (T&E) software was developed to support this field evaluation. The T&E software,

T. Hsiao

1986-01-01

289

CIS communication facilities, data transmission and computer-aided experiment evaluation for users of the Mir Space Station  

NASA Astrophysics Data System (ADS)

Cooperation between western countries and the former Soviet Union and the present Commonwealth of Independent States (CIS) in manned spaceflight to the Mir Space Station began in 1988 and continued to grow over the following years. During this western involvement in flights to Mir, it become apparent that the conduct of the scientific flight programme itself was the prime mission objective, with the majority of the data-evaluation work being carried out in western laboratories and not in the CIS. However, few western scientific investigators have detailed knowledge of the availability of the CIS space infrastructure or the technical capabilities of the Mir space programme. This applies particularly to the CIS's data-transmission capabilities and electronic data-processing services. This lack of availability of detailed information is due in part to the fact that the Russians tend to provide background information to other partners only in response to specific requests. This paper is therefore an attempt to summarize both the radio data-transmission capabilities that exist in the context of the Mir programme, and how data can be evaluated via CIS electronic ground equipment. It is aimed primarily at potential users of the Mir Space Station. Subsequent articles in this series will describe Mir's scientific and technological experimentation and accommodation aspects.

Griethe, W.; Burfeindt, J.

290

Analysis of Incoming Wave Distribution in Vertical Plane in Urban Area and Evaluation of Base Station Antenna Effective Gain  

NASA Astrophysics Data System (ADS)

In order to reduce the amount of interference to neighboring cells in cellular systems, we generally use base station (BS) antennas that have sharp beam patterns in the vertical plane; however, the distribution of incoming waves at the BS affects the effective gain of the BS antennas which have directional pattern. Therefore, we have to clarify the characteristics of the distribution of the incoming waves. A recent trend is decreasing the cell radius; therefore, clarifying the distribution of the incoming waves at the BS when mobile stations (MSs) are located within 1km from the BS is important. In this report, we evaluate the effective gains of the BS antennas, which are calculated using the measured vertical power angle profile (PAP). Moreover, we examine the application of a simple incoming wave model to the evaluation of the antenna effective gains. In the model, the average power of the incoming waves is set to the Laplacian function and each wave is changed to a lognormal distribution. The antenna effective gain calculated using the model agrees well with that calculated using the measured PAP.

Kitao, Koshiro; Imai, Tetsuro

291

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

292

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

293

Simulation of a weather radar display for over-water airborne radar approaches  

NASA Technical Reports Server (NTRS)

Airborne radar approach (ARA) concepts are being investigated as a part of NASA's Rotorcraft All-Weather Operations Research Program on advanced guidance and navigation methods. This research is being conducted using both piloted simulations and flight test evaluations. For the piloted simulations, a mathematical model of the airborne radar was developed for over-water ARAs to offshore platforms. This simulated flight scenario requires radar simulation of point targets, such as oil rigs and ships, distributed sea clutter, and transponder beacon replies. Radar theory, weather radar characteristics, and empirical data derived from in-flight radar photographs are combined to model a civil weather/mapping radar typical of those used in offshore rotorcraft operations. The resulting radar simulation is realistic and provides the needed simulation capability for ongoing ARA research.

Clary, G. R.

1983-01-01

294

Radar Antenna.  

National Technical Information Service (NTIS)

An antenna is described for range-gated, pulse doppler, radar systems. The antenna includes first and second, shortened, half-wave dipoles and first and second reflecting screens. One dipole is fed through a fixed 22 1/2 degree phase-shift network while t...

O. E. Rittenback

1978-01-01

295

Radar Roadmap.  

National Technical Information Service (NTIS)

Instrumentation radar has played a very significant role in testing and training for more than 50 years. Along with optics, it has been a major supplier of time space position information (TSPI). With the advent of the Global Positioning System (GPS), the...

1998-01-01

296

Radar nomenclature  

Microsoft Academic Search

Like much of the equipment used by the armed forces, both civil and military radar systems may be allocated an identification resolved from a synonym, mnemonic, project name, number, application notation, or specialised nomenclature and sometimes may even be based upon the whims of an intelligence reporting service. Of these, mnemonics are very popular; whilst of designation systems used by

J. C. Wise

2004-01-01

297

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

298

Evaluation of EBR-II driver-fuel elements following an unprotected station blackout accident  

SciTech Connect

One of the current design objectives for a liquid metal reactor (LMR) is the inherent shutdown-cooling capability of the reactor, such that the reactor itself can safely reduce power following a total loss of pump power without activating the reactor shutdown system (RSS). Following a loss-of-flow (LOF) accident and a failure of RSS, in EBR-II, reactor core damage and plant restartability is of considerable interest. In the LOF event, high temperature in the reactor causes negative reactivity feedback that reduces reactor power. After an accident, reactor fuel performance is one of the factors used to assess the restartability of the plant. A thermal-hydraulic-neutronic analysis was performed to determine the response of the plant and the temperature of individual subassemblies. These temperatures were then used to assess the damage to driver fuel elements caused by the station blackout accident. The maximum depth of cladding wastage from molten eutectic at temperatures >715/sup 0/C was found to be 0.0053 mm for the hottest subassembly; this value is considerably less than the 0.28 mm cladding thickness. 12 refs.

Chang, L.K.; Bottcher, J.H.

1986-01-01

299

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

300

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

301

Microstructural Evaluation and Comparison of Solder Samples Processed Aboard the International Space Station  

NASA Technical Reports Server (NTRS)

Samples from the In-Space Soldering Investigation (ISSI), conducted aboard the International Space Station (ISS), are being examined for post-solidification microstructural development and porosity distribution. In this preliminary study, the internal structures of two ISSI processed samples are compared. In one case 10cm of rosin-core solder was wrapped around a coupon wire and melted by conduction, whereas, in the other a comparable length of solder was melted directly onto the hot wire; in both cases the molten solder formed ellipsoidal blobs, a shape that was maintained during subsequent solidification. In the former case, there is clear evidence of porosity throughout the sample, and an accumulation of larger pores near the hot end that implies thermocapillary induced migration and eventual coalescence of the flux vapor bubbles. In the second context, when solder was fed onto the wire. a part of the flux constituting the solder core is introduced into and remains within the liquid solder ball, becoming entombed upon solidification. In both cases the consequential porosity, particularly at a solder/contact interface, is very undesirable. In addition to compromising the desired electrical and thermal conductivity, it promotes mechanical failure.

Grugel, R. N.; Hua, F.; Anilkumar, A. V.

2008-01-01

302

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

303

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

304

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

305

Long life monopropellant hydrazine thruster evaluation for Space Station Freedom application  

NASA Technical Reports Server (NTRS)

In support of propulsion system thruster development activity for Space Station Freedom (SSF), NASA Johnson Space Center (JSC) is conducting a hydrazine thruster technology demonstration program. The goal of this program is to identify impulse life capability of state-of-the-art long life hydrazine thrusters nominally rated for 50 pounds thrust at 300 psia supply pressure. The SSF propulsion system requirement for impulse life of this thruster class is 1.5 million pound-seconds, corresponding to a throughput of approximately 6400 pounds of propellant, with a high performance (234 pound-seconds per propellant pound). Long life thrusters were procured from Hamilton Standard, The Marquardt Company, and Rocket Research Company. Testing has initiated on the thruster designs to identify life while simulating expected thruster firing duty cycles and durations for SSF using monopropellant grade hydrazine. This paper presents a review of the SSF propulsion system and requirements as applicable to hydrazine thrusters, the three long life thruster designs procured by JSC and the resultant acceptance test data for each thruster, and the JSC test plan and facility.

Popp, Christopher G.; Henderson, John B.

1991-01-01

306

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

307

22. SITE BUILDING 002 SCANNER BUILDING RADAR CONTROL ...  

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

22. SITE BUILDING 002 - SCANNER BUILDING - RADAR CONTROL ROOM. RECEIVER EQUIPMENT ON RIGHT WITH RF RADIATION MONITOR CABINET. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

308

Modelisation DU Signal Radar EN Milieu Stratifie et Evaluation de Techniques de Mesure de L'humidite DU Sol  

NASA Astrophysics Data System (ADS)

La presente etude se penche sur des problemes relies a l'echantillonnage de l'humidite de sol et a l'estimation du signal radar sur sols nus. Le travail se divise en deux volets. Le volet 1 evalue trois techniques de mesure de l'humidite du sol (gravimetrie, reflectometrie temporelle et sonde dielectrique) et deux protocoles d'echantillonnage. Dans le volet 2, un modele de simulation du signal en milieu stratifie est developpe, et les estimes de signal obtenus sont compares aux estimes bases uniquement sur une valeur moyenne d'humidite du sol prise sur une profondeur fixe d'echantillonnage. Les differences entre les deux estimes dependent de la frequence et du choix judicieux de la profondeur d'echantillonnage; elles sont plus importantes aux faibles angles et en polarisation HV, puis VV. Le modele de simulation a aussi ete utilise pour etudier la profondeur de penetration du signal et en deduire la profondeur optimale d'echantillonnage en tenant compte des caracteristiques du signal. Une variation de 25 ^circ de l'angle d'incidence a peu d'effet sur la profondeur de penetration en bande Ku; l'ecart reste inferieur ou egal a 0,5 cm en bande C mais peut atteindre 1,3 cm en bande L. L'impact de la polarisation est nul en bande Ku mais croi t avec l'angle d'incidence en bande C et L. A 50^circ, il est, en moyenne de 1 cm en bande C et de 2 cm en bande L. En polarisation VV, la profondeur croi t avec une augmentation de l'angle alors que l'effet est inverse en polarisation HH. Deux methodes pour estimer la profondeur d'echantillonnage en conditions operationnelles sont presentees. Lorsqu'on inverse un modele pour estimer l'humidite du sol a partir du signal, ces methodes permettent aussi d'estimer l'epaisseur de sol representee par l'humidite ainsi estimee.

Boisvert, Johanne

309

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

310

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

311

Evaluation of the 29-km Eta Model. Part I: Objective Verification at Three Selected Stations  

NASA Technical Reports Server (NTRS)

A subjective evaluation of the National Centers for Environmental Prediction 29-km (meso-) eta model during the 1996 warm (May-August) and cool (October-January) seasons is described. The overall evaluation assessed the utility of the model for operational weather forecasting by the U.S. Air Force 45th Weather Squadron, National Weather Service (NWS) Spaceflight Meteorology Group (SMG) and NWS Office in Melbourne, FL.

Manobianco, John; Nutter, Paul

1998-01-01

312

Equatorial radar system  

Microsoft Academic Search

A large clear air radar with the sensitivity of an incoherent scatter radar for observing the whole equatorial atmosphere up to 1000 km altitude is now being designed in Japan. The radar, called the Equatorial Radar, will be built in Pontianak, Kalimantan Island, Indonesia (0.03 N, 109.3 E). The system is a 47 MHz monostatic Doppler radar with an active

S. Rukao; T. Tsuda; T. Sato; S. Kato

1989-01-01

313

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

314

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

315

Evaluation of geophysical logs, Phase I, at Willow Grove Naval Air Station, Montgomery County, Pennsylvania  

USGS Publications Warehouse

Between April and June 1997, the U.S. Navy contracted Brown and Root Environmental, Inc., to drill 20 monitor wells at the Willow Grove Naval Air Station in Horsham Township, Montgomery County, Pa. The wells were installed to monitor water levels and allow collection of water samples from shallow, intermediate, and deep water-bearing zones. Analysis of the samples will determine the horizontal and vertical distribution of any contaminated ground water migrating from known contaminant sources. Eight wells were drilled near the Fire Training Area (Site 5), five wells near the 9th Street Landfill (Site 3), four wells at the Antenna Field Landfill (Site 2), and three wells near Privet Road Compound (Site 1). Depths range from 73 to 167 feet below land surface. The U.S. Geological Survey conducted borehole-geophysical and borehole-video logging to identify water-bearing zones so that appropriate intervals could be screened in each monitor well. Geophysical logs were run on the 20 monitor wells and 1 existing well. Video logs were run on 16 wells. Caliper and video logs were used to locate fractures, inflections on fluid-temperature and fluid-resistivity logs were used to locate possible water-bearing fractures, and flowmeter measurements verified these locations. Single-point-resistance and natural-gamma logs provided information on stratigraphy. After interpretation of geophysical logs, video logs, and driller's notes, all wells were screened such that water-level fluctuations could be monitored and discrete water samples collected from one or more shallow and intermediate water-bearing zones in each borehole.

