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1

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

2

Laser radar observations at the helwan station in 1979  

NASA Astrophysics Data System (ADS)

A brief description of the Intercosmos Laser Radar system at the Helwan station is given. The use of a 2-generation laser with 0.5 nsec counter for laser ranging allows increasing the accuracy of results up to 20 - 30 cm. The results of calibrations and satellite observations are given.

Mateev, D. T.; Towadrows, M. Y.

3

Passive Tracking and Locating Radar Based on Double GSM Base Stations  

Microsoft Academic Search

Passive radar is a kind of that without its own transmitter and receive the thermal emission energy of an object or its source of microwave energy reflected from the radar to detect targets. The widely distributed GSM base station signals have GMSK frequency modulation characteristics, these signals can be used as a passive radar radiation source for its ambiguity function

Zhang Ping-chuan; Li Bu-yin

2010-01-01

4

Bird Activity Analysis Using Avian Radar Information in Naval Air Station airport, WA  

NASA Astrophysics Data System (ADS)

The number of bird strikes on aircraft has increased sharply over recent years and airport bird hazard management has gained increasing attention in wildlife management and control. Evaluation of bird activity near airport is very critical to analyze the hazard of bird strikes. Traditional methods for bird activity analysis using visual counting provide a direct approach to bird hazard assessment. However this approach is limited to daylight and good visual conditions. Radar has been proven to be a useful and effective tool for bird detection and movement analysis. Radar eliminates observation bias and supports consistent data collection for bird activity analysis and hazard management. In this study bird activity data from the Naval Air Station Whidbey Island was collected by Accipiter Avian Radar System. Radar data was pre-processed by filtering out non-bird noises, including traffic vehicle, aircraft, insects, wind, rainfall, ocean waves and so on. Filtered data is then statistically analyzed using MATLAB programs. The results indicated bird movement dynamics in target areas near the airport, which includes (1) the daily activity varied at dawn and dusk; (2) bird activity varied by target area due to the habitat difference; and (3) both temporal and spatial movement patterns varied by bird species. This bird activity analysis supports bird hazard evaluation and related analysis and modeling to provide very useful information in airport bird hazard management planning.

Wang, J.; Herricks, E.

2010-12-01

5

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

6

Detection of crevasses near McMurdo station, Antarctica with airborne short-pulse radar  

NASA Astrophysics Data System (ADS)

Airborne short-pulse radar is evaluated experimentally as a rapid reconnaissance tool for locating snow-bridged crevasses. An immediate need for a crevasse detector is present within the U.S. Antarctic Program, which is planning a major surface traverse from McMurdo to deliver construction materials to South Pole Station. This feasibility study of a crevasse detection system was performed near McMurdo Station, Antarctica, in Jan. 1994. The radar utilized pulses centered near 200 and 500 MHz and was operated from a low flying helicopter with altitude and speed as variables. A global positioning system (GPS) was used for survey control. Results are presented over glacial ice on Ross Island and at various locations on the Ross Ice Shelf near White and Black Islands and near the Aurora Glacier terminus. These studies include a control line along which crevasse width and snow-bridge thickness were measured, transects along which crevasses were apparent, and also where crevasses were expected, but were not apparent. Strong evidence of crevassing was recorded at flight speeds near 20 m 5-1 (45 mph), at altitudes near 15 m, and at a data acquisition rate of 51 scans/second. Crevasses are detected by the reflections and diffractions from distorted layering in snow bridges, and by the strong diffractions from within the crevasses. The strongest diffractions apparently emanated from within the crevasse and not from the base of the snow bridge. Along the control line, a crevasse with no surface expression was detected by radar and verified by probing and digging. Transects devoid of crevasses show layering without the small scale distortion seen over snow bridges. Future plans are to use data acquisition rates of 160 scans/second, available with commercial equipment, to allow a survey speed of about 64 ms-1 (140 mph).

Delaney, Allan J.; Arcone, Steven A.

1995-03-01

7

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

NASA Technical Reports Server (NTRS)

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

1983-01-01

8

Generic evaluation tracker database for OTH radar  

NASA Astrophysics Data System (ADS)

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

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

1999-10-01

9

Independent evaluation of the ability of spaceborne radar and lidar  

E-print Network

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

Hogan, Robin

10

PAVEMENT OVERLAY THICKNESS EVALUATION USING GROUND PENTRATING RADAR (GPR)  

E-print Network

deflectometer (FWD), and ground penetrating radar (GPR). Core drilling provides very accurate pin point pavementPAVEMENT OVERLAY THICKNESS EVALUATION USING GROUND PENTRATING RADAR (GPR) Dwayne Harris, M.Sc., PG for determining pavement thickness are core drilling, falling weight deflectometer (FWD), and ground penetrating

Shan, Jie

11

Role of Radar Cross Section facilities in a Radar and Electronic Warfare Defence Research and Evaluation capability  

Microsoft Academic Search

Abstract: This paper demonstrates the role of Radar Cross Section (RCS) facilities, consisting of modelling and simulation (M&S), Hardware in the Loop- (HWIL) and field Test and Evaluation (T&E) environments, in a Radar and Electronic Warfare (EW) Defence Research and Evaluation capability. The link between the development and utilisation of radar and EW facilities and the scientific process is illustrated

Ewerlank Pienaar; Thomas Küsel; Pieter Goosen; Christo Cloete; Louis Botha

12

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

13

Evaluating a Radar-Based, Non Contact Streamflow Measurement System in the San  

E-print Network

profiler BD BoogieDopp discharge measurement system Deg. Degrees GHz GigaHertz GPR Ground penetrating radar................................................................................................................. 5 Ground-Penetrating RadarEvaluating a Radar-Based, Non Contact Streamflow Measurement System in the San Joaquin River

14

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

NASA Astrophysics Data System (ADS)

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 for the first time classification of precipitating systems are studied. With the presence or absence of bright band a radar signature of melting layer one can classify particular rain type as convective or stratiform. For present study MRR data from September 2005 onwards are collected. The main objective is to classify precipitation system into Stratiform and Convective with the presence or absence of Bright band. Another potential of this radar is ability to give information of vertical structure of fall velocity of hydrometeors. This also gives profiles of number concentration of various ranges of Drop sizes, liquid water content and rain rate for different heights. There is a dearth of rain drop Size data and distribution models for the tropics, especially over Indian continent. Models for drop size distribution are required for the evaluation of microwave and millimeter wave propagation effects due to rainfall. In the present paper various DSD models namely exponential, gamma model and lognormal model with different combination of moments for observing the characteristic features of tropical rain are studied. These results are compared with the collocated ground based Disdrometer. Attenuation at Microwave frequencies during the presence of rain is a serious concern to the communication. Once temporal and spatial information of DSD is known microwave attenuation can be studied. These results will be presented in this paper.

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

2007-07-01

15

Beamformer evaluation of low power coastal HF surface wave radar  

Microsoft Academic Search

Owing to large operational range and relatively low cost of operation coastal HF Surface Wave Radar has witnessed an increased interest in monitoring coastal territories. Using a well established sea clutter model this paper evaluates the state of art beamformer (Hamming) employed by such coastal systems. Evaluation parameters are degradation during beam scanning and target azimuth resolution in high sea

Anshu Gupta; Thomas Fickenscher

2011-01-01

16

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

17

Bridge Deck Evaluation with Ground Penetrating Radar Dryver Huston, Jing Hu, Noel Pelczarski, and Brian Esser  

E-print Network

Bridge Deck Evaluation with Ground Penetrating Radar Dryver Huston, Jing Hu, Noel Pelczarski Health Monitoring Stanford University September 1999 ABSTRACT Ground Penetrating Radar (GPR) uses. Several technologies are available for the nondestructive evaluation of pavements. Ground penetrating

Huston, Dryver R.

18

Sea Wind Power Energy Evaluation by HF Radar System  

Microsoft Academic Search

This paper presents a remote sensing method for wind energy measurement and evaluation on sea surface, which can be used for the investigation of wind farm. It provides a valid proof for building wind plants or monitoring wind farms on the sea surface. The wind speed and direction can be derived from radar echo spectrum as well as wind profile,

Wei Shen; Biyang Wen

2009-01-01

19

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

SciTech Connect

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

Whorton, M.

1999-01-20

20

Geomorphic Evaluation of Radar Imagery of Southeastern Panama and Northwestern Colombia  

E-print Network

Layover. • • • • • • • • • • • • 35 2.4 2.5 Radar Power Return. . • • • • • • • • • • • • • • · . . 2.4. 1 Slope Determination from Radar Power Return. • Radar Shadow . • • ... . • . • • . . .* ~ • • • • • • • 2.5. 1 Types of Elevated Terrain... . . • • • • • . 4. 3 Radar Power Return • . 4.3 • 1 Background. • 4.3.2 Methodology.. • 0 • 4.3.3 Results. . • • . • ••.•• 4.3.4 Explanation and Limitation of Results iv · . . . . . . 118 118 122 129 131 136 136 136 137 138 CHAPTER 5 - EVALUATION...

Lewis, Anthony J.

1971-02-01

21

Fabrication of Radar Absorbing Shells Made of Hybrid Composites and Evaluation of Radar Cross Section  

Microsoft Academic Search

** , Seoung-Bae Park ** and Myung-Shik Won *** ABSTRACT The avoidance of enemy's radar detection is very important issue in the modern electronic weapon system. Researchers have been studied to minimize reflected signals of radar. In this research, two types of radar absorbing structure (RAS), \\

Woo-Kyun Jung; Sung-Hoon Ahn; Bierng-Chearl Ahn

2005-01-01

22

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

23

Multi-Watershed Evaluation of WSR-88D (NEXRAD) Radar-Precipitation Products  

Microsoft Academic Search

The National Weather Service (NWS) operates a network of Doppler-radar stations (NEXRAD, WSR- 88D) that produce hourly-rainfall estimates, at approximately 4-km2 resolution, with nominal coverage of 96% of the conterminous US. Utilization of these data by the NWS is primarily for the detection and modeling of extreme-weather events. Radar- precipitation estimates were compared with gauge estimates at six ARS watershed-research

Stuart Hardegree; Steven Van Vactor; Kathleen Healy; Carlos Alonso; James Bonta; David Bosch; Dwight Fisher; Daren Harmel; Jean Steiner; Michael Van Liew

24

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

25

Universal Ground Control Station (UGCS) joystick evaluation  

Microsoft Academic Search

A goal of commonality and interoperability across U.S. Army and Joint Service unmanned aerial systems (UASs) was outlined by the Office of the Secretary of Defense. The Universal Ground Control Station (UGCS) is a U.S. Army initiative to meet this requirement. With an objective to control heterogeneous assets with expanded payloads, both displacement and force sensing hand-controllers have been reviewed

Susan R. Flaherty; Lisa Fern; Terry Turpin; Scott Scheff

2012-01-01

26

Technology evaluation for space station atmospheric leakage  

SciTech Connect

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

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

1990-02-01

27

Evaluation of Station Post Porcelain Insulators with Room Temperature  

E-print Network

Evaluation of Station Post Porcelain Insulators with Room Temperature Vulcanized (RTV) Silicone Temperature Vulcanized (RTV) Silicone Rubber Coating Final Project Report Ravi Gorur, Project Leader Arizona grease, oils and room temperature vulcanized (RTV) silicone rubber material, fluorinated compounds

28

Radar sounding of Mars from the orbit of the Mars-Express automatic interplanetary station  

Microsoft Academic Search

On the base of the laser altimetry results obtained using the orbital altimeter MOLA (the MGS mission) and the data of radio occultation experiments of transionospheric sounding of the Mars ionosphere, a method for interpretation of the planet radar sounding data is developed. The proposed method includes a program package for numerical simulation of the process of radiowave propagation through

V. M. Smirnov; L. F. Chernaya; O. V. Yushkova; K. N. Rykov

2006-01-01

29

Antenna evaluation study for the shuttle multispectral radar, phase 2  

NASA Technical Reports Server (NTRS)

The results of the second phase of the Antenna Evaluation Study for the Shuttle Imaging Radar are presented. The objectives of Phase II were (1) to complete the specifications for the subarray test panels, (2) to begin a study of the effects of electrical and mechanical tolerance variations on overall SIRA performance, (3) to initiate the development of a mathematical model which adequately described the array performance and (4) to begin the development of a comprehensive computer program which will eventually simulate the performance characteristics of the antenna in a spaceborne environment. Items (2), (3), and (4) were begun in Phase I (ahead of schedule), and because of this, it has been possible to accelerate the Phase II modeling/simulation objectives to the point where simulations of expected mechanical/electrical errors have already been produced.

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

1977-01-01

30

Radar sounding of Mars from the orbit of the Mars-Express automatic interplanetary station  

Microsoft Academic Search

On the base of the laser altimetry results obtained using the orbital altimeter MOLA (the MGS mission) and the data of radio occultation experiments of transionospheric sounding of the Mars ionosphere, a method for\\u000a interpretation of the planet radar sounding data is developed. The proposed method includes a program package for numerical\\u000a simulation of the process of radiowave propagation through

V. M. Smirnov; L. F. Chernaya; O. V. Yushkova; K. N. Rykov

2006-01-01

31

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

32

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

33

Simultaneous observations of Vertically Pointing Micro Rain Radar (MRR) and Disdrometer over a tropical station Thumba  

NASA Astrophysics Data System (ADS)

The Micro Rain Radar (MRR) and disdrometer (RD-80 model by Distromet Ltd., Switzer-land) was installed at Thumba (8.50N, 76.90E) under Ka band propagation experiment is used extensively to measure the rain rate along with the Raindrop size distribution (DSD) of trop-ical continental rainfall. In this study, simultaneous observations of Micro Rain Radar and disdrometer data collected for 3 years are analyzed to retrieve DSD parameters using gamma distribution for different precipitating systems. First, using the disdrometer data, the rainfall events were separated into convective, transition and stratiform rainfall by an algorithm based on variation of DSD parameters. At the same time, profiler-derived equivalent reflectivity and Doppler velocity from Doppler spectra were used to classify precipitation. Overall agreement between the two instruments is found to be reasonable. A Comparison of the retrieved gamma parameters with disdrometer measurements shows very good agreement. Correlation coefficient of ?=0.95,0.94 and 0.95 for the rain rate, liquid water content and median volume diameter respectively are observed between profiler and disdrometer for the whole observation period. During stratiform regime vertical variability of gamma parameters shows very little variation where as during transition mixed large and small drop spectra are observed. The significance of the present results demonstrates the capability of Ka band in classifying the precipitating systems and shows the spatial and temporal variability of DSD in transition and stratiform rain type.

Nadimpally, Kirankumar; Pk, Kunhikrishnan

34

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

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

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

35

Gravity waves and turbulence from troposphere to mesosphere over the Indian MST radar station  

NASA Astrophysics Data System (ADS)

The Indian MST radar facility at Gadanki (13.5° N, 79.2° E) has been utilised to study the backscattered signals received near simultaneously from troposphere, stratosphere and meso-sphere. The main objective is to identify the signatures of gravity waves in the troposphere/stratosphere and their upward propagation to produce mesospheric turbulence. The observations were car-ried out during different months of 2001-2003 using five beam positions for E-W, N-S at 10° beam angle and the Zenith direction, variable pulse widths (range bins between 150 m to 2.4 km) and minimum time resolution of 80 s (for one radar scan) covering the height range of 4-85 km. While results shown on the intermittent, inhomogeneous and anisotropic nature of mesospheric scattering regions are explained by the neutral turbulence driven perturbations in the radio refractive index corresponding to the Bragg scale of about 3 m for the radar frequency of 53 MHz, the seasonal variation in the occurrence of scattering layer heights between 70-80 km (including stratification and multiple layers) and signal strengths are dependent on (but may not be limited to) the severe weather related tropical convective sources generating grav-ity waves in the troposphere, their propagation through the stratosphere and breaking in the mesosphere. The spectrum of gravity waves of a convective event with different phase velocities would go through various interaction regimes with the mean flows acting as filters as well as producing turbulence in all the three regions of interest. On a typical day (e.g. 25 June 2002) of well developed mesospheric scattering layer, the height profile of SNR (related to different turbulence patches) shows an average maximum value of 15 dB below 18 km with 3-4 prominent and continuous tropospheric scatter layers of 3 km thickness and 5 dB in the mesosphere with 2 km thick intermittent layer around 74 km. Wind velocity contours show a reversal in mean wind direction around 8-10 km for zonal and meridional components. The time sequence of horizontal and vertical winds in the scatter-ing layers of troposphere/stratosphere show background mean wind superimposed by random peaks pertaining to perturbations due to mean flow-gravity wave interactions. The growth or decay of these perturbation fields with height depends on their filtering and dissipation states to produce turbulence. The unobstructed gravity waves are able to reach higher altitudes of even mesosphere where they may break down to generate turbulence. Wavelet analyses of (a) wind velocities in selected scattering and non-scattering height regions of troposphere/stratosphere and (b) SNR data of mesosphere provide details of scales and coefficients of available gravity wave spectra at each altitude and their relation to the onset of turbulence at various levels. The 19 November 2001 data subjected to wavelet analysis shows that the gravity waves observed in the tropospheric scattering layers at 15 and 18 km propagate up and produce two scattering layers at 70 and 75 km. Available gravity wave propagation models like that of Lindzen (1981) is used and extended to incorporate the observed interplay of mean wind, gravity wave pertur-bations and turbulence in the lower atmosphere and the prediction of generation of turbulence in the mesosphere.

Chakravarty, Subhas

36

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

37

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

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

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

38

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

PubMed

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

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

2014-03-01

39

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

Microsoft Academic Search

This report provides a detailed evaluation of synthetic aperture radar (SAR) as a potential technology improvement over the Coast Guard's existing side-looking airborne radar (SLAR) for oil-spill surveillance applications. The U.S. Coast Guard Research and Development Center (RD Center), Environmental Safety Branch, sponsored a joint experiment including the U.S. Coast Guard, Sandia National Laboratories, and the National Oceanographic and Atmospheric

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

1993-01-01

40

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

41

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

NASA Technical Reports Server (NTRS)

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

1975-01-01

42

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

43

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

44

Multi-Watershed Evaluation of WSR-88D (NEXRAD) Radar-Precipitation Products for Hydrologic and Natural Resources Modeling Applications  

Microsoft Academic Search

The National Weather Service (NWS) operates a network of Doppler-radar stations (NEXRAD, WSR-88D) that produce hourly-rainfall estimates, at approximately 4-km2 resolution, with nominal coverage of 96% of the conterminous US. Utilization of these data by the NWS are primarily for the detection and modeling of extreme-weather events. Radar-precipitation estimates were compared with gauge estimates at 6 ARS watershed-research locations in

S. P. Hardegree; S. S. van Vactor; K. R. Healy; C. V. Alonso; J. V. Bonta; D. D. Bosch; D. S. Fisher; D. C. Goodrich; R. D. Harmel; J. L. Steiner; M. W. van Liew

2003-01-01

45

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

46

Summary of monitoring station component evaluation project 2009-2011.  

SciTech Connect

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

Hart, Darren M.

2012-02-01

47

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

48

Evaluation of polarimetric through-the-wall radar measurements  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

49

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

50

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

Microsoft Academic Search

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

Liao Guisheng; Bao Zheng; Xu Zhiyong

1996-01-01

51

Performance Evaluation of SeaSonde High-Frequency Radar for Vessel Detection  

E-print Network

P A P E R Performance Evaluation of SeaSonde High-Frequency Radar for Vessel Detection A U T H O R collaborated on the development of vessel detection and tracking capabilities from compact HF ra- dars., 2010a). Technology demonstrations determined (a) that vessels could be detected, (b) that multilook

52

Intelligent system for non-destructive evaluation of historic walls using Ground-Penetrating Radar  

Microsoft Academic Search

This paper presents a novel system evaluation of ashlar masonry walls inspec Penetrating Radar (GPR). The system inclu processing of the GPR signal: elimination o from the backscattered signals; depth reso automatic gain control for visualization generation of B-Scans (radargrams) of the in wall. Inhomogeneities in the structure of the from the B-Scans. Several experiments we models of historic ashlar

Gonzalo Safont; Addisson Salazar; Jorge Gosalbez; Luis Vergara

2010-01-01

53

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

SciTech Connect

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

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

1993-10-01

54

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

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

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

55

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

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

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

56

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

57

Microbial Diversity Aboard Spacecraft: Evaluation of the International Space Station  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

58

Combination of Radar Altimeter and In-Situ Measurements to deduce Rating-Curves at Some Virtual Stations in the Ungauged Amazon and Orinoco Basins  

NASA Astrophysics Data System (ADS)

In the last two years, virtual gauged stations have been proposed to increase the density of hydrological network in ungauged or very poorly monitored basins (Leon, 2006). In spatial hydrology a virtual station is considered as any crossing of water body surface (i.e., large rivers) by radar altimeter satellite tracks. The main objective of this study is to review the usefulness of altimetric data presenting rating curves obtained for some virtual stations at the poorly gauged basins of Caqueta (Colombian Amazon basin), Uaupes and Upper Negro (Brazilian Amazon basin) and Upper Orinoco. Rating curve parameters at virtual stations are estimated by fitting with a power law distribution the temporal series of water surface altitude derived from ENVISAT satellite measurements and modeled discharges. The applied methodology (Leon et al. 2006a) allows the ellipsoidal height of effective zero flow to be estimated. This parameter is a good proxy of the mean water depth from which the river bed slope can be computed. These quantities combined with rating-curve parameters are highly valuable for understanding hydrological behaviour, especially at ungauged basins where hydrodynamical studies had always been prevented by the lack of in-situ data. The results obtained allow to propose a new insight into the hydrological behaviour of the region shared by Colombia, Brazil and Venezuela, which is very difficult to access, and then very poorly known.

Leon, J.; Seyler, F.; Calmant, S.; Bonnet, M.

2008-12-01

59

Comparison of TRMM precipitation data with a K-Band Radar, Disdrometer and Manual Rain Gauge data during different monsoon seasons at Coastal and High altitude tropical Stations  

NASA Astrophysics Data System (ADS)

TRMM Merged High Quality/Infrared Precipitation estimates obtained from the TRMM `3B-42' algorithm provides high resolution satellite-based rainfall estimates. To understand the reliability of these remote sensing measurements especially over the tropics, "ground-truth" is mandatory. This paper presents such a preliminary comparison carried out for 2 west coast stations Thiruvananthapuram and Kochi; one east coast station Sriharikota (SHAR) and a high altitude station Munnar in the western ghats 40 km just east to Kochi in the peninsular India using a Micro Rain Radar (MRR), Disdrometer and a manual rain gauge. TRMM rain rate is available as 3-hourly data over a 0.25o X 0.25o grid. The analyses have been done for 3-hourly, daily and monthly accumulations. Out of the total number of events (daily data), 79 percentage of the total events could be detected together by the TRMM and disdrometer sensors. The Correlation coefficient for the comparison is ¿0.9, 0.6 and 0.4 respectively for monthly, daily and 3-hourly for pre, southwest and the northeast monsoon periods at all the stations. The poor comparison shown by coastal stations indicate the "coastal-grid effect" due to the land and ocean back-ground emissivity with in the same grid box in the scenario of satellite measurements. The number of events detected by single sensor only is being high indicates that the rainfall is not uniform even over a small grid size of 0.25X0.25 degrees. This suggests the need to have closely knit network of ground stations within the grid.

Harikumar, R.; Sampath, S.; Varikoden, Hamza; G, Mohan Kumar; v, Sasi Kumar; M, Gairola R.

60

HF Radar Sounding of TIDs with the Use of the DPS System and Signals from Broadcasting Stations  

Microsoft Academic Search

Atmospheric gravity waves (AGW) propagating in the ionosphere produce quasiperiodic varia- tions of the ionospheric electron density, known as traveling ionospheric disturbances (TID). In its turn, these wavelike processes modulate parameters of the radio signals in the medium; this effect is widely used for the remote sensing of TIDs. For example, paper (1) presents a bistatic radar technique for recovering

V. S. Beley; V. G. Galushko; D. Paznukhov; B. W. Reinisch; Y. M. Yampolski

61

Vertical profiles of Rain Drop Size Distribution at a tropical station using a k-band Doppler Radar  

NASA Astrophysics Data System (ADS)

Rain drop size distribution measurements are being carried out at CESS, Thiruvananthapuram (Lat: 8.3 N, Long: 76.9 E) using a Joss-Waldvogel disdrometer and a micro rain radar. The disdrometer, an electromechanical instrument, gives the DSD at the surface. The micro rain radar, a Doppler radar, gives the DSD at different heights, starting from 200 m. Both the instruments are deployed at the same site. Measurements made during a few rainfall events are compared and the general characteristics are derived. The DSD measured at the surface and at 200m with short term averaged follows a log-normal distribution. But the radar measurements differ from the log-normal distribution, irrespective of the averaging time above 400m altitude. The smaller drop sizes show an exponential decrease with increasing drop diameter rather than the increase as expected from a log-normal distribution. The presence of a large number of smaller drops above 400 m and their relative absence below this altitude are presented and discussed. This point out that the larger drops coming from above colliding with smaller drops could coalesce, thus sweeping out the smaller drops as they fall. All these observed phenomena in the natural rain are the observational evidence for the findings by Low and List in 1982.

Harikumar, R.; Sampath, S.; v, Sasi Kumar

62

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

63

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

64

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

65

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

66

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

67

[Evaluation of medication advertising broadcast on radio stations].  

PubMed

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

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

2013-02-01

68

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

69

Evaluation of bait stations for broadacre control of rabbits  

Microsoft Academic Search

The efficacy of bait stations (200-L drum cut in half longitudinally) for the broadacre control of rabbits was compared with that obtained with standard trail-baiting procedures in the southern agricultural region of Western Australia. Bait stations were tested with and without the provision of pre-feed. The bait used was 1.0% 1080 One-shot oats, and corresponding experimental control sites were treated

Laurie E. Twigg; Tim J. Lowe; Gary R. Martin

2002-01-01

70

On the Potential of Kinematic GPR Surveying Using a Self-Tracking Total Station: Evaluating System Crosstalk and Latency  

Microsoft Academic Search

In this paper, we present an efficient kinematic ground-penetrating radar (GPR) surveying setup using a self-tracking total station (TTS). This setup combines the ability of modern GPR systems to interface with Global Positioning System (GPS) and the capability of the employed TTS system to immediately make the positioning information available in a standardized GPS data format. Wireless communication between the

Urs Boniger; Jens Tronicke

2010-01-01

71

Radar applications  

NASA Astrophysics Data System (ADS)

Papers are presented on air-traffic control radar, surveillance radar, missile guidance radar, and high-performance tactical three-dimensional radar. Also considered are the airborne early warning radar, the Foxhunter airborne intercept radar, and environmental remote sensing. Other topics include spaceborne SARs, the Pioneer Orbiter radar, and a bistatic pulse-Doppler intruder-detection radar.

Skolnik, Merrill I.

72

Radar applications  

Microsoft Academic Search

Papers are presented on air-traffic control radar, surveillance radar, missile guidance radar, and high-performance tactical three-dimensional radar. Also considered are the airborne early warning radar, the Foxhunter airborne intercept radar, and environmental remote sensing. Other topics include spaceborne SARs, the Pioneer Orbiter radar, and a bistatic pulse-Doppler intruder-detection radar.

Merrill I. Skolnik

1988-01-01

73

Performance evaluation of a Doppler radar system for wind shear detection  

NASA Technical Reports Server (NTRS)

Nonlinear stochastic differential equations are used to model wind shear, and extended Kalman filters are used to generate state estimates from measurements received from a Doppler radar onboard an aircraft. Likelihood-ratio tests are then used to detect the presence of wind shear. The performance of the system is evaluated by deriving theoretical expressions for the false alarm and miss error probabiilties. The approach uses a Fokker-Planck equation. The overall methodology is general and should be of interest in other applications.