Conger, R. W.

1997-01-01

316

An evaluation of the IRI-2007 storm time model at low latitude stations  

NASA Astrophysics Data System (ADS)

This paper discusses the ability of the International Reference Ionosphere IRI-2007 storm time model to predict foF2 ionospheric parameter during geomagnetic storm periods. Experimental data (based on availability) from two low latitude stations: Vanimo (geographic coordinates, 2.7 °S, 141.3 °E, magnetic coordinates, 12.3 °S, 212.50 °E) and Darwin (geographic coordinates, 12.45 °S, 130.95 °E, magnetic coordinates, 22.9 °S, 202.7 °E) during nine storms that occurred in 2000 (Rz12 = 119), 2001(Rz12 = 111) and 2003 (Rz12 = 64) are compared with those obtained by the IRI-2007 storm model. The results obtained show that the percentage deviation between the experimental and IRI predicted foF2 values during these storm periods is as high as 100% during the main and recovery phases. Based on the values of "relative deviation module mean" (RDMM) obtained (i.e. between 0.08 and 0.60), it is observed that there is a reasonable to poor agreement between measured foF2 values and the IRI-storm model prediction values during main and recovery phases of the storms under investigation. As a result, in addition to other studies that have been carried out from different sectors, more studies are required to be carried out. This will enable IRI community to improve on the present performance of the model. In general the IRI-storm model predictions follow normal trend of the foF2 measured values but does not reproduce well the measured values.

Oyeyemi, E. O.; Adewale, A. O.; Adeloye, A. B.; Olugbon, B.

2013-11-01

317

Bats Avoid Radar Installations: Could Electromagnetic Fields Deter Bats from Colliding with Wind Turbines?  

Microsoft Academic Search

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

Barry Nicholls; Paul A. Racey

2007-01-01

318

XOQDOQ: computer program for the meteorological evaluation of routine effluent releases at nuclear power stations. Final report  

SciTech Connect

Provided is a user's guide for the US Nuclear Regulatory Commission's (NRC) computer program X0QDOQ which implements Regulatory Guide 1.111. This NUREG supercedes NUREG-0324 which was published as a draft in September 1977. This program is used by the NRC meteorology staff in their independent meteorological evaluation of routine or anticipated intermittent releases at nuclear power stations. It operates in a batch input mode and has various options a user may select. Relative atmospheric dispersion and deposition factors are computed for 22 specific distances out to 50 miles from the site for each directional sector. From these results, values for 10 distance segments are computed. The user may also select other locations for which atmospheric dispersion deposition factors are computed. Program features, including required input data and output results, are described. A program listing and test case data input and resulting output are provided.

Sagendorf, J.F.; Goll, J.T.; Sandusky, W.F.

1982-09-01

319

Evaluation of a Treadmill with Vibration Isolation and Stabilization (TVIS) for Use on the International Space Station  

NASA Technical Reports Server (NTRS)

A treadmill with vibration isolation and stabilization designed for the International Space Station (ISS) was evaluated during Shuttle mission STS-81. Three crew members ran and walked on the device, which floats freely in zero gravity. For the majority of the more than 2 hours of locomotion studied, the treadmill showed peak to peak linear and angular displacements of less than 2.5 cm and 2.5 deg, respectively. Vibration transmitted to the vehicle was within the microgravity allocation limits that are defined for the ISS. Refinements to the treadmill and harness system are discussed. This approach to treadmill design offers the possibility of generating 1G-like loads on the lower extremities while preserving the microgravity environment of the ISS for structural safety and vibration free experimental conditions.

McCrory, Jean L.; Lemmon, David R.; Sommer, H. Joseph; Prout, Brian; Smith, Damon; Korth, Deborah W.; Lucero, Javier; Greenisen, Michael; Moore, Jim

1999-01-01

320

Evaluation of a Treadmill with Vibration Isolation and Stabilization (TVIS) for use on the International Space Station.  

PubMed

A treadmill with vibration isolation and stabilization designed for the International Space Station (ISS) was evaluated during Shuttle mission STS-81. Three crew members ran and walked on the device, which floats freely in zero gravity. For the majority of the more than 2 hours of locomotion studied, the treadmill showed peak to peak linear and angular displacements of less than 2.5 cm and 2.5 degrees, respectively. Vibration transmitted to the vehicle was within the microgravity allocation limits that are defined for the ISS. Refinements to the treadmill and harness system are discussed. This approach to treadmill design offers the possibility of generating 1G-like loads on the lower extremities while preserving the microgravity environment of the ISS for structural safety and vibration free experimental conditions. PMID:11541844

McCrory, J L; Lemmon, D R; Sommer, H J; Prout, B; Smith, D; Korth, D W; Lucero, J; Greenisen, M; Moore, J; Kozlovskaya, I; Pestov, I; Stepansov, V; Miyakinchenko, Y; Cavanagh, P R

1999-08-01

321

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

322

Holographic surveillance radar  

Microsoft Academic Search

Since the 1940s, radar development has focused on narrow-beam, scanning sensors. A wide field of view has advantages in terms of extended acquisition time for any target, and when combined with a high Doppler sampling frequency can yield high-resolution Doppler spectra. Unambiguous range and Doppler can be achieved under certain circumstances, resulting in enhanced ability to evaluate the characteristics of

Gordon K. A. Oswald

2009-01-01

323

Evaluation of the radar response to land surfaces and volumes: Examination of theoretical models, target statistics, and applications  

NASA Technical Reports Server (NTRS)

Four areas of L-band radar remote sensing of terrain were examined: (1) the behavior of the radar backscatter coefficient of distributed surface and volumes as a function of the targets' dielectric and geometric parameters and as a fnction of their physical parameters; (2) the correspondence of the angular behavior of the relative backscatter coefficient as extracted from SIR-B digital imagery and truck mounted L-band scatterometer measurements for about 100 fields; (3) the statistical behavior of SIR-B image density for targets that appear homogeneous on Thematic Mapper (TM) optical imagery and/or color IR photography; and (4) the applicability of SIR-B imagery both alone and in conjunction with TM imagery for the classification and monitoring of land cover and renewable resources.

Ulaby, F. T.; Fung, A. K.; Dobson, M. C.; Cihlar, J.

1984-01-01

324

TRMM radar  

NASA Astrophysics Data System (ADS)

The results of a conceptual design study and the performance of key components of the Bread Board Model (BBM) of the Tropical Rainfall Measuring Mission (TRMM) radar are presented. The radar, which operates at 13.8 GHz and is designed to meet TRMM mission objectives, has a minimum measurable rain rate of 0.5 mm/h with a range resolution of 250 m, a horizontal resolution of about 4 km, and a swath width of 220 km. A 128-element active phased array system is adopted to achieve contiguous scanning within the swath. The basic characteristics of BBM were confirmed by experiments. The development of EM started with the cooperation of NASDA and CRL.

Okamoto, Kenichi

1993-05-01

325

TRMM radar  

NASA Technical Reports Server (NTRS)

The results of a conceptual design study and the performance of key components of the Bread Board Model (BBM) of the Tropical Rainfall Measuring Mission (TRMM) radar are presented. The radar, which operates at 13.8 GHz and is designed to meet TRMM mission objectives, has a minimum measurable rain rate of 0.5 mm/h with a range resolution of 250 m, a horizontal resolution of about 4 km, and a swath width of 220 km. A 128-element active phased array system is adopted to achieve contiguous scanning within the swath. The basic characteristics of BBM were confirmed by experiments. The development of EM started with the cooperation of NASDA and CRL.

Okamoto, Kenichi

1993-01-01

326

Long term monitoring of atmospheric depositions in a PO valley station. Evaluation of environmental effects  

Microsoft Academic Search

The availability of long term data concerning a period of six years has allowed for the first time a detailed study of the trend and evolution of atmospheric depositions, and the evaluation of their interaction with the surrounding environment. Moreover the work is preliminary to a forthcoming study where the local patterns of the exceedances of current deposition over critical

R. Francaviglia; A. Costantini; L. Morselli

1995-01-01

327

Planetary Radar Studies.  

National Technical Information Service (NTIS)

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 an...

T. W. Thompson J. A. Cutts

1981-01-01

328

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

329

Southeast oblique (southeast to northwest) of controlled area sentry station/visitor ...  

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

Southeast oblique (southeast to northwest) of controlled area sentry station/visitor center - Stanley R. Mickelsen Safeguard Complex, Controlled Area Sentry Station, On Access Road at entrance to Perimeter Acquisition Radar Site, Nekoma, Cavalier County, ND

330

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

331

Evaluation of 25 y of environmental monitoring data around Madras Atomic Power Station (MAPS), Kalpakkam, India.  

PubMed

The Environmental Survey Laboratory at Kalpakkam, India carries out elaborate monitoring programme involving atmospheric, terrestrial and aquatic samples for radioactivity to evaluate the impact of operating two pressurised heavy water reactors. This paper presents the evaluation of 25 y (1983-2008) data. Statistical analysis of the environmental data for different radionuclides showed that the data best fits log-normal distribution. The data analysed showed that fission products such as (137)Cs, (90)Sr and (131)I were due to global fallout only. A ratio of 0.2 was obtained for (90)Sr to (137)Cs in air filter samples, only during Chernobyl accident period. The transfer factor of (137)Cs and (90)Sr for rice was computed to be 0.23 and 0.03 and vegetables 0.25 and 0.10, respectively. Activation products (3)H and (41)Ar are the only radionuclides that are related to MAPS operation. A strong correlation (r = 0.9) was observed between (3)H activity in air and (3)H discharged to the atmosphere. A similar correlation (r = 0.8) was observed in (3)H concentration in seawater and (3)H discharged in the liquid waste. The annual internal dose due to (3)H and annual external dose due to (41)Ar evaluated in the last 25 y show that the members of the public received less than 2 % of the dose limit (1 mSv y(-1)) set by ICRP 72. PMID:20829204

Rajaram, S; Brindha, J Thulasi; Sreedevi, K R; Manu, Anitha; Thilakavathi, A; Ramkumar, S; Santhanakrishnan, V; Balagurunathan, M R; Jesan, T; Kannan, V; Hegde, A G

2010-12-01

332

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

333

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

334

Evaluation of atmospheric turbulence, energy exchanges and structure of convective cores during the occurrence of mesoscale convective systems using MST radar facility at Gadanki  

NASA Astrophysics Data System (ADS)

Mesoscale convective systems (MCSs) wreak lots of havoc and severe damage to life and property due to associated strong gusty winds, rainfall and hailstorms even though they last for an hour or so. Planetary boundary layer (PBL) plays an important role in the transportation of energy such as momentum, heat and moisture through turbulence into the upper layers of the atmosphere and acts as a feedback mechanism in the generation and sustenance of MCS. In the present study, three severe thunderstorms that occurred over mesosphere–stratosphere–troposphere (MST) radar facility at National Atmospheric Research Laboratory (NARL), Gadanki, India, have been considered to understand turbulence, energy exchanges and wind structure during the different epochs such as pre-, during and after the occurrence of these convective episodes. Significant changes in the turbulence structure are noticed in the upper layers of the atmosphere during the thunderstorm activity. Identified strong convective cores with varying magnitudes of intensity in terms of vertical velocity at different heights in the atmosphere discern the presence of shallow as well as deep convection during initial, mature and dissipative stages of the thunderstorm. Qualitative assessments of these convective cores are verified using available Doppler Weather Radar imageries in terms of reflectivity. The MST radar derived horizontal wind profiles are in good comparison with observed radiosonde winds. Significant variations in the surface meteorological parameters, sensible heat flux and turbulent kinetic energy as well as horizontal wind profiles are noticed during the different epochs of the convective activity. This work is useful in evaluating the performance of PBL schemes of mesoscale models in simulating MCS.

Satyanarayana, A. N. V.; Sultana, Sabiha; Narayana Rao, T.; Satheesh Kumar, S.

2014-06-01

335

Aging of nuclear station diesel generators: Evaluation of operating and expert experience: Workshop  

SciTech Connect

Pacific Northwest Laboratory (PNL) 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 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. The technical issues discussed most extensively were: man/machine interfaces, component interfaces, thermal gradients of startup and cooldown and the need for an accurate industry database for trend analysis of the diesel generator system.

Hoopingarner, K.R.; Vause, J.W.

1987-08-01

336

Health hazard evaluation report No. HETA 81-278-1371, Warrick Generating Station, Yankeetown, Indiana  

SciTech Connect

Environmental samples were collected to evaluate employee exposures to airborne concentrations of nitrogen dioxide, nitric oxide, sulfur dioxide, coal dust, fly ash, crystalline silica, and inorganic metals. In addition, gas leaks from the boilers were evaluated. While the majority of personal samples were below current criteria, a health hazard did exist for some employees exposed to sulfur dioxide, coal dust, and crystalline silica. Highest concentrations were obtained on samples worn by electrical and maintenance personnel and employees working on the positive pressure boiler (unit 4). In addition, the potential exists for employee exposure to boiler gases due to boiler leaks. Respiratory symptoms of cough, phlegm production, and wheezing were twice the expected rate for this group of workers. If preventive maintenance and engineering measures are employed, the occurrence of continued group health effects will likely be reduced. Recommendations are made in the body of the full report for an improved respiratory protection program, reducing leaks from boiler units, and for periodic environmental monitoring of the employees.

Zey, J.N.; Donohue, M.

1983-09-01

337

Ground Penetrating Radar (GPR) Analysis: Phase 1.  

National Technical Information Service (NTIS)

The objective of this work is to evaluate the feasibility of expanding the MDT's Ground Penetrating Radar (GPR) program to a broader range of pavement evaluation activities. Currently, MDT uses GPR in conjunction with its Falling Weight Deflectometer (FWD...

J. Puccinelli K. R. Maser

2009-01-01

338

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

339

Structural review of the San Onofre Nuclear Generation Station Unit 1 containment structure under combined loads. Systematic Evaluation Program  

SciTech Connect

This report is a structural assessment of the containment structure of the San Onofre Nuclear Generation Station Unit 1, performed for the Nuclear Regulatory Commission as part of the Systematic Evaluation Program (SEP). The San Onofre assessment focused on the overall structural integrity of the containment structure under a safe shutdown earthquake an a postulated design basis accident. The safe shutdown earthquake was represented by the Housner Spectra, scaled to 0.67 g peak ground acceleration. The postulated design basis accident was either a loss of coolant accident or a main steam line break. Several combined stresses were evaluated for their adherence to the 1980 edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code allowables. All the calculated stress intensities were found to be acceptable according to this code except the general primary membrane stress due to combined dead and pressure loads under level A service limits. Because the containment structure was previously tested under combined dead and pressure loads for a higher peak pressure than the one used here, this study concluded that it was acceptable.

Lo, T.Y.

1982-05-01

340

TRACALS Evaluation Report. Airport Surveillance and Precision Approach Radar AN/GPN-24(V), Initial Evaluation Report, RAF Upper Heyford, England 11 Mar-25 April 81.  

National Technical Information Service (NTIS)

This report presents data collected 11 March - 25 April 1981 to define the capabilities and limitations of the AN/GPN-24(V) Landing Control, Central facility at RAF Upper Heyford, England. This report includes descriptions of the useable radar coverage an...

R. M. Fisher M. E. Fisher

1981-01-01

341

TRACALS Evaluation Report. Precision Approach Radar, AN/GPN-22V, Initial Evaluation Report, Homestead AFB, Florida, 21 June-2 July 1981.  

National Technical Information Service (NTIS)

This report presents data collected 21 June - 2 July 1981 to define the capabilities and limitations of the High Power Precision Approach Radar (HI-PAR) facility at Homestead AFB, Florida. This report includes discussions of the usable PAR coverage and tr...

J. C. caballero L. G. Bryant

1981-01-01

342

Health hazard evaluation report No. HHE-80-233-793, Davis Bessie Nuclear Power Station, Toledo Edison Company, United Engineers and Contractors Company (UE and C), Oak Harbor, Ohio  

Microsoft Academic Search

Personal air samples were analyzed and employees were given medical evaluations at Davis Bessie Nuclear Power Station (SIC-4911) in Oak Harbor, Ohio. Requests for evaluation were made by a union representative of the United Engineers and Contractors and a union representative of employees of Toledo Edison Company, working on site at the power station, to evaluate employee skin and scalp

J. Cone; R. Hartle

1981-01-01

343

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

344

Adjusting weather radar data to rain gauge measurements with data-driven models  

NASA Astrophysics Data System (ADS)

Weather radar networks provide data with good spatial coverage and temporal resolution. Hence they are able to describe the variability of precipitation. Typical radar stations determine the rain rate for every square kilometre and make a full volume scan within about 5 minutes. A weakness however, is their often poor metering precision limiting the applicability of the radar for hydrological purposes. In contrast to rain gauges, which measure precipitation directly on the ground, the radar determines the reflectivity aloft and remote. Due to this principle, several sources of possible errors occur. Therefore improving the radar estimates of rainfall is still a vital topic in radar meteorology and hydrology. This paper presents data-driven approaches to improve radar estimates of rainfall by mapping radar reflectivity measurements Z to rain gauge data R. The analysis encompasses several input configurations and data-driven models. Reflectivity measurements at a constant altitude and the vertical profiles of reflectivity above a rain gauge are used as input parameters. The applied models are Artificial Neural Network (ANN), Model Tree (MT), and IBk a k-nearest-neighbour classifier. The relationship found between the data of a rain gauge and the reflectivity measurements is subsequently applied to another site with comparable terrain. Based on this independent dataset the performance of the data-driven models in the various input configurations is evaluated. For this study, rain gauge and radar data from the province of Styria, Austria, were available. The data sets extend over a two-year period (2001 and 2002). The available rain gauges use the tipping bucket principle with a resolution of 0.1 mm. Reflectivity measurements are obtained from the Doppler weather radar station on Mt. Zirbitzkogel (by courtesy of AustroControl GmbH). The designated radar is a high-resolution C-band weather-radar situated at an altitude of 2372 m above mean sea level. The data-driven models exhibit different performances on the various input configurations. Also data transformations were applied. The logarithm recommends itself for this transformation because the original Z-R-relationship is a power function, and the logarithm linearises this non-linear relationship. The MT which is a piecewise linear model performs best on logarithmised data. The IBk works well when transforming the reflectivity data in rain rate first. Overall the ANN exhibits the best performance showing a 10 % improvement in correlation and RMSE compared to the standard Z-R-relationship. When applying the vertical profile of reflectivity as input parameter, the correlation exhibits a more than 30 % improvement. The results indicate that the vertical profile of reflectivity provided by weather radars yields not only information on the type of precipitation, whether it is stratiform or convective. In data-driven models the vertical profile of reflectivity can help to get better estimates of rain rates on the ground, even in mountainous terrain without low-altitude radar measurements.

Teschl, Reinhard; Randeu, Walter; Teschl, Franz

2010-05-01

345

Radar data processing - A mature technique  

NASA Astrophysics Data System (ADS)

This paper gives an overview of the theory and applications of radar data processing (RDP) techniques. The following topics are considered: (1) review of the mathematical tools to derive the RDP algorithms; (2) description of the track-while-scan system; (3) tracking algorithms; (4) netted radar systems; (5) simulation techniques to evaluate the RDP performance; and (6) applications of RDP.

Farina, A.

346

A simulation program for the Firefinder radar  

Microsoft Academic Search

Thales-Raytheon Systems' Firefinder PC Simulation (PCS) tool allows a rapid simulated evaluation of Firefinder radar performance from a personal desktop computer. Firefinder radars are designed to track hostile rocket, artillery and mortar projectiles in order to accurately estimate weapon ground location. The Firefinder tactical code is used within PCS. This design provides a low risk path to rapid prototyping and

Boris Abramov; H. Walker Birrell; Eric P. Lam; Randall C. Schalk

2008-01-01

347

System performance prediction of Firefinder radar  

Microsoft Academic Search

Thales Raytheon Systems' PC Simulation (PCS) tool allows a rapid simulated evaluation of Firefinder radar performance from a personal desktop computer. Firefinder radars are designed to track hostile rocket, artillery and mortar (RAM) projectiles in order to accurately estimate weapon ground location. The Firefinder tactical code is used within PCS. This design provides a low risk path to rapid prototyping

Eric P. Lam; H. Walker Birrell; Julianna Magallon

2010-01-01

348

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

349

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

350

Safety Evaluation Report Related to the Operation of Beaver Valley Power Station, Unit 2, Docket No. 50-412, Duquesne Light Company, et al. Supplement No. 2.  

National Technical Information Service (NTIS)

Supplement No. 2 to the Safety Evaluation Report for the application filed by Duquesne Light Company, et al., for license to operate the Beaver Valley Power Station, Unit 2 (Docket No. 50-412), located in Beaver County, Pennsylvania, has been prepared by ...

1986-01-01

351

Safety Evaluation Report: Related to the License Renewal of Three Mile Island Nuclear Station, Unit. 1, Docket No. 50-289.  

National Technical Information Service (NTIS)

This safety evaluation report (SER) documents the technical review of the Three Mile Island Nuclear Station, Unit 1, (TMI-1) license renewal application (LRA) by the U.S. Nuclear Regulatory Commission (NRC) staff (the staff). By letter dated January 08, 2...

2009-01-01

352

Experimental phased array radar ELRA with extended flexibility  

Microsoft Academic Search

An update of a phased array radar 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

I. Groger; W. Sander; W.-D. Wirth

1990-01-01

353

Radar-cross-section reduction of wind turbines. part 1  

Microsoft Academic Search

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

Billy C. Brock; Hung Loui; Jacob J. McDonald; Joshua A. Paquette; David A. Calkins; William K. Miller; Steven E. Allen; Paul Gilbert Clem; Ward E. Patitz

2012-01-01

354

Equatorial Radar System.  

National Technical Information Service (NTIS)

A large clear air radar with the sensitivity of an incoherent scatter radar for observing the whole equatorial atmosphere up to 1000 km altitude is now being designed in Japan. The radar, called the Equatorial Radar, will be built in Pontianak, Kalimantan...

S. Rukao T. Tsuda T. Sato S. Kato

1989-01-01

355

Wind shear radar simulation  

NASA Technical Reports Server (NTRS)

Viewgraphs used in a presentation on wind shear radar simulation are given. Information on a microburst model of radar reflectivity and wind velocity, radar pulse output, the calculation of radar return, microburst power spectrum, and simulation plans are given. A question and answer session is transcribed.