Khalaf, Camille S.; Hibey, Joseph L.; Staton, Leo D.

1990-01-01

74

[Development of innovative methods of electromagnetic field evaluation for portable radio-station].  

PubMed

The results of portable radio-station "Radiy-301" electromagnetic fields (EMF) emission measurement and specific absorption rate data evaluation has shown that workers' exposure EMF levels may elevate hygienic norms and hereupon can be health risk factor. Possible way of portable radio-station EMF dosimetry enhancement by means of domestic and international approaches harmonization is considered. PMID:23785811

Rubtsova, N B; Perov, S Iu; Bogacheva, E V; Kuster, N

2013-01-01

75

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

NASA Technical Reports Server (NTRS)

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

1983-01-01

76

Evaluation of absorption cycle for space station environmental control system application  

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

77

Numerical modelling calculations for evaluating exposure to radio-frequency emissions from base station antennas  

Microsoft Academic Search

The availability of reliable, simple procedures providing assistance in evaluating human exposure to radiofrequency fields from base station antennas is essential for mobile communications. In the paper, sample results of 'rigorous' full-wave numerical analysis of the electromagnetic field morphology in vicinity of a representative base station (BS) panel antenna are presented. Having recognized the field morphology, two simple approximate calculational

Andnej Karwowski

2002-01-01

78

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

79

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

NASA Technical Reports Server (NTRS)

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

Helmreich, Robert L.; Wilhelm, John A.

1985-01-01

80

Evaluating exposure to radio-frequency emissions from base station antennas  

Microsoft Academic Search

The availability of efficient, reliable and reasonably simple procedures providing assistance in evaluating human exposure to radiofrequency fields from base station antennas is essential for mobile communications. In this paper, sample results of \\

Andrzej Karwowski

2002-01-01

81

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

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

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

82

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

83

Statistical evaluation of a radar rainfall system for sewer system management  

NASA Astrophysics Data System (ADS)

Urban areas are faced with mounting demands for managing waste and stormwater for a cleaner environment. Rainfall information is a critical component in efficient management of urban drainage systems. A major water quality impact affecting receiving waterbodies is the discharge of untreated waste and stormwater during precipitation, termed wet weather flow. Elimination or reduction of wet weather flow in metropolitan sewer districts is a major goal of environmental protection agencies and often requires considerable capital improvements. Design of these improvements requires accurate rainfall data in conjunction with monitored wastewater flow data. Characterizing the hydrologic/hydraulic performance of the sewer using distant rain gauges can cause oversizing and wasted expenditures. Advanced technology has improved our ability to measure accurately rainfall over large areas. Weather radar, when combined with rain gauge measurements, provides detailed information concerning rainfall intensities over specific watersheds. Knowing how much rain fell over contributing areas during specific periods aids in characterizing inflow and infiltration to sanitary and combined sewers, calibration of sewer system models, and in operation of predictive real-time control measures. Described herein is the design of a system for managing rainfall information for sewer system management, along with statistical analysis of 60 events from a large metropolitan sewer district. Analysis of the lower quartile rainfall events indicates that the expected average difference is 25.61%. Upper quartile rainfall events have an expected average difference of 17.25%. Rain gauge and radar accumulations are compared and evaluated in relation to specific needs of an urban application. Overall, the events analyzed agree to within ± 8% based on the median average difference between gauge and radar.

Vieux, B. E.; Vieux, J. E.

2005-09-01

84

Altitudinal and Temporal Evolution of Rain Drop Size Distribution Observed Over a Tropical Station Using a Micro Rain Radar  

NASA Astrophysics Data System (ADS)

Rain drop size distribution (DSD) measurements at different heights were made using a Micro Rain Radar (MRR-2) at Thiruvananthapuram (8.3 N, 76.9 E). The rain DSD data obtained from MRR has been compared with a Joss waldvogel impact type Disdrometer (RD-80) deployed nearby and they are in good agreement. The analysis uses the data for different rain episodes. Here presents the data during a continuous rainfall episode from 16:10:01 hrs to 16:12:31 hrs on 12th August 2006 only. The fall velocity (velocity of those drops which contribute most to rain rate) was more or less constant at different altitudes and also with time and the average value is 4.6 m/s. The rain rate was below 5 mm/hr for all the heights throughout the time. At the beginning of the rain episode, the number of drops at any given altitude was higher for smaller drops and lower for larger drops. But towards the end of the episode, the number of drops in the smallest size class has reduced at almost all heights, while the number of drops in the larger size classes has increased. This means that the larger drops coming from above collide with smaller drops and coalesce, thus sweeping out the smaller drops as they fall. It is also observed that, the number of drops falls exponentially with diameter at all heights. The number of drops at the small diameter end is very high at the highest altitude and decreases drastically as altitude decreases. This also suggests that, coalescence is more predominant than break-up during collisions of the rain drops as they fall.

Harikumar, R.

85

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

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

86

International Space Station Bacteria Filter Element Service Life Evaluation  

NASA Technical Reports Server (NTRS)

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

Perry, J. L.

2005-01-01

87

Comparison of Airborne and Spaceborne 95-GHz Radar Reflectivities and Evaluation of Multiple Scattering Effects in Spaceborne Measurements  

E-print Network

and to the evaluation of the CloudSat­Cloud- Aerosol Lidar and Infrared Pathfinder Satellite Obser- vations (CALIPSO. To fulfill these objectives, the French Falcon 20 (F-F20) was deployed with a 95-GHz Doppler radar Society #12;(CNES) Afternoon Satellite Constellation (A-Train) track and to then document the cross-track

Protat, Alain

88

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

89

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

90

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

91

Use of radars to monitor stream discharge by noncontact methods  

USGS Publications Warehouse

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. Copyright 2006 by the American Geophysical Union.

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

2006-01-01

92

Performance evaluation of the Enraf-Nonius Model 872 radar gage  

SciTech Connect

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

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

1992-12-01

93

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

94

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 ...

95

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

96

Evaluation of near field of the GSM base station antennas in urban environment  

Microsoft Academic Search

A simple and efficient method for evaluation of the near field of GSM base station antennas in an urban environment is presented in this paper. The method is based on the replacement of the panel antenna with a discrete linear array. Moreover, the geometrical optics approach is used to consider the influence of the environment. The approximate results are found

D. Wojcik

2002-01-01

97

Microwave emissions from police radar  

E-print Network

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

Fink, John Michael

2012-06-07

98

The Pyla 2001 Experiment: Evaluation of Polarimetric Radar Capabilities over a Forested Area  

NASA Astrophysics Data System (ADS)

Low frequency SAR (P-band) represents a promising tool for remote sensing, since it allows us to investigate the sub-surface down to several meters under certain circumstances as well as the vegetation cover. On the other hand, polarimetric capabilities of such system bring also new contributions in SAR measurements. ONERA developed a multi-frequency, full polarimetric, high resolution airborne SAR facility named RAMSES which now operates at P- band (435 MHz). An experiment was performed over the Pyla region near Bordeaux, in France during April and May 2001, in order to assess the benefit of low frequency, multi-polarization and polarimetric in interpreting SAR measurements over natural sites. This area was chosen as a suitable laboratory site for fieldwork validation : (1) sub- surface soil moisture detection (Pyla sand dune), (2) biomass evaluation (Nezer forest), (3) mapping of the ocean bathymetry and salinity (basin of Arcachon), and (4) archeology. In addition, a dedicated P-band calibration site was set up in order to fully exploit the polarimetric information as well as ground measurements in order to derive the biophysical and geophysical characteristics of the terrain. During this workshop, firt results of this experiment obtained over the Nezer test site (a forested area located in les Landes) will be investigated. Amplitude and phase distributions of the radar signal derived from several images will be considered in terms of the geometrical tree parameters and the biomass.

Dechambre, M.; Le Hégarat, S.; Cavelier, S.; Dreuillet, P.; Champion, I.

2003-04-01

99

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

Code of Federal Regulations, 2011 CFR

...Doppler Radar and Inertial Navigation System (INS): Request...Doppler Radar or Inertial Navigation System must submit...program curriculum for initial approval under § 121...Training programs. The initial training program for Doppler Radar and Inertial Navigation Systems must...

2011-01-01

100

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

Code of Federal Regulations, 2012 CFR

...Doppler Radar and Inertial Navigation System (INS): Request...Doppler Radar or Inertial Navigation System must submit...program curriculum for initial approval under § 121...Training programs. The initial training program for Doppler Radar and Inertial Navigation Systems must...

2012-01-01

101

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

Code of Federal Regulations, 2013 CFR

...Doppler Radar and Inertial Navigation System (INS): Request...Doppler Radar or Inertial Navigation System must submit...program curriculum for initial approval under § 121...Training programs. The initial training program for Doppler Radar and Inertial Navigation Systems must...

2013-01-01

102

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

...Doppler Radar and Inertial Navigation System (INS): Request...Doppler Radar or Inertial Navigation System must submit...program curriculum for initial approval under § 121...Training programs. The initial training program for Doppler Radar and Inertial Navigation Systems must...

2014-01-01

103

Planetary Radar with the Green Bank Telescope  

NASA Astrophysics Data System (ADS)

The large aperture and sensitive receivers of the National Radio Astronomy Observatory's Robert C. Byrd Green Bank Telescope (GBT) make it an attractive receiving station for bistatic radar experiments. Consequently, it has been used as a receive station for radar observations since its commissioning in 2001. The GBT is equipped with receivers for all common planetary radar transmitters at P, S, and X band, as well as for future radars at up to 86 GHz. We describe the technical capabilities of the GBT and its instrumentation in terms of its tracking and RF performance, the available radar backends, and select science results obtained through the use of the GBT.

Ford, Alyson; Ford, John M.; Watts, Galen

2014-11-01

104

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

105

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

106

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

107

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

108

Evaluation of single- and full-polarization two-dimensional Prony techniques applied to radar data  

NASA Astrophysics Data System (ADS)

The recently developed 2-D TLS-Prony technique is applied to a single and full-polarization synthetically generated radar data set. The radar target analyzed is a generic aircraft consisting of a fuselage, wing, stabilizer, and tail. The 2-D TLS-Prony technique is a parametric estimation technique that models the radar return frequency domain data (multiple angle, multiple frequency data, e.g., SAR/ISAR) using damped exponentials. The technique's ability to accurately model and characterize the target are investigated. Scattering center location and characterization are accomplished by the technique. Issues such as model order selection, bandwidth requirements, and modeling error are examined for both single and full polarization data sets.

Sacchini, Joseph J.; Romano, Anthony; Steedly, William M.

1994-07-01

109

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

110

Performance evaluation of the Enraf-Nonius Model 872 radar gage  

Microsoft Academic Search

There are indications that the Enraf-Nonius Radar Gage installed in Tank 241-SY-101 may not be providing an accurate reading of the true surface level in the waste tank. The Pacific Northwest Laboratory (PNL) performed an initial study to determine the effect of the following items on the distance read by the gage: Tank riser; Material permittivity and conductivity Foam; Proportion

T. J. Peters; W. R. Park

1992-01-01

111

Evaluation of the radar cross section of circular microstrip patches on anisotropic and chiral substrates  

Microsoft Academic Search

Galerkin's method in the Hankel transform domain (HTD) is applied to the determination of the radar cross section (RCS) of a circular microstrip patch printed on a substrate which may be an uniaxial anisotropic dielectric, a magnetized ferrite, or a chiral material. The results obtained for circular patches on magnetized ferrites show that the RCS of these patches can be

V. Losada; R. R. Boix; F. Medina

2001-01-01

112

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

113

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

114

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

NASA Astrophysics Data System (ADS)

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

2012-12-01

115

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

NASA Astrophysics Data System (ADS)

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

Vitale, Q.; Rejiba, F.; Guérin, R.

2012-12-01

116

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

117

Significance of spatial variability in precipitation for process-oriented modelling: results from two nested catchments using radar and ground station data  

Microsoft Academic Search

The importance of considering the spatial distribution of rainfall for process-oriented hydrological modelling is well-known. However, the application of rainfall radar data to provide such detailed spatial resolution is still under debate. In this study the process-oriented TACD (Tracer Aided Catchment model, Distributed) model had been used to investigate the effects of different spatially distributed rainfall input on simulated discharge

D. Tetzlaff; S. Uhlenbrook

2005-01-01

118

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

119

Radar rain field evaluation and possible use of its high temporal and spatial resolution for hydrological purposes  

Microsoft Academic Search

The purpose of this paper is to show how accurate radar-estimated rainfall, with good temporal and spatial resolution, can be used for hydrological purposes. A recent methodological advance in rainfall measurement using conventional weather radars has made it possible to account for much of the variation between the precipitation radar echo intensity and rain intensity. A method known as the

J. Morin; D. Rosenfeld; E. Amitai

1995-01-01

120

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

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

121

Using an Airborne Doppler Lidar to Evaluate QuikSCAT and RadarSat Derived Winds  

NASA Astrophysics Data System (ADS)

While near surface winds derived from space-based remote sensing have proven very useful, both operationally and for research, there remain several issues not fully resolved. Besides the persistent wind direction uncertainty, high wind speeds (> 25 m/s) and organized circulations such as those associated with large marine atmospheric boundary layer eddies continue to introduce magnitude and representativeness errors in the data products. The US Navy and the Integrated Program Office of NPOESS have jointly sponsored the installation and use of a scanning Doppler wind lidar on a Navy Twin Otter aircraft. The lidar is a 2 micron coherent system with a side door mounted hemispherical scanner. Returns from aerosols are processed to obtain wind profiles (above and below flight level). The measurement accuracy is on the order of a few cm/sec in speed and a degree or two in direction. The footprint of the lidar beam is < 1 meter and the full profiles are constructed with wind observations over a one l kilometer flight segment. The vertical resolution is usually < 50 meters. In the nadir looking mode, the Doppler lidar can resolve wave structures with < 5 cm/sec vertical motion accuracy and with .5 meter horizontal resolution. In the Spring of 2002, the lidar was flown over Monterey Bay (CA)during QuikSCAT and RadarSat overpasses. Cloud streets were observed from the aircraft and with the lidar in the vicinity of organized patterns in the RadarSAT returns. The lidar data offer detailed insight into the velocity and aerosol structures within the larger footprints of the space-based sensors. Detailed analyses of the collocated lidar, QuikScat and RadarSat data will be presented along with plans for the future use of this new research facility.

Emmitt, G. D.; O'Handley, C.; Brown, R. A.; Foster, R.

2002-12-01

122

Synthetic aperture radar for search and rescue: evaluation of advanced capabilities in preparation for RADARSAT-2  

NASA Astrophysics Data System (ADS)

Researchers at the Canada Centre for Remote Sensing of Natural Resources Canada are exploring the use of remotely sensed imagery to assist Search and Rescue in Canada. Studies have been examining the use of Synthetic Aperture Radar for the detection of crashed aircraft. Promising results have been obtained with techniques for detection of dihedrals in interferometric and polarimetric data. With further development in technologies and techniques, and improved coverage of the Canadian landmass by future spaceborne systems such as RADARSAT-2, it is expected that it will be possible to assist in Search and Rescue for land targets.

Lukowski, Tom I.; Khellah, Fakhry; Charbonneau, Francois J.; Yue, Bing

2002-07-01

123

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

124

Holographic surveillance radar  

NASA Astrophysics Data System (ADS)

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 targets and clutter. Holographic radar has a range of applications in which the ability to discriminate targets among clutter is key. An example of such an application is in mitigation of wind farm interference with Air Traffic Control radar.

Oswald, Gordon K. A.

2009-05-01

125

Micropower impulse radar  

SciTech Connect

Invented and developed at Lawrence Livermore National Laboratory is an inexpensive and highly sensitive, low-power radar system that produces and samples extremely short pulses of energy at the rate of 2 million per second. Called micropower impulse radar (MIR), it can detect objects at a greater variety of distances with greater sensitivity than conventional radar. Its origins in the Laboratory`s Laser Directorate stem from Nova`s transient digitizer. The MIR`s extraordinary range of applications include security, search and rescue, life support, nondestructive evaluation, and transportation.

Azevedo, S.; McEwan, T.E.

1996-01-01

126

Evaluation of the biological effects of police radar RAMER 7F  

SciTech Connect

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

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

1993-06-01

127

Experimental evaluation of battery cells for space-based radar application  

NASA Technical Reports Server (NTRS)

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

Maskell, Craig A.; Metcalfe, John R.

1994-01-01

128

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

NASA Technical Reports Server (NTRS)

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

Macdonald, H.; Waite, W. P.

1977-01-01

129

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

E-print Network

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

Stoffelen, Ad

130

Summary of Turbulence Data Obtained During United Air Lines Flight Evaluation of an Experimental C Band (5.5 cm) Airborne Weather Radar  

NASA Technical Reports Server (NTRS)

Data on atmospheric turbulence in the vicinity of thunderstorms obtained during a flight evaluation of an experimental C band (5.5 cm) airborne radar are summarized. The turbulence data were obtained with an NACA VGH recorder installed in a United Air Lines DC-3 airplane.

Coe, E. C.; Fetner, M. W.

1954-01-01

131

Evaluation of a voice recognition system for the MOTAS pseudo pilot station function  

NASA Technical Reports Server (NTRS)

The Langley Research Center has undertaken a technology development activity to provide a capability, the mission oriented terminal area simulation (MOTAS), wherein terminal area and aircraft systems studies can be performed. An experiment was conducted to evaluate state-of-the-art voice recognition technology and specifically, the Threshold 600 voice recognition system to serve as an aircraft control input device for the MOTAS pseudo pilot station function. The results of the experiment using ten subjects showed a recognition error of 3.67 percent for a 48-word vocabulary tested against a programmed vocabulary of 103 words. After the ten subjects retrained the Threshold 600 system for the words which were misrecognized or rejected, the recognition error decreased to 1.96 percent. The rejection rates for both cases were less than 0.70 percent. Based on the results of the experiment, voice recognition technology and specifically the Threshold 600 voice recognition system were chosen to fulfill this MOTAS function.

Houck, J. A.

1982-01-01

132

Measurement System Testbed for the robotic evaluation and characterization of the Space Station Remote Manipulator System  

NASA Astrophysics Data System (ADS)

The rationale and the initial concept for a measurement systems testbed (MST) to support the Robotics Evaluation and Characterization (REACH) Project are outlined. Geometric scale, kinematics, general mass and stiffness distributions of the Space Station Remote Manipulator System (SSRMS), and the orbital illumination are considered important in the design. The MST objectives are to validate: the REACH concept, SSRMS measurement systems capabilities relative to the project's needs, calibration methods for measurement systems, data processing and parameter identification algorithms and techniques, in-orbit tests, and in-orbit operational configurations and procedures. A practical suspension system is required in order to allow the MST to simulate, for measurement and other purposes, a reasonable approximation of the 0-g response of the SSRMS.

Kujath, Marek R.; Graham, William B.

1992-11-01

133

Test and evaluation of the heat recovery incinerator system at Naval Station, Mayport, Florida  

NASA Astrophysics Data System (ADS)

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

1981-05-01

134

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

135

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. PMID:24106524

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

2013-01-01

136

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

137

EMP (electro-magnetic pulse) hardening of a relocatable radar  

Microsoft Academic Search

The problem of ensuring radar survivability in a HEMP (high-altitude electromagnetic pulse) environment is examined with particular reference to experimental results obtained for the relocatable TRS 22XX radar. The approach used here is global hardening, whereby the whole system except the antenna is enclosed in a Faraday cage. Every penetration of the radar station is protected, the energy input is

G. J. Deville

1987-01-01

138

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

139

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

140

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

141

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

142

Laser radar  

Microsoft Academic Search

The general theory of laser tracking and ranging and the principles governing the design of laser radar systems are examined. Major problems related to optimum reception of laser radar signals and parameter measurement are analyzed from the standpoint of the theory of statistical solutions. Attention is given to methods for processing trajectory measurements and various methods for obtaining noncoordinate information,

I. N. Matveev; V. V. Protopopov; I. N. Troitskii; N. D. Ustinov

1984-01-01

143

Start discriminator for mode locked train laser radar.  

NASA Astrophysics Data System (ADS)

A problem of start detector is very topical in laser radar station working with a train of pulses generated by mode locked Nd:YAG laser. This article deals with a newly developed start detector used in Intercosmos laser radar station in Helwan, Egypt. The time resolution of the detector is better than 150 ps.

?ech, M.

144

Target Tracking for Multistatic Radar with Transmitter Uncertainty  

E-print Network

demodulated essentially without error (television and radio would not work, otherwise) there is no concern-located; in passive radar radio or television stations take the place of the sender and only the receiver is under passive radar using DAB/DVB versus more traditional systems using, for example, commercial FM stations [12

Zhou, Shengli

145

Performance evaluation of the impact of mobile base station on clustered wireless sensor networks  

Microsoft Academic Search

Base station mobility can be exploited to minimise the energy consumption in a wireless sensor network. This paper investigates the impact that base station movement has upon the performance of cluster-based wireless sensor networks. Three types of base station movement are considered: movement influenced by the position of cluster-heads, random movement and movement partially influenced by the position of cluster-heads.

Siddeswara Mayura Guru; Daniel Smith; Yanfeng Shu; Paulo de Souza

2009-01-01

146

The Retrieval of Ice Water Content from Radar Reflectivity Factor and Temperature and Its Use in Evaluating a Mesoscale Model  

E-print Network

The Retrieval of Ice Water Content from Radar Reflectivity Factor and Temperature and Its Use form 11 June 2005) ABSTRACT Ice clouds are an important yet largely unvalidated component of weather, demonstrating that, for stratiform midlatitude ice clouds, radar reflectivity in the Rayleigh-scattering regime

Hogan, Robin

147

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

Microsoft Academic Search

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

M. Vogt; M. Gerding; T. Musch

2010-01-01

148

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

149

Evaluation of the Vitotox and RadarScreen assays for the rapid assessment of genotoxicity in the early research phase of drug development.  

PubMed

The Vitotox and RadarScreen assays were evaluated as early screens for mutagenicity and clastogenicity, respectively. The Vitotox assay is a bacterial reporter assay in Salmonella typhimurium based on the SOS-response, and it contains a luciferase gene under control of the recN promoter. The RadarScreen assay is a RAD54 promoter-linked beta-galactosidase reporter assay in yeast. The expression of this beta-galactosidase can easily be quantified by use of the substrate d-luciferin-o-beta-galactopyranoside, which is converted into galactose and luciferin that can be measured luminometrically. Recently, an ECVAM workgroup defined a list of 20 genotoxic and 42 non-genotoxic compounds [D. Kirkland, P. Kasper, L. Muller, R. Corvi, G. Speit, Recommended lists of genotoxic and non-genotoxic chemicals for assessment of the performance of new or improved genotoxicity tests: a follow-up to an ECVAM workshop, Mutat. Res. 653 (2008) 99-108.] that can be used for the validation and/or optimization of in vitro genotoxicity assays. In the present study, this compound set was used for the validation of the assays. Moreover, an additional set of 192 compounds was used to broaden this validation study. The compounds of this additional set can be classified as non-genotoxins and genotoxins and consists of both in-house and reference compounds. In case of the ECVAM compound list, the results from the Vitotox and RadarScreen assays were compared to the genotoxic/non-genotoxic classification of the compounds in this list. In case of the additionally tested compounds, the results of the Vitotox and RadarScreen assays were compared, respectively, with bacterial mutagenicity (Ames) results or in vitro clastogenicity data obtained in-house or from the literature. The validation with respect to the ECVAM compound list resulted in a sensitivity for both the Vitotox and RadarScreen assay of 70% (14/20). If both assays were combined the sensitivity increased to 85% (17/20). Both tests also gave a low number of false positive results. The specificity of the Vitotox and RadarScreen assays was 93% (39/42) and 83% (35/42), respectively. This resulted in a predictivity of the Vitotox and RadarScreen assay of 85% (53/62) and 79% (49/62), respectively. In case both tests were combined the specificity and the predictivity of the Vitotox and RadarScreen assay turned out to be 81% (34/42) and 82% (51/62), respectively. The results from the additional list of 192 compounds confirmed the results found with the ECVAM compound list. The results from the Vitotox assay showed a high correlation with Ames test of 91% (132/145). Subsequently, the RadarScreen assay had a correlation with in vitro clastogenicity of 76% (93/123). The specificity of the Vitotox assay was 94% (90/96) for Ames test results and that of the RadarScreen assay was 74% (34/46) for clastogenicity. Moreover, the sensitivities of the Vitotox and RadarScreen assays were 86% (42/49) and 77% (59/77), respectively. Implementation of the Vitotox and RadarScreen assays in the early research phase of drug development can lead to fast de-selection for genotoxicity. It is expected that this application will reduce the number of compounds that have a positive score in the regulatory Ames and clastogenicity tests. Moreover, problems with a complete compound class can be foreseen at an early time point in the research phase, which gives more time for issue resolution than late detection of these problems with the regulatory tests. PMID:19393335

Westerink, Walter M A; Stevenson, Joe C R; Lauwers, Annick; Griffioen, Gerard; Horbach, G Jean; Schoonen, Willem G E J

2009-05-31

150

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

EPA Science Inventory

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

151

The Patriot radar in tactical air defense  

NASA Astrophysics Data System (ADS)

The Patriot radar is a C-band, phased-array, multifunction radar that, under the control of the weapon control computer in the engagement control station, performs target search and track; missile search, track, and communications during midcourse guidance; and target-via-missile terminal guidance. This paper describes the functions the radar performs and provides descriptions of the subsystems. The use of a multichannel, multifunction receiver and digital signal processor is emphasized to demonstrate the control and processing for multiple radar actions required to support the tactical air defense mission. A summary of results of an extensive test program at the White Sands Missile Range is presented.

Carey, David R.; Evans, William

1988-05-01

152

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

153

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

NASA Technical Reports Server (NTRS)

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

Dever, Joyce A.

1998-01-01

154

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

155

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

156

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

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

157

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

158

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

159

New weather radar coming  

NASA Astrophysics Data System (ADS)

What would you call the next generation of radar for severe weather prediction? NEXRAD, of course. A prototype for the new system was recently completed in Norman, Okla., and by the early 1990s up to 195 stations around the United States will be tracking dangerous weather and sending faster, more accurate, and more detailed warnings to the public.NEXRAD is being built for the Departments of Commerce, Transportation, and Defense by the Unisys Corporation under a $450 million contract signed in December 1987. Th e system will be used by the National Weather Service, the Federal Aviation Administration (FAA), and the U.S. Air Force and Navy. The NEXRAD radar tower in Norman is expected to be operational in October.

Maggs, William Ward

160

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

161

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

E-print Network

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

Ortega, Jose Alberto, 1978-

2006-01-01

162

Evaluation of ionospheric sporadic-E clutter in an arctic environment for the assessment of high-frequency surface-wave radar surveillance  

Microsoft Academic Search

This paper studies the Arctic ionospheric environment using ionosonde data and assesses the potential of high-frequency surface-wave radar (HFSWR) surveillance for surface vessels and low-altitute air targets. The evaluation is based on sporadic-E (Es) interference in the HFSWR signal. For surveillance problems up to 150 km, such as in the Northwest Passage through Canada's Arctic islands, the ionospheric Es clutter

Thayananthan Thayaparan; John MacDougall

2005-01-01

163

Geothermal resource evaluation at Naval Air Station Fallon, Nevada. Final report, June 1985-August 1986  

SciTech Connect

During the summer of 1986, Fallon Observation Hole 2 (FOH-2) was drilled in the southeast corner of Naval Air Station (NAS) Fallon, Nevada, to provide additional information on the geothermal resource at that installation.

Katzenstein, A.M.; Bjornstad, S.C.

1987-08-01

164

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

PubMed

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

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

2013-09-01

165

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

PubMed

In the early morning, during workdays, intensive activity is observed at both bus and railway stations. This particular time is critical because of the combination of three factors: (1) simultaneous departure of many buses and trains, (2) cold engines, and, quite frequently, (3) stable meteorological conditions. In our approach, we use ARIA Local, a simulation package applying CFD tools to air pollution modeling, to study different scenarios. The CFD model used in this study is the MERCURE model, developed by Electricite de France. For a bus station, we simulate a typical morning peak hour situation and study in detail how the pollution is accumulated in the station courtyard and the impact on the close vicinity. Two scenarios are presented: one with classical diesel engine and one with buses using AQUAZOL or NGV fuel. The definition of the sources inside the Eulerian grid is described as static linear sources. The total emission is averaged over the mean path driven by the bus from the bus stop to the exit of the bus station. For a railway station, we simulate a situation in a real railway station within the city of Paris. The emission from a diesel "locomotive" and its impact on air quality is computed and compared to the impact of other nonmobile emissions. In this case, the definition of sources is described as mobile point sources following the trajectory of the train. These two scenarios are discussed in an urban context, taking into account the flow around buildings and different meteorological conditions. PMID:15504509

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

2004-12-01

166

INUNDAÇÕES EM SÃO CARLOS, SP: AVALIAÇÃO DE CHUVAS COM RADAR  

Microsoft Academic Search

This work presents three flood events in the urban catchment of the Gregorio creek basin in São Carlos, SP, and the rain evaluation of rain estimated by the Bauru weather radar. The radar rain quantification was made using a Z-R relationship derived from radar reflectivity and total rain from raingage, in these flood cases. Another radar rain quantification for those

Mauricio de Agostinho Antonio

167

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

168

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

USGS Publications Warehouse

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

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

2004-01-01

169

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

170

Biomarker approach to evaluating the impact of scientific stations on the antarctic environment using Trematomus bernacchii as a bioindicator organism  

Microsoft Academic Search

A biomonitoring study was performed to evaluate the human impact on two small coves adjacent to the Italian Scientific Station at Terra Nova Bay in November 1995. The study used the fish species Trematomus bernacchii as a bioindicator organism for a biomarker analysis based on porphyrin levels, and BPMO (Benzo(a)pyrene MonoOxygenase) and EROD (Ethoxyresorufin-O-deethylase) activities. Porphyrin levels and EROD and

B. Jiménez; M. C. Fossi; M. Nigro; S. Focardi

1999-01-01

171

Use of radar to estimate precipitation in a semi-arid area  

E-print Network

raingauge and radar data. This study concerns 11 daily rainfall events observed in the Paris region by a 10-cm weather radar for 98 stations spread over 20, 000 kmz. This method improved the results of radar data slightly and is better than... raingauge and radar data. This study concerns 11 daily rainfall events observed in the Paris region by a 10-cm weather radar for 98 stations spread over 20, 000 kmz. This method improved the results of radar data slightly and is better than...

Al-Khalaf, Abdulrahman Khalaf

2012-06-07

172

Preliminary evaluation of polarimetric parameters from a new dual-polarization C-band weather radar in an alpine region  

NASA Astrophysics Data System (ADS)

The first operational weather radar with dual polarization capabilities was recently installed in Austria. The use of polarimetric radar variables rises several expectations: an increased accuracy of the rain rate estimation compared to standard Z-R relationships, a reliable use of attenuation correction methods, and finally hydrometeor classification. In this study the polarimetric variables of precipitation events are investigated and the operational quality of the parameters is discussed. For the new weather radar also several polarimetric rain rate estimators, which are based on the horizontal polarization radar reflectivity, ZH, the differential reflectivity, ZDR, and the specific differential propagation phase shift, KDP, have been tested. The rain rate estimators are further combined with an attenuation correction scheme. A comparison between radar and rain gauge indicates that ZDR based rain rate algorithms show an improvement over the traditional Z-R estimate. KDP based estimates do not provide reliable results, mainly due to the fact, that the observed KDP parameters are quite noisy. Furthermore the observed rain rates are moderate, where KDP is less significant than in heavy rain.

Paulitsch, H.; Teschl, F.; Randeu, W. L.

2010-05-01

173

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

NASA Technical Reports Server (NTRS)

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

1998-01-01

174

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

NASA Technical Reports Server (NTRS)

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

1997-01-01

175

33. Site Plan: Custer Air Force Station, Battle Creek, Michigan, ...  

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

33. Site Plan: Custer Air Force Station, Battle Creek, Michigan, FD Radar Facilities-FPS-27, Electrical Plot Plan and Duet Details, USACOE, not date. - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

176

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

177

Measurement-Based Evaluation of Vertical Separation MIMO Antennas for Base Station  

Microsoft Academic Search

It is worth noting that the use of vertical separation antenna configuration provides an easy way to form large separation on a single pole. In this letter, the effect of vertical separation multiple-input–multiple-output (MIMO) antenna configurations for base station is investigated by field drive tests. The results show that vertical separation antenna configurations can meet the requirement of spatial multiplexing

Weiliang Xie; Tao Yang; Xuetian Zhu; Fengyi Yang; Qi Bi

2012-01-01

178

Measuring Winds With Pulsed C-Band Radar  

NASA Technical Reports Server (NTRS)

Research has begun on use of pulsed C-band radar in multistatic configuration to measure winds in absence of clouds. Experimental system based on principle of multistatic radar. Multiple receivers track on same point in sky to measure winds from different angles, obtaining complete wind vector at that point. Includes one radar station that both transmits and receives and one or more other stations receiving only. Advantage of multistatic configuration greatly reduces effects of ground clutter on receive-only stations. Objective of effort to develop capability to use wind-measurement data to predict, as early and accurately as possible, formation of local thunderstorms-with lead times of several hours.

Lennon, Carl; Wesenberg, Richard; Britt, Thomas O.; Brooks, Michael; Edwards, Deloris; Franklin, Chris; Kiriazes, John; Kitayama, Brad; Medina, Jim

1989-01-01

179

Surveillance Technology Study and Analysis. Volume IV. Considerations in the Analysis and Performance of Radar Systems.  

National Technical Information Service (NTIS)

This report presents results of studies, investigations, and technique developments which will be useful in future HF long range radar applications. This report is intended to aid the radar engineer in design and evaluation of HF radar systems. Major emph...

R. M. Davis, L. C. Widmann

1967-01-01

180

A simulation model for reliability evaluation of Space Station power systems  

NASA Technical Reports Server (NTRS)

A detailed simulation model for the hybrid Space Station power system is presented which allows photovoltaic and solar dynamic power sources to be mixed in varying proportions. The model considers the dependence of reliability and storage characteristics during the sun and eclipse periods, and makes it possible to model the charging and discharging of the energy storage modules in a relatively accurate manner on a continuous basis.

Singh, C.; Patton, A. D.; Kumar, Mudit; Wagner, H.

1988-01-01

181

Recent Radar Speckle Observations of Near-Earth Asteroids  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

182

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

183

State of subsoil in a former petrol station: physicochemical characterization and hydrocarbon contamination evaluation  

NASA Astrophysics Data System (ADS)

Former petrol stations are, possibly, potential hydrocarbon contaminated soil areas due to leakage in Underground Storage Tanks and fuel dispensing activities. Volatile Organic Compounds (VOCs) in gasoline, like benzene and semi-volatile organics in diesel, are carcinogenic and very toxic substances which can involve a serious risk for ecosystem and human health. Based on Electrical Resistivity Tomography 2D results from a previous work, there have been selected three potentially contaminated goal areas in a former petrol station located in SE Spain in order to obtain soil samples by drilling and to assess the gasoline and diesel contamination. A special sampling design was carried out and soil samples for VOCs were preserved at field with a KCl solution to minimize volatilization losses. It had been chosen Headspace-GC-MS as the better technique to quantify individual VOCs and GC-FID to get a Total Petroleum Hydrocarbon (TPH) assessment after a solid/fluid pressurized extraction. The physicochemical characterization of the subsoil was performed to know how humidity, clay content or pH data could be related to the presence of hydrocarbons in the soil samples. Results show that VOCs concentrations in subsoil samples of the petrol station are around ppb levels. TPH ranged between 17 mg/kg soil and 93 mg/kg soil (ppm levels) what involves diesel and gasoline leaks due to these detected residual concentrations in the subsoil. The maximum value was found at 6 m deep in an intermediate zone between Underground Storage Tanks positions (located at 4 m deep). Therefore, these results confirm that organic compounds transference with strong vertical component has taken place. It has been observed that humidity minimum values in the subsoil are related to TPH maximum values that could be explained because of the vapour phase and the retention of hydrocarbon in soil increases when humidity goes down. Adsorption of hydrocarbons in the subsoil tend to be pH-dependent and clay content dependent: maximum of adsorption taken place at minimum pH what encourage protonation and minimum clay content in the subsoil make organic compounds infiltration downstream easier. It could be noticed the importance of physicochemical subsoil characterization and contamination assessment in the subsoil of petrol stations in order to avoid the hydrocarbons pollution of the groundwater. Then plan the best remediation technique according to this characterization taking into account the residual hydrocarbon concentration in the subsoil and the associated risk for human and ecosystems.

María Rosales, Rosa; Martinez-Pagán, Pedro; Faz, Ángel; Bech, Jaume

2013-04-01

184

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

185

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

186

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

187

Agricultural and hydrological applications of radar  

NASA Technical Reports Server (NTRS)

Program objectives, covering a wide range of disciplines and activities in radar remote sensing, include radar systems development and analysis, data processing and display, and data interpretation in geology, geography and oceanography. Research was focused on the evaluation of radar remote sensing applications in hydrology and agriculture based on data acquired with the Microwave Active Spectrometer (MAS) system. The title, author(s) and abstract of each of the 62 technical reports generated under this contract are appended.

Ulaby, F. T.

1976-01-01

188

Weather Radar Fundamentals  

NSDL National Science Digital Library

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

Comet

2012-03-21

189

Engineering evaluation of magma cooling-tower demonstration at Nevada Power Company's Sunrise Station  

NASA Astrophysics Data System (ADS)

The Magma Cooling Tower (MCT) process utilizes a falling film heat exchanger integrated into an induced draft cooling tower to evaporate waste water. A hot water source such as return cooling water provides the energy for evaporation. Water quality control is maintained by removing potential scaling constituents to make concentrations of the waste water possible without scaling heat transfer surfaces. A pilot-scale demonstration test of the MCT process was performed from March 1979 through June 1979 at Nevada Power Company's Sunrise Station in Las Vegas, Nevada. The pilot unit extracted heat from the powerplant cooling system to evaporate cooling tower blowdown. Two water quality control methods were employed: makeup/sidestream softening and fluidized bed crystallization. The 11 week softening mode test was successful.

1980-11-01

190

Performance and evaluation of gas-engine-driven split-system cooling equipment at the Willow Grove Naval Air Station  

SciTech Connect

DOE`s Federal Energy Management Program supports efforts to reduce energy use and associated expenditures within the federal sector; one such effort, the New Technology Demonstration Program (NTDP)(formerly the Test Bed Demonstration program), seeks to evaluate new energy saving US technologies and secure their more timely adoption by the federal government. This report describes the field evaluation conducted to examine the performance of a 15-ton natural-gas-engine- driven, split-system, air-conditioning unit. The unit was installed at a multiple-use building at Willow Grove Naval Air Station, a regular and reserve training facility north of Philadelphia, and its performance was monitored under the NTDP.

Armstrong, P.R.; Schmelzer, J.R.

1997-01-01

191

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

192

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

E-print Network

cts within the state of Texas. In 1977 the TEA published a booklet outlining the princ1ples, standards, and procedures for the accreditation of school di stri cts under its j urisd1ction (Texas Education Agency, 1977). Cond1t1on 0 5... and evaluated, Some believe that evaluators should base their evaluations upon qualitative or subjective knowledge (Finn, 1969), while others contend that more quantitative or objective knowledge is needed. Eisner (1979, 1976) has spearheaded a move toward...

Conner, Paul William

2012-06-07

193

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 46, NO. 10, OCTOBER 2008 3067 Evaluation of X-Band Polarimetric-Radar Estimates  

E-print Network

for the correction of rain-path atten- uation at X-band radar frequency and the estimation of rain parameters of X-Band Polarimetric-Radar Estimates of Drop-Size Distributions From Coincident S-Band Polarimetric estimates from S-band radar observations and in situ disdrometer spectra. We present compar- isons

Marzano, Frank Silvio

194

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

195

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

196

Economic and Conservation Evaluation of Capital Renovation Projects: United Irrigation District of Hidalgo County (United) – Rehabilitation of Main Canal, Laterals, and Diversion Pump Station – Final  

E-print Network

TR-288 March 2006 Economic and Conservation Evaluation of Capital Renovation Projects: United Irrigation District of Hidalgo County (United) – Rehabilitation of Main Canal, Laterals, and Diversion Pump Station – Final M. Edward Rister Ronald D...) – Rehabilitation of Main Canal, Laterals, and Diversion Pump Station – Final This research was supported by the “Rio Grande Basin Initiative” which is administered by the Texas Water Resources Institute of the Texas A&M University System with funds provided...

Rister, M. Edward; Lacewell, Ronald D.; Sturdivant, Allen W.

197

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

198

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

199

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

200

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

201

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

202

Engineering evaluation of magma cooling-tower demonstration at Nevada Power Company's Sunrise Station. Final report  

SciTech Connect

The Magma Cooling Tower (MCT) process utilizes a falling film heat exchanger integrated into an induced draft cooling tower to evaporate wastewater. A hot water source such as return cooling water (90/sup 0/F to 110/sup 0/F) provides the energy for evaporation. Water quality control is maintained by removing potential scaling constituents to make concentration of the wastewater possible without scaling heat transfer surfaces. A pilot-scale demonstration test of the MCT process was performed from March 1979 through June 1979 at Nevada Power Company's Sunrise Station in Las Vegas, Nevada. The pilot unit extracted heat from the powerplant cooling system to evaporate cooling tower blowdown. Two water quality control methods were employed: makeup/sidestream softening and fluidized bed crystallization. The 11-week softening mode test was successful. The unit operated without biofouling or scaling at 100,000 ppM TDS levels under a wide range of operating conditions. Successful operation was not demonstrated in the 10-day crystallization mode test; calcium sulfate (CaSO/sub 4/) scaling occurred on the last day of the test at a maximum brine concentration of less than 40,000 ppM. An economic and technical comparison with other zero-discharge technologies showed that, for application at Sunrise, the MCT process had competitive capital, operating, and levelized annual costs. No major technical problems were encountered that would preclude the commercial application of a properly designed MCT unit operating in the softening mode.

Not Available

1980-11-01

203

Evaluation of the prompt alerting systems at four nuclear power stations  

SciTech Connect

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

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

1982-09-01

204

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

205

Remote sensing of sea state by radar  

Microsoft Academic Search

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

D. Barrick

1972-01-01

206

Imaging radar for bridge deck inspection  

Microsoft Academic Search

Lawrence Livermore National Laboratory is developing a prototype imaging radar for inspecting steel reinforced concrete bridge decks. The system is designed to acquire synthetic aperture radar data and provide high-resolution images of internal structure, flaws, and defects enabling bridge inspectors to nondestructively evaluate and characterized bridge deck condition. Concrete delamination resulting from corrosion of steel reinforcing bars (rebars) is an

John P. Warhus; Jeffrey E. Mast; Scott D. Nelson

1995-01-01

207

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

208

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

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

209

Radar electronic warfare  

Microsoft Academic Search

An overview of radar and electronic warfare is given. Definitions, common terms, and principles of radar and electronic warfare, and simple analyses of interactions between radar systems and electronic countermeasures (ECM) are presented. Electronic counter-countermeasure and electronic support measures are discussed. Background material in mathematics, electromagnetics, and probability necessary for an understanding of radar and electronic warfare is given and

August Golden Jr.

1987-01-01

210

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

211

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

212

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

213

Risk-based evaluation of technical specification problems at the La Salle County Nuclear Station: Final report  

SciTech Connect

Probabilistic risk assessment (PRA) methods are used to evaluate alternatives to existing requirements for three operationally burdensome technical specifications at La Salle Nuclear Station. The study employs a decision logic to minimize the detailed analysis necessary to show compliance with given acceptance criteria; in this case, no risk increase resulting from a proposed change. The analyses provide insights to choose from among alternative options. The SOCRATES computer code was used for the probabilistic analysis. Results support a change to less frequent diesel generator testing, eliminations of one reactor scram setpoint, and establishing an allowed out-of-service time for valves in a reactor scram system. In each case, the change would result in a safety improvement.

Bizzak, D.J.; Trainer, J.E.; McClymont, A.S.

1987-06-01

214

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

ERIC Educational Resources Information Center

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

Jacobs, C. O.

215

Health hazard evaluation report No. HETA 81-112-1372, Culley Generating Station, Yankeetown, Indiana  

SciTech Connect

To evaluate worker exposure to boiler gases and coal dust, NIOSH conducted a combined environmental and medical evaluation at the Culley facility in August 1981. Environmental samples were collected to evaluate employee exposure to airborne concentrations of nitrogen dioxide, nitric oxide, sulfur dioxide, coal dust, fly ash, crystalline silica, and asbestos. In addition, boiler gas leaks were evaluated. While the majority of personal samples were below current criteria, a health hazard did exist for some employees exposed to sulfur dioxide. In addition, a potential for exposure to boiler gases exists due to boiler leaks. Respiratory symptoms of cough, phlegm production, and wheezing were twice the expected rate for this group of workers. The X-ray data revealed four cases of pneumoconiosis in the Culley workers. The relative youth and the low seniority of this workforce may explain the absence of group PFT reductions. If preventive engineering measures are employed, the occurrence of continued group health effects will likely be reduced. Recommendations are made for an improved respiratory protection program, reducing leaks from process equipment, and for periodic environmental monitoring of the employees.

Zey, J.N.; Donohue, M.

1983-09-01

216

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

217

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

218

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

219

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

220

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

221

Hard threshold correlation detector for mobile HF Surface Wave Radar  

Microsoft Academic Search

Mobile HF Surface Wave Radar (SWR) can be realized by an offshore distributed receiver array structure which communicates to the central processing unit at the base station via a wireless link. State of the art detectors demand a sophisticated signal processing which can only be done at base station hence making it imperative to transmit raw data form receiver to

Anshu Gupta; Th. Fickenscher

2012-01-01

222

Comparison and evaluation of nuclear power plant options for geosynchronous power stations  

NASA Technical Reports Server (NTRS)

The suitability of eleven types of nuclear fission reactors in combination with five potential energy conversion systems for use in geosynchronous power plants is evaluated. Gas turbine, potassium Rankine liquid metal MHD, and thermionic energy conversion systems are considered. The existing technology of reactors in near-term, intermediate-term, and long-term classes is discussed, together with modifications for use in large-scale power production in space. Unless the temperature is high enough for MHD, reactors which heat gases are generally more suitable for use with gas turbines. Those which heat liquid metals will be more useful for potassium Rankine or liquid metal MHD conversion systems.

Williams, J. R.

1975-01-01

223

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

SciTech Connect

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

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

1984-04-01

224

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

225

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

NASA Technical Reports Server (NTRS)

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

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

2015-01-01

226

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

227

Report on the Radar/PIREP Cloud Top Discrepancy Study  

NASA Technical Reports Server (NTRS)

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

Wheeler, Mark M.

1997-01-01

228

Radar electronic warfare  

NASA Astrophysics Data System (ADS)

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

Golden, August, Jr.

229

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

230

Microwave emissions from police radar.  

PubMed

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

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

1999-01-01

231

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

Microsoft Academic Search

In response to a request from workers at the Texas Utilities Electric Company (SIC-4911), Martin Lake Steam Electric Station in Tatum, Texas, the incidence of neurologic symptoms and exposure to electromagnetic fields and organophosphates were investigated. Workers reported neurological symptoms, including memory loss, dizziness and fatigue. A site visit to the station revealed electromagnetic field levels below the current occupational

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

1996-01-01

232

Environmental monitoring and fuzzy synthetic evaluation of municipal solid waste transfer stations in Beijing in 2001-2006.  

PubMed

Transfer station (TS) is an integral part of present-day municipal solid waste (MSW) management systems. To provide information for the incorporation of waste facilities within the current integrated waste management system, the authors measured the existing environmental quality at five MSW TSs. Discharged wastewater, air, and noise were monitored and assayed at the five TSs in Beijing in 2001-2006 during rainy seasons (RSs) and dry seasons (DSs). Except Ammonia (NH3) and hydrogen sulfide (H2S), the analytical results of total suspended particles (TSPs), odor, noise, ammonium nitrogen (NH4(+)-N), chemical oxygen demand (COD(Cr)), biochemical oxygen demand (BOD5), suspended solid (SS), and fecal coliform concentrations were all degree-varied higher than the criteria limit in China. Using fuzzy mathematics, the environmental quality of MSW TSs in Beijing was classified into five categories, with levels of certainty of belonging to different categories and evaluations. The result indicated that the whole environmental quality of Datun TS, Majialou TS, and Xiaowuji TS, in Beijing, were bad during 2001-2006 in RSs and DSs. Except in 2002, the entire environmental quality of the Wuluju TS during 2001-2006 in RSs was poor. Only in the DSs of 2002 and 2003 was the whole environmental quality of the Wuluju TS good. The whole environmental quality of the Yamenkou TS during 2001-2006 in DSs was bad, which was lower than that of 2001-2006 DSs. PMID:18817081

Li, Chunping; Li, Guoxue; Luo, Yiming; Li, Yanfu; Huang, Jian

2008-01-01

233

Rain-Mapping Radar  

NASA Technical Reports Server (NTRS)

Orbiting radar system measures rates of rainfall from 0.5 to 60 mm/h. Radar waves scattered and absorbed by rainfall to extents depending on wavelength, polarization, rate of rainfall, and distribution of sizes and shapes of raindrops. Backscattered radar signal as function of length of path through rain used to infer detailed information about rain. Accumulated radar return signals processed into global maps of monthly average rainfall for use in climatological studies.

Im, K. E.; Li, F. K.; Wilson, W. J.; Rosing, D.

1988-01-01

234

The Southern Argentine Agile Meteor Radar (SAAMER)  

NASA Astrophysics Data System (ADS)

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

Janches, Diego

2014-11-01

235

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

236

Radar augmentation device  

NASA Technical Reports Server (NTRS)

The radar augmentation device (RAD) serves to increase the radar response of a target body and thus expedite radar acquisition. The design and development of the RAD are discussed with particular emphasis on technical problems that were encountered and solved. Discussions of the mode of operation of the RAD and the ground test history are also included.

Riedel, J. K.

1972-01-01

237

Micropower impulse radar  

Microsoft Academic Search

Invented and developed at Lawrence Livermore National Laboratory is an inexpensive and highly sensitive, low-power radar system that produces and samples extremely short pulses of energy at the rate of 2 million per second. Called micropower impulse radar (MIR), it can detect objects at a greater variety of distances with greater sensitivity than conventional radar. Its origins in the Laboratory`s

S. Azevedo; T. E. McEwan

1996-01-01

238

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

239

Controlling radar signature  

SciTech Connect

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, K.W. (U.S. Navy, Naval Air Warfare Center, China Lake, CA (United States))

1992-08-01

240

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

241

Radar hydrology: rainfall estimation  

Microsoft Academic Search

Radar observations of rainfall and their use in hydrologic research provide the focus for the paper. Radar-rainfall products are crucial for input to runoff and flood prediction models, validation of satellite remote sensing algorithms, and for statistical characterization of extreme rainfall frequency. In this context we discuss the issues of radar-rainfall product development, and the theoretical and practical requirements of

W. F. Krajewski; J. A. Smith

2002-01-01

242

Space stations - A historical perspective  

NASA Technical Reports Server (NTRS)

This paper discusses the historical evolution of the space station concept, with particular attention to NASA plans in the 1960-1980 period. Emphasis is given to the changing justification presented for station development during that period and to the political context within which station proposals were evaluated.

Logsdon, J. M.

1983-01-01

243

Cloud and Precipitation Radar  

NASA Astrophysics Data System (ADS)

Precipitation or weather radar is an essential tool for research, diagnosis, and nowcasting of precipitation events like fronts or thunderstorms. Only with weather radar is it possible to gain insights into the three-dimensional structure of thunderstorms and to investigate processes like hail formation or tornado genesis. A number of different radar products are available to analyze the structure, dynamics and microphysics of precipitation systems. Cloud radars use short wavelengths to enable detection of small ice particles or cloud droplets. Their applications differ from weather radar as they are mostly orientated vertically, where different retrieval techniques can be applied.

Hagen, Martin; Höller, Hartmut; Schmidt, Kersten

244

Space Station  

NASA Technical Reports Server (NTRS)

The official start of a bold new space program, essential to maintain the United States' leadership in space was signaled by a Presidential directive to move aggressively again into space by proceeding with the development of a space station. Development concepts for a permanently manned space station are discussed. Reasons for establishing an inhabited space station are given. Cost estimates and timetables are also cited.

Anderton, D. A.

1985-01-01

245

Radar investigation of the Cote Blanche salt dome  

E-print Network

, and the salt was probed in horizontal and vertical directions with both horizontally and vertically polarized electro- magnetic waves at several radar stations in the salt mine. Hori- zontal probing yielded some data about the nature of the salt which lies... THE COTE BLANCHE SALT DOME. Geology of the Cote Blanche Salt-Dome Azea. . Economic History of the Cote BLanche Salt-Dome Azea, Salt. . Oil and gas. III. ELECTROMAGNETIC WAVE PROPAGATION. . . Radar Speed in Air and in Salt. . . Velocity...

Stewart, Robert Donald

2012-06-07

246

Radar data pre-processing for reliable rain field estimation  

Microsoft Academic Search

A comparative analysis of different pre-processing methods applied to radar data for the minimization of the uncertainty of the produced Z-R relationship is conducted. The study focuses on measurements from 3 ground precipitation stations which are located in close proximity to the Souda Bay C-Band radar in Crete, Greece. While precipitation and reflectivity measurements were both collected in almost synchronized

Ioannis N. Daliakopoulos; Ioannis K. Tsanis

2010-01-01

247

Use of a combined personal computer and Rock-Eval in an integrated petroleum evaluation work station to estimate volumes of hydrocarbons generated and migrated in sedimentary basins  

SciTech Connect

A petroleum evaluation work station consisting in a modified Rock-Eval apparatus connected to an IBM personal computer has been designed at Institut Francais du petrole to estimate the amount of hydrocarbon generated and migrated in sedimentary basins. The work-station is provided with specific software for Rock-Eval data analysis, quick determination of kinetic parameters (Optim model), and quantitative hydrocarbon generation (Matoil model). Along with the classical Rock-Eval parameters (S{sub 0}, S{sub 1}, S{sub 2}, TOC, and T{sub max}), new parameters concerning the source rocks, such as the transformation efficiency ratio (TER), the migration efficiency ration (MER), and the initial generation capacity (IGC), are defined. These new parameters combined with geological data give access to a rapid volumetric estimation (in 10{sup 6}MT/km{sup 2}) of hydrocarbon generation and migration in the studied area. These data can be displayed on different specific maps for rapid visualization. This work station has been successfully used in the Paris and Aquitaine basins, making possible a better assessment of their petroleum potential. The petroleum evaluation work station appears to be a very valuable tool that can be used in the different phases of exploration in a sedimentary basin.