Britt, Charles L.

1988-01-01

356

Radar cross section  

Microsoft Academic Search

The technological evolution in signal processing that has been made in last decades led to improvements in radar performances. Increasing the radar range by improving its sensitivity has been made by the designers of aircraft and other military systems to try to decrease the radar cross section of these types of equipment. The radar cross section is a matter of

L. Nicolaescu; Teofil Oroian

2001-01-01

357

The spaceborne imaging radar experiments  

NASA Technical Reports Server (NTRS)

The Spaceborne Imaging Radar (SIR), a multifrequency multipolarization synthetic aperture radar (SAR) with variable image geometry, is being developed, as part of the Space Station's Earth Observing System (Eos), for the launching of the SIR-C and SIR-D planned for the early 1990's. This SAR will operate in L-band, C-band and X-band, with quadpolarization available for the L-band and C-band. Multiincidence data will be acquired using electronic beam steering and other imaging geometries by mechanically pitching, yawing, and rolling the antenna. The present SIR-C design includes a bandwidth of 20 MHz, to provide better resolution than that available on SIR-B with four looks, and a 10-MHz bandwidth for a low resolution mode which will increase the swath for a given available data rate.

Cimino, J. B.

1987-01-01

358

Health-hazard evaluation report HETA 89-262-1994, Chapman Corporation, Albright Power Station, Albright, West Virginia  

SciTech Connect

In response to a request from the International Brotherhood of Electrical Workers, Local 425, an evaluation was made of possible asbestos exposures to electrical workers employed by Chapman Corporation engaged in electrical rewiring tasks on a boiler at the Albright Power Station, Albright, West Virginia. At the time the survey was undertaken, a complete refurbishing of boiler number 3 was being performed, part of which included an asbestos-abatement project. The electricians in question did not work inside the asbestos-containment area during the survey, but they did perform work outside and around the asbestos-containment area. Air sampling results indicated that asbestos-fiber releases did occur outside the containment area. Bulk samples of settled dust revealed asbestos contamination in the work areas surrounding the boiler. There were several deficiencies in the abatement program, including the lack of adequate containment and breaches in the enclosure. The study concludes that workers in the vicinity of this boiler had potential exposure to airborne asbestos fibers. Recommendations are made to help management representatives minimize potential risks through the establishment of a comprehensive asbestos-abatement program and policies.

Stephenson, R.L.

1989-11-01

359

Space station  

NASA Technical Reports Server (NTRS)

The history of American space flight indicates that a space station is the next logical step in the scientific pursuit of greater knowledge of the universe. The Space Station and its complement of space vehicles, developed by NASA, will add new dimensions to an already extensive space program in the United States. The Space Station offers extraordinary benefits for a comparatively modest investment (currently estimated at one-ninth the cost of the Apollo Program). The station will provide a permanent multipurpose facility in orbit necessary for the expansion of space science and technology. It will enable significant advancements in life sciences research, satellite communications, astronomy, and materials processing. Eventually, the station will function in support of the commercialization and industrialization of space. Also, as a prerequisite to manned interplanetary exploration, the long-duration space flights typical of Space Station missions will provide the essential life sciences research to allow progressively longer human staytime in space.

Stewart, Donald F.; Hayes, Judith

1989-01-01

360

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

361

Storm Water Toxicity Evaluation Conducted at Naval Station San Diego, Naval Submarine Base San Diego, Naval Amphibious Base Coronado, and Naval Air Station North Island.  

National Technical Information Service (NTIS)

This report describes results of a study to evaluate the toxicity of industrial storm water discharges from U.S. Navy facilities bordering San Diego Bay. The study was conducted to support a request from the San Diego Regional Water Quality Control Board ...

C. Katz E. Arias G. Rosen

2006-01-01

362

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

363

An overview of developments and applications of oceanographic radar networks in Asia and Oceania countries  

NASA Astrophysics Data System (ADS)

More than 110 radar stations are in operation at the present time in Asia and Oceania countries, which is nearly half of all the existing radar stations in the world, for purposes related to marine safety, oil spill response, tsunami warning, coastal zone management and understanding of ocean current dynamics, depending mainly on each country's coastal sea characteristics. This paper introduces the oceanographic radar networks of Australia, China, Japan, Korea and Taiwan, presented at the 1st Ocean Radar Conference for Asia (ORCA) held in May 2012, Seoul, Korea, to share information about the radar network developments and operations, knowledge and experiences of data management, and research activity and application of the radar-derived data of neighbouring countries. We hope this overview paper may contribute as the first step to promotion of regional collaborations in the radar observations and data usages and applications in order to efficiently monitor the coastal and marginal sea waters along the western Pacific Ocean periphery.

Fujii, Satoshi; Heron, Malcolm L.; Kim, Kuh; Lai, Jian-Wu; Lee, Sang-Ho; Wu, Xiangbai; Wu, Xiongbin; Wyatt, Lucy R.; Yang, Wen-Chang

2013-03-01

364

Inferring radar mode changes from elementary pulse features using fuzzy ARTMAP classification  

Microsoft Academic Search

A method for radar mode inference using fuzzy ARTMAP classification is presented. In this method elementary radar parameters, pulse width (PW) and pulse repetition interval (PRI) originating from a radar operating in a certain mode is input to a fuzzy ARTMAP classifier. Radar parameters were simulated at different signal-to-noise ratios (SNRs) to train and evaluate the fuzzy ARTMAP classifier without

PIETER F. POTGIETER; JAN C. OLIVIER

2007-01-01

365

Evaluation of cloud microphysics simulated by a meso-scale model coupled with a bin-based scheme using observation data by W-band radar  

Microsoft Academic Search

Radar reflectivity factors measured by W-band radars were directly compared with the corresponding values calculated from a three-dimensional non-hydrostatic meso-scale model coupled with a bin-based cloud microphysical scheme. Three case studies are studied: one targets a part of shipborne observation using 95 GHz Doppler radar over the Pacific Ocean near Japan in May 2001; other two aim at two short

T. Iguchi; N. Teruyuki; A. Khain; K. Saito; T. Takemura; H. Okamoto; T. Nishizawa; W. Tao

2009-01-01

366

The large-scale spatio-temporal variability of precipitation over Sweden observed from the weather radar network  

NASA Astrophysics Data System (ADS)

Using measurements from the national network of 12 weather radar stations for the 11-year period 2000-2010, we investigate the large-scale spatio-temporal variability of precipitation over Sweden. These statistics provide useful information to evaluate regional climate models as well as for hydrology and energy applications. A strict quality control is applied to filter out noise and artifacts from the radar data. We focus on investigating four distinct aspects: the diurnal cycle of precipitation and its seasonality, the dominant timescale (diurnal versus seasonal) of variability, precipitation response to different wind directions, and the correlation of precipitation events with the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO). When classified based on their intensity, moderate- to high-intensity events (precipitation > 0.34 mm/3 h) peak distinctly during late afternoon over the majority of radar stations in summer and during late night or early morning in winter. Precipitation variability is highest over the southwestern parts of Sweden. It is shown that the high-intensity events (precipitation > 1.7 mm/3 h) are positively correlated with NAO and AO (esp. over northern Sweden), while the low intensity events are negatively correlated (esp. over southeastern parts). It is further observed that southeasterly winds often lead to intense precipitation events over central and northern Sweden, while southwesterly winds contribute most to the total accumulated precipitation for all radar stations. Apart from its operational applications, the present study demonstrates the potential of the weather radar data set for studying climatic features of precipitation over Sweden.

Devasthale, A.; Norin, L.

2014-06-01

367

The large-scale spatio-temporal variability of precipitation over Sweden observed from the weather radar network  

NASA Astrophysics Data System (ADS)

Using measurements from the national network of 12 weather radar stations for the last decade (2000-2010), we investigate the large-scale spatio-temporal variability of precipitation over Sweden. These statistics provide useful information to evaluate regional climate models as well as for hydrology and energy applications. A strict quality control is applied to filter out noise and artifacts from the radar data. We focus on investigating four distinct aspects namely, the diurnal cycle of precipitation and its seasonality, the dominant time scale (diurnal vs. seasonal) of variability, precipitation response to different wind directions, and the correlation of precipitation events with the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO). When classified based on their intensity, moderate to high intensity events (precipitation > 0.34 mm (3 h)-1) peak distinctly during late afternoon over the majority of radar stations in summer and during late night or early morning in winter. Precipitation variability is highest over the southwestern parts of Sweden. It is shown that the high intensity events (precipitation > 1.7mm (3 h)-1) are positively correlated with NAO and AO (esp. over northern Sweden), while the low intensity events are negatively correlated (esp. over southeastern parts). It is further observed that southeasterly winds often lead to intense precipitation events over central and northern Sweden, while southwesterly winds contribute most to the total accumulated precipitation for all radar stations. Apart from its operational applications, the present study demonstrates the potential of the weather radar data set for studying climatic features of precipitation over Sweden.

Devasthale, A.; Norin, L.

2013-12-01

368

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

369

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.

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

2013-01-01

370

Fifty years of radar  

NASA Astrophysics Data System (ADS)

A development history of radar technology is presented, with attention to the driving of radar system design advances by the emergence of such weapon systems as long range aircraft and cruise missiles in World War II and the range of current applications for state-of-the-art radar techniques. The applications noted encompass over-the-horizon backscatter radars for aircraft detection at 500-1800 nmi ranges, ultralow sidelobe antenna military radars, a long range, frequency scanning three-dimensional S-band radar, a shipborne phased array radar for the collection of exoatmospheric and endoatmospheric data on ballistic missile reentry vehicles, multimission/multimode X-band fighter aircraft radars, and phased array air defense radars.

Skolnik, M. I.

1985-02-01

371

Radar attenuation in desert soil  

Microsoft Academic Search

Soil properties make a significant impact in the observed responses of various sensors for subsurface target detection. Ground penetrating radars (GPRs) have been extensively researched as a tool for subsurface target detection. A key soil parameter of interest for evaluating GPR performance is the soil attenuation rate. The information about the soil attenuation rate coupled with target properties (size, shape,

Gary Koh

2008-01-01

372

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

373

Ocean monitoring by satellite radar altimeter  

NASA Astrophysics Data System (ADS)

The end-to-end operational mission design, establishing the validity of monitoring the ocean with light weight altimeter satellites, is presented. A compact, light weight, low power radar altimeter instrument that achieves full Geosat measurement capability in one-half weight and power (95 pounds and 69 watts) is described. An operational light-weight radar altimeter satellite mission includes a radiometer for water vapor correction, a GPS receiver for precision orbits, and a tactical data downlink to terminals on major Navy ships and shore stations.

Finkelstein, Jay L.; Kilgus, Charles C.

1992-03-01

374

Lokalt Foervarningssystem med LS-Radar (Local Early Warning Systems with LS-Radar),  

National Technical Information Service (NTIS)

The report gives a description of a complement to the local optical early warning system. 'The LS-system' (LS = local optical early warning station) is suggested to use simple marine radars equipped with MTI circuits. It is possible for land based MTI-rad...