Espitalie, J.; Lafargue, E.; Drouet, S. (Institut Francais du Petrole, Rueil-Malmaison)

1989-09-01

248

Space-based radar clutter cancellation techniques  

NASA Astrophysics Data System (ADS)

The ability of a space-based radar surveillance system to obtain target information from a clutter corrupted radar echo signal is dependent upon the clutter cancellation technique employed. In this paper, radar clutter is described using temporal probability models, spectral models, and average backscatter coefficient models. Capitalizing on the different spectral characteristics between clutter and targets, three representative Doppler clutter cancellation schemes are described. Using the clutter models and cancellation schemes described, the clutter attenuation factors for the various cancellation methods against different backgrounds are computed to evaluate the clutter cancellation ability of different cancellation schemes.

Devenuto, J.; Castor, K. G.

249

EMP (electro-magnetic pulse) hardening of a relocatable radar  

NASA Astrophysics Data System (ADS)

The problem of ensuring radar survivability in a HEMP (high-altitude electromagnetic pulse) environment is examined with particular reference to experimental results obtained for the relocatable TRS 22XX radar. The approach used here is global hardening, whereby the whole system except the antenna is enclosed in a Faraday cage. Every penetration of the radar station is protected, the energy input is correctly filtered, and the signal input/output is implemented with optical fibers. Specific technological solutions for HEMP hardening are discussed.

Deville, G. J.

250

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

251

Coastal radar observations reveal complex surface circulations  

NASA Astrophysics Data System (ADS)

The behavior of nearshore ocean surface currents has important effects on the coastal ecosystem, with the alongshore propagating waves helping transport marine organisms and affecting how nutrients, salt, and heat are distributed. Using a network of 61 high-frequency radar stations off the U.S. West Coast, Kim et al. got a detailed look at the motion of the coastal ocean. They found that there are essentially two distinct sets of poleward propagating waves driving the nearshore flow.

Schultz, Colin

2013-11-01

252

Submitted to the Arctic Centre on April 22, 2003 A snow-cover experiment at Tarfala Research Station  

E-print Network

Station with ultra-high frequency ground-penetrating radar Sang De Brabander Department of Geography-scope radiogram. Ground- penetrating radar demonstrated to resolve the hidden targets thanks to the use ground-penetrating radar (GPR) is an equivalent alternative tool to study snow cover. To meet this goal

Moore, John

253

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

254

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

255

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

256

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

257

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

SciTech Connect

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

Not Available

1988-06-01

258

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

259

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

260

Incorporating WAAS Data Into an Ionospheric Model for Correcting Satellite Radar  

E-print Network

for the entire visible sky. Comparisons with range residuals on laser calibration spheres have shown in the radar metric data is verified via range residuals on calibration satellites. 1. INTRODUCTION The MIT laser ranging stations, using lasers

Toews, Carl

261

Caribbean Radar Cases  

NSDL National Science Digital Library

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

Comet

2013-12-31

262

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

263

Hazard evaluation and technical assistance report No. Ta 79-2, Department of Tranportation, Vehicle Inspection Stations, Washington, DC  

Microsoft Academic Search

Atmospheric air samples were analyzed, and pre- and post-shift carboxyhemoglobin levels were measured to determine employee exposures to carbon monoxide (630080), lead (7439921), asbestos (1332214), hydrogen sulfide (7783064) and sulfur dioxide (7446095) at the Northeast and Southwest Vehicle Inspection Stations (Standard Industrial Classification 754) in Washington, DC, on November 7 and 8, 1978. The survey was requested by the Office

1979-01-01

264

An evaluation of the effectiveness of instruction and audience reaction to programming on an educational television station  

Microsoft Academic Search

The achievement of students enrolled in elementary psychology and biology television instruction and non-television instruction was compared. No significant differences were found. An audience-reaction survey of Houston televiewers revealed that 75% of the audience watched the station from as often as three times a week to at least once in two weeks. Highly preferred programs included sports, a psychology course,

Richard I. Evans; H. Burr Roney; Walter J. McAdams

1955-01-01

265

Environmental monitoring and fuzzy synthetic evaluation of municipal solid waste transfer stations in Beijing in 2001–2006  

Microsoft Academic Search

Transfer station (TS) is an integral part of present-day municipal solid waste (MSW) management systems. To provide information for the incorporation of waste facilities within the current integrated waste management system, the authors measured the existing environmental quality at five MSW TSs. Discharged wastewater, air, and noise were monitored and assayed at the five TSs in Beijing in 2001–2006 during

Chunping LI; Guoxue LI; Yiming LUO; Yanfu LI; Jian HUANG

2008-01-01

266

The Invisible Radar Triangle  

NSDL National Science Digital Library

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

RET-ENET Program, Electrical Engineering Department,

267

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

268

Imaging radar for bridge deck inspection  

NASA Astrophysics Data System (ADS)

Lawrence Livermore National Laboratory is developing a prototype imaging radar for inspecting steel reinforced concrete bridge decks. The system is designed to acquire synthetic aperture radar data and provide high-resolution images of internal structure, flaws, and defects enabling bridge inspectors to nondestructively evaluate and characterized 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, John P.; Mast, Jeffrey E.; Nelson, Scott D.

1995-05-01

269

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

270

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

SciTech Connect

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

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

1996-01-01

271

Micropower impulse radar  

Microsoft Academic Search

Invented and developed at LLNL (Lawrence Livermore National Laboratory), this inexpensive and highly sensitive radar system produces and samples extremely short pulses of energy. This novel technology is finding dozens of new uses in Laboratory programs and in sensor devices for homes, automobiles, factories, and hospitals. We have invented and patented a fundamentally different type of compact, low-power radar system

S. Azevedo; T. E. McEwan

1997-01-01

272

Radar illusion via metamaterials  

NASA Astrophysics Data System (ADS)

An optical illusion is an image of a real target perceived by the eye that is deceptive or misleading due to a physiological illusion or a specific visual trick. The recently developed metamaterials provide efficient approaches to generate a perfect optical illusion. However, all existing research on metamaterial illusions has been limited to theory and numerical simulations. Here, we propose the concept of a radar illusion, which can make the electromagnetic (EM) image of a target gathered by radar look like a different target, and we realize a radar illusion device experimentally to change the radar image of a metallic target into a dielectric target with predesigned size and material parameters. It is well known that the radar signatures of metallic and dielectric objects are significantly different. However, when a metallic target is enclosed by the proposed illusion device, its EM scattering characteristics will be identical to that of a predesigned dielectric object under the illumination of radar waves. Such an illusion device will confuse the radar, and hence the real EM properties of the metallic target cannot be perceived. We designed and fabricated the radar illusion device using artificial metamaterials in the microwave frequency, and good illusion performances are observed in the experimental results.

Jiang, Wei Xiang; Cui, Tie Jun

2011-02-01

273

Java Radar Analysis Tool  

NASA Technical Reports Server (NTRS)

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

Zaczek, Mariusz P.

2005-01-01

274

Input uncertainty in catchment models: an evaluation of the suitability of multiplicative rainfall error models using high resolution raingauge and radar data  

NASA Astrophysics Data System (ADS)

This paper presents an investigation of rainfall error models used in rainfall-runoff model calibration and prediction. A growing number of studies now specify an error model for rainfall input, usually simple in form due to computational constraints during parameter estimation. Such rainfall error models have not typically been validated against experimental evidence. If the data uncertainty hypotheses and assumptions are unsupported, the interactions between input and structural model error may significantly contaminate the inference and lead to unreliable parameter estimates and model predictions. It is therefore important that the data error models should be developed using data analysis that is independent from the hydrological model calibration, to bring genuine independent information into the inference. In this study we use data from the 50 km2 Mahurangi catchment in Northland, New Zealand, where there is detailed space-time information on rainfall from both a dense tipping bucket raingauge network (13 stations) and X-band radar rainfall estimates. This high resolution data is used to provide insights on the suitability of the common multiplicative rainfall error model for use at varying spatial and temporal scales of hydrological models. We first present an analysis of the spatial variability and uncertainty in rainfall when considered solely as a binary (wet/dry) process. This type of analysis is a crucial check on the assumptions underlying multiplicative rainfall error models, since the latter cannot account for rain events with only partial catchment cover that are hence not recorded by a rain gauge. Secondly, we examine the consistency of rainfall quantities over the catchment; based both on complete rainfall records and also for individual storm events when correct estimation of rainfall is most crucial. This allows us to estimate the statistical distributions of rainfall multipliers and test if these could form the basis of an adequate rainfall error model and put multipliers into the context of events. Results highlight some important results for understanding rainfall uncertainty and deriving data-based probabilistic error models for use in hydrological calibration. In the Mahurangi catchment, multiplicative error appears to be a suitable formulation for correcting mean catchment rainfall values during high-rainfall periods (e.g. intensities over 1 mm/hour); or for longer timesteps at any rainfall intensity (timestep 1 day or greater). We suggest that the effect of timestep on multiplier suitability is regulated by catchment size: specifically the time required for typical raincells to cross the catchment could be used as a first estimate of critical timestep. The standard distribution used for rainfall multipliers, the lognormal, provided a relatively close fit to the empirical multiplier distributions. However the empirical distributions have greater excess kurtosis and positive skew than the lognormal. Since heavy rainfall events display multiplier distributions differing most significantly from the lognormal, a skewed and heavier-tailed distribution to be used for times of high rainfall would more faithfully reproduce the observed error characteristics. Lastly, the high resolution of the data available demonstrated the time/space complexity of rainfall behaviour that cannot be corrected by a simple multiplicative error on measured rainfall. A hydrological model that aims to capture the full effects of rainfall variability would need an additional mechanism, such as a distribution function approach to rainfall input; or a blurred threshold for processes such as infiltration excess.

Jackson, Bethanna; McMillan, Hilary; Clark, Martyn; Kavetski, Dmitri; Woods, Ross

2010-05-01

275

Equatorial MU Radar project  

NASA Astrophysics Data System (ADS)

Research Institute for Sustainable Humanosphere, Kyoto University (RISH) has been studying the atmosphere by using radars. The first big facility was the MU (Middle and Upper atmosphere) radar installed in Shiga, Japan in 1984. This is one of the most powerful and multi-functional radar, and is successful of revealing importance of atmospheric waves for the dynamical vertical coupling processes. The next big radar was the Equatorial Atmosphere Radar (EAR) installed at Kototabang, West Sumatra, Indonesia in 2001. The EAR was operated under close collaboration with LAPAN (Indonesia National Institute for Aeronautics and Space), and conducted the long-term continuous observations of the equatorial atmosphere/ionosphere for more than 10 years. The MU radar and the EAR are both utilized for inter-university and international collaborative research program for long time. National Institute for Polar Research (NIPR) joined EISCAT Scientific Association together with Nagoya University, and developed the PANSY radar at Syowa base in Antarctica as a joint project with University of Tokyo. These are the efforts of radar study of the atmosphere/ionosphere in the polar region. Now we can find that Japan holds a global network of big atmospheric/ionospheric radars. The EAR has the limitation of lower sensitivity compared with the other big radars shown above. RISH now proposes a plan of Equatorial MU Radar (EMU) that is to establish the MU-radar class radar next to the EAR. The EMU will have an active phased array antenna with the 163m diameter and 1055 cross-element Yagis. Total output power of the EMU will be more than 500kW. The EMU can detect turbulent echoes from the mesosphere (60-80km). In the ionosphere incoherent-scatter observations of plasma density, drift, and temperature would be possible. Multi-channel receivers will realize radar-imaging observations. The EMU is one of the key facilities in the project "Study of coupling processes in the solar-terrestrial system" for Master Plan 2014 of the Science Council of Japan (SCJ). We show the EMU project and its science in the presentation.

Yamamoto, Mamoru; Hashiguchi, H.; Tsuda, Toshitaka; Yamamoto, Masayuki

276

An Evaluation of the Observational Capabilities of A Scanning 95-GHz Radar in Studying the 3D Structures of Marine Stratocumulus Clouds  

NASA Astrophysics Data System (ADS)

Marine stratocumulus clouds play a critical role in Earth's radiative balance primarily due to the role of their high albedo reflecting incoming solar radiation, causing a cooling effect, while weakly reflecting outgoing infrared radiation. Characterization of the 3-Dimensional (3D) structure of these cloud systems over scales of 20-40 km is required to accurately account for the role of cloud inhomogeneity and structure on their shortwave forcing and lifetime, which has important applications for Global Climate Models. For first time, such 3D measurements in clouds were made available from a scanning cloud radar during the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program's Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) field campaign in the Azores Islands. The scanning radar observations were complemented by a suite of zenith-pointing active and passive remote sensors that were deployed to provide a detailed description of marine stratus over a long-term observation period in the ideal marine environment commonly found at the Azores. The scanning cloud radar observations present a shift from a multi-instrument, vertically pointing 'soda-straw' observation technique to a radar-only, 'radar-centric' observation technique. The scanning radar observations were gridded using a nearest-neighbor type scheme devised to take the natural variability of the observed field into account. The ability of the scheme to capture primary cloud properties (cloud fraction, cloud boundaries, drizzle detection) was assessed using measurements from the vertically pointing sensors. Despite the great sensitivity of the scanning cloud radar (-42.5 dBZ at 1 km range), the drop in sensitivity with range resulted in an artificial thinning of clouds with range from the radar. Drizzle-free cloud structures were undetectable beyond 5 km from the radar. Cloud fields containing drizzle were generally detectable to ranges exceeding 10 km from the radar. Well-defined streaking patterns in the drizzle field (reflectivity greater than -15 dBZ) at cloud base were concluded to be concomitant with the formation of boundary layer rolls. Sounding data for these well-defined (unbroken) rolls revealed a mean sub-cloud layer wind exceeding 3.9 ms -1, sub-cloud layer shear exceeding 7.5 x 10-3 s-1, and a majority of streaks oriented within 20° of the mean sub-cloud layer wind, satisfying many boundary layer roll criteria proposed in past studies. Attempts to reconstruct the 3D cloud liquid water content and 2D column liquid water path across the scanning radar domain using Z (Reflectivity) vs. LWC (Liquid Water Content) regressions trained using the zenith measurements were proved ineffective due to the overall extent of drizzle at Graciosa, and errors associated with sensitivity loss at range. Despite some difficulties, the SWACR satisfied ARM metrics for success by proving effective at detecting weak clouds for extended time periods across a 10 km plane, and drizzle across a 20 km range, at high spatial resolutions. Difficulties in resolving accurate vertical velocity patterns also suggest the need for an adaptive sampling strategy to most effectively remove horizontal wind components.

Bowley, Kevin

277

Spaceborne weather radar  

NASA Technical Reports Server (NTRS)

The present work on the development status of spaceborne weather radar systems and services discusses radar instrument complementarities, the current forms of equations for the characterization of such aspects of weather radar performance as surface and mirror-image returns, polarimetry, and Doppler considerations, and such essential factors in spaceborne weather radar design as frequency selection, scanning modes, and the application of SAR to rain detection. Attention is then given to radar signal absorption by the various atmospheric gases, rain drop size distribution and wind velocity determinations, and the characteristics of clouds, as well as the range of available estimation methods for backscattering, single- and dual-wavelength attenuation, and polarimetric and climatological characteristics.

Meneghini, Robert; Kozu, Toshiaki

1990-01-01

278

Micropower impulse radar imaging  

SciTech Connect

From designs developed at the Lawrence Livermore National Laboratory (LLNL) in radar and imaging technologies, there exists the potential for a variety of applications in both public and private sectors. Presently tests are being conducted for the detection of buried mines and the analysis of civil structures. These new systems use a patented ultra-wide band (impulse) radar technology known as Micropower Impulse Radar (GPR) imaging systems. LLNL has also developed signal processing software capable of producing 2-D and 3-D images of objects embedded in materials such as soil, wood and concrete. My assignment while at LLNL has focused on the testing of different radar configurations and applications, as well as assisting in the creation of computer algorithms which enable the radar to scan target areas of different geometeries.

Hall, M.S.

1995-11-01

279

Laser radar improvements  

NASA Astrophysics Data System (ADS)

A short history of the uses of various laser radars is presented, and appropriate applications of laser and microwave radars are discussed. CO2 laser radar, operating at 10.6 microns, is considered for use in aircraft navigation systems, fire-control systems for armored vehicle and aircraft, missile guidance, severe storm research, line-of-sight command of missiles, wind turbine site surveys, clear-air turbulence monitors for aircraft, and satellite tracking. Microwave radar is all-weather, but is subject to multipath inaccuracies, countermeasures, and angular resolution limitations, so hybrid laser microwave systems look promising for microwave target acquisition and laser tracking. Advantages and disadvantages of the use of ruby, YAG, and CO2 lasers in varying atmospheric conditions are discussed. Development of a laser radar pod for obstacle detection, Doppler navigation, automatic terrain following, hover control, weapon delivery, and precision searching is noted.

Jelalian, A. V.

1981-11-01

280

Airborne Doppler radar flight experiments for the detection of microbursts  

NASA Technical Reports Server (NTRS)

In the interest of aviation safety, NASA and the FAA are jointly conducting research to determine the applicability of airborne, coherent Doppler radar techniques to detect early microburst in wind shear conditions during aircraft takeoff and landing. Researchers have developed a computer model of the radar which predicts its response when viewing a simulated microburst against the simulated clutter background of an airport, the so-called radar microburst ground clutter model. Studies employing this model revealed that Doppler radar can accurately detect microburst ahead of the aircraft in time for pilot evasive response, but flight experiments will be required for complete performance evaluation of the system. An experimental X band radar is being developed for future flight experiments to verify the simulation modeling results. A description of the experimental radar, recording equipment, and its installation on the NASA 515 aircraft is presented. The flight experiments to be conducted are also described.

Blume, Hans-J. C.; Lytle, C. D.; Jones, W. R.; Bracalente, E. M.; Britt, C. L.

1989-01-01

281

Radar Location Equipment Development Program: Phase I  

SciTech Connect

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

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

1985-06-01

282

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

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

283

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

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

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

284

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

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

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

285

Meteor radar wind observations during the Energy Budget Campaign 1980  

Microsoft Academic Search

Equipment and data processing at a meteor radar station near Bologna are described, and results of zonal wind observations for 7-30 Nov 1980 are presented. Measurements were made between 75 and 115 km altitude. Monthly wind means disagree with those established during Nov 1976 and 1978 observations, and with the Cospar 1972 model for 45 deg N seasonal variations. Gravity

G. Cevolani; A. Dardi

1981-01-01

286

Investigations with SECAR - a bistatic HF surface wave radar  

Microsoft Academic Search

This paper describes a bistatic HF surface wave radar, designated SECAR, which was deployed near Darwin, Australia, and used to conduct a variety of scientific investigations related to radar design, siting and target detection, as well as providing a test-bed for evaluating the operational utility of HFSWR as an element of a national surveillance network. The scientific results are significant

S. J. Anderson; P. J. Edwards; P. Marrone; Y. I. Abramovich

2003-01-01

287

Application of HF radar currents to oil spill modelling  

Microsoft Academic Search

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

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

2009-01-01

288

The evolution of the SEASAT imaging radar  

NASA Technical Reports Server (NTRS)

The paper describes the design parameters and development of a synthetic aperture radar for use on the SEASAT spacecraft. This imaging radar is designed to operate at altitudes of 800 km with an orbital inclination of 108 deg, a nominal resolution of 25 m, and a swath width of 100 km. The design evolved from planetary imaging radar studies conducted over many years where an L-band imaging radar was developed and tested on aircraft flights as a prototype system to map the surface of Venus. A solid-state transmitter is used where the pulse repetition frequency is a function of altitude and will be about 2kHz for a 12-m long antenna. The receiver consists of the receiver protector, input filters, the gain control, and the RF amplifier. The ground station uses the standard NASA receiver with a 10-m antenna. The correlator, either optical or digital, must be able to compensate for the pitch and yaw variations of the spacecraft as well as the inherent effective yaw caused by the rotation of the earth, and extract the range curvature and range walk effects.

Brown, W. E., Jr.

1975-01-01

289

Spaceborne meteorological radar studies  

NASA Technical Reports Server (NTRS)

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

Meneghini, R.

1988-01-01

290

Planetary Radar Astronomy  

NASA Technical Reports Server (NTRS)

Radar is a powerful technique that has furnished otherwise unavailable information about solar system bodies for three decades. The advantages of radar in planetary astronomy result from: (1) the observer's control of all the attributes of the coherent signal used to illuminate the target, especially the wave form's time/frequency modulation and polarization; (2) the ability of radar to resolve objects spatially via measurements of the distribution of echo power in time delay and Doppler frequency; (3) the pronounced degree to which delay-Doppler measurements constrain orbits and spin vectors; and (4) centimeter-to-meter wavelengths, which easily penetrate optically opaque planetary clouds and cometary comae, permit investigation of near-surface macrostructure and bulk density, and are sensitive to high concentrations of metal or, in certain situations, ice. Planetary radar astronomy has primarily involved observations with Earth-based radar telescopes, but also includes some experiments with a spaceborne transmitter or receiver. In addition to providing a wealth of information about the geological and dynamical properties of asteroids, comets, the inner planets, and natural satellites, radar experiments have established the scale of the solar system, have contributed significantly to the accuracy of planetary ephemerides, and have helped to constrain theories of gravitation. This review outlines radar astronomical techniques and describes principal observational results.

Ostro, Steven J.

1993-01-01

291

Space object observation with radar  

NASA Astrophysics Data System (ADS)

FGAN developed a High Power Radar System, able to track and image low Earth orbiting objects, for experimental radar research. The system is unique in Germany; it consists of a narrow band tracking radar and a high resolution imaging radar. The radars are supported from one 34-m parabolic dish antenna. They operate simultaneously on the object of interest. All information which a radar can gain about physical characteristics of targets have to be extracted from the backscattered electromagnetic field of transmitted pulses. L-band tracking data provide information on range, range rate, angular direction, and radar cross-section. From high resolution polarimetric Ku-band radar data projections of the 1- and 2-dimensional scatter centre distributions are computed. This paper gives a brief description of the FGAN radar and summarizes some radar based methods for orbit analysis, orbital lifetime prediction, reconstruction of object images, assessment of object dimensions, shape, attitude, and mass.

Mehrholz, D.

1993-08-01

292

Radar applications overview  

NASA Astrophysics Data System (ADS)

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

Greenspan, Marshall

1996-06-01

293

Cassini radar : system concept and simulation results  

NASA Astrophysics Data System (ADS)

The Cassini mission is an international venture, involving NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI), for the investigation of the Saturn system and, in particular, Titan. The Cassini radar will be able to see through Titan's thick, optically opaque atmosphere, allowing us to better understand the composition and the morphology of its surface, but the interpretation of the results, due to the complex interplay of many different factors determining the radar echo, will not be possible without an extensive modellization of the radar system functioning and of the surface reflectivity. In this paper, a simulator of the multimode Cassini radar will be described, after a brief review of our current knowledge of Titan and a discussion of the contribution of the Cassini radar in answering to currently open questions. Finally, the results of the simulator will be discussed. The simulator has been implemented on a RISC 6000 computer by considering only the active modes of operation, that is altimeter and synthetic aperture radar. In the instrument simulation, strict reference has been made to the present planned sequence of observations and to the radar settings, including burst and single pulse duration, pulse bandwidth, pulse repetition frequency and all other parameters which may be changed, and possibly optimized, according to the operative mode. The observed surfaces are simulated by a facet model, allowing the generation of surfaces with Gaussian or non-Gaussian roughness statistic, together with the possibility of assigning to the surface an average behaviour which can represent, for instance, a flat surface or a crater. The results of the simulation will be discussed, in order to check the analytical evaluations of the models of the average received echoes and of the attainable performances. In conclusion, the simulation results should allow the validation of the theoretical evaluations of the capabilities of microwave instruments, when considering topics like the surface topography, stratigraphy and identification of different materials.

Melacci, P. T.; Orosei, R.; Picardi, G.; Seu, R.

1998-10-01

294

Evaluation of relative merits\\/demerits of different signaling schemes used at a railway station for an approaching train in Indian Railways today  

Microsoft Academic Search

Indian Railways, one of the largest railway networks in the world today, has a peculiarity that a station exists almost every 5-7 km. Most trains do not stop at all stations and run through more stations than they stop at. The speed at which the trains run through the stations, therefore, is a crucial parameter that determines the run time

P. R. Goundan; Ashok Jhunjhunwala

2002-01-01

295

Radar\\/Balloon Measurement of Vertical Air Motions Between the Surface and 15 km  

Microsoft Academic Search

An estimate of the vertical wind component up to an altitude of 15 km is derived from FPS-16 radar\\/Jimsphere ascent-rate measurements. The method involves removing ascent-rate profile variations which are not associated with vertical air motions.Radar noise errors are evaluated by comparing simultaneous measurements by two radars of a single balloon ascent. Radar noise is shown to be a high-frequency

R. E. de Mandel; S. J. Krivo

1971-01-01

296

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

NASA Technical Reports Server (NTRS)

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

1975-01-01

297

Rendezvous radar for the orbital maneuvering vehicle  

NASA Technical Reports Server (NTRS)

The Rendezvous Radar Set (RRS) was designed at Motorola's Strategic Electronics Division in Chandler, Arizona, to be a key subsystem aboard NASA's Orbital Maneuvering Vehicle (OMV). The unmanned OMV, which was under development at TRW's Federal Systems Division in Redondo Beach, California, was designed to supplement the Shuttle's satellite delivery, retrieval, and maneuvering activities. The RRS was to be used to locate and then provide the OMV with vectoring information to the target satellite (or Shuttle or Space Station) to aid the OMV in making a minimum fuel consumption approach and rendezvous. The OMV development program was halted by NASA in 1990 just as parts were being ordered for the RRS engineering model. The paper presented describes the RRS design and then discusses new technologies, either under development or planned for development at Motorola, that can be applied to radar or alternative sensor solutions for the Automated Rendezvous and Capture problem.

Locke, John W.; Olds, Keith A.; Quaid, Thomas

1991-01-01

298

Space station structures development  

NASA Technical Reports Server (NTRS)

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

Teller, V. B.

1986-01-01

299

Noise calibration and the development of remote receiver stations for TARA  

NASA Astrophysics Data System (ADS)

The Telescope Array RAdar (TARA) detector is based on a remote sensing technique known as bi-static radar that aims to achieve remote coverage over large portions of the Earth's surface in search of cosmic ray induced radio echoes. In conjunction with North America's largest cosmic ray observatory (The Telescope Array) in radio quiet western Utah, the radar project's pilot receiver and transmitter stations have been functional for just over a year and a half, giving insight into the detect-ability of air shower radar echoes. Currently the receiver stations comprise an array of Log Periodic Dipole Antennas with an oscilloscope-based data acquisition system implemented for noise calibration including tracking galactic noise as the galactic plane migrates through the sky. Our experiences thus far have given impetus for upgrades, including the deployment of additional remote receiver stations. We discuss some of the results of this oscilloscope-based DAQ system and the development of these remote stations.

Kunwar, Samridha

2013-04-01

300

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

301

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

302

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

303

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

USGS Publications Warehouse

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

Herzog, D.C.

1990-01-01

304

Simple, Practical Method for Determining Station Weights Using Thiessen Polygons and Isohyetal Maps  

E-print Network

estimation likely lies with remote sensing tech- niques, data collected at rain gauges is currently is aimed at improving the use of radar and satellite data to determine MAP, and the future of MAP of using radar data, if available, all use station weights annual or seasonal as the sole means

Fiedler, Fritz R.