E. Arvidsson

1988-01-01

375

Characterization of ice cloud properties obtained by shipborne radar/lidar over the tropical western Pacific Ocean for evaluation of an atmospheric general circulation model  

NASA Astrophysics Data System (ADS)

This study analyzed 95-GHz radar/lidar data collected from the R/V Mirai over the tropical western Pacific to characterize the vertical distribution of ice cloud effective radius reff, ice water content IWC, and in-cloud vertical velocity of the region in conjunction with weather regimes classified by International Satellite Cloud Climatology Project (ISCCP) cluster analysis. Ice clouds observed from the Mirai were roughly consistent with the ISCCP weather regimes; more convectively active regimes had larger amounts of high cloud consisting of deeper cloud with larger ice water path (IWP) and precipitating ice fraction. Ice cloud microphysics of the Center for Climate System Research, National Institute for Environmental Studies, Frontier Research Center for Global Change atmospheric general circulation model (AGCM) was then evaluated using the radar-lidar simulator and ISCCP weather regimes for comparison of the statistics at different scales. The model tended to produce a high cloud fraction that was two times larger in the cirrus regimes but 50% lower in the deepest convective regime. The simulated IWP could only weakly reproduce the observed variety and generally underestimated the observed values despite the weather regimes. Cutoff in the simulated grid mean IWC around 0.1 g-3 was too small, especially above 11 km. The AGCM successfully predicted the observed frequency distribution for reff above 11 km, but produced large overestimation in the peak value below 11 km due to the excessively large fraction of reff ˜100 ?m. Establishing a cutoff for cloud ice at reff > 120 ?m was found to be quite reasonable, although it would miss some of the larger particles that were observed.

Sato, Kaori; Okamoto, Hajime; Takemura, Toshihiko; Kumagai, Hiroshi; Sugimoto, Nobuo

2010-08-01

376

Hallett Station Cleanup  

NSF Publications Database

Title : Hallett Station Cleanup Type : Antarctic EAM NSF Org: OD / OPP Date : November 1, 1993 File : opp94009 National Science Foundation Office of Polar Programs ENVIRONMENTAL DOCUMENT AND FINDING OF NO SIGNIFICANT AND NOT GREATER THAN MINOR OR TRANSITORY IMPACT Hallett Station Cleanup - Phase I Site Stabilization NOVEMBER 1, 1993 I. Findings The National Science Foundation (NSF) has prepared an Initial Environmental Evaluation (IEE) and an Environmental Assessment (EA) as a combined ...

377

An evaluation of water-quality data obtained at four streamflow daily-record stations in Idaho  

USGS Publications Warehouse

Chemical data for four stream-gaging stations in Idaho, each having 6 to 22 years of available records, were analyzed to determine functional relations between concentrations of the major inorganic constituents, specific conductance, and stream discharge. Three of the four stations had sufficient available record for assessing changes in constituent relations with time. The records for each long-term station were subdivided into segments of approximately 5 years each. Plots and regression equations were derived for each record segment to show the relations of each major constituent value to levels of specific conductance and stream discharge. At only one stations, Boise River at Notus, was there was an apparent significant change in chemical characteristics with time. Between 1940 and 1951, the percentages of chloride and sulfate in solution at this station declined appreciably and were largely replaced by bicarbonate. In general, there were highly significant correlations between the major inorganic ions and specific conductance, although those observed at Bear River at Border were distinctly poorer than those observed for the other stations. Corresponding correlations between the major ions and discharge were almost always less significant than those observed between the same ions and specific conductance. The common ion-discharge relations observed on the Snake River near Heise were more highly correlated before 1957 than thereafter--probably because of changes induced by the construction of Palisades Dam. A similar decline in correlation of common ion-discharge relations was observed at the Snake River at King Hill station after 1957, and this also might be attributable to changes in water regulation at various upstream impoundments.

Dyer, Kenneth L.

1973-01-01

378

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

379

Evaluation of local versus remote areas of CH4 sources at IC3 stations using a combined analysis of 222Rn tracer and Atmospheric Particles Transport Model (APTM) results. Application at the Gredos and Iruelas station (GIC3), Spain.  

NASA Astrophysics Data System (ADS)

The Gredos and Iruelas station (GIC3) is part of the IC3 (Institut Català de Ciències del Clima) atmospheric monitoring network. This station is located in the Gredos Natural Park (40.22º N; -5.14º E) in the Spanish central plateau. The IC3 network consists of 8 stations distributed across Spain. It has been developed with the aim of studying climatic processes and the responses of impacted systems at different temporal and spatial scales. Since 2012, CO2, CH4, 222Rn (a natural radioactive gas) and meteorological variables are continuously measured at GIC3 at 20 m a.g.l. (1100 m a.s.l.). Furthermore, 4-days backward simulations are run daily for each IC3 station using the FLEXPART model. Simulations use ECMWF meteorological data as input and a horizontal spatial resolution of 0.2 degrees. The Laboratory of the Atmosphere and the Oceans (LAO) of the IC3 has elaborated a new approach to evaluate the local or remote greenhouse gases emissions using the radon gas as tracer and the atmospheric particles transport model FLEXPART under nocturnal and winter conditions. The ratios between the normalized and rescaled measured concentrations of CH4 and 222Rn during nocturnal hours (21h, 00h, 03h and 06h) and in the winter season, in order to reduce local radon flux and methane source due to seasonal livestock migration and to get stable atmospheric conditions, have been analyzed in relation to the influence of the local area (set to an initial dimension of 20x20 km2). The influence area (IA) has been defined as the percentage of the ratio between the residence time of the fictitious particles released in FLEXPART simulations over the area of interest (TLocal Area) and the residence time of these fictitious particles over the total area included in the simulation (TTotal Area ), i.e. IA = (TLocal Area/TTotal Area * 100). First results considering an area of interest of 20x20 km2 show a linear increase of the radon concentration with IA until reaching a maximum when IA is about 50%. This can be explained taking into consideration that GIC3 station area has high radon exhalation rates according to the literature and the radon uptake from air masses can reach a plateau. On the other hand, CH4 concentrations do not seem to be significantly influenced by IA. The log-log plot between the ratio of normalized and rescaled gases concentrations (CH4/222Rn) and the percentage of the influence of the local area shows a negative linear relation under nocturnal and winter conditions which could depend on the increase of the radon not compensated by the methane increase. Indeed, when the influence of the local area of Gredos and Iruelas station is under the 20% the major methane contribution seems to come from outside the 20x20 km2 IA. Results considering a larger area of interest (up to 80x80 km2) may indicate possible methane sources detected at the GIC3 station.

Grossi, Claudia; Morguí, Josep Anton; Curcoll, Roger; Àgueda, Alba; Arnold, Delia; Batet, Oscar; Cañas, Lidia; Nofuentes, Manel; Occhipinti, Paola; Vogel, Felix; Vargas, Arturo; Rodó, Xavier

2014-05-01

380

Imaging radar observations of Askja Caldera, Iceland  

NASA Technical Reports Server (NTRS)

A 'blind' test involving interpretation of computer-enhanced like- and cross-polarized radar images is used to evaluate the surface roughness of Askja Caldera, a large volcanic complex in central Iceland. The 'blind' test differs from earlier analyses of radar observations in that computer-processes images and both qualitative and quantitative analyses are used. Attention is given to photogeologic examination and subsequent survey-type field observations, along with aerial photography during the field trip. The results indicate that the 'blind' test of radar interpretation of the Askja volcanic area can be considered suitable within the framework of limitations of radar data considered explicitly from the onset. The limitations of the radar techniques can be eliminated by using oblique-viewing conditions to remove geometric distortions and slope effects.

Malin, M. C.; Evans, D.; Elachi, C.

1978-01-01

381

A new method for combining radar and raingauge data: Modified Conditional Merging  

NASA Astrophysics Data System (ADS)

The estimation of rainfall fields, especially its spatial distribution and position is a crucial task both for rainfall nowcasting and for modeling catchment response to rainfall. Some studies of literature about multisensor have suggested that discharge estimations are improved when radar and rain gauge data are combined to estimate input rainfall fields.Sinclair and Peagram (2004) have proposed the Conditional Merging (CM) technique, a merging algorithm which extract the information content from the observed data and use it within an interpolation method to obtain the rainfall maps. The idea is to combine the "real", but punctual amount of rainfall measured by raingauges with the structure of covariance and correlation of rainfall maps estimated from remote sensors (radar network or satellite constellation). In this work is studied an enhanced algorithm based on CM, called Modified Conditional Merging.. The main innovation respect to classical CM is the estimation of the structure of covariance and the length of spatial correlation ?, for every raingauge, directly from the cumulated radar rainfall fields. The domain of application is the Italy, where are both available a dense network of raingauge measurements (about 2500 stations) and a QPE estimated by the Italian Radar composite. The MCM algorithm can be used in real-time over the whole domain to produce hourly the optimal rainfall maps. An application to several test cases together with the evaluation of algorithm performances are presented and discussed.

Pignone, Flavio; Rebora, Nicola; Silvestro, Francesco

2013-04-01

382

Estimation of rainfall field by combining radar data and raingauge observations: the modified conditional merging technique  

NASA Astrophysics Data System (ADS)

The estimation of rainfall fields, especially its spatial distribution and position is a crucial task both for rainfall nowcasting and for modeling catchment response to rainfall. Some studies of literature about multisensor datafusion prove that combining data from raingauges and radar represents the best way to obtain an enhanced ad more reliable estimation of QPE and of the associated river discharge. Sinclair and Peagram (2004) have proposed the Conditional Merging (CM) technique, a merging algorithm which extract the information content from the observed data and use it within an interpolation method to obtain the rainfall maps. The raingauges provide a punctual measure of the ground-observed rainfall while the remote sensors (radar network or satellite constellation) supply rainfall estimation maps which give an idea of the correlation and structure of covariance of the observed field. In this work is presented an algorithm called Modified Conditional Merging that is based on CM and which is used for real-time estimation of the optimal rainfall maps. The area of interest is Italy, where are both available a dense network of raingauge measurements (about 2000 stations) and a QPE estimated by the Italian Radar composite. The main innovation respect to classical CM is to estimate the structure of covariance and the length of spatial correlation ?, for every raingauge, directly from the cumulated radar rainfall fields. An application to several test cases together with the evaluation of algorithm performances are presented and discussed.

Pignone, F.; Rebora, N.; Silvestro, F.

2012-04-01

383

TRACALS Evaluation Report. Airport Surveillance Radar AN/GPN-12. Special Evaluation Report. Salt lake City International Airport and Wendover Auxiliary Airfield, Utah, 3 and 6-15 June 1981.  

National Technical Information Service (NTIS)

This report presents data collected to define the capabilities and limitations of the radar facility at Wendover AAF, Utah, the microwave remoting, and the indicators at Salt Lake City IAP, Utah. This report includes descriptions of the useable radar cove...

J. C. Caballero K. M. Slater

1981-01-01

384

Evaluation of the Submerged Demineralizer System (SDS) flowsheet for decontamination of high-activity-level water at the Three Mile Island Unit 2 Nuclear Power Station  

SciTech Connect

This report discusses the Submerged Demineralizer System (SDS) flowsheet for decontamination of the high-activity-level water at the Three Mile Island Unit 2 Nuclear Power Station was evaluated at Oak Ridge National Laboratory in a study that included filtration tests, ion exchange column tests, and ion exchange distribution tests. The contaminated waters, the SDS flowsheet, and the experiments made are described. The experimental results were used to predict the SDS performance and to indicate potential improvements.

Campbell, D.O., Collins, E.D., King, L.J., Knauer, J.B.

1980-07-01

385

31. Construction Drawing: Fort Custer Air Force Station, Battle Creek, ...  

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

31. Construction Drawing: Fort Custer Air Force Station, Battle Creek, Michigan, Emergency Power Building, Floor Plans and Details, USACOE, no date. - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

386

30. Construction Drawing: Fort Custer Air Force Station, Battle Creek, ...  

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

30. Construction Drawing: Fort Custer Air Force Station, Battle Creek, Michigan, Emergency Power Building, Sections and Elevations, USACOE, no date. - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

387

Radar, Target and Ranging.  

National Technical Information Service (NTIS)

This Test Operations Procedure (TOP) provides conventional test methods employing conventional test instrumentation for testing conventional radars. Single tests and subtests designed to test radar components, transmitters, receivers, antennas, etc., and ...