305

Caribbean Radar Products  

NSDL National Science Digital Library

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

Comet

2013-12-31

306

Radar Calibration Test Satellite  

Microsoft Academic Search

A satellite has been designed for application to radar calibration. Electromagnetic and mechanical characteristics of the satellite and their influence on the selection of shape and other parameters are discussed. Theoretical and experimental scattering data are included.

L. J. Kaplan; J. F. A. Ormsby; EVERT N. FOWLE; KENT R. JOHNSON; Richard T. Bates; S. H. Bickel

1969-01-01

307

A smart radar absorber  

Microsoft Academic Search

This paper proposes a configuration for a smart radar absorber which is capable of both self-tuning and absorb while scan operation. The discussion is complemented by modelled and measured performance data.

Barry Chambers

1999-01-01

308

Laser Radar Animation  

NASA Video Gallery

Laser and radar instruments aboard NASA aircraft provide measurements of the snow and ice surface and down to the bedrock under the ice. Lasers, with a shorter wavelength, measure the surface eleva...

309

Phased-array radars  

NASA Astrophysics Data System (ADS)

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

Brookner, E.

1985-02-01

310

Downhole pulse radar  

DOEpatents

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

Chang, Hsi-Tien

1987-09-28

311

Downhole pulse radar  

DOEpatents

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

Chang, Hsi-Tien (Albuquerque, NM)

1989-01-01

312

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

313

On wave radar measurement  

NASA Astrophysics Data System (ADS)

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

Ewans, Kevin; Feld, Graham; Jonathan, Philip

2014-09-01

314

Intercontinental Bistatic Radar Test Observation of Asteroid 1998 WT24  

NASA Astrophysics Data System (ADS)

We describe the first intercontinental planetary radar test performed in Italy observing the near Earth asteroid (NEA) 33342 (1998 WT24) in December 2001 by means of the bistatic configurations Goldstone (California, USA)-Medicina (Italy) and Evpatoria (Ukraine)-Medicina. The experiment goal was to characterize the system for realtime radar follow-up observations of NEAs and artificial orbiting debris, in the framework of a feasibility study which aims at using the Sardinia Radio Telescope, at present under construction, also as a planetary radar facility. We report the preliminary results of the radar observations carried out by the IRA-CNR (Instituto di Radioastronomia - Consiglio Nazionale delle Ricerche) and the OATo (Osservatorio Astronomico di Torino) groups, aimed at exploring the scientific potentials of a new space radar program, using the existing facilities in Italy. The planetary radar technique is uniquely capable of investigating geometry and surface properties of various solar system objects, demonstrating advantages over the optical methods in its high spatial resolution and ability to obtain three-dimensional images. A single radar detection allows to obtain extremely accurate orbital elements, improving the instantaneous positional uncertainties by orders of magnitude with respect to an optically determined orbit. Radar is a powerful means to spatially resolve NEAs by measuring the distribution of the echo power in time delay (range) and Doppler frequency (line-of-sight velocity) with extreme precision in each coordinate, as it provides detailed information about the target physical properties like size, shape, rotation, near-surface bulk density and roughness and internal density distribution. The Medicina 32m antenna had been successfully used for the first time as the receiving part of a bistatic configuration during a test experiment (September 2001) held to check the capabilities of the entire data acquisition system. This test was possible thanks to the collaboration undertaken with the Evpatoria radar station, and consisted in the observation of the ETALON-1 low orbit satellite

Righini, S.; Poppi, S.; Montebugnoli, S.; DiMartino, M.; Saba, L.; Delbo, M.; Ostro, S.; Monari, J.; Poloni, M.; Orlati, A.

2002-01-01

315

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

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

316

Inversion of swell frequency from a 1-year HF radar dataset collected in Brittany (France)  

NASA Astrophysics Data System (ADS)

This article presents long period ocean wave (swell) frequencies inverted from a 13-month dataset of high-frequency (HF) phased array radars and an assessment of these estimates by comparison with WAVEWATCH III model data. The method of swell frequency inversion from high-frequency radar sea echo Doppler spectra is described. Radar data were collected from a two-site HF Wellen Radar (WERA) radar system on the west coast of Brittany (France) operating at 12 MHz. A standard beam-forming processing technique has been used to obtain Doppler spectra of processed radar cells. Swell frequencies are obtained from the frequencies of particular spectral peaks of the second-order continuum in hourly averaged Doppler spectra. The data coverage of effective Doppler spectra considered for swell frequency estimates shows the influence of islands and shallow water effects. Swell estimates from both radar stations are in good agreement. The comparison of radar-derived results to WAVEWATCH III (WW3) estimates shows that radar measurements agree quite well with model results. The bias and standard deviation between two estimates are very small for swells with frequency less than 0.09 Hz (period >11 s), whereas radar estimates are generally lower than model estimates for shorter swells, along with higher standard deviation. Statistical analysis suggests that radar measurement uncertainty explains most of the difference between radar and model estimates. For each swell event, time series of frequency exhibits a quasi-linear frequency increase which is associated with the dispersive property of wave phase velocity. The use of swell frequency estimates from both radars on common radar cells only slightly increases the accuracy of swell frequency measurement.

Wang, Weili; Forget, Philippe; Guan, Changlong

2014-10-01

317

Inversion of swell frequency from a 1-year HF radar dataset collected in Brittany (France)  

NASA Astrophysics Data System (ADS)

This article presents long period ocean wave (swell) frequencies inverted from a 13-month dataset of high-frequency (HF) phased array radars and an assessment of these estimates by comparison with WAVEWATCH III model data. The method of swell frequency inversion from high-frequency radar sea echo Doppler spectra is described. Radar data were collected from a two-site HF Wellen Radar (WERA) radar system on the west coast of Brittany (France) operating at 12 MHz. A standard beam-forming processing technique has been used to obtain Doppler spectra of processed radar cells. Swell frequencies are obtained from the frequencies of particular spectral peaks of the second-order continuum in hourly averaged Doppler spectra. The data coverage of effective Doppler spectra considered for swell frequency estimates shows the influence of islands and shallow water effects. Swell estimates from both radar stations are in good agreement. The comparison of radar-derived results to WAVEWATCH III (WW3) estimates shows that radar measurements agree quite well with model results. The bias and standard deviation between two estimates are very small for swells with frequency less than 0.09 Hz (period >11 s), whereas radar estimates are generally lower than model estimates for shorter swells, along with higher standard deviation. Statistical analysis suggests that radar measurement uncertainty explains most of the difference between radar and model estimates. For each swell event, time series of frequency exhibits a quasi-linear frequency increase which is associated with the dispersive property of wave phase velocity. The use of swell frequency estimates from both radars on common radar cells only slightly increases the accuracy of swell frequency measurement.

Wang, Weili; Forget, Philippe; Guan, Changlong

2014-08-01

318

The Capabilities of Space Stations  

NASA Technical Reports Server (NTRS)

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

1995-01-01

319

Broad perspectives in radar for ocean measurements  

NASA Technical Reports Server (NTRS)

The various active radar implementation options available for the measurement functions of interest for the SEASAT follow-on missions were evaluated. These functions include surface feature imaging, surface pressure and vertical profile, atmospheric sounding, surface backscatter and wind speed determination, surface current location, wavelength spectra, sea surface topography, and ice/snow thickness. Some concepts for the Synthetic Aperture Imaging Radar were examined that may be useful in the design and selection of the implementation options for these missions. The applicability of these instruments for the VOIR mission was also kept under consideration.

Jain, A.

1978-01-01

320

Estimating water discharge from large radar altimetry datasets  

NASA Astrophysics Data System (ADS)

The objective of this study is to evaluate the potential of large altimetry datasets as a complementary gauging network capable of providing water discharge in ungauged regions. A rating curve-based methodology is adopted to derive water discharge from altimetric data provided by the Envisat satellite at 475 virtual stations (VS) within the Amazon basin. From a global-scale perspective, the stage-discharge relations at VS are built based on radar altimetry and outputs from a modeling system composed of a land surface model and a global river routing scheme. In order to quantify the impact of model uncertainties on rating-curve based discharges, a second experiment is performed using outputs from a simulation where daily observed discharges at 135 gauging stations are introduced in the modeling system. Discharge estimates at 90 VS are evaluated against observations during the curve fitting calibration (2002-2005) and evaluation (2006-2008) periods, resulting in mean normalized RMS errors as high as 39 and 15% for experiments without and with direct insertion of data, respectively. Without direct insertion, uncertainty of discharge estimates can be mostly attributed to forcing errors at smaller scales, generating a positive correlation between performance and drainage area. Mean relative streamflow volume errors (RE) of altimetry-based discharges varied from 15 to 84% for large and small drainage areas, respectively. Rating curves produced a mean RE of 51% versus 68% from model outputs. Inserting discharge data into the modeling system decreases the mean RE from 51 to 18%, and mean NRMSE from 24 to 9%. These results demonstrate the feasibility of applying the proposed methodology to the continental or global scales.

Getirana, A. C. V.; Peters-Lidard, C.

2013-03-01

321

Radar precipitation echo patterns associated with midwestern severe storms  

E-print Network

sequnmes. 'The radar echo vsrhe widely fxum sttatiform type (light, fussy eche with ill- defbied edges) to caevecttve type. Generally, the prectp5atkou is of Ught-co-moderate intensity, but lightuhg is often xeporced by surface stations and ls sometimes... ?oak cold front lytnN on a Ni SW lhN just to ON TIorONlest of DOU84 ~ Tones, 'fhs norIhwoet edge of the echooo observed at DuncauvQIO, Tease, wite defbNd hf this cohl front. ~ oortNdcos or funnel clouds were reported wtodn tense of the radar site oc...

Inman, Rex Lee

2012-06-07

322

Meteorological radar methods for validating space observations of precipitation  

NASA Technical Reports Server (NTRS)

Meteorological approaches to verification of space measurements of rainfall are examined; validation of Tropical Rainfall Measuring Mission (TRMM) observations is expected to depend significantly on ground-based radars. Two methods of comparison are initially contemplated. TRMM rainfall data over time periods of a month for large areas (500 x 500 km) are averaged and compared with similarly averaged ground truth measurements. Both the rainfall and height distribution data from TRMM are compared with the instantaneous values observed at one or more 'ground truth' stations and from airborne radar and radiometers as available.

Thiele, Otto W.

1991-01-01

323

Mapping diverse forest cover with multipolarization airborne radar  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

324

Performance evaluation of PBL and cumulus parameterization schemes of WRF ARW model in simulating severe thunderstorm events over Gadanki MST radar facility — Case study  

NASA Astrophysics Data System (ADS)

In the present study, an attempt has been made to simulate three severe thunderstorm events that occurred over Gadanki (13.5° N, 79.2° E) region of the Mesosphere-Stratosphere-Troposphere (MST) Radar facility using Weather Research Forecasting (WRF ARW version 3.2) model. We examined the performance of five planetary boundary layer (PBL) parameterization schemes namely, the Yonsei University (YSU), Mellor-Yamada-Janjic (MYJ), Mellor-Yamada Nakanishi and Niino Level 2.5 PBL (MYNN2), and Medium-Range Forecast (MRF) and Asymmetric Convective Model version 2 (ACM2) and three cumulus parameterization schemes Kain-Fritisch (KF), Betts-Miller-Janjic (BMJ) and Grell-Devenyi ensemble scheme (GD) in simulating boundary layer parameters, thermodynamic structure and vertical velocity profiles on the days of the thunderstorm events. Triple nested domain having the inner-most domain of 3 km grid resolution over the study area is considered. The model simulated parameters are validated with the available in situ meteorological observations obtained from micro-meteorological tower, radiosonde, MST radar wind profiler and observed rainfall along with the surface fluxes at Gadanki. After validating the model simulations with the available PBL observations and the statistical assessment reveal that the MYJ scheme could be able to capture the characteristic variations of surface meteorological variables such as air temperature, relative humidity, wind component, vertical profiles of wind, relative humidity and equivalent potential temperature and surface layer fluxes during the study period. Cores of strong convective updrafts with a time lag and lead of one and half hour are better represented by the model with MYJ scheme with GD as seen in the vertical velocity profiles obtained from MST radar observations. The present study advocates that the MYJ-GD combination is suitable for the simulation of thunderstorm events over the study region.

Madala, Srikanth; Satyanarayana, A. N. V.; Rao, T. Narayana

2014-03-01

325

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

Microsoft Academic Search

This study investigated the impact of using community radio stations to extend information and communication technology (ICT) benefits to poor communities in South Africa. Six community radio stations in six rural South African communities were studied, using face-to-face interviews, community conversations, and observation method. The study found these radio stations have ICT presence, but because of a lack of resources

Eronini R. Megwa

2007-01-01

326

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

SciTech Connect

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

NONE

1996-04-22

327

Evaluation of the carbon dioxide removal assembly requirements for the Space Station Freedom in the Manned Tended Capability through Permanently Manned Capability configurations  

NASA Technical Reports Server (NTRS)

Analyses have been conducted to assess the capability of the Atmosphere Revitalization Subsystem to control ambient CO2 levels of the Space Station Freedom (SSF). The adequacy of the Carbon Dioxide Removal Assembly (CDRA) performance to meet design requirements has been evaluated. Analyses considered transient effects of crew location and metabolic loading on SSF Restructure configurations. The analyses consisted of computer simulations of on-orbit conditions using both supplier-provided and adjusted CO2 removal performance approximations along with derived crew metabolic activities and locations. Results show that while the current performance of the CDRA will maintain CO2 levels within specifications for Man-Tended Operations, it cannot maintain the SSF atmosphere below specifications during Permanently Manned Operations. Potential design options are discussed and other relevant analyses are summarized.

Knox, J. C.; Gilley, S. D.

1992-01-01

328

Utilite des images de radar aeroporte en bande C pour l'evaluation du stade de croissance de la canne a sucre et des cultures maraicheres en milieu tropical, dans une optique de conservation des sols  

NASA Astrophysics Data System (ADS)

This study aims at determining how images from an airborne Synthetic Aperture Radar System, in C-band and with two polarisation configurations, can help evaluate the degree of protection offered to soils by vegetation against erosion in tropical areas. With the objective of supplying information to improve the planning of images from the RADARSAT satellite for soil conservation projects, the study aims at establishing which incident angles and which climatic conditions improve contrasts between bare and protected soils. The study encompasses three sites in Costa Rica. Two of them are located in the central cordillera, in mountainous terrain: the Tierra Blanca site where root crops dominate, and the Juan Vinas site where sugar cane is cultivated. The images have been prepared to allow the quantitative analysis of radar backscattering. The first stage of the analysis compares the discriminating capacities of images acquired on each site with different incident angles and polarisations. In general, the backscattering coefficient of crops has shown a lower tendency to diminish in function of local incident angle than that of bare soil. Results suggest that for sugar cane in relatively dry conditions, it is possible to distinguish plots of bare soil from vegetated ones on the basis of their average backscattering coefficient, except for very high incident angles (higher than 73°). The second part of the analysis treats of the complementarity of the HH and VV polarisations and of images acquired with different incident angles. From the results of this study, we can draw recommendations for the acquisition of RADARSAT images even if the images studied here present a higher spatial resolution and higher incident angles, in many cases. Higher incident angles are recommended because they enhance contrasts between bare soil plots and vegetated ones. The very high incident angles at which we observed the opposite effect are not attainable with satellite radars. Relief causes important radiometric variations that must be corrected in order to appreciate the variations caused by changes in land cover. The correction method developed here can also be applied to satellite radar images. Its approach is to calculate the backscattering coefficient for a reference terrain that is flat, perfectly rough (producing isotropic backscattering) with the elevation considered for calibration, supposing that the studied terrain is also perfectly rough. (Abstract shortened by UMI.)

Beaulieu, Nathalie Lucie

329

An Independent Human Factors Analysis and Evaluation of the Emergency Medical Protocol Checklist for the International Space Station  

NASA Technical Reports Server (NTRS)

Emergency medical capabilities aboard the ISS include a Crew Medical Officer (CMO) (not necessarily a physician), and back-up, resuscitation equipment, and a medical checklist. It is essential that CMOs have reliable, usable and informative medical protocols that can be carried out independently in flight. The study evaluates the existing ISS Medical Checklist layout against a checklist updated to reflect a human factors approach to structure and organization. Method: The ISS Medical checklist was divided into non-emergency and emergency sections, and re-organized based on alphabetical and a body systems approach. A desk-top evaluation examined the ability of subjects to navigate to specific medical problems identified as representative of likely non-emergency events. A second evaluation aims to focus on the emergency section of the Medical Checklist, based on the preliminary findings of the first. The final evaluation will use Astronaut CMOs as subjects comparing the original checklist against the updated layout in the task of caring for a "downed crewmember" using a Human Patient Simulator [Medical Education Technologies, Inc.]. Results: Initial results have demonstrated a clear improvement of the re-organized sections to determine the solution to the medical problems. There was no distinct advantage for either alternative, although subjects stated having a preference for the body systems approach. In the second evaluation, subjects will be asked to identify emergency medical conditions, with measures including correct diagnosis, time to completion and solution strategy. The third evaluation will compare the original and fully updated checklists in clinical situations. Conclusions: Initial findings indicate that the ISS Medical Checklist will benefit from a reorganization. The present structure of the checklist has evolved over recent years without systematic testing of crewmember ability to diagnose medical problems. The improvements are expected to enable ISS Crewmembers to more speedily and accurately respond to medical situations on the ISS.

Marshburn, Thomas; Whitmore, Mihriban; Ortiz, Rosie; Segal, Michele; Smart, Kieran; Hughes, Catherine

2003-01-01

330

Venus wind-altitude radar  

NASA Technical Reports Server (NTRS)

A design study on adding a radar altimeter to the Pioneer Venus small probe is review. Block and timing diagrams are provided. The inherent and interface ambiguities, resolution, and data handling logic for radar altimeters are described.

Levanon, N.

1974-01-01

331

Phase modulating the Urbana radar  

NASA Technical Reports Server (NTRS)

The design and operation of a switched phase modulation system for the Urbana Radar System are discussed. The system is implemented and demonstrated using a simple procedure. The radar system and circuits are described and analyzed.

Herrington, L. J., Jr.; Bowhill, S. A.

1983-01-01

332

Space station propulsion-ECLSS interaction study  

NASA Technical Reports Server (NTRS)

The benefits of the utilization of effluents of the Space Station Environmental Control and Life Support (ECLS) system are examined. Various ECLSS-propulsion system interaction options are evaluated and compared on the basis of weight, volume, and power requirements. Annual propulsive impulse to maintain station altitude during a complete solar cycle of eleven years and the effect on station resupply are considered.

Brennan, Scott M.

1986-01-01

333

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

SciTech Connect

In recent years, increasing deployment of large wind-turbine farms has become an issue of growing concern for the radar community. The large radar cross section (RCS) presented by wind turbines interferes with radar operation, and the Doppler shift caused by blade rotation causes problems identifying and tracking moving targets. Each new wind-turbine farm installation must be carefully evaluated for potential disruption of radar operation for air defense, air traffic control, weather sensing, and other applications. Several approaches currently exist to minimize conflict between wind-turbine farms and radar installations, including procedural adjustments, radar upgrades, and proper choice of low-impact wind-farm sites, but each has problems with limited effectiveness or prohibitive cost. An alternative approach, heretofore not technically feasible, is to reduce the RCS of wind turbines to the extent that they can be installed near existing radar installations. This report summarizes efforts to reduce wind-turbine RCS, with a particular emphasis on the blades. The report begins with a survey of the wind-turbine RCS-reduction literature to establish a baseline for comparison. The following topics are then addressed: electromagnetic model development and validation, novel material development, integration into wind-turbine fabrication processes, integrated-absorber design, and wind-turbine RCS modeling. Related topics of interest, including alternative mitigation techniques (procedural, at-the-radar, etc.), an introduction to RCS and electromagnetic scattering, and RCS-reduction modeling techniques, can be found in a previous report.

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

2012-03-05

334

Mapping Wintering Waterfowl Distributions Using Weather Surveillance Radar  

PubMed Central

The current network of weather surveillance radars within the United States readily detects flying birds and has proven to be a useful remote-sensing tool for ornithological study. Radar reflectivity measures serve as an index to bird density and have been used to quantitatively map landbird distributions during migratory stopover by sampling birds aloft at the onset of nocturnal migratory flights. Our objective was to further develop and validate a similar approach for mapping wintering waterfowl distributions using weather surveillance radar observations at the onset of evening flights. We evaluated data from the Sacramento, CA radar (KDAX) during winters 1998–1999 and 1999–2000. We determined an optimal sampling time by evaluating the accuracy and precision of radar observations at different times during the onset of evening flight relative to observed diurnal distributions of radio-marked birds on the ground. The mean time of evening flight initiation occurred 23 min after sunset with the strongest correlations between reflectivity and waterfowl density on the ground occurring almost immediately after flight initiation. Radar measures became more spatially homogeneous as evening flight progressed because birds dispersed from their departure locations. Radars effectively detected birds to a mean maximum range of 83 km during the first 20 min of evening flight. Using a sun elevation angle of ?5° (28 min after sunset) as our optimal sampling time, we validated our approach using KDAX data and additional data from the Beale Air Force Base, CA (KBBX) radar during winter 1998–1999. Bias-adjusted radar reflectivity of waterfowl aloft was positively related to the observed diurnal density of radio-marked waterfowl locations on the ground. Thus, weather radars provide accurate measures of relative wintering waterfowl density that can be used to comprehensively map their distributions over large spatial extents. PMID:22911816

Buler, Jeffrey J.; Randall, Lori A.; Fleskes, Joseph P.; Barrow, Wylie C.; Bogart, Tianna; Kluver, Daria

2012-01-01

335

Mapping wintering waterfowl distributions using weather surveillance radar  

USGS Publications Warehouse

The current network of weather surveillance radars within the United States readily detects flying birds and has proven to be a useful remote-sensing tool for ornithological study. Radar reflectivity measures serve as an index to bird density and have been used to quantitatively map landbird distributions during migratory stopover by sampling birds aloft at the onset of nocturnal migratory flights. Our objective was to further develop and validate a similar approach for mapping wintering waterfowl distributions using weather surveillance radar observations at the onset of evening flights. We evaluated data from the Sacramento, CA radar (KDAX) during winters 1998–1999 and 1999–2000. We determined an optimal sampling time by evaluating the accuracy and precision of radar observations at different times during the onset of evening flight relative to observed diurnal distributions of radio-marked birds on the ground. The mean time of evening flight initiation occurred 23 min after sunset with the strongest correlations between reflectivity and waterfowl density on the ground occurring almost immediately after flight initiation. Radar measures became more spatially homogeneous as evening flight progressed because birds dispersed from their departure locations. Radars effectively detected birds to a mean maximum range of 83 km during the first 20 min of evening flight. Using a sun elevation angle of -5° (28 min after sunset) as our optimal sampling time, we validated our approach using KDAX data and additional data from the Beale Air Force Base, CA (KBBX) radar during winter 1998–1999. Bias-adjusted radar reflectivity of waterfowl aloft was positively related to the observed diurnal density of radio-marked waterfowl locations on the ground. Thus, weather radars provide accurate measures of relative wintering waterfowl density that can be used to comprehensively map their distributions over large spatial extents.

Buler, Jeffrey J.; Randall, Lori A.; Fleskes, Joseph P.; Barrow, Wylie C.; Bogart, Tianna; Kluver, Daria

2012-01-01

336

Special applications of radar systems  

Microsoft Academic Search

Developments at Dornier in radar equipment are discussed. Characteristics of the Tasyll-1 scoring system for air target simulation are examined with emphasis on the Doppler radar principle for missile location. The RADOBS-R (Radar-object shield panorama sensor) system creates a ring-shaped alarm zone around an object for protection and has an operating frequency around 14 GHz. A Synthetic Aperture Radar and

U. Knepper; R. Kremer; H. Lamprecht; R. Schotter

1980-01-01

337

Radar data smoothing filter study  

NASA Technical Reports Server (NTRS)

The accuracy of the current Wallops Flight Facility (WFF) data smoothing techniques for a variety of radars and payloads is examined. Alternative data reduction techniques are given and recommendations are made for improving radar data processing at WFF. A data adaptive algorithm, based on Kalman filtering and smoothing techniques, is also developed for estimating payload trajectories above the atmosphere from noisy time varying radar data. This algorithm is tested and verified using radar tracking data from WFF.

White, J. V.

1984-01-01

338

Characteristics of Sunset radar  

NASA Technical Reports Server (NTRS)

Located in a narrow canyon 15 km west of Boulder, Colorado, the Sunset pulsed Doppler radar was the first radar designed and constructed specifically as a VHF ST radar. The antenna system is a phased array of coaxial-colinear dopoles with computer-controlled phase shifters for each line of dipoles. It operates at a frequency of 40.475 MHz and a wavelength of 7.41M. Peak transmitter power is 100 kW. Aperture efficiency is 0.58 and resistive loss is 0.30 for its 3600 sq m area. The practical steering rate is 1 record/minute/position to any arbitrary antenna beam position. The first clear-air turbulence echoes and wind velocity measurements were obtained in 1974. Significant accomplishments are listed.

Green, J. L.

1983-01-01

339

Radar sector blanker  

NASA Astrophysics Data System (ADS)

A radar sector blanker comprises in analog-to-digital converter and a sector controller unit. The analog-to-digital converter receives the analog synchro voltages describing the positioning of a radar antenna and changes these voltages into binary-coded decimal (BCD) information. The sector controller unit comprises a portable housing, a controller system, and a power supply. The controller system includes an OFF comparator circuit, an ON comparator circuit, an S-R latch, and a solid-state switch. Each comparator circuit comprises three cascaded transistor-transistor logic (TTL) integrated chips. The power supply gives a direct-current voltage to the solid-state switch and the TTL chips. The sector blanker blocks transmission for a predetermined rotational region or sector of a radar system.

Hall, Roger B.

1994-03-01

340

Side looking radar calibration study  

NASA Technical Reports Server (NTRS)

Calibration of an airborne sidelooking radar is accomplished by the use of a model that relates the radar parameters to the physical mapping situation. Topics discussed include: characteristics of the transmitters; the antennas; target absorption and reradiation; the receiver and map making or radar data processing; and the calibration process.

Edwards, W. D.

1975-01-01

341

HF radar ionospheric clutter  

NASA Astrophysics Data System (ADS)

The characteristics of HF radar echoes reflected from ionization irregularities aligned along the lines of force of the Earth's magnetic field are presented. Utilizing experimental radar-ionospheric clutter data acquired at frequencies between HF and UHF, an analysis is made of the amplitude, the cross-sectional area and the angular extent statistics of HF field-aligned echoes. The Doppler frequency variation, the frequency of occurrence and the diurnal and seasonal variation of HF ionospheric backscatter echoes and their correlation with solar-geophysical conditions are also discussed.

Millman, G. H.

1982-08-01

342

Polarization diversity in radars  

NASA Astrophysics Data System (ADS)

Many polarization techniques, which have been proposed and analyzed to enhance radar performance, are reviewed in this paper in order to assess the possible improvement they can provide in the signal-to-disturbance ratio, target detectability, target discrimination and resolution, and target classification and identification. Some recent experimentally-based results relating to these applications are also presented. Those techniques are emphasized for which polarization-based capabilities appear sufficiently assessed, such as adaptive polarization cancellation of clutter, chaff, and jamming. Polarization Doppler processing of dual-polarization radar signals, meteorologic applications, and polarization adaptation for target detection in the clear (in free space) are also examined.

Giuli, D.

1986-02-01

343

Spaceborne Imaging Radar Symposium  

NASA Technical Reports Server (NTRS)

An overview of the present state of the art in the different scientific and technological fields related to spaceborne imaging radars was presented. The data acquired with the SEASAT SAR (1978) and Shuttle Imaging Radar, SIR-A (1981) clearly demonstrated the important emphasis in the 80's is going to be on in-depth research investigations conducted with the more flexible and sophisticated SIR series instruments and on long term monitoring of geophysical phenomena conducted from free-flying platforms such as ERS-1 and RADARSAT.

Elachi, C.

1983-01-01

344

Evaluation of severe accident risks and the potential for risk reduction: Surry Power Station, Unit 1: Draft report for comment  

SciTech Connect

The Severe Accident Risk Reduction Program (SARRP) has completed a rebaselining of the risks to the public from a particular pressurized water reactor with a subatmospheric containment (Surry, Unit 1). Emphasis was placed on determining the magnitude and character of the uncertainties, rather than focusing on a point estimate. The risk-reduction potential of a set of proposed safety option backfits was also studied, and their costs and benefits were also evaluated. It was found that the risks from internal events are generally lower than previously evaluated in the Reactor Safety Study (RSS). However, certain unresolved issues (such as direct containment heating) caused the top of the uncertainty band to appear at a level that is comparable with the RSS point estimate. None of the postulated safety options appears to be cost effective for the Surry power plant. This work supports the Nuclear Regulatory Commission's assessment of severe accidents in NUREG-1150.

Benjamin, A.S.; Boyd, G.J.; Kunsman, D.M.; Murfin, W.B.; Williams, D.C.

1987-02-01

345

Kiowa Creek Switching Station  

SciTech Connect

The Western Area Power Administration (Western) proposes to construct, operate, and maintain a new Kiowa Creek Switching Station near Orchard in Morgan County, Colorado. Kiowa Creek Switching Station would consist of a fenced area of approximately 300 by 300 feet and contain various electrical equipment typical for a switching station. As part of this new construction, approximately one mile of an existing 115-kilovolt (kV) transmission line will be removed and replaced with a double circuit overhead line. The project will also include a short (one-third mile) realignment of an existing line to permit connection with the new switching station. In accordance with the Council on Environmental Quality (CEQ) regulations for implementing the procedural provisions of the National Environmental Policy Act of 1969 (NEPA), 40 CFR Parts 1500--1508, the Department of Energy (DOE) has determined that an environmental impact statement (EIS) is not required for the proposed project. This determination is based on the information contained in this environmental assessment (EA) prepared by Western. The EA identifies and evaluates the environmental and socioeconomic effects of the proposed action, and concludes that the advance impacts on the human environment resulting from the proposed project would not be significant. 8 refs., 3 figs., 1 tab.

Not Available

1990-03-01

346

Evaluation of a Human Modeling Software Tool in the Prediction of Extra Vehicular Activity Tasks for an International Space Station Assembly Mission  

NASA Technical Reports Server (NTRS)

The difficulty of accomplishing work in extravehicular activity (EVA) is well documented. It arises as a result of motion constraints imposed by a pressurized spacesuit in a near-vacuum and of the frictionless environment induced in microgravity. The appropriate placement of foot restraints is crucial to ensuring that astronauts can remove and drive bolts, mate and demate connectors, and actuate levers. The location on structural members of the foot restraint sockets, to which the portable foot restraint is attached, must provide for an orientation of the restraint that affords the astronaut adequate visual and reach envelopes. Previously, the initial location of these sockets was dependent upon the experienced designer's ability to estimate placement. The design was tested in a simulated zero-gravity environment; spacesuited astronauts performed the tasks with mockups while submerged in water. Crew evaluation of the tasks based on these designs often indicated the bolt or other structure to which force needed to be applied was not within an acceptable work envelope, resulting in redesign. The development of improved methods for location of crew aids prior to testing would result in savings to the design effort for EVA hardware. Such an effort to streamline EVA design is especially relevant to International Space Station construction and maintenance. Assembly operations alone are expected to require in excess of four hundred hours of EVA. Thus, techniques which conserve design resources for assembly missions can have significant impact. We describe an effort to implement a human modelling application in the design effort for an International Space Station Assembly Mission. On Assembly Flight 6A, the Canadian-built Space Station Remote Manipulator System will be delivered to the U.S. Laboratory. It will be released from its launch restraints by astronauts in EVA. The design of the placement of foot restraint sockets was carried out using the human model Jack, and the modelling results were compared with actual underwater test results. The predicted locations of the sockets was found to be acceptable for 94% of the tasks attempted by the astronauts, This effort provides confidence in the capabilities of this package to accurately model tasks. It therefore increases assurance that the tool maybe used early in the design process.

Dischinger, H. Charles; Loughead, Tomas E.

1997-01-01

347

Interior view to the south of computer work stations in ...  

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

Interior view to the south of computer work stations in front of elevated work area 1570 on left and elevated glassed in work area 1870 on right - Over-the-Horizon Backscatter Radar Network, Mountain Home Air Force Operations Building, On Desert Street at 9th Avenue Mountain Home Air Force Base, Mountain Home, Elmore County, ID

348

Space Radar Image of Florence, Italy  

NASA Technical Reports Server (NTRS)

This radar image shows land use patterns in and around the city of Florence, Italy, shown here in the center of the image. Florence is situated on a plain in the Chianti Hill region of Central Italy. The Arno River flows through town and is visible as the dark line running from the upper right to the bottom center of the image. The city is home to some of the world's most famous art museums. The bridges seen crossing the Arno, shown as faint red lines in the upper right portion of the image, were all sacked during World War II with the exception of the Ponte Vecchio, which remains as Florence's only covered bridge. The large, black V-shaped feature near the center of the image is the Florence Railroad Station. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the Space Shuttle Endeavour on April 14, 1994. SIR-C/X-SAR, a joint mission of the German, Italian, and United States space agencies, is part of NASA's Mission to Planet Earth. This image is centered at 43.7 degrees north latitude and 11.15 degrees east longitude with North toward the upper left of the image. The area shown measures 20 kilometers by 17 kilometers (12.4 miles by 10.6 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received; blue is C-band horizontally transmitted, vertically received.

1994-01-01

349

Spaceborne precipitation radar  

NASA Technical Reports Server (NTRS)

The performances and characteristics of a satelliteborne radar operating in the millimeter wavelength region of the spectrum with emphasis placed on the 35 and 94 GH3 frequency bands are discussed. It is concluded that millimetric wavelengths provide an acceptable solution for the design of satelliteborne active microwave equipment.

Eckerman, J.; Meneghini, R.

1981-01-01

350

The Newcastle meteor radar  

NASA Technical Reports Server (NTRS)

A brief history and development of the Newcastle Meteor Radar system is given. Also described are its geographical coordinates and its method of operation. The initial objective when the project was commenced was to develop an entirely digital analyzer capable of recognizing meteor echo signals and recording as many of their parameters as possible. This objective was achieved.

Keay, Colin

1987-01-01

351

RADAR “SAIL” satellite concept  

Microsoft Academic Search

The Radar SAIL concept is based on the use of a rectangular antenna lying in the dawn-dusk orbital plane with the length (along speed vector) smaller than the height. Such geometry makes it possible to place the solar cells on the back of the antenna, to use gravity gradient stabilisation, and to implement multipath-free GPS interferometric measurement of the antenna

Jean Paul Aguttes; Jacques Sombrin; Eric Conde

1996-01-01

352

Thin Wideband Radar Absorbers  

Microsoft Academic Search

A procedure for the optimal design of thin wideband radar absorbers is presented. The resulting absorbers are implemented by printing a frequency selective surface on a lossy perforated substrate. A binary hill climbing optimization scheme with random restart is used to find optimal solutions. The method of moments in conjunction with the transmission line method is used to calculate the

Arya Fallahi; Alireza Yahaghi; Hans-Rudolf Benedickter; Habibollah Abiri; Mahmoud Shahabadi; Christian Hafner

2010-01-01

353

The use of radar data in the investigation of precipitation distributions and anomalous propagation  

E-print Network

importance in their effects upon local weather con- ditions are escaping observation by surface stations with disturbing frequency as ia shown by the observations of radar meteorologists (6) and the results of meso scale studies (4), It appears... it from west to east. This configuration could not be deduced from surface reports. Clixmtological conclusions based upon synoptic data should also have incorporated within them 1nferences from supplenmntary data observed by radar, In certain regions...

Truppi, Lawrence Ernest

2012-06-07

354

Forecasting of storm rainfall by combined use of radar, rain gages and linear models  

Microsoft Academic Search

An integrated approach to real-time prediction of point rainfall is presented. This is based on the assumption that hourly rainfall at a station can be predicted by a Multivariate AutoRegressive Integrated Moving Average (MARIMA) process. The real-time calibration of the multivariate model is performed by combining radar maps and data from rain gages. Accordingly, radar maps provide the basic information

Paolo Burlando; Alberto Montanari; Roberto Ranzi

1996-01-01

355

RADAR: An In-Building RF-based User Location and Tracking System  

Microsoft Academic Search

The proliferation of mobile computing devices and local-area wireless networks has fostered a growing interest in location-aware systems and services. In this paper we present RADAR, a radio-frequency (RF) based system for locating and tracking users inside buildings. RADAR operates by recording and processing signal strength information at multiple base stations positioned to provide overlapping coverage in the area of

Paramvir Bahl; Venkata N. Padmanabhan

2000-01-01

356

On an 8 km-altitude cloud and precipitation radar echo peak observed during EPIC Paquita Zuidema  

E-print Network

On an 8 km- altitude cloud and precipitation radar echo peak observed during EPIC Paquita Zuidema precipitation radar data evaluates the vertical structure of the precipitation and can provide statistics for a larger spatial area than is sampled by the cloud radar. This poster presents the cloud and precipitation

Zuidema, Paquita

357

The Atmospheric Radiation Measurement Program Cloud Profiling Radars: Second-Generation Sampling Strategies, Processing, and Cloud Data Products  

Microsoft Academic Search

The United States Department of Energy Atmospheric Radiation Measurement program operates millimeter-wavelength cloud radars in several climatologically distinct regions. The digital signal processors for these radars were recently upgraded and allow for enhancements in the operational parameters running on them. Recent evaluations of millimeter-wavelength cloud radar signal processing performance relative to the range of cloud dynamical and microphysical conditions encountered

Pavlos Kollias; Eugene E. Clothiaux; Mark A. Miller; Edward P. Luke; Karen L. Johnson; Kenneth P. Moran; Kevin B. Widener; Bruce A. Albrecht

2007-01-01

358

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

SciTech Connect

NASA and the Air Force at Kennedy Space Center/Cape Canaveral Air Station (KSC/CCAS) are attempting to upgrade and improve their capabilities for emergency response dispersion modeling and mesoscale meteorological forecasting. Their goal is to improve short range forecasts (up to 24 hours) for phenomena such as thunderstorms and sea breezes and to more accurately predict toxic diffusion concentrations in case of hazardous spills. To assist NASA and the Air Force in achieving this goal, the Applied Meteorology Unit (AMU) has been evaluating the Emergency Response Dose Assessment System (ERDAS). ERDAS is a prototype software and hardware system configured to produce routine mesoscale meteorological forecasts and enhanced dispersion estimates on an operational basis for the KSC/CCAS region. ERDAS includes two major software systems which is run and accessed through a graphical user interface. The first software system is the Regional Atmospheric Modeling System (RAMS), a three-dimensional, multiple nested grid prognostic mesoscale model. The second software system is the Hybrid Particle and Concentration Transport (HYPACT) model, a pollutant trajectory and concentration model. ERDAS also runs the Rocket Exhaust Effluent Diffusion Model (REEDM). This paper describes the system, the model evaluation, the process of transitioning ERDAS from a research project to an operational system, and also presents the results of the launch case studies.

Evans, R.J. [ENSCO, Inc., Melbourne, FL (United States). Applied Meteorology Unit; Tremback, C.J.; Lyons, W.A. [MRC/ASTER, Ft. Collins, CO (United States)

1996-12-31

359

Space station advanced automation  

NASA Technical Reports Server (NTRS)

In the development of a safe, productive and maintainable space station, Automation and Robotics (A and R) has been identified as an enabling technology which will allow efficient operation at a reasonable cost. The Space Station Freedom's (SSF) systems are very complex, and interdependent. The usage of Advanced Automation (AA) will help restructure, and integrate system status so that station and ground personnel can operate more efficiently. To use AA technology for the augmentation of system management functions requires a development model which consists of well defined phases of: evaluation, development, integration, and maintenance. The evaluation phase will consider system management functions against traditional solutions, implementation techniques and requirements; the end result of this phase should be a well developed concept along with a feasibility analysis. In the development phase the AA system will be developed in accordance with a traditional Life Cycle Model (LCM) modified for Knowledge Based System (KBS) applications. A way by which both knowledge bases and reasoning techniques can be reused to control costs is explained. During the integration phase the KBS software must be integrated with conventional software, and verified and validated. The Verification and Validation (V and V) techniques applicable to these KBS are based on the ideas of consistency, minimal competency, and graph theory. The maintenance phase will be aided by having well designed and documented KBS software.

Woods, Donald

1990-01-01

360

Space station tracking requirements feasibility study, volume 2  

NASA Technical Reports Server (NTRS)

The objective of this feasibility study is to determine analytically the accuracies of various sensors being considered as candidates for Space Station use. Specifically, the studies were performed whether or not the candidate sensors are capable of providing the required accuracy, or if alternate sensor approaches should be investigated. Other topics related to operation in the Space Station environment were considered as directed by NASA-JSC. The following topics are addressed: (1) Space Station GPS; (2) Space Station Radar; (3) Docking Sensors; (4) Space Station Link Analysis; (5) Antenna Switching, Power Control, and AGC Functions for Multiple Access; (6) Multichannel Modems; (7) FTS/EVA Emergency Shutdown; (8) Space Station Information Systems Coding; (9) Wanderer Study; and (10) Optical Communications System Analysis. Brief overviews of the abovementioned topics are given. Wherever applicable, the appropriate appendices provide detailed technical analysis. The report is presented in two volumes. This is Volume 2, containing Appendices K through U.

Udalov, Sergei; Dodds, James

1988-01-01

361

The bistatic radar capabilities of the Medicina radiotelescopes in space debris detection and tracking  

NASA Astrophysics Data System (ADS)

An accurate measurement of the position and trajectory of the space debris fragments is of primary importance for the characterization of the orbital debris environment. The Medicina Radioastronomical Station is a radio observation facility that is here proposed as receiving part of a ground-based space surveillance system for detecting and tracking space debris at different orbital regions (from Low Earth Orbits up to Geostationary Earth Orbits). The proposed system consists of two bistatic radars formed by the existing Medicina receiving antennas coupled with appropriate transmitters. This paper focuses on the current features and future technical development of the receiving part of the observational setup. Outlines of possible transmitting systems will also be given together with the evaluation of the observation strategies achievable with the proposed facilities.

Montebugnoli, S.; Pupillo, G.; Salerno, E.; Pluchino, S.; di Martino, M.

2010-03-01

362

Ground data system architecture for precipitation determination from space-based radar  

NASA Technical Reports Server (NTRS)

The Tropical Rain Mapping Radar (Tramar) is proposed as an attached payload as part of the Space Station Earth Observing System Program. Tramar would measure rainfall rates, rain velocity, and rain cell areal extent in the latitude band from 30 deg S to 30 deg N for use in studies of large-scale atmospheric circulation, variations of latent heating, tropical hydrologic processes, and mesoscale precipitation systems. The Tramar science requirements, radar design, and ground data system architecture are examined, including the three-dimensional scan geometry, the radar system performance parameters, the production of earth-gridded maps, and the telemetry, sensor, radiometric, and geophysical data that would be obtained by Tramar.

Hilland, Jeffrey E.

1989-01-01

363

Observation of snowfall with a low-power FM-CW K-band radar (Micro Rain Radar)  

NASA Astrophysics Data System (ADS)

Quantifying snowfall intensity especially under arctic conditions is a challenge because wind and snow drift deteriorate estimates obtained from both ground-based gauges and disdrometers. Ground-based remote sensing with active instruments might be a solution because they can measure well above drifting snow and do not suffer from flow distortions by the instrument. Clear disadvantages are, however, the dependency of e.g. radar returns on snow habit which might lead to similar large uncertainties. Moreover, high sensitivity radars are still far too costly to operate in a network and under harsh conditions. In this paper we compare returns from a low-cost, low-power vertically pointing FM-CW radar (Micro Rain Radar, MRR) operating at 24.1 GHz with returns from a 35.5 GHz cloud radar (MIRA36) for dry snowfall during a 6-month observation period at an Alpine station (Environmental Research Station Schneefernerhaus, UFS) at 2,650 m height above sea level. The goal was to quantify the potential and limitations of the MRR in relation to what is achievable by a cloud radar. The operational MRR procedures to derive standard radar variables like effective reflectivity factor ( Z e) or the mean Doppler velocity ( W) had to be modified for snowfall since the MRR was originally designed for rain observations. Since the radar returns from snowfall are weaker than from comparable rainfall, the behavior of the MRR close to its detection threshold has been analyzed and a method is proposed to quantify the noise level of the MRR based on clear sky observations. By converting the resulting MRR- Z e into 35.5 GHz equivalent Z e values, a remaining difference below 1 dBz with slightly higher values close to the noise threshold could be obtained. Due to the much higher sensitivity of MIRA36, the transition of the MRR from the true signal to noise can be observed, which agrees well with the independent clear sky noise estimate. The mean Doppler velocity differences between both radars are below 0.3 ms-1. The distribution of Z e values from MIRA36 are finally used to estimate the uncertainty of retrieved snowfall and snow accumulation with the MRR. At UFS low snowfall rates missed by the MRR are negligible when comparing snow accumulation, which were mainly caused by intensities between 0.1 and 0.8 mm h-1. The MRR overestimates the total snow accumulation by about 7%. This error is much smaller than the error caused by uncertain Z e-snowfall rate relations, which would affect the MIRA36 estimated to a similar degree.

Kneifel, Stefan; Maahn, Maximilian; Peters, Gerhard; Simmer, Clemens

2011-06-01

364

Ground-penetrating radar monitoring of a controlled DNAPL release: 200 MHz radar  

SciTech Connect

A controlled release of tetrachloroethylene was performed in a saturated, natural sandy aquifer to evaluate the effectiveness of various geophysical techniques for detecting and monitoring dense nonaqueous phase liquids (DNAPLs) in the subsurface. Tetrachloroethylene, typical of most DNAPLs, has a low relative dielectric permittivity (2.3), which contrasts with the high relative permittivity (80) of the pore water it displaces, making it a potential target for detection by ground-penetrating radar (GPR). GPR data were acquired using 200 MHz antennas. Radar sections collected at different times over the same spatial location clearly show the changes induced by the movement of DNAPL in the subsurface. Temporal changes can be examined through the evolution of a radar data trace collected at a single spatial location. Normal moveout analysis of common-midpoint (CMP) data demonstrates induced changes in electromagnetic (EM) wave velocities of up to 30% caused by the presence of DNAPL. The distribution of DNAPL can be mapped in three dimensions at different times using a network of 16 radar lines. The 200 MHz GPR proved to be an effective technique for monitoring the movement of DNAPL in the subsurface. Direct detection of DNAPLs by radar is also feasible in this simple environment.

Brewster, M.L. (Komex International Ltd., Calgary, Alberta (Canada) Univ. of Waterloo, Ontario (Canada). Waterloo Centre for Groundwater Research); Annan, A.P. (Sensors and Software, Inc., Mississauga, Ontario (Canada) Univ. of Waterloo, Ontario (Canada). Waterloo Centre for Groundwater Research)

1994-08-01

365

High-Frequency Radar Mapping of Surface Currents Using WERA  

Microsoft Academic Search

A dual-station high-frequency Wellen Radar (WERA), transmitting at 16.045 MHz, was deployed along the west Florida shelf in phased array mode during the summer of 2003. A 33-day, continuous time series of radial and vector surface current fields was acquired starting on 23 August ending 25 September 2003. Over a 30-min sample interval, WERA mapped coastal ocean currents over an

Lynn K. Shay; Jorge Martinez-Pedraja; Thomas M. Cook; Brian K. Haus; Robert H. Weisberg

2007-01-01

366

Physically based simulator for measurements of precipitation with polarimetric and space-borne radars  

NASA Astrophysics Data System (ADS)

A radar is a powerful tool for measurement of the 3-D structure of precipitation. Recently, polarimetric radar is widely used because it can measure the size of raindrops to some degree and therefore can measures more accurate rainfall rate than the conventional weather radar. A space-borne radar is also widely used in precipitation studies. The Tropical Rainfall Measuring Mission (TRMM) satellite has been continuously monitoring precipitation on a global scale since the launch in November, 1977. Following the TRMM, the Global Precipitation Mission (GPM) is scheduled to launch in 2013. The polarimetric parameters observed with the polarimetric radar depend on various precipitation properties in a complex way. Multiple scattering contributions cannot be neglected for a radar operated at higher frequency of 35 GHz higher onboard the GPM. To develop a robust algorithm for more accurate measurements of precipitation from those radars, we should evaluate how micro-physical properties of precipitation link to the received signals. We have developed a generalized radar simulator for polarimetric and space-borne radar (GPASS). This is a physically-based simulator in which the scattering properties of cloud and raindrops are calculated by using radio wave scattering theory. Thus we can make detailed study how the radar signals vary with micro-physical properties of precipitation by using the simulator. We will present the simulator in detail and the limit of the Rayleigh approximation for polarimetric radar.

Kobayashi, Takahisa; Masuda, Kazuhiko; Yamauchi, Hiroshi; Adachi, Ahoro

2011-11-01

367

Airborne ground penetrating imaging radar operating at L-band  

NASA Astrophysics Data System (ADS)

The FOPEN radar was designed and fabricated in response to the need to detect items buried below the surface using a rapid detection method from an airborne platform. The system uses Synthetic Aperture Radar Processing in the form of ratcheting spot light SAR. The image of the ground at a slant range of 40 degrees on either the right or left side of the aircraft and gives a two dimensional image of the ground. The antenna can also point in a nadir position to sound the ground. The radar was developed to image 1 sq mile with each frame with a resolution of 1 meter in the slant range. This requires the use of the entire L-Band radar spectrum of 150 Meg Hz. In order to detect images below the ground additional processing must be performed on the raw data, accordingly the raw data is recorded at a data rate of 200 Mbyte/second. The data is recorded as both I and Q data. The radar has on board processing but only for verifying that the system is operating. Not all adjacent frames are processed for this reason. The processing and analysis is performed on the ground by a system that has multiple work stations and software to process the image of the surface and the sub surface. By further processing the data the surface can be removed and the lower level glint points can be seen and enhanced using signal processing techniques.

Gordy, Robert S.; Markell, David P.

2010-04-01

368

An inverse method to retrieve 3D radar reflectivity composites  

NASA Astrophysics Data System (ADS)

Dense radar networks offer the possibility of getting better Quantitative Precipitation Estimates (QPE) than those obtained with individual radars, as they allow increasing the coverage and improving quality of rainfall estimates in overlapping areas. Well-known sources of error such as attenuation by intense rainfall or errors associated with range can be mitigated through radar composites. Many compositing techniques are devoted to operational uses and do not exploit all the information that the network is providing. In this work an inverse method to obtain high-resolution radar reflectivity composites is presented. The method uses a model of radar sampling of the atmosphere that accounts for path attenuation and radar measurement geometry. Two significantly different rainfall situations are used to show detailed results of the proposed inverse method in comparison to other existing methodologies. A quantitative evaluation is carried out in a 12 h-event using two independent sources of information: a radar not involved in the composition process and a raingauge network. The proposed inverse method shows better performance in retrieving high reflectivity values and reproducing variability at convective scales than existing methods.

Roca-Sancho, Jordi; Berenguer, Marc; Sempere-Torres, Daniel

2014-11-01

369

UAV-based Radar Sounding of Antarctic Ice  

NASA Astrophysics Data System (ADS)

We developed a compact radar for use on a small UAV to conduct measurements over the ice sheets in Greenland and Antarctica. It operates at center frequencies of 14 and 35 MHz with bandwidths of 1 MHz and 4 MHz, respectively. The radar weighs about 2 kgs and is housed in a box with dimensions of 20.3 cm x 15.2 cm x 13.2 cm. It transmits a signal power of 100 W at a pulse repletion frequency of 10 kHz and requires average power of about 20 W. The antennas for operating the radar are integrated into the wings and airframe of a small UAV with a wingspan of 5.3 m. We selected the frequencies of 14 and 35 MHz based on previous successful soundings of temperate ice in Alaska with a 12.5 MHz impulse radar [Arcone, 2002] and temperate glaciers in Patagonia with a 30 MHz monocycle radar [Blindow et al., 2012]. We developed the radar-equipped UAV to perform surveys over a 2-D grid, which allows us to synthesize a large two-dimensional aperture and obtain fine resolution in both the along- and cross-track directions. Low-frequency, high-sensitivity radars with 2-D aperture synthesis capability are needed to overcome the surface and volume scatter that masks weak echoes from the ice-bed interface of fast-flowing glaciers. We collected data with the radar-equipped UAV on sub-glacial ice near Lake Whillans at both 14 and 35 MHz. We acquired data to evaluate the concept of 2-D aperture synthesis and successfully demonstrated the first successful sounding of ice with a radar on an UAV. We are planning to build multiple radar-equipped UAVs for collecting fine-resolution data near the grounding lines of fast-flowing glaciers. In this presentation we will provide a brief overview of the radar and UAV, as well as present results obtained at both 14 and 35 MHz. Arcone, S. 2002. Airborne-radar stratigraphy and electrical structure of temperate firn: Bagley Ice Field, Alaska, U.S.A. Journal of Glaciology, 48, 317-334. Blindow, N., C. Salat, and G. Casassa. 2012. Airborne GPR sounding of deep temperate glaciers—examples from the Northern Patagonian Icefield, 14th International Conference on Ground Penetrating Radar (GPR) June 4-8, 2012, Shanghai, China, ISBN 978-1-4673-2663-6.

Leuschen, Carl; Yan, Jie-Bang; Mahmood, Ali; Rodriguez-Morales, Fernando; Hale, Rick; Camps-Raga, Bruno; Metz, Lynsey; Wang, Zongbo; Paden, John; Bowman, Alec; Keshmiri, Shahriar; Gogineni, Sivaprasad

2014-05-01

370

Evaluation of trends in some temperature series at some Italian stations and their modelling by means of spectral methods: first results in the Latium coastal area  

NASA Astrophysics Data System (ADS)

The investigation of the presence of signals indicating possible climatic changes in progress during the second half of the last century in the coastal area of the central Tyrrhenian sea has been carried out within the context of a research programme promoted by the Italian Science Academy (alias "the Academy of the XL") and financed by the Presidential Bureau. Our goal has been a better understanding of the behaviour of the minimum and maximum temperature variations in the period 1951-1999 and the modelling of their stochastic residuals through spectral analysis and the optimized construction of suitable autoregressive one-parameter processes. The meteorological data source for this research was the Italian "Agrometeorological National DataBase" (BDAN) of the Agrometeorological Informatics National System (SIAN). The spectral and stochastic analysis of meteorological data usually require full data sets without gaps, but, in BDAN, numerous data sets taken at stations located in the investigated area were incomplete. Thus, after the selection of an adequate number of stations, both representative of the region under study and characterized by a low number of data gaps, the first step was to fill all the gaps in the daily series using specific statistical techniques. After this preliminary treatment, we were left with seven temperature series that showed enough good characteristics in order to carry out an efficient modelling. Spectral analysis of minimum and maximum temperature series permitted to identify an auto-regressive one-parameter model well representing the stochastic residual of each series. With the aid of the complete model, consisting of a deterministic component (a linear trend plus two seasonal oscillations) and a stochastic residual, one can satisfactorily reconstruct the data in the past (climatic historical analysis) and to try a prediction of future values (forecasting). Thus the proposed model appears to represent a valid method to evaluate the whole variability of each climatic series in a multi-decadal time scale. As for the deterministic component, the Fourier analysis of minimum and maximum temperatures series showed for each station the existence, beside the secular linear trend, of a first oscillation (annual), and a secondary oscillation (half-yearly), each characterized by an amplitude and a phase. On the other hand, the stochastic residual can always be regarded as the superposition of an AR(1) process and a residual white noise. The lower half-yearly seasonal component, although small, can produce an amplitude attenuation or enhancement, and a phase advance or delay, among the climatic expected values and the standard meteorological sequences. The results of the stochastic analysis showed the presence during the period 1951-1999 of a discrete variability in the minimum and maximum temperature series along the Tyrrhenian coastal area, more intense for minimum temperatures. This behaviour can have direct and indirect consequences on natural vegetation and on the planning of agricultural activity, in particular for what concerns the evaluation of the quantity of the "available energy" for plant development and the assessment of "production sustainability" for the agricultural crops in terms of quantity, cost and quality of the agro products.