1984-01-01

388

Radar Absorbing Material Design.  

National Technical Information Service (NTIS)

Low observable platforms have extremely low radar cross section specifications that cannot be achieved by shaping alone. The application of radar absorbing material is necessary, in which case the appropriate constitutive parameters and thickness must be ...

C. K. Yuzcelik

2003-01-01

389

The MST radar technique  

NASA Technical Reports Server (NTRS)

The coherent radar technique is reviewed with special emphasis to mesosphere-stratosphere-troposphere (MST) radars operating in the VHF band. Some basic introduction to Doppler radar measurements and the radar equation is followed by an outline of the characteristics of atmospheric turbulence, viewed from the scattering and reflection processes of radar signals. Radar signal acquisition and preprocessing, namely coherent detection, digital sampling, pre-integration and coding, is briefly discussed. The data analysis is represented in terms of the correlation and spectrum analysis, yielding the essential parameters: power, signal-to-noise ratio, average and fluctuating velocity and persistency. The techniques to measure wind velocities, viz. the different modes of the Doppler method as well as the space antenna method are surveyed and the feasibilities of the MST radar interferometer technique are elucidated. A general view on the criteria to design phased array antennas is given. An outline of the hardware of a typical MST radar system is presented.

Roettger, J.

1984-01-01

390

Equatorial radar system  

Microsoft Academic Search

A large clear air radar with the sensitivity of an incoherent scatter radar for observing the whole equatorial atmosphere up to 1000 km altitude is now being designed in Japan. The radar will be built in Pontianak, West Kalimantan, Indonesia (0.03 deg N, 109.29 deg E). The system is a 47-MHz monostatic Doppler radar with an active phased array configuration

Shoichiro Fukao; Toshitaka Tsuda; Toru Sato; Susumu Kato

1990-01-01

391

Radar observations of asteroids  

NASA Technical Reports Server (NTRS)

The type of information that can be obtained from radar observations of asteroids includes sizes, shapes, spin vectors, and such surface characteristics as the decimeter-scale morphology, topographic relief, regolith porosity, and metal concentration. This paper describes the two radar facilities active in asteroid studies (the Arecibo Observatory in Puerto Rico and the Goldstone Radar in California) and techniques used in radar observations of asteroids. Results available for main-belt and near-earth asteroids are discussed.

Ostro, Steven J.

1989-01-01

392

Fifty years of radar  

Microsoft Academic Search

A development history of radar technology is presented, with attention to the driving of radar system design advances by the emergence of such weapon systems as long range aircraft and cruise missiles in World War II and the range of current applications for state-of-the-art radar techniques. The applications noted encompass over-the-horizon backscatter radars for aircraft detection at 500-1800 nmi ranges,

M. I. Skolnik

1985-01-01

393

Application of electromagnetic environment simulation to radar performance testing, operability assessment and training  

NASA Astrophysics Data System (ADS)

Automatic target detection and tracking features in radar sensors affect the testing and evaluation of radar performance, the assessment of equipment readiness for verification of sensor, command/control and engagement systems' operability, and operational training of radar operators and sensor management teams. Attention is presently given to Radar Environment Simulator Systems (RESSs), which facilitate the interjection of testing and training scenarios into the front end of radar receivers. RESSs are applicable to shipboard, air, and ground environments.

Michaels, J. F.

394

Harmonic Radar Literature Harmonisk Radar - en Litteraturstudie.  

National Technical Information Service (NTIS)

A harmonic radar sends on a given frequency f sub o and receives on another frequency usually 3 f sub o. The overtone is generated on joints between the metal parts of the radar target. The generated high harmonic frequency is very weak, which is why this...

B. Jansson

1980-01-01

395

Harmonic radar literature  

Microsoft Academic Search

A harmonic radar sends on a given frequency f sub o and receives on another frequency usually 3 f sub o. The overtone is generated on joints between the metal parts of the radar target. The generated high harmonic frequency is very weak, which is why this radar has an extremely low range of detection. Natural objects in the target

B. Jansson

1980-01-01

396

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

397

Automatic Radar Waveform Recognition  

Microsoft Academic Search

In this paper, a system for automatically recognizing radar waveforms is introduced. This type of techniques are needed in various spectrum management, surveillance and cognitive radio or radar applications. The intercepted radar signal is classified to eight classes based on the pulse compression waveform: linear frequency modulation (LFM), discrete frequency codes (Costas codes), binary phase, and Frank, P1, P2, P3,

Jarmo Lundn; Visa Koivunen

2007-01-01

398

Controlling radar signature  

Microsoft Academic Search

Low observable technologies for military and tactical aircraft are reviewed including signature-reduction techniques and signal detection\\/jamming. Among the applications considered are low-signature sensors and the reduction of radar cross section in conjunction with radar-absorbing structures and materials. Technologies for reducing radar cross section are shown to present significant technological challenges, although they afford enhanced aircraft survivability.

Foulke

1992-01-01

399

Space station propulsion technology  

NASA Technical Reports Server (NTRS)

The progress on the Space Station Propulsion Technology Program is described. The objectives are to provide a demonstration of hydrogen/oxygen propulsion technology readiness for the Initial Operating Capability (IOC) space station application, specifically gaseous hydrogen/oxygen and warm hydrogen thruster concepts, and to establish a means for evolving from the IOC space station propulsion to that required to support and interface with advanced station functions. The evaluation of concepts was completed. The accumulator module of the test bed was completed and, with the microprocessor controller, delivered to NASA-MSFC. An oxygen/hydrogen thruster was modified for use with the test bed and successfully tested at mixture ratios from 4:1 to 8:1.

Briley, G. L.

1986-01-01

400

Evaluation of C. P. Crane Generating Station thermal discharge effects on the finfish community, summer 1980. Final report  

SciTech Connect

The objective of this study was to verify if patterns of abundance observed during Summer, 1980 reflected response to the thermal discharge of the power plant or if they might be attributed to other factors. Fish were collected by both trawling and gill nets at seven stations. Results indicated that the patterns previously attributed to thermal effects may be better explained by habitat preference.

Not Available

1981-01-01

401

An evaluation of the effects of local control station design configurations on human performance and nuclear power plant risk  

Microsoft Academic Search

A human factors analysis was performed to assess how identified upgrades to local control stations (LCSs) in nuclear power plants affect both human performance and plant risk. Upgrades in the design of individual control panels and overall improvement of functional centralization were considered. The analysis methodology was accomplished in four stages. First, a list of LCS human engineering design deficiencies

J. OHara; C. Ruger; J. Higgins; W. Luckas; D. Crouch

1990-01-01

402

Use of nautical radar as a wave monitoring instrument  

Microsoft Academic Search

Common marine X-Band radars can be used as a sensor to survey ocean wave fields. The wave field images provided by the radars are sampled and analysed by a wave monitoring system (called WaMoS II) developed by the German research institute GKSS. This measuring system can be mounted on a ship, on offshore stations or at coastal locations. The measurement

José Carlos Nieto Borge; Konstanze Reichert; Jürgen Dittmer

1999-01-01

403

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

404

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

405

Use of Borehole-Radar Methods to Monitor a Steam-Enhanced Remediation Pilot Study at a Quarry at the Former Loring Air Force Base, Maine.  

National Technical Information Service (NTIS)

Single-hole radar reflection and crosshole radar tomography surveys were used in conjunction with conventional borehole-geophysical methods to evaluate the effectiveness of borehole-radar methods for monitoring the movement of steam and heat through fract...

C. Gregoire J. W. Lane P. K. Joesten

2006-01-01

406

Health Hazard Evaluation Report: HETA-2007-0055-3073, Huntington Coach Corporation, Huntington Station, New York, October 2008. Evaluation of Employee Exposures in a Bus Maintenance Shop.  

National Technical Information Service (NTIS)

NIOSH received a confidential employee request for an HHE at the Huntington Coach Corporation bus repair and body shops, Huntington Station, New York, in November 2006. Employees were concerned that exposures to cleaning solvents, paint vapors, diesel exh...

A. Sussell L. Tapp

2008-01-01

407

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

2007-08-16

408

Synthetic Data for Testing TRMM Radar Algorithms  

NASA Technical Reports Server (NTRS)

Test data are required to test algorithms for the TRMM Precipitation Radar. These data are needed to test the design of the computer codes under development for the operational phase of the mission, and also to test and evaluate alternative or improved precipitation retrieval algorithms. Over a number of years we have developed and used a 3-dimensional radar model for simulating spaceborne precipitation radars. We have adapted this code to produce data files as close as possible to the TRMM file specifications. In this paper, we will describe the model as it is currently implemented, and show some samples of the synthetic data sets.

Jones, Jeffrey A.; Meneghini, Robert; Iguchi, Toshio; Tao, Wei-Kuo

1997-01-01

409

The Mid-Canada Radar Line and First Nations' people of the James Bay region, Canada: an evaluation using log-linear contingency modelling to analyze organochlorine frequency data.  

PubMed

Abandoned radar line stations in the North American arctic and sub-arctic regions are point sources of contamination, especially for PCBs. Few data exist with respect to human body burden of organochlorines (OCs) in residents of communities located in close proximity to these radar line sites. We compared plasma OC concentration (unadjusted for total lipids) frequency distribution data using log-linear contingency modelling for Fort Albany First Nation, the site of an abandoned Mid-Canada Radar Line station, and two comparison populations (the neighbouring community of Kashechewan First Nation without such a radar installation, and Hamilton, a city in southern Ontario, Canada). This type of analysis is important as it allows for an initial investigation of contaminant data without imputing any values. The two-state log-linear model (employing both non-detectable and detectable concentration frequencies and applicable to PCB congeners 28 and 105 and cis-nonachlor) and the four-state log-linear model (using quartile concentration frequencies for Aroclor 1260, PCB congeners [99,118,138,153,156,170,180,183,187], beta-HCH, p,p'-DDT +p,p'-DDE, HCB, mirex, oxychlordane, and trans-nonachlor) revealed that the effects of subject gender were inconsequential. Significant differences (p < 0.05) between the groups examined were attributable to the effect of location on the frequency of detection of OCs or on their differential distribution among the concentration quartiles. In general, people from Hamilton had higher frequencies of non-detections and of concentrations in the first quartile (p < 0.05) for most OCs compared to people from Fort Albany and Kashechewan (who consume a traditional diet of wild meats that does not include marine mammals). An unexpected finding was that, for Kashechewan males, the frequency of many OCs was significantly higher (p < 0.05) in the 4th concentration quartile than that predicted by the four-state log-linear model, but significantly lower than expected in the 1st quartile for beta-HCH. The levels of PCBs found for women in Fort Albany and Kashechewan were greater than those reported for Dene (First Nation people) and Métis (mixed heritage) of the western Northwest Territories (NWT) who did not consume marine mammals, and for Inuit living in the central NWT (occasional consumers of marine mammals). Moreover, the levels of total p,p'-DDT were greater for Fort Albany and Kashechewan women compared to these same aboriginal groups. PMID:16121269

Tsuji, Leonard J S; Wainman, Bruce C; Martin, Ian D; Weber, Jean-Philippe; Sutherland, Celine; Elliott, J Richard; Nieboer, Evert

2005-09-01

410

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

411

Multidimensional radar picture  

NASA Astrophysics Data System (ADS)

In marine navigation systems, the three-dimensional (3D) visualization is often and often used. Echosonders and sonars working in hydroacustic systems can present pictures in three dimensions. Currently, vector maps also offer 3D presentation. This presentation is used in aviation and underwater navigation. In the nearest future three-dimensional presentation may be obligatory presentation in displays of navigation systems. A part of these systems work with radar and communicates with it transmitting data in a digital form. 3D presentation of radar picture require a new technology to develop. In the first step it is necessary to compile digital form of radar signal. The modern navigation radar do not present data in three-dimensional form. Progress in technology of digital signal processing make it possible to create multidimensional radar pictures. For instance, the RSC (Radar Scan Converter) - digital radar picture recording and transforming tool can be used to create new picture online. Using RSC and techniques of modern computer graphics multidimensional radar pictures can be generated. The radar pictures mentioned should be readable for ECDIS. The paper presents a method for generating multidimensional radar picture from original signal coming from radar receiver.