Beltrano, M. C.; Testa, O.; Malvestuto, V.; Esposito, S.

2010-09-01

371

Evaluation of Station Blackout accidents at nuclear power plants. Technical findings related to Unresolved Safety Issue A-44. Draft report for comment  

Microsoft Academic Search

''Station Blackout,'' which is the complete loss of alternating current (ac) electrical power in a nuclear power plant, has been designated as Unresolved Safety Issue A-44. Because many safety systems required for reactor core decay heat removal and containment heat removal depend on ac power, the consequences of a station blackout could be severe. This report documents the findings of

Baranowsky

1985-01-01

372

A queuing-theory-based approach to evaluate the efficiency of a network of automated stations and of a communication system  

Microsoft Academic Search

The Regional Meteorological Service for the Emilia-Romagna Region manages a network of automatic weather stations equipped with electronic sensors suitable for measuring meteorological parameters. The automatic stations consist of electronic instruments, which are subject to failures at more or less frequent intervals. A summary of their performance is necessary. In this paper, we compare the results of the summary, such

G. Galliani; F. Filippini; F. Screpanti

1999-01-01

373

41. Perimeter acquisition radar building radar element and coaxial display, ...  

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

41. Perimeter acquisition radar building radar element and coaxial display, with drawing of typical antenna section. Drawing, from left to right, shows element, aluminum ground plane, cable connectors and hardware, cable, and back-up ring. Grey area is the concrete wall - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

374

Space station group activities habitability module study  

NASA Technical Reports Server (NTRS)

This study explores and analyzes architectural design approaches for the interior of the Space Station Habitability Module (originally defined as Habitability Module 1 in Space Station Reference Configuration Decription, JSC-19989, August 1984). In the Research Phase, architectural program and habitability design guidelines are specified. In the Schematic Design Phase, a range of alternative concepts is described and illustrated with drawings, scale-model photographs and design analysis evaluations. Recommendations are presented on the internal architectural, configuration of the Space Station Habitability Module for such functions as the wardroom, galley, exercise facility, library and station control work station. The models show full design configurations for on-orbit performance.

Nixon, David

1986-01-01

375

Analyzing NEXRAD doppler radar images to assess nightly dispersal patterns and population trends in Brazilian free-tailed bats (Tadarida brasiliensis)  

Microsoft Academic Search

Synopsis Operators of early weather-surveillance radars often observed echoes on their displays that did not behave like weather pattern, including expanding ring-like shapes they called angels. These echoes were caused by high-flying insects, migrating birds, and large colonies of bats emerging from roosts to feed. Modern weather-surveillance radar stations in the United States (NEXt-generation RADar or NEXRAD) provide detailed images

Jason W. Horn; Thomas H. Kunz

2008-01-01

376

RADAR Reveals Titan Topography  

NASA Technical Reports Server (NTRS)

The Cassini Titan RADAR Mapper is a K(sub u)-band (13.78 GHz, lambda = 2.17 cm) linear polarized RADAR instrument capable of operating in synthetic aperture (SAR), scatterometer, altimeter and radiometer modes. During the first targeted flyby of Titan on 26 October, 2004 (referred to as Ta) observations were made in all modes. Evidence for topographic relief based on the Ta altimetry and SAR data are presented here. Additional SAR and altimetry observations are planned for the T3 encounter on 15 February, 2005, but have not been carried out at this writing. Results from the T3 encounter relevant to topography will be included in our presentation. Data obtained in the Ta encounter include a SAR image swath

Kirk, R. L.; Callahan, P.; Seu, R.; Lorenz, R. D.; Paganelli, F.; Lopes, R.; Elachi, C.

2005-01-01

377

Floor-plan radar  

NASA Astrophysics Data System (ADS)

Urban-warfare specialists, law-enforcement officers, counter-drug agents, and counter-terrorism experts encounter operational situations where they must assault a target building and capture or rescue its occupants. To minimize potential casualties, the assault team needs a picture of the building's interior and a copy of its floor plan. With this need in mind, we constructed a scale model of a single- story house and imaged its interior using synthetic-aperture techniques. The interior and exterior walls nearest the radar set were imaged with good fidelity, but the distal ones appear poorly defined and surrounded by ghosts and artifacts. The latter defects are traceable to beam attenuation, wavefront distortion, multiple scattering, traveling waves, resonance phenomena, and other effects not accounted for in the traditional (noninteracting, isotropic point scatterer) model for radar imaging.

Falconer, David G.; Ueberschaer, Ronald M.

2000-07-01

378

Preliminary site characterization summary and engineering evaluation/cost analysis for Site 2, New Fuel Farm, Naval Air Station Fallon, Fallon, Nevada  

SciTech Connect

This report addresses subsurface contamination associated with Site 2, the New Fuel Farm at Naval Air Station Fallon (NAS Fallon), Nevada and is an integral part of Phase 2 of the Installation Restoration Program (IR Program) currently underway at the facility. This report: (1) reviews and assesses environmental information characterizing Site 2; (2) determine if site-characterization information is sufficient to design and evaluate removal actions; and, (3) investigates, develops, and describes any removal actions deemed feasible. Previous environmental investigations at Site 2 indicate the presence of floating product (primarily JP-5, jet fuel) on the water table underlying the facility. While the extent of floating-produce plumes has been characterized, the degree of associated soil and groundwater contamination remains uncertain. A comprehensive characterization of soil and groundwater contamination will be completed as the Remedial Investigation/Feasibility Study progresses. Corrective actions are recommended at this time to remove free-phase floating product. Implementing these removal actions will also provide additional information which will be used to direct further investigations of the extent, mobility, and potential environmental threat from soil and groundwater contaminants at this side.

Cronk, T.A.; Smuin, D.R. (Oak Ridge National Lab., TN (United States)); Schlosser, R.M. (Oak Ridge Associated Universities, Inc., TN (United States))

1991-09-01

379

Evaluation test on a landfill gas-fired turbine at the Los Angeles County Sanitation District's Puente Hill Landfill Electric Generation Station. Air pollution test report  

SciTech Connect

A cooperative test program was conducted from February 25 through February 27, 1986 by Air Resources Board (ARB) and South Coast Air Quality Management District (SCAQMD) staff to evaluate the gaseous constituents from untreated landfill gas used to fuel a turbine and the emissions from that turbine located at the Los Angeles County Sanitation District's Puente Hills Electric Generating Station. The turbine was fueled with gases generated by the anaerobic decomposition of buried refuse at the Los Angeles County Sanitation District's Puente Hills Landfill. Emissions of criteria pollutant as determined from ARB test data are reported. Mass flow rates and destruction and removal efficiencies (DRE) of non-criteria pollutant compounds determined at the stack from SCQAMD bag-sample test data and mass-flow rates and DRE's for chlorinated and aromatic compounds determined from data from ARB resin samples are presented. Destruction and removal efficiencies based on mass-flow rates for chlorinated compounds ranged from 17 to 99+ percent and for aromatic compounds ranged from negative to 99+ percent. The possible formation of the compounds - chlorinated dioxins, furans, and polychlorinated biphenyls - was considered and samples were taken for analyses for these compounds. Dioxins, furans, and polychlorinated biphenyls were not detected in the inlet nor the outlet gas stream samples.

Not Available

1986-07-01

380

Radar signal processing  

NASA Astrophysics Data System (ADS)

The role of clutter in radar signal processing is considered with particular reference to an air-traffic environment. The characteristics of clutter are described, and the use of conventional moving-target indication filters to reduce the effects of clutter is considered. Adaptive clutter suppression schemes are addressed, and the adaptive detection of a moving target in the presence of clutter of unknown statistics is discussed. The use of a parametric spectrum estimation procedure as the basis of clutter classification is described.

Haykin, S.

1985-04-01

381

Airborne bistatic radar applications  

Microsoft Academic Search

Applications of bistatic radar when one or both of the units are airborne are discussed. Scenarios that merit deeper consideration are covert strike and head-on SAR using a stand-off illuminator, either airborne or space-based; area air defense with passive ground-based receivers and stand-off illuminators; an airborne picket line to detect stealth aircraft and missiles; AWACS aircraft providing mutual support in

James A. Foster

1987-01-01

382

Imaging synthetic aperture radar  

DOEpatents

A linear-FM SAR imaging radar method and apparatus to produce a real-time image by first arranging the returned signals into a plurality of subaperture arrays, the columns of each subaperture array having samples of dechirped baseband pulses, and further including a processing of each subaperture array to obtain coarse-resolution in azimuth, then fine-resolution in range, and lastly, to combine the processed subapertures to obtain the final fine-resolution in azimuth. Greater efficiency is achieved because both the transmitted signal and a local oscillator signal mixed with the returned signal can be varied on a pulse-to-pulse basis as a function of radar motion. Moreover, a novel circuit can adjust the sampling location and the A/D sample rate of the combined dechirped baseband signal which greatly reduces processing time and hardware. The processing steps include implementing a window function, stabilizing either a central reference point and/or all other points of a subaperture with respect to doppler frequency and/or range as a function of radar motion, sorting and compressing the signals using a standard fourier transforms. The stabilization of each processing part is accomplished with vector multiplication using waveforms generated as a function of radar motion wherein these waveforms may be synthesized in integrated circuits. Stabilization of range migration as a function of doppler frequency by simple vector multiplication is a particularly useful feature of the invention; as is stabilization of azimuth migration by correcting for spatially varying phase errors prior to the application of an autofocus process.

Burns, Bryan L. (Tijeras, NM); Cordaro, J. Thomas (Albuquerque, NM)

1997-01-01

383

Radar response to vegetation  

Microsoft Academic Search

Active microwave measurements of vegetation backscatter were conducted to determine the utility of radar in 1) mapping soil moisture through vegetation and 2) mapping crop types. Using a truck-mounted boom, spectral response data were obtained for four crop types (corn, milo, soybeans, and alfalfa) over the 4-8 GHz frequency band, at incidence angles of0deg-70degin10degsteps, and for all four linear polarization

F. Ulaby

1975-01-01

384

Convolutional Neural Networks for Radar Detection  

Microsoft Academic Search

The use of convolutional neural networks (CNN’s) for radar detection is evaluated. The detector includes a time-frequency\\u000a block that has been implemented by the Wigner-Ville distribution and the Short-Time Fourier Transform to test the suitability\\u000a of both techniques. The CNN detectors are compared with the classic multilayer perceptron and with several traditional non-neural\\u000a detectors. Preliminary results are shown using non-correlated

Gustavo López-risueño; Jesús Grajal; Simon Haykin; Rosa Díaz-oliver

2002-01-01

385

A review of array radars  

NASA Astrophysics Data System (ADS)

Achievements in the area of array radars are illustrated by such activities as the operational deployment of the large high-power, high-range-resolution Cobra Dane; the operational deployment of two all-solid-state high-power, large UHF Pave Paws radars; and the development of the SAM multifunction Patriot radar. This paper reviews the following topics: array radars steered in azimuth and elevation by phase shifting (phase-phase steered arrays); arrays steered + or - 60 deg, limited scan arrays, hemispherical coverage, and omnidirectional coverage arrays; array radars steering electronically in only one dimension, either by frequency or by phase steering; and array radar antennas which use no electronic scanning but instead use array antennas for achieving low antenna sidelobes.

Brookner, E.

1981-10-01

386

Cognitive processing for nonlinear radar  

NASA Astrophysics Data System (ADS)

An increasingly cluttered electromagnetic environment (EME) is a growing problem for radar systems. This problem is becoming critical as the available frequency spectrum shrinks due to growing wireless communication device usage and changing regulations. A possible solution to these problems is cognitive radar, where the cognitive radar learns from the environment and intelligently modifies the transmit waveform. In this paper, a cognitive nonlinear radar processing framework is introduced where the main components of this framework consist of spectrum sensing processing, target detection and classification, and decision making. The emphasis of this paper is to introduce a spectrum sensing processing technique that identifies a transmit-receive frequency pair for nonlinear radar. It will be shown that the proposed technique successfully identifies a transmit-receive frequency pair for nonlinear radar from data collected from the EME.

Martone, Anthony; Ranney, Kenneth; Hedden, Abigail; Mazzaro, Gregory; McNamara, David

2013-05-01

387

Radar gun hazards  

SciTech Connect

Radar guns - hand-held units used by the law to nail speeders - have been in use since the early '60s. Now they've been accused of causing cancer. Police officers in several states have so far filed eight suits against the manufacturer, claiming that they have contracted rare forms of cancer, such as of the eyelid and the testicle, from frequent proximity to the devices. Spurred by concerns expressed by police groups, researchers at the Rochester Institute of Technology are conducting what they believe to be the first research of its kind in the nation. Last month psychologist John Violanti, an expert in policy psychology and health, sent out a one-page survey to 6,000 active and retired police officers in New York State, asking them about their health and their use of radar guns. Violanti says melanoma, leukemia, and lymph node cancer may be linked to these as well as other electromagnetic devices. The Food and Drug Administration earlier this year issued a warning about radar guns, telling users not to operate them closer than 6 inches from the body. But this may not be a sufficient safeguard since the instruments can give off crisscrossing wave emissions within a police vehicle. The survey will be used to help determine if it would be safer to mount the guns, which are currently either hand-held or mounted on dashboards, outside troopers' cars.

Not Available

1991-12-20

388

Spaceborne Imaging Radar Project  

NASA Technical Reports Server (NTRS)

In June of 1985 the Project Initiation Agreement was signed by the Jet Propulsion Laboratory and the NASA Office of Space Science and Applications for the Spaceborne Imaging Radar Project (SIR). The thrust of the Spaceborne Imaging Radar Project is to continue the evolution of synthetic aperture radar (SAR) science and technology developed during SEASAT, SIR-A and SIR-B missions to meet the needs of the Earth Observing System (EOS) in the mid 1990's. As originally formulated, the Project plans were for a reflight of the SIR-B in 1987, the development of a new SAR, SIR-C, for missions in mid 1989 and early 1990, and the upgrade of SIR-C to EOS configuration with a qualification flight aboard the shuttle in the 1993 time frame (SIR-D). However, the loss of the shuttle Challenger has delayed the first manifest for SIR to early 1990. This delay prompted the decision to drop SIR-B reflight plans and move ahead with SIR-C to more effectively utilize this first mission opportunity. The planning for this project is discussed.

Herman, Neil

1986-01-01

389

Performance and evaluation of gas engine driven rooftop air conditioning equipment at the Willow Grove (PA) Naval Air Station. Interim report, 1992 cooling season  

SciTech Connect

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

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

1993-05-01

390

Radar studies of bird migration  

NASA Technical Reports Server (NTRS)

Observations of bird migration with NASA radars were made at Wallops Island, Va. Simultaneous observations were made at a number of radar sites in the North Atlantic Ocean in an effort to discover what happened to those birds that were observed leaving the coast of North America headed toward Bermuda, the Caribbean and South America. Transatlantic migration, utilizing observations from a large number of radars is discussed. Detailed studies of bird movements at Wallops Island are presented.

Williams, T. C.; Williams, J. M.

1974-01-01

391

Space Radar Image of Manaus, Brazil  

NASA Technical Reports Server (NTRS)

These two images were created using data from the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR). On the left is a false-color image of Manaus, Brazil acquired April 12, 1994, onboard space shuttle Endeavour. In the center of this image is the Solimoes River just west of Manaus before it combines with the Rio Negro to form the Amazon River. The scene is around 8 by 8 kilometers (5 by 5 miles) with north toward the top. The radar image was produced in L-band where red areas correspond to high backscatter at HH polarization, while green areas exhibit high backscatter at HV polarization. Blue areas show low backscatter at VV polarization. The image on the right is a classification map showing the extent of flooding beneath the forest canopy. The classification map was developed by SIR-C/X-SAR science team members at the University of California,Santa Barbara. The map uses the L-HH, L-HV, and L-VV images to classify the radar image into six categories: Red flooded forest Green unflooded tropical rain forest Blue open water, Amazon river Yellow unflooded fields, some floating grasses Gray flooded shrubs Black floating and flooded grasses Data like these help scientists evaluate flood damage on a global scale. Floods are highly episodic and much of the area inundated is often tree-covered. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.v. (DLR), the major partner in science, operations and data processing of X-SAR.

1999-01-01

392

Output Tube Emission Characteristics of Operational Radars.  

National Technical Information Service (NTIS)

This report contains the emission spectra of 19 different types of radars, selected to show the different emission spectrum characteristics produced by a variety of radar output tube technologies. The radars include examples of ground-based search, airpor...

R. J. Matheson, J. D. Smilley, G. D. Falcon, V. S. Lawrence

1982-01-01

393

Neural-network laser radar.  

PubMed

A laser radar whose resolution is greater than 1 µm is reported. We present the radar results when they are used for such purposes as determining the size of a void inside a silicon wafer, profiling a cross-sectional pattern of an optical fiber, studying the birefringence of a lithium-niobate crystal, or finding a fault in an optical guide in an optical integrated-circuit wafer. Neural-network theory was used in processing the radar signal. Radar processing based on neural-network theory gave significantly superior resolution compared with Fourier-transform-based processing. PMID:20885600

Lizuka, K; Fujii, S

1994-05-01

394

Radar data processing and analysis  

NASA Technical Reports Server (NTRS)

Digitized four-channel radar images corresponding to particular areas from the Phoenix and Huntington test sites were generated in conjunction with prior experiments performed to collect X- and L-band synthetic aperture radar imagery of these two areas. The methods for generating this imagery are documented. A secondary objective was the investigation of digital processing techniques for extraction of information from the multiband radar image data. Following the digitization, the remaining resources permitted a preliminary machine analysis to be performed on portions of the radar image data. The results, although necessarily limited, are reported.

Ausherman, D.; Larson, R.; Liskow, C.

1976-01-01

395

Model for optimal parallax in stereo radar imagery  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

396

Diurnal tides at low latitudes: Radar, satellite, and model results  

NASA Astrophysics Data System (ADS)

Mean winds and tidal signatures in the mesosphere and lower thermosphere (MLT) region are derived from meteor radar observations at three sites around 22°S acquired in 2005. The observed differences of mean winds and tides are discussed in relation to the meteorological situation in the lower atmosphere and the possible generation of non-migrating tides. The longitudinally well separated radar sites allowed the evaluation of the migrating tidal component. The seasonal variation of signatures of the diurnal tide derived from ground-based radar observations, TIDI measurements aboard TIMED satellite, and model results obtained with HAMMONIA (Hamburg Model of the Neutral and Ionized Atmosphere) are compared. The ground-based, satellite, and model results of the total diurnal tide are in good agreement. The same is true for the migrating diurnal tide obtained from the radar observations, TIDI observations and from the model studies of HAMMONIA and GSWM00 (Global Scale Wave Model).

Kishore Kumar, G.; Singer, W.; Oberheide, J.; Grieger, N.; Batista, P. P.; Riggin, D. M.; Schmidt, H.; Clemesha, B. R.

2014-10-01

397

Millimeter Wave Cloud Radar (MMCR) Handbook  

SciTech Connect

The millimeter cloud radar (MMCR) systems probe the extent and composition of clouds at millimeter wavelengths. The MMCR is a zenith-pointing radar that operates at a frequency of 35 GHz. The main purpose of this radar is to determine cloud boundaries (e.g., cloud bottoms and tops). This radar will also report radar reflectivity (dBZ) of the atmosphere up to 20 km. The radar possesses a doppler capability that will allow the measurement of cloud constituent vertical velocities.

KB Widener; K Johnson

2005-01-30

398

Monitoring internal organ motion with continuous wave radar in CT  

SciTech Connect

Purpose: To avoid motion artifacts in medical imaging or to minimize the exposure of healthy tissues in radiation therapy, medical devices are often synchronized with the patient's respiratory motion. Today's respiratory motion monitors require additional effort to prepare the patients, e.g., mounting a motion belt or placing an optical reflector on the patient's breast. Furthermore, they are not able to measure internal organ motion without implanting markers. An interesting alternative to assess the patient's organ motion is continuous wave radar. The aim of this work is to design, implement, and evaluate such a radar system focusing on application in CT.Methods: The authors designed a radar system operating in the 860 MHz band to monitor the patient motion. In the intended application of the radar system, the antennas are located close to the patient's body inside the table of a CT system. One receive and four transmitting antennas are used to avoid the requirement of exact patient positioning. The radar waves propagate into the patient's body and are reflected at tissue boundaries, for example at the borderline between muscle and adipose tissue, or at the boundaries of organs. At present, the authors focus on the detection of respiratory motion. The radar system consists of the hardware mentioned above as well as of dedicated signal processing software to extract the desired information from the radar signal. The system was evaluated using simulations and measurements. To simulate the radar system, a simulation model based on radar and wave field equations was designed and 4D respiratory-gated CT data sets were used as input. The simulated radar signals and the measured data were processed in the same way. The radar system hardware and the signal processing algorithms were tested with data from ten volunteers. As a reference, the respiratory motion signal was recorded using a breast belt simultaneously with the radar measurements.Results: Concerning the measurements of the test persons, there is a very good correlation (?= 0.917) between the respiratory motion phases received by the radar system and the external motion monitor. Our concept of using an array of transmitting antennas turned out to be widely insensitive to the positioning of the test persons. A time shift between the respiratory motion curves recorded with the radar system and the motion curves from the external respiratory monitor was observed which indicates a slight difference between internal organ motion and motion detected by the external respiratory monitor. The simulations were in good accordance with the measurements.Conclusions: A continuous wave radar operating in the near field of the antennas can be used to determine the respiratory motion of humans accurately. In contrast to trigger systems used today, the radar system is able to measure motion inside the body. If such a monitor was routinely available in clinical CT, it would be possible optimizing the scan start with respect to the respiratory state of the patient. Breathing commands would potentially widely be avoided, and as far as uncooperative patients or children are concerned, less sedation might be necessary. Further applications of the radar system could be in radiation therapy or interventional imaging for instance.

Pfanner, Florian [Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen, Germany and Siemens AG, Healthcare Sector, Siemensstr. 1, 91301 Forchheim (Germany)] [Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen, Germany and Siemens AG, Healthcare Sector, Siemensstr. 1, 91301 Forchheim (Germany); Maier, Joscha [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)] [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Allmendinger, Thomas; Flohr, Thomas [Siemens AG, Healthcare Sector, Siemensstr. 1, 91301 Forchheim (Germany)] [Siemens AG, Healthcare Sector, Siemensstr. 1, 91301 Forchheim (Germany); Kachelrieß, Marc [Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen, Germany and Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)] [Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen, Germany and Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

2013-09-15

399

Space Station fluid resupply  

Microsoft Academic Search

Viewgraphs on space station fluid resupply are presented. Space Station Freedom is resupplied with supercritical O2 and N2 for the ECLSS and USL on a 180 day resupply cycle. Resupply fluids are stored in the subcarriers on station between resupply cycles and transferred to the users as required. ECLSS contingency fluids (O2 and N2) are supplied and stored on station

Al Winters

1990-01-01

400

Planetary radar studies. [radar mapping of the Moon and radar signatures of lunar and Venus craters  

NASA Technical Reports Server (NTRS)

Progress made in studying the evolution of Venusian craters and the evolution of infrared and radar signatures of lunar crater interiors is reported. Comparison of radar images of craters on Venus and the Moon present evidence for a steady state Venus crater population. Successful observations at the Arecibo Observatory yielded good data on five nights when data for a mix of inner and limb areas were acquired. Lunar craters with radar bright ejects are discussed. An overview of infrared radar crater catalogs in the data base is included.

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

1981-01-01

401

ERS-ENVISAT radar altimetry over the Amazon basin  

NASA Astrophysics Data System (ADS)

Since the launch of satellite embarking radar altimeters in the late 80’s, scientists have investigated the feasibility of using these ocean-dedicated data over the continental waters. In fact, satellite radar altimetry is being recognized as a powerful tool to obtain time series of water stage consistent to those obtained by conventional in situ gauge stations. In addition, this technology has been proved to provide reliable information about the dynamics of large water bodies such as lakes and inner seas. However, the results should be deeply examined as we shift the analysis to water levels acquired during satellite crosses over rivers. Yet, hydrologists are still reluctant in using these data, as neither the neces¬sary time sampling nor accuracy is achieved, leading to endless debates in specialized workshops. Noteworthy to highlight, few published studies are dedicated to an in depth assessment of the radar altimetry over rivers, in¬cluding comparisons with water levels at fluviometric gauges. In this work, we present an extensive analysis of the quality of times series of river stages that we have constructed in the Amazon basin for a variety of water bodies such as large rivers, narrow stems, lakes and flooded areas using radar altimeters embarked on¬board ERS-2 and ENVISAT. The approach includes the sensitivity to the raw data processing methodology such as the tracking algorithm, the data selection at the crossings between satellite track and river bed (so-called virtual stations) and correction for off-nadir effects. The VALS toolbox was developed to process altimetry data at virtual stations under the framework of this study. Results of internal validation at cross-overs and external validation by comparison with in situ gauges are presented.

Santos da Silva, J.; Calmant, S.; Rotunno Filho, O. C.; Seyler, F.; Mansur, W. J.; Cochonneau, G.

2009-12-01

402

Bistatic radar using a spaceborne illuminator  

NASA Astrophysics Data System (ADS)

A bistatic radar has a physically separated transmitter and receiver. This research pro gramme investigates a bistatic radar system which uses a spaceborne synthetic aperture radar transmitter on board the European Space Agency's Envisat satellite and a station ary, ground based receiver. The advantages of this variant of the bistatic configuration includes the passive and therefore covert nature of the receiver, its relatively low cost, in addition to the possibility of using a non-cooperative transmitter. The theory behind bistatic SAR systems is covered, including the specific case investi gated. The design, construction and testing of the bistatic receiver, which uses two separate channels, for the direct signal from the satellite (for synchronisation purposes) and the re flected signals from the imaged scene is also described. A SAR processing scheme using an adapted chirp scaling algorithm is presented and demonstrated through simulations to produce focused images for the scenario. The results of several bistatic imaging experiments are analysed through comparisons with theoretical impulse responses, and comparisons with satellite photographs, the corresponding monostatic image produced by Envisat, and the bistatic ambiguity function. It is demonstrated that focused images may be produced with such a system, although the performance achievable is dependent upon the imaging geometry. Different look direc tions of the receiver produce widely differing resolution values. The optimum choice of look direction must be weighed against possible direct signal interference in the reflected signal channel. Other effects, such as azimuth ambiguities caused by the sampling of the mov ing transmitter beam by the pulse repetition frequency may also have an effect, depending upon the combined transmit/receive beam pattern. Aspects of the system that could be investigated in the future are identified, for example the addition of an extra channel to the receiver in order to perform bistatic displaced phase centre antenna or interferometry experiments.

Whitewood, Aric Pierre

403

Space station functional relationships analysis  

NASA Technical Reports Server (NTRS)

A systems engineering process is developed to assist Space Station designers to understand the underlying operational system of the facility so that it can be physically arranged and configured to support crew productivity. The study analyzes the operational system proposed for the Space Station in terms of mission functions, crew activities, and functional relationships in order to develop a quantitative model for evaluation of interior layouts, configuration, and traffic analysis for any Station configuration. Development of the model involved identification of crew functions, required support equipment, criteria of assessing functional relationships, and tools for analyzing functional relationship matrices, as well as analyses of crew transition frequency, sequential dependencies, support equipment requirements, potential for noise interference, need for privacy, and overall compatability of functions. The model can be used for analyzing crew functions for the Initial Operating Capability of the Station and for detecting relationships among these functions. Note: This process (FRA) was used during Phase B design studies to test optional layouts of the Space Station habitat module. The process is now being automated as a computer model for use in layout testing of the Space Station laboratory modules during Phase C.

Tullis, Thomas S.; Bied, Barbra R.

1988-01-01

404

Millimeter radar improves target identification  

NASA Astrophysics Data System (ADS)

Recently developed millimeter wave radar has advantages for target identification over conventional microwave radar which typically use lower frequencies. We describe the pertinent features involved in the construction of the new millimeter wave radar, the pseudo-optical cavity source and the quasi-optical duplexer. The long wavelength relative to light allows the radar beam to penetrate through most weather because the wavelength is larger than the particle size for dust, drizzle rain, fog. Further the mm wave beam passes through an atmospheric transmission window that provides a dip in attenuation. The higher frequency than conventional radar provides higher Doppler frequencies, for example, than X-band radar. We show by simulation that small characteristic vibrations and slow turns of an aircraft become visible so that the Doppler signature improves identification. The higher frequency also reduces beam width, which increases transmit and receive antenna gains. For the same power the transmit beam extends to farther range and the increase in receive antenna gain increases signal to noise ratio for improved detection and identification. The narrower beam can also reduce clutter and reject other noise more readily. We show by simulation that the radar can be used at lower elevations over the sea than conventional radar.

McAulay, Alastair D.

2011-06-01

405

Imaging Radar for Ecosystem Studies  

NASA Technical Reports Server (NTRS)

Recently a number of satellites have been launched with radar sensors, thus expanding opportunities for global assessment. In this article we focus on the applications of imaging radar, which is a type of sensor that actively generates pulses of microwaves and, in the interval between sending pulses, records the returning signals reflected back to an antenna.

Waring, Richard H.; Way, JoBea; Hunt, E. Raymond J.; Morrissey, Leslie; Ranson, K. Jon; Weishampel, John F.; Oren, Ram; Franklin, Steven E.

1996-01-01

406

Landform Identification on Radar Images  

NASA Technical Reports Server (NTRS)

Polarized radar echo images of the Moon acquired using 3.8 and 70 cm wavelengths were examined to learn more about (1) the relationships between theoretical resolutions of the radars and the sizes of landforms that can be identified and (2) the factors that effect landform identification.

Moore, H. J.; Thompson, T. W.

1985-01-01

407

4, 695729, 2004 Radar observations  

E-print Network

ACPD 4, 695­729, 2004 Radar observations of meteor trails W. G. Elford Title Page Abstract Discussion © EGU 2004 Atmos. Chem. Phys. Discuss., 4, 695­729, 2004 www.atmos-chem-phys.org/acpd/4/695/ SRef Discussions Radar observations of meteor trails, and their interpretation using Fresnel holography: a new tool

Paris-Sud XI, Université de

408

New Radar and Navigation Systems  

Microsoft Academic Search

It is not the intention of this paper to give a complete coverage of all new radar and navigation systems, but to concentrate rather more on specific areas and examples where microwaves are used. Also, general coverage of the radar area is felt to be unnecessary following the invited paper given by R. Voles at Microwave 74, however recent advances

K L Fuller

1975-01-01

409

CO2 laser radar  

NASA Astrophysics Data System (ADS)

CO2 laser-based radars operating at 10 microns are both highly energy-efficient and eye-safe, as well as compact and rugged; they also furnish covertness-enhancing fine pointing accuracy, and are difficult to jam or otherwise confuse. Two modes of operation are generally employed: incoherent, in which the laser is simply used as a high power illumination source, and in the presently elaborated coherent or heterodyne mode. Applications encompass terrain-following and obstacle avoidance, Doppler discrimination of missile and aircraft targets, pollutant gas detection, wind measurement for weapons-aiming, and global wind field monitoring.

Brown, D.; Callan, R.; Constant, G.; Davies, P. H.; Foord, R.

410

Risk assessment Barter Island radar installation, Alaska  

SciTech Connect

This document contains the baseline human health risk assessment and the ecological risk assessment (ERA) for the Barter Island Distant Early Warning (DEW) Line radar installation. Fourteen sites at the Barter Island radar installation underwent remedial investigations (RIS) during the summer of 1993. The presence of chemical contamination in the soil, sediments, and surface water at the installation was evaluated and reported in the Barter Island Remedial Investigation/Feasibility Study (RI/FS) United States Air Force 1994a. The analytical data reported in the RI/FS form the basis for the human health and ecological risk assessment. The primary contaminants of concern at the 14 sites are diesel and gasoline from past spills and/or leaks. The general location of the Barter Island radar installation is shown in Figure 1-1. The 14 sites investigated and the types of samples collected at each site are presented in Table 1-1. The purpose of the risk assessment is to evaluate the human and ecological health risks that may be associated with chemicals released to the environment at the 14 sites investigated during the RIs. The risk assessment characterizes the probability that measured concentrations of hazardous chemical substances will cause adverse effects in humans or the environment in the absence of remediation. The risk assessment will be used to determine if remediation (site cleanup) is necessary and also to rank sites for remedial action. Additionally, it will be used as a model for the risk assessment to be performed at the other DEW Line installations (Bullen Point, Oliktok Point, Point Lonely, Barrow Point, Wainwright, and Point Lay) and the Cape Lisburne radar installation. pg18. JMD.

NONE

1995-05-05

411

Radar image registration and rectification  

NASA Technical Reports Server (NTRS)

Two techniques for radar image registration and rectification are presented. In the registration method, a general 2-D polynomial transform is defined to accomplish the geometric mapping from one image into the other. The degree and coefficients of the polynomial are obtained using an a priori found tiepoint data set. In the second part of the paper, a rectification procedure is developed that models the distortion present in the radar image in terms of the radar sensor's platform parameters and the topographic variations of the imaged scene. This model, the ephemeris data and the digital topographic data are then used in rectifying the radar image. The two techniques are then used in registering and rectifying two examples of radar imagery. Each method is discussed as to its benefits, shortcomings and registration accuracy.

Naraghi, M.; Stromberg, W. D.

1983-01-01

412

A radar image time series  

NASA Technical Reports Server (NTRS)

A set of ten side-looking radar images of a mining area in Arizona that were aquired over a period of 14 yr are studied to demonstrate the photogrammetric differential-rectification technique applied to radar images and to examine changes that occurred in the area over time. Five of the images are rectified by using ground control points and a digital height model taken from a map. Residual coordinate errors in ground control are reduced from several hundred meters in all cases to + or - 19 to 70 m. The contents of the radar images are compared with a Landsat image and with aerial photographs. Effects of radar system parameters on radar images are briefly reviewed.

Leberl, F.; Fuchs, H.; Ford, J. P.

1981-01-01

413

A Three-Dimensional Ray Tracing Simulation of a Synthetic Aperture Ground Penetrating Radar System  

NASA Astrophysics Data System (ADS)

Ground Penetrating Radar (GPR) is a useful tool for imaging the area below the Earth's surface. GPR works on the same principle as traditional radar, evaluating the electromagnetic returns reflected from an object or scene of interest to determine characteristics of the object that reflected the signal. Synthetic Aperture Radar (SAR) is a technique which combines radar returns of a given scene collected at several positions. By compiling the information contained in the returns, an image of a scene can be generated. Combining these two concepts allows us to create an image of an underground scene.

Jeter, James W., III

2002-10-01

414

An overview of radar-based, automatic, noncooperative target recognition techniques  

NASA Astrophysics Data System (ADS)

Radar target recognition techniques tend to fall into two principle classes: those that exploit the radar characterization of a platform's physical shape and those that exploit the radar characterization of the dynamic characteristics of the moving parts of the target. The former are based on the platform's (essentially instantaneous) range (time)-amplitude radar signature and are exploited through generation and analysis of the platform's ultrahigh range resolution (UHRR) profile. The latter are based on the platform's frequency-amplitude radar signature as represented in the time evolution of its high-resolution Doppler signature. The methodologies applicable to automatic, noncooperative recognition of platforms based on both these classes of techniques are discussed. The choice and implications of radar parameters, signal processing techniques, and pattern recognition techniques are discussed, compared, and evaluated in terms of their impact on recognition system performance.

Cohen, Marvin N.

415

Simulation of a surface-penetrating radar for Mars exploration  

NASA Astrophysics Data System (ADS)

In the near future, several exploratory missions to Mars are planned, which will include orbital radar sounders capable of characterizing the planet's subsurface structure to depths of up to a few kilometers. Due to the limited amount of resources concerning the properties of the Martian soils, in particular, those governing electromagnetic propagation and scattering, the ability of a radar system to detect and distinguish between subsurface interfaces is difficult to predict. Up to this time, most radar sounding simulations have been based on simplified models and do not accurately account for many of the factors that influence the response. To aid in the system evaluation and data interpretation for these missions, we developed a radar simulator to accurately model the response for various geological conditions. The simulator uses a frequency domain algorithm and is capable of modeling the effects of dielectric layering, volume debris, frequency dispersion, ohmic losses, and interface roughness. In this paper a geophysical model appropriate to the radar simulator is described, and the simulation algorithms are presented in detail. Factors influencing wave propagation and scattering are identified, including those that directly impact radar performance, specifically pertaining to expected penetration depths and unambiguous detection of water or ice. Finally, using a set of ``standard'' crustal models of different geological regions, simulation results are generated and presented.

Leuschen, Carl; Clifford, Stephen; Gogineni, Prasad

2003-03-01

416

Radar calibration by gage, disdrometer, and polarimetry: Theoretical limit caused by the variability of drop size distribution and application to fast scanning operational radar data  

NASA Astrophysics Data System (ADS)

SummaryA long time record of drop size distributions (DSDs) is used to evaluate the effect of the DSD variability on the accuracy of radar adjustment by comparison with a rain gage on a daily basis. Radar and gage measurements are simulated from DSDs. When a single R-Z relationship is used in the adjustment of the radar as a hydrological instrument, a standard deviation of fractional error of ˜28% is expected. This uncertainty is related to the DSD variability in time. A calibration of reflectivity can be done if a disdrometer is available. This disdrometric radar calibration is not affected by the DSD variability. Thus, the uncertainty that is expected in the radar adjustment with a gage is eliminated. Some uncertainty in radar-disdrometer comparison due to the difference in sampling volumes is minimized by applying a sequential intensity filtering technique (SIFT). Good correlations between radar and disdrometric reflectivities indicate that this could be an excellent way of calibrating radar on a daily basis when a disdrometer is located at close range (less than 30 km) from radar. Furthermore, the consistency of independent checks of radar calibration error with different disdrometers and polarimetry validates the argument that the radar-disdrometer comparison can be used as a tool for absolute radar calibration. The information from the McGill operational S-band polarimetric radar is also used to calibrate radar. This method is based on the fact that the specific differential phase shift ( KDP) or differential phase shift ( ?DP) between the horizontal and vertical polarized beams is immune to the radar calibration error whereas the reflectivity is affected by the calibration error. Due to the variability of DSDs only, the uncertainty in polarimetric calibration is the standard deviation of 1 dB with a single parameter KDP and reduces to 0.5 dB when the differential reflectivity ( ZDR) is added as well. To guarantee the stability of this calibration method, data longer than at least an hour is necessary to calculate the calibration error for the fast scanning McGill operational polarimetric radar and contamination by bright band or snow should be avoided. The sensitivity of this calibration method with respect to the drop deformation is tested.

Lee, GyuWon; Zawadzki, Isztar

2006-08-01

417

Estimating surface soil moisture over Sahel1 using ENVISAT radar altimetry2  

E-print Network

1 Estimating surface soil moisture over Sahel1 using ENVISAT radar altimetry2 3 C. Fatras, F estimating surface soil moisture in the semi-arid Gourma region in Northern Mali. To this19 end between the backscattering coefficients and23 surface soil moisture measured at six different stations

Paris-Sud XI, Université de

418

Radar-optronic tracking experiment for short and medium range aerial combat  

Microsoft Academic Search

The combination of optronic and radar sensors significantly improves combat aircraft potential. After having studied the fusion and estimation algorithms required by this combination, Thomson-CSF has set up a ground experiment in order to evaluate the performance of a combined radar-optronic system in short and medium range aerial combat. A system of this type can be used in combination with

C. Ravat; J. P. Mestre; C. Rose; M. Schorter

1991-01-01

419

Target Simulator to Calibrate Wideband Radar in Measuring the Internal Layers of the Greenland Ice Sheet  

Microsoft Academic Search

We developed a hardware target simulator for measuring the system response and testing of an airborne wideband radar that operates over the frequency range 600-900 MHz to map the near-surface internal layers in glacial ice. It uses optical and microwave delay lines for evaluating and optimizing the performance of the wideband radar in the continental United States without expensive field

B. Parthasarathy; T. Plummer; P. Kanagaratnam

2004-01-01

420

DAMAGE DETECTION IN ROADWAYS WITH GROUND PENETRATING RADAR D. Huston, N. Pelczarski, B. Esser,  

E-print Network

DAMAGE DETECTION IN ROADWAYS WITH GROUND PENETRATING RADAR D. Huston, N. Pelczarski, B. Esser penetrating radar (GPR). Concrete roadways, particularly those on bridges, are high-performance structural is an excellent opportunity for the application of nondestructive evaluation techniques, such as ground

Huston, Dryver R.

421

End-to-end laser radar range code for coherent cw lasers  

Microsoft Academic Search

A user friendly modular computer code is described for CW coherent laser radar which includes all relevant physical effects needed to evaluate the probability of detection versus time after launch for ballistic missiles or other targets of interest. The beginning point of the code is the conventional laser radar range equation. Atmospheric attenuation is determined from an integral FASCODE calculation,

M. John Yoder; Dima Seliverstov

1996-01-01

422

Comparação entre modelos digitais de elevação gerados por sensores ópticos e por radar  

Microsoft Academic Search

The aim of this paper is to compare the quality and accuracy of Digital Elevation Models (DEM) generated from different sources. Three different DEMs, covering the same geographic area (region of Uberaba, MG), are tentatively evaluated in this work. The first is a DEM derived from radar interferometry, through the Shuttle Radar Topographic Mission (SRTM). The other two are DEMs

Lucas de Melo Melgaço; Roberto de Souza; Michael Steinmayer; Caixa Postal; R. Felipe Neri

2005-01-01

423

The Sporadic Meteoroid Environment: Radar and Optical Fluxes  

NASA Astrophysics Data System (ADS)

Sporadic meteoroids come from comets, asteroids and even outside the solar system, and cannot be directly associated with a parent body. Understanding their origins gives us insight to the distribution, composition and history of their parent bodies. More practically, knowing their spatial density, speed and mass distribution helps to assess the threat to spacecraft in Earth orbit and on interplanetary missions. Recent meteor radar data, obtained with the Canadian Meteor Orbit Radar, has provided the most complete picture of the orbital distribution of meteoroids at the Earth and how that distribution changes with solar longitude. Meteor radars, however, suffer from a significant number of observing biases which are not currently well constrained. Optical systems have many fewer biases, but the collection and analysis of data has been much more labour intensive than in the past. In this work, we present a rigorous method for calculating the collecting area of a two-station video system, and apply the method to calculating the flux of meteoroids from the major sporadic sources. The method is tested on meteor showers, where the activity is better constrained. Fig. 1: Density of radiants of orbits observed with the Canadian Meteor Orbit Radar, 2002 - 2008. Each pixel represents the number of orbits in a 2x2 degree bin, in sun-centered ecliptic coordinates.

Campbell-Brown, M. D.; Braid, D.

2009-12-01

424

Antarctic Mapping Project ACTIVE RADAR CALIBRATOR  

E-print Network

and Space Administration and National Science Foundation sponsored second mapping of Antarctica using satellite radar. The ARC is required in the calibration of these radar image data. This active radar. The first radar mapping of Antarctica was completed in 1997. The second mapping will also be accomplished

Howat, Ian M.

425

A new algorithm for radar emitter recognition  

Microsoft Academic Search

A radar electronic support measures (ESM) system performs the functions of threat detection and area surveillance. The received radar pulses are sorted and segregated by the deinterleaver into a number of radar cells depending on the measured parameters of the received pulses. These radar cells will be submitted to the threat library and compared with the stored parameters of known

H. E. Hassan

2003-01-01

426

Joint deinterleaving\\/recognition of radar pulses  

Microsoft Academic Search

A radar electronic support measures (ESM) system performs the functions of threat detection and area surveillance to determine the bearing and the identity of the surrounding radar emitters. The received pulses arc sorted and segregated into a number of deinterleaved radar cells depending on their measured parameters. The parameters of the deinterleaved radar cells will be submitted to the threat

H. E. Hassan

2003-01-01

427

Radar absorbing materials used for target camouflage  

Microsoft Academic Search

As a result of the developments within signal processing, transmitters and receivers areas radar technology has improved steadily over the past 50 years gaining in the sensor sensitivity, miniaturisation, power consumption, etc which allow to build smaller, more reliable and user friendly radar sensors. The effectiveness of these radar sensors is sufficiently threatening to merit the reduction of radar signature

I. NICOLAESCU

2006-01-01

428

Radar, Insect Population Ecology, and Pest Management  

NASA Technical Reports Server (NTRS)

Discussions included: (1) the potential role of radar in insect ecology studies and pest management; (2) the potential role of radar in correlating atmospheric phenomena with insect movement; (3) the present and future radar systems; (4) program objectives required to adapt radar to insect ecology studies and pest management; and (5) the specific action items to achieve the objectives.

Vaughn, C. R. (editor); Wolf, W. (editor); Klassen, W. (editor)

1979-01-01

429

Course Syllabus Course name: Radar Meteorology  

E-print Network

Course Syllabus Course name: Radar Meteorology Course number: AT741 Instructor: Prof. Steven652, or permission of instructor Course goals and Objectives: AT741 is designed to provide principles, polarimetric radar, dual-wavelength radar, mm-wave radars with applications. The course also

430

Next generation SAR demonstration on space station  

NASA Astrophysics Data System (ADS)

This paper describes the next generation synthetic aperture radar (SAR) that enables future low cost space-borne radar missions. In order to realize these missions, we propose to use an inflatable, membrane, microstrip antenna that is particularly suitable for low frequency science radar missions. In order to mitigate risks associated with this revolutionary technology, the space station demonstration will be very useful to test the long-term survivability of the proposed antenna. This experiment will demonstrate several critical technology challenges associated with space-inflatable technologies. Among these include space-rigidization of inflatable structures, controlled inflation deployment, flatness and uniform separation of thin-film membranes and RF performance of membrane microstrip antennas. This mission will also verify the in-space performance of lightweight, high performance advanced SAR electronics. Characteristics of this SAR instrument include a capability for high resolution polarimetric imaging. The mission will acquire high quality scientific data using this advanced SAR to demonstrate the utility of these advanced technologies. We will present an inflatable L-band SAR concept for commercial and science applications and a P-band design concept to validate the Biomass SAR mission concept. The ionospheric effects on P-band SAR images will also be examined using the acquired data.

Edelstein, Wendy; Kim, Yunjin; Freeman, Anthony; Jordan, Rolando

1999-01-01

431

Survey of Public Television Station Managers 1973.  

ERIC Educational Resources Information Center

A survey of public television station managers was conducted for 1973 to evaluate different activities, types of services being performed or desired, and other information of interest to the Public Broadcasting System (PBS). Responses to questionnaires and/or interviews by the station managers showed that the overall quality of PBA programing was…

Meierhenry, W. C.

432

Development of the satellite solar power station  

Microsoft Academic Search

The economic and social acceptability and feasibility of a satellite solar power station (SSPS) beaming intercepted solar energy at microwave frequencies to receiving stations on the earth (ERS) are evaluated. With 24-hr constant energy input, there are no energy storage problems in space; solar energy available in synchronous orbit is 6-15 times that available optimally at the earth's surface; technological

P. E. Glaser

1977-01-01

433

Refueling stations for natural gas vehicles  

Microsoft Academic Search

The unavailability of natural gas vehicle (NGV) refueling stations constitutes one of the major barriers to the wide spread utilization of natural gas in the transportation market. The purpose of this paper is to review and evaluate the current technical and economic status of compressed natural gas vehicle refueling stations and to identify the components or design features that offer

C. F. Blazek; J. A. Kinast; R. T. Biederman; W. Jasionowski

1991-01-01

434

Automatic Near Surface Estimation from Radar Imagery  

NASA Astrophysics Data System (ADS)

The Center for Remote Sensing of Ice Sheets has developed radars for NASA's Operation Ice Bridge program in order to map near-surface internal layers for estimating the accumulation rate. In snow and ice, internal layers are created by changes in the ambient conditions at the time of deposition, and represent contrasts in density, electrical conductivity, and ice crystal orientation. By identifying and tracing internal layers in radar images of the Antarctic snow cover, these layers can be used to measure snow accumulation over time. Scientists have manually traced layers in large data volumes, and it requires time-consuming sparse hand-selection and interpolating between selections to save time. An automated algorithm will allow for studying more images and developing models to reconstruct and forecast ice sheet dynamics. We have developed an approach for automatically estimating near surface layers in snow radar echograms using a computer vision technique. The approach uses active contour models, which finds high-intensity edges likely to correspond to layer boundaries, while simultaneously imposing constraints on smoothness of layer depth and parallelism between layers. Results are evaluated and presented using metrics of accuracy and computation time.

Mitchell, J.; Crandall, D.; Fox, G.; Paden, J. D.

2012-12-01

435

Integrating Radar Remote Sensing of Habitat Structure:  

E-print Network

may be extrapolated to maps of potential species occurrences. In the case of vegetation requirements for habitat, most current datasets of actual vegetation have been derived from optical (e.g. aerial photography or Landsat) remotely sensed data. These data are largely limited to describing horizontal structure: vegetation community composition and landscape spatial metrics. This paper introduces new radar remote sensors that are more suited to directly measure vegetation height and other multi-dimensional forest structural variables such as density, basal area, and biomass, and to map these as continuous fields over large areas. We discuss this in the context of bird species, one of the taxonomic groups whose habitat preferences may be strongly influenced by multi-dimensional structure. The site for the pilot study is the Michigan Forests Test Site (MFTS) in the Upper Peninsula of Michigan, an area of mixed hardwood and coniferous forest communities. Our study uses two methods, one inductive and one deductive, to investigate the utility of incorporating radar data into biodiversity informatics databases. We evaluate the use of radar alone and also in combination with Landsat data for mapping of bird habitat for biodiversity informatics.

Pilot Project For; Kathleen M. Bergen; Daniel G. Brown; Eric J. Gustafson; M. Craig Dobson

2002-01-01

436

Vertical and latitudinal wave forcing observed with network of Radars over Indian region  

NASA Astrophysics Data System (ADS)

It is well known that gravity waves and tides play an important role in delineating the middle atmospheric structure and dynamics. Significant advancement has been in recent days in understanding the role of gravity waves and tides using different techniques in the lower, middle and upper atmosphere. However, only few results are available with simultaneous observations of all the three regions mentioned above. Further, no effort has been made so far in dealing with the latitudinal forcing of these waves and tides. With the establishment of advanced meteor radar at Sri Venkateswara University, Tirupati (13.63N, 79.4E) and up gradation of MF radar at Kolhapur (16.8N, 74.2E) together with existing MST radar at Gadanki (13.5N, 79.2E), Meteor radar at Thumba (8.5N, 77E) and MF radar located at Tirunalveli (8.7N, 77.8E) forms a unique network to address lower atmospheric forcing and its impact on middle and upper atmospheric structure and dynamics. All the above mentioned radars have been operated for few days simultaneously for investigating the short period gravity waves and tides (diurnal, semi-diurnal and ter-diurnal). Using simultaneous MST radar, Rayleigh lidar located at Gadanki and SVU meteor radar, lower atmospheric forcing and its impact of upper atmospheric is investigated. First results on short period gravity waves and tides are presented. Large day-to-day day variability in gravity waves and tides is observed within a station and among the stations providing insight on vertical and lateral coupling. Thus, long-term measurements with all the above mentioned instruments is planned to address effectively the vertical and latitudinal wave forcing.

Sunkara, Eswaraiah; Gurubaran, Subramanian; Sundararaman, Sathishkumar; Venkat Ratnam, Madineni; Karanam, Kishore Kumar; Vijaya Bhaskara Rao, Sarangam; Eethamakula, Kosalendra

437

Station Tour: Russian Segment  

NASA Video Gallery

Expedition 33 Commander Suni Williams concludes her tour of the International Space Station with a visit to the Russian segment, which includes Zarya, the first segment of the station launched in 1...

438

Transient ultra wide band measurement applications: radar cross section, synthetic aperture radar, electromagnetic compatibility  

Microsoft Academic Search

The Electronic Armament Centre (CELAR: Centre d'Electronique de L'Armement) and the Research Institute of Microwave and Optical Communications (IRCOM: Institut de Recherches en Communications Optiques et Micro-ondes) has evaluated the use of ultra-wide-band (UWB) short pulse measurement facilities to characterize target electromagnetic signatures. A first device is capable of determining the radar cross section (RCS) within a 200 MHz to

J. Andrieu; C. Dubois; M. Lalande; V. Bertrand; P. Delmote; B. Beillard; E. Martinod; B. Jecko; R. Guilleret; F. Monnier; M. Legoff

2003-01-01

439

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

NASA Astrophysics Data System (ADS)

The PANSY radar is the first Mesosphere-Stratosphere-Troposphere/Incoherent Scatter (MST/IS) radar in the Antarctic region. It is a large VHF monostatic pulse Doppler radar operating at 47 MHz, consisting of an active phased array of 1045 Yagi antennas and an equivalent number of transmit-receive (TR) modules with a total peak output power of 500 kW. The first stage of the radar was installed at Syowa Station (69°00?S, 39°35?E) in early 2011, and is currently operating with 228 antennas and modules. This paper reports the project's scientific objectives, technical descriptions, and the preliminary results of observations made to date. The radar is designed to clarify the role of atmospheric gravity waves at high latitudes in the momentum budget of the global circulation in the troposphere, stratosphere and mesosphere, and to explore the dynamical aspects of unique polar phenomena such as polar mesospheric clouds (PMC) and polar stratospheric clouds (PSC). The katabatic winds as a branch of Antarctic tropospheric circulation and as an important source of gravity waves are also of special interest. Moreover, strong and sporadic energy inputs from the magnetosphere by energetic particles and field-aligned currents can be quantitatively assessed by the broad height coverage of the radar which extends from the lower troposphere to the upper ionosphere. From engineering points of vie