Waz, Mariusz

2010-05-01

412

Comparison of Ambient Noise From Two Station Designs, Evaluating USArray's Transportable and Flexible Arrays in the Pacific Northwest  

NASA Astrophysics Data System (ADS)

The USArray program within the National Science Foundation-funded Earthscope program is comprised of two portable broadband seismic projects; the Transportable Array (TA), and the Flexible Array (FA). The TA consists of 400 stations occupy locations within the United States on a nominal 70 km spacing for a period of approximately 24 months. As a network, these TA stations roll from west to east so that within 10 years the entire lower 48 states will have been occupied by the TA network. As a complementary component of USArray, the FA pool of instruments is comprised of 1200 active-source, 120 short-period and 326 broadband portable stations. These instruments are used by Principal Investigator-driven studies which focus on geologic targets within the TA footprint. Currently the TA network is transitioning from the Rocky Mountains into the Great Plains. The FA currently has four experiments installed. In this study we quantify the overall performance of these two tandem networks using a controlled set of continuous recordings in Western Washington. We compare the background noise levels between the standard deep TA and shallow FA broadband sensor vault system. We use McNamara’s probability density function (PDF) analysis as the basis of the comparison. We combine the network wide PDF’s of each network for a period of over 600 days of contemporaneous recordings. Preliminary analysis using data from 28 TA stations in western Washington and 47 nearby FA stations from the CAFE experiment (Abers, et al. Eos Trans. AGU 88(52), Fall Meet. Suppl. S43D-07), show that the TA stations are quieter at periods below 20 seconds by about 12 dB on the horizontal components. The vertical components for both the TA and FA are equivalent for periods below 5 seconds. At higher frequencies (> 2 Hz), however, the FA shallower vault is quieter by approximately 10 dB on both the vertical and horizontal components. The question addressed is, what is contributing to the difference in ambient noise level? Both vault systems are designed to minimize noise from either cultural, electronic or environmental sources. In the case for the TA vault, a 2 meter deep hole is dug using heavy excavation equipment with over a square meter of concrete used for a base and Earth coupling. A deeper vault is known to reduce the diurnal temperature fluctuations that are a major source of noise for the broadband sensor. The standard FA vault is typically less than 1 meter deep dug by hand with approximately 1/10 square meter of concrete as a base. The construction materials and the seismic equipment for both these vaults are otherwise equivalent. We propose the following explanation for the difference in noise levels as a function of frequency and sensor component. The deeper TA vault is more stable with respect tilt which reduces the diurnal and seasonal temperature changes resulting in quieter horizontal data. The general location of TA stations near cultural noise sources such as roadways and population centers contribute to the elevated high frequency noise as compared to FA stations that are often located in very remote locations.

Pfeifer, M.; Alvarez, M.; Woodward, R.; Yang, Z.

2009-12-01

413

Evaluation of Greenland Ice Sheet Surface Climate in the HIRHAM Regional Climate Model Using Automatic Weather Station Data  

Microsoft Academic Search

The 1998 annual cycle and 1991-98 summer simulations of Greenland ice sheet surface climate are made with the 0.5°-horizontal resolution HIRHAM regional climate model of the Arctic. The model output is compared with meteorological and energy balance observations from 15 Greenland Climate Network automatic weather stations. The model reproduces the monthly average surface climate parameters, to a large extent within

Jason E. Box; Annette Rinke

2003-01-01

414

Rendezvous radar for the orbital maneuvering vehicle  

NASA Technical Reports Server (NTRS)

This paper describes the development of the Rendezvous Radar Set (RRS) for the Orbital Maneuvering Vehicle (OMV) for the National Aeronautics and Space Administration (NASA). The RRS was to be used to locate, and then provide vectoring information to, target satellites (or Shuttle or Space Station) to aid the OMV in making a minimum-fuel-consumption approach and rendezvous. The RRS design is that of an X-Band, all solid-state, monopulse tracking, frequency hopping, pulse-Doppler radar system. The development of the radar was terminated when the OMV prime contract to TRW was terminated by NASA. At the time of the termination, the development was in the circuit design stage. The system design was virtually completed, the PDR had been held. The RRS design was based on Motorola's experiences, both in the design and production of radar systems for the US Army and in the design and production of hi-rel communications systems for NASA space programs. Experience in these fields was combined with the latest digital signal processor and micro-processor technology to design a light-weight, low-power, spaceborne radar. The antenna and antenna positioner (gimbals) technology developed for the RRS is now being used in the satellite-to-satellite communication link design for Motorola's Iridium telecommunications system.

Locke, John W.; Olds, Keith; Parks, Howard

1991-01-01

415

7. CLOSEUP FRONT VIEW OF RADAR SYSTEM EMITTER/ANTENNA (TYPICAL DEVICE ...  

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

7. CLOSE-UP FRONT VIEW OF RADAR SYSTEM EMITTER/ANTENNA (TYPICAL DEVICE PHOTOGRAPH). - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

416

Radar attenuation in desert soil  

NASA Astrophysics Data System (ADS)

Soil properties make a significant impact in the observed responses of various sensors for subsurface target detection. Ground penetrating radars (GPRs) have been extensively researched as a tool for subsurface target detection. A key soil parameter of interest for evaluating GPR performance is the soil attenuation rate. The information about the soil attenuation rate coupled with target properties (size, shape, material properties and depth of burial) can be used to estimate the effectiveness of radar sensors in a particular soil environment. Radar attenuation in desert soil is of interest in today's political and military climate. Laboratory measurements of desert soil attenuation were conducted using samples collected from a desert in Southwestern United States and in Iraq. These measurements were made in a coaxial waveguide over the frequency ranging from 250 MHz to 4 GHz. The soil grain size distribution, mineralogy, moisture and salinity were also measured. This report describes the experimental procedure and presents the radar attenuation rates observed in desert soils. The results show that the soluble salt content is an important parameter affecting the attenuation behavior of desert soils.

Koh, Gary

2008-05-01

417

Radar sounder performances for ESA JUICE mission  

NASA Astrophysics Data System (ADS)

The Jupiter Icy moons Explorer (JUICE) is the first Large-class mission chosen as part of ESA's Cosmic Vision 2015-2025 program. The mission will study Jovian icy moons Ganymede and Europa as potential habitats for life, addressing two key themes of Cosmic Vision namely the conditions for planet formation and the emergence of life, and the Solar System interactions. The radar sounder instrument on this mission will have great potential to address specific science questions such as the presence of subsurface liquid water and ice shell geophysical structures. One major constraint for radar sounding is the roughness of the planetary surface. The work presented will focus on the characterization of Ganymede's surface topography to better understand its surface properties from a radar point of view. These results should help to put constraints on the design of JUICE's radar sounder. We use topographic data derived from the Voyager and Galileo missions images to try to characterize the surface structure and to quantify its geometry (in terms of slopes and RMS heights mainly). This study will help us evaluating the radar budget in a statistical approach. In addition, deterministic simulations of surface radar echoes conducted on synthetic surfaces -extrapolated from Digital Elevation Models- will be presented to better assess radar sounding performances.

Berquin, Y. P.; Kofman, W. W.; Heggy, E.; Hérique, A.

2012-12-01

418

Performance characteristics of wind profiling radars  

NASA Technical Reports Server (NTRS)

Doppler radars used to measure winds in the troposphere and lower stratosphere for weather analysis and forecasting are lower-sensitivity versions of mesosphere-stratosphere-troposphere radars widely used for research. The term wind profiler is used to denote these radars because measurements of vertical profiles of horizontal and vertical wind are their primary function. It is clear that wind profilers will be in widespread use within five years: procurement of a network of 30 wind profilers is underway. The Wave Propagation Laboratory (WPL) has operated a small research network of radar wind profilers in Colorado for about two and one-half years. The transmitted power and antenna aperture for these radars is given. Data archiving procedures have been in place for about one year, and this data base is used to evaluate the performance of the radars. One of the prime concerns of potential wind profilers users is how often and how long wind measurements are lacking at a given height. Since these outages constitute an important part of the performance of the wind profilers, they are calculated at three radar frequencies, 50-, 405-, and 915-MHz, (wavelengths of 6-, 0.74-, and 0.33-m) at monthly intervals to determine both the number of outages at each frequency and annual variations in outages.

Strauch, R. G.; Frisch, A. S.; Weber, B. L.

1986-01-01

419

GIMA ground penetrating radar system for monitoring concrete bridge decks  

Microsoft Academic Search

Ground Penetrating Radar (GPR) has been investigated as a non-destructive method for evaluating damage in concrete structures. However, the commercially available techniques are limited to detection of gross quantities of deterioration, due to the limited resolution of the system. The objective of this research is to evaluate a ground penetrating radar system with a novel Good Impedance Match Antenna (GIMA)

Dryver Huston; Jing Qiong Hu; Kenneth Maser; William Weedon; Chris Adam

2000-01-01

420

Convective activities associated with intraseasonal variation over Sumatera, Indonesia, observed with the equatorial atmosphere radar  

Microsoft Academic Search

The influence of intraseasonal variation (ISV) on convective activities over Sumatera (or Sumatra) is studied by using data derived from the Equatorial Atmosphere Radar (EAR), the Boundary Layer Radar (BLR), the surface weather station, the Geostationary Meteorological Satellite (GMS), and NCEP\\/NCAR reanalysis. In June 2002, convective activities over the Indian Ocean, the maritime continent, and the western Pacific were significantly

T. H. Seto; M. K. Yamamoto; H. Hashiguchi; S. Fukao

2004-01-01

421

APPLICATION OF GROUND PENETRATING RADAR TO EVALUATE THE EXTENT OF POLYURETHANE GROUT INFILTRATION FOR MINE ROOF CONTROL - A CASE STUDY  

Microsoft Academic Search

Over the period 2000 to 2003, roof falls have accounted for 4 to 14% of the fatalities in underground mining operations. The National Institute for Occupational Safety and Health (NIOSH) is conducting research to reduce the frequency, exposure, and risk of these events through an ongoing program of field and laboratory studies. One area of research involves the evaluation of

William D. Monaghan

422

Apollo experience report: Lunar module landing radar and rendezvous radar  

NASA Technical Reports Server (NTRS)

A developmental history of the Apollo lunar module landing and rendezvous radar subsystems is presented. The Apollo radar subsystems are discussed from initial concept planning to flight configuration testing. The major radar subsystem accomplishments and problems are discussed.

Rozas, P.; Cunningham, A. R.

1972-01-01

423

Reflectivity retrieval in a networked radar environment  

NASA Astrophysics Data System (ADS)

Monitoring of precipitation using a high-frequency radar system such as X-band is becoming increasingly popular due to its lower cost compared to its counterpart at S-band. Networks of meteorological radar systems at higher frequencies are being pursued for targeted applications such as coverage over a city or a small basin. However, at higher frequencies, the impact of attenuation due to precipitation needs to be resolved for successful implementation. In this research, new attenuation correction algorithms are introduced to compensate the attenuation impact due to rain medium. In order to design X-band radar systems as well as evaluate algorithm development, it is useful to have simultaneous X-band observation with and without the impact of path attenuation. One way to obtain that data set is through theoretical models. Methodologies for generating realistic range profiles of radar variables at attenuating frequencies such as X-band for rain medium are presented here. Fundamental microphysical properties of precipitation, namely size and shape distribution information, are used to generate realistic profiles of X-band starting with S-band observations. Conditioning the simulation from S-band radar measurements maintains the natural distribution of microphysical parameters associated with rainfall. In this research, data taken by the CSU-CHILL radar and the National Center for Atmospheric Research S-POL radar are used to simulate X-band radar variables. Three procedures to simulate the radar variables at X-band and sample applications are presented. A new attenuation correction algorithm based on profiles of reflectivity, differential reflectivity, and differential propagation phase shift is presented. A solution for specific attenuation retrieval in rain medium is proposed that solves the integral equations for reflectivity and differential reflectivity with cumulative differential propagation phase shift constraint. The conventional rain profiling algorithms that connect reflectivity and specific attenuation can retrieve specific attenuation values along the radar path assuming a constant intercept parameter of the normalized drop size distribution. However, in convective storms, the drop size distribution parameters can have significant variation along the path. In this research, a dual-polarization rain profiling algorithm for horizontal-looking radars incorporating reflectivity as well as differential reflectivity profiles is developed. The dual-polarization rain profiling algorithm has been evaluated with X-band radar observations simulated from drop size distribution derived from high-resolution S-band measurements collected by the CSU-CHILL radar. The analysis shows that the dual-polarization rain profiling algorithm provides significant improvement over the current algorithms. A methodology for reflectivity and attenuation retrieval for rain medium in a networked radar environment is described. Electromagnetic waves backscattered from a common volume in networked radar systems are attenuated differently along the different paths. A solution for the specific attenuation distribution is proposed by solving the integral equation for reflectivity. The set of governing integral equations describing the backscatter and propagation of common resolution volume are solved simultaneously with constraints on total path attenuation. The proposed algorithm is evaluated based on simulated X-band radar observations synthesized from S-band measurements collected by the CSU-CHILL radar. Retrieved reflectivity and specific attenuation using the proposed method show good agreement with simulated reflectivity and specific attenuation.

Lim, Sanghun

424

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

425

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

426

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

427

Fire Station Location Package, User's Guide.  

National Technical Information Service (NTIS)

The report presents the COBOL version of a fire station location computer program which is directed to local administrators and fire officials who evaluate the adequacy of station locations, present and planned, on response time rather than arbitrary dist...

1974-01-01

428

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

429

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.

430

Multifunction laser radar: II  

NASA Astrophysics Data System (ADS)

Laser radar systems are required for various military applications including obstacle detection, target recognition, and terrain mapping. Each application requires different system parameters such as pulse energy, repetition rate, and field of view. This paper is the second in a series of papers describing the progress toward a multifunction laser radar system under construction for the Cooperative Eyesafe Laser Radar Program (CELRAP) of the U.S. Army CECOM Night Vision and Electronic Sensors Directorate.

Hutchinson, James A.; Trussell, Charlie W.; Allik, Toomas H.; Hamlin, Scott J.; McCarthy, John C.; Jack, Michael D.

2000-09-01

431

FPGA based Ultra-Wideband pseudo-noise radar  

Microsoft Academic Search

A high accuracy experimental platform for Ultra Wide Band (UWB) PN radar performance evaluation has been created. This PN radar platform could be used for the applications such as unmanned- aerial-vehicle anti-collision and short-range distance measurement etc (3). It includes compact size X-band radar transceiver, baseband signal processing in FPGA, high speed analog to digital converter (ADC), and Matlab tools.

Amutha Jayakumar; Asha Durafe

2011-01-01

432

HF radar data assimilation in the Monterey Bay area  

Microsoft Academic Search

The utility of high-frequency (HF) radar data for improving numerical circulation model predictions is evaluated. Comparisons of the statistical properties of the (CODAR-type) HF radar data and the observed wind indicate a strong correlation between the dominant alongshore, upwelling-favoring wind-forcing and HF radar-derived surface currents along the central California coastline. Because inadequate knowledge of the wind stress is probably a

Jeffrey D. Paduan; Igor Shulman

2004-01-01

433

Imaging radar for bridge deck inspection  

SciTech Connect

Lawrence Livermore National Laboratory (LLNL)l is developing a prototype imaging radar for inspecting steel reinforced concrete bridge decks. The system is designed to acquire Synthetic Aperture Radar (SAR) data and provide high-resolution images of internal structure, flaws, and defects enabling bridge inspectors to nondestructively evaluate and characterize bridge deck condition. Concrete delamination resulting from corrosion of steel reinforcing bars (rebars) is an important structural defect that the system is designed to detect. The prototype system uses arrays of compact, low-cost Micropower Impulse Radar (MIR) modules, supported by appropriate data acquisition and storage subsystems, to generate and collect the radar data, and unique imaging codes to reconstruct images of bridge deck internals. In this paper, we provide an overview of the prototype system concept, discuss its expected performance, and present recent experimental results showing the capability of this approach to detect thin delamination simulations embedded in concrete.

Warhus, J.; Mast, J.; Nelson, S.

1995-04-13

434

Radar Imaging and Feature Extraction.  

National Technical Information Service (NTIS)

Advanced spectral estimation methods are presented for radar imaging and target feature extraction. We study problems involved in inverse synthetic aperture radar (ISAR) autofocus and imaging, synthetic aperture radar (SAR) autofocus and motion compensati...

J. Li

1999-01-01

435

Stepped Frequency Imaging Radar Simulation.  

National Technical Information Service (NTIS)

In this thesis, a technique involving Stepped Frequency and Inverse Synthetic Aperture Radar (ISAR) processing have been employed to develop two- dimensional radar images of an aircraft target. Radar returns from prominent scatterers of various parts of t...

K. L. Mun

2000-01-01

436

Review of Radar Absorbing Materials.  

National Technical Information Service (NTIS)

Radar is a sensitive detection tool and since its development, methods for reducing microwave reflections have been explored. Radar absorbers can be classified as impedance matching or resonant absorbers. Radar absorbing materials are made from resistive ...

P. Saville

2005-01-01

437

Landform Identification: Lunar Radar Images.  

National Technical Information Service (NTIS)

Three sets of polarized radar-echo images of the Moon were examined to establish the relation between radar resolution and landform-identification resolution. After comparison with lunar maps and photographs, real and apparent landforms on the radar image...

H. J. Moore T. W. Thompson

1987-01-01

438

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

439

Seasat-A Synthetic Aperture Radar - Radar system implementation  

NASA Technical Reports Server (NTRS)

The Synthetic Aperture Radar (SAR) onboard the Seasat-A satellite will conduct a number of experiments involving deep ocean waves, coastal wave patterns, polar ice and land forms. The SAR will have a 25 m by 25 m resolution over a swath of 100 km width centered about 300 km to the right of the spacecraft track. The SAR's high data rate limits operations to times when Seasat-A is in view of a few ground stations with special SAR receiving equipment. However, the SAR will collect much useful data about deep ocean and coastal waves in the Atlantic and Pacific Oceans; about ice in the Northwest Atlantic, in the Great Lakes and off the coast of Alaska; and about land over much of the United States and Canada.

Thompson, T. W.; Laderman, A.

1976-01-01

440

Equatorial radar system  

NASA Astrophysics Data System (ADS)

A large clear air radar with the sensitivity of an incoherent scatter radar for observing the whole equatorial atmosphere up to 1000 km altitude is now being designed in Japan. The radar, called the Equatorial Radar, will be built in Pontianak, Kalimantan Island, Indonesia (0.03 N, 109.3 E). The system is a 47 MHz monostatic Doppler radar with an active phased array configuration similar to that of the MU radar in Japan, which has been in successful operation since 1983. It will have a PA product of more than 5 x 10(9) sq. Wm (P = average transmitter power, A = effective antenna aperture) with sensitivity more than 10 times that of the MU radar. This system configuration enables pulse-to-pulse beam steering within 25 deg from the zenith. As is the case of the MU radar, a variety of sophisticated operations will be made feasible under the supervision of the radar controller. A brief description of the system configuration is presented.

Rukao, S.; Tsuda, T.; Sato, T.; Kato, S.

1989-04-01

441

Equatorial radar system  

NASA Technical Reports Server (NTRS)

A large clear air radar with the sensitivity of an incoherent scatter radar for observing the whole equatorial atmosphere up to 1000 km altitude is now being designed in Japan. The radar, called the Equatorial Radar, will be built in Pontianak, Kalimantan Island, Indonesia (0.03 N, 109.3 E). The system is a 47 MHz monostatic Doppler radar with an active phased array configuration similar to that of the MU radar in Japan, which has been in successful operation since 1983. It will have a PA product of more than 5 x 10(9) sq. Wm (P = average transmitter power, A = effective antenna aperture) with sensitivity more than 10 times that of the MU radar. This system configuration enables pulse-to-pulse beam steering within 25 deg from the zenith. As is the case of the MU radar, a variety of sophisticated operations will be made feasible under the supervision of the radar controller. A brief description of the system configuration is presented.

Rukao, S.; Tsuda, T.; Sato, T.; Kato, S.

1989-01-01

442

Harmonic radar literature  

NASA Astrophysics Data System (ADS)

A harmonic radar sends on a given frequency f sub o and receives on another frequency usually 3 f sub o. The overtone is generated on joints between the metal parts of the radar target. The generated high harmonic frequency is very weak, which is why this radar has an extremely low range of detection. Natural objects in the target area do not disturb the high frequency harmonics. The radar becomes clutter free. The principals of generating high frequency harmonics cover tunneling, semiconductor and microwave effects. Signal generation is most powerful when f sub o is between 100 and 1000 MHz.

Jansson, B.

1980-07-01

443

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

2000-01-01

444

Meteorological and dynamical requirements for MST radar networks: Waves  

NASA Technical Reports Server (NTRS)

Studies of wave motions using the MST radar have concentrated on single station time series analyses of gravity waves and tides. Since these radars collect high time resolution data they have the potential to become a significant tool for mesoscale research. In addition, radars are operated almost continuously unattended and, consequently, data sets are available for analyzing longer period wave motions such as tides and planetary scale waves. Although there is much to learn from single station data, the possibilities of new knowledge from a network of radars is exciting. The scales of wave motions in the atmosphere cover a broad range. Consequently the choice of a radar network depends to a large extent on the types of wave motions that are studied. There are many outstanding research problems that would benefit from observations from a MST radar network. In particular, there is a strong need for measurements of gravity wave parameters and equatorial wave motions. Some of the current problems in wave dynamics are discussed.

Avery, S. K.

1983-01-01

445

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

446

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

447

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.

1997-01-01

448

Laser radar observation of the polar stratospheric aerosol layer  

NASA Technical Reports Server (NTRS)

The polar stratosphere has been speculated to be an active sink region of various stratospheric materials; ozone, water vapor, NOX, aerosol particles and so on, but this process is not theoretically and/or observationally made clear. The observation of the polar stratospheric aerosol layer using laser radar certainly contributes to the study of the global transport of these stratospheric minor constituents. In addition to this, from the viewpoint of aerosol science, there may be many interesting phenomena which cannot be found in the stratosphere at mid and low latitudes; the effect of precipitation of high energy molecules and atoms, of very cold winter stratosphere, of very cold mesopause in summer. Laser radar observation is one of the main activities of the Antarctic Middle Atmosphere (AMA) project at Syowa Station (69.00 deg S, 39.35 deg E), Antarctica since May 1983. Laser radar measurement at Syowa Station is discussed in detail.

Iwasaka, Y.; Hirasawa, T.; Fukunishi, H.; Fujiwara, M.; Fujii, R.; Miyaoka, H.

1985-01-01