These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Terrain height estimation using GMTI radar  

Microsoft Academic Search

We simulate the performance of existing and planned tactical GMTI (ground moving target indicator) systems using data cubes derived from high-fidelity interferometric SAR measurements, to assess the utility of these GMTI systems for an auxiliary terrain height estimation function. The two systems are current and next generation GMTI radars with linear and planar arrays, respectively, that could be mounted on

Charles Morgan; Steven Jaroszewski; Paul Mountcastle

2004-01-01

2

Lightweight SAR GMTI radar technology development  

NASA Astrophysics Data System (ADS)

A small and lightweight dual-channel radar has been developed for SAR data collections. Using standard Displaced Phase Center Antenna (DPCA) radar digital signal processing, SAR GMTI images have been obtained. The prototype radar weighs 5-lbs and has demonstrated the extraction of ground moving targets (GMTs) embedded in high-resolution SAR imagery data. Heretofore this type of capability has been reserved for much larger systems such as the JSTARS. Previously, small lightweight SARs featured only a single channel and only displayed SAR imagery. Now, with the advent of this new capability, SAR GMTI performance is now possible for small UAV class radars.

Kirk, John C.; Lin, Kai; Gray, Andrew; Hseih, Chung; Darden, Scott; Kwong, Winston; Majumder, Uttam; Scarborough, Steven

2013-05-01

3

GMTI radar minimum detectable velocity.  

SciTech Connect

Minimum detectable velocity (MDV) is a fundamental consideration for the design, implementation, and exploitation of ground moving-target indication (GMTI) radar imaging modes. All single-phase-center air-to-ground radars are characterized by an MDV, or a minimum radial velocity below which motion of a discrete nonstationary target is indistinguishable from the relative motion between the platform and the ground. Targets with radial velocities less than MDV are typically overwhelmed by endoclutter ground returns, and are thus not generally detectable. Targets with radial velocities greater than MDV typically produce distinct returns falling outside of the endoclutter ground returns, and are thus generally discernible using straightforward detection algorithms. This document provides a straightforward derivation of MDV for an air-to-ground single-phase-center GMTI radar operating in an arbitrary geometry.

Richards, John Alfred

2011-04-01

4

GMTI MIMO radar  

E-print Network

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

Bliss, Daniel W., Jr.

5

MIMO Radar Waveform Constraints for GMTI  

E-print Network

Ground moving-target indication (GMTI) provides both an opportunity and challenge for coherent multiple-input multiple-output (MIMO) radar. MIMO techniques can improve a radar's angle estimation and the minimum detectable ...

Forsythe, Keith W.

6

Robust radar detection of GMTI targets with STAP D. M. Carrington and Dr. P. G. Kealey  

E-print Network

Robust radar detection of GMTI targets with STAP D. M. Carrington and Dr. P. G. Kealey Qineti. Introduction. Ground Moving Target Indication (GMTI) radar is able to detect moving targets using short dwell times by distinguishing the weak radar signal of the moving target from the dominant returns due

Haddadi, Hamed

7

Gmti Motion Compensation  

DOEpatents

Movement of a GMTI radar during a coherent processing interval over which a set of radar pulses are processed may cause defocusing of a range-Doppler map in the video signal. This problem may be compensated by varying waveform or sampling parameters of each pulse to compensate for distortions caused by variations in viewing angles from the radar to the target.

Doerry, Armin W. (Albuquerque, NM)

2004-07-20

8

Circular SAR GMTI  

NASA Astrophysics Data System (ADS)

We describe techniques for improving ground moving target indication (GMTI) performance in multi-channel synthetic aperture radar (SAR) systems. Our approach employs a combination of moving reference processing (MRP) to compensate for defocus of moving target SAR responses and space-time adaptive processing (STAP) to mitigate the effects of strong clutter interference. Using simulated moving target and clutter returns, we demonstrate focusing of the target return using MRP, and discuss the effect of MRP on the clutter response. We also describe formation of adaptive degrees of freedom (DOFs) for STAP filtering of MRP processed data. For the simulated moving target in clutter example, we demonstrate improvement in the signal to interference plus noise (SINR) loss compared to more standard algorithm configurations. In addition to MRP and STAP, the use of tracker feedback, false alarm mitigation, and parameter estimation techniques are also described. A change detection approach for reducing false alarms from clutter discretes is outlined, and processing of a measured data coherent processing interval (CPI) from a continuously orbiting platform is described. The results demonstrate detection and geolocation of a high-value target under track. The endoclutter target is not clearly visible in single-channel SAR chips centered on the GMTI track prediction. Detections are compared to truth data before and after geolocation using measured angle of arrival (AOA).

Page, Douglas; Owirka, Gregory; Nichols, Howard; Scarborough, Steven

2014-06-01

9

Development of a GMTI Processing System for the Extraction of Traffic Information from TerraSAR-X Data  

Microsoft Academic Search

Synthetic aperture radar (SAR) has a day-and-night and all-weather operating capability, can acquire high- resolution images of large areas within short time frames and can measure the speed of moving objects. That is why its application to ground moving target indication (GMTI) and to traffic monitoring has been intensively investigated in the recent years. The German SAR satellite TerraSAR-X, which

S. Suchandt; M. Eineder; R. Müller; A. Laika; S. Hinz; F. Meyer; G. Palubinskas

10

GMTI processing using back projection.  

SciTech Connect

Backprojection has long been applied to SAR image formation. It has equal utility in forming the range-velocity maps for Ground Moving Target Indicator (GMTI) radar processing. In particular, it overcomes the problem of targets migrating through range resolution cells.

Doerry, Armin Walter

2013-07-01

11

Airborne array aperture UWB UHF radar-motivation and system considerations  

Microsoft Academic Search

The paper discusses the necessity, feasibility and technology of FOPEN GMTI. It argues that this functionality may be one mode in a multi-function UWB UHF system, which jointly possesses the capabilities for air target MTI and high resolution FOPEN SAR. The radar platform may be a UAV or an aircraft, whereas it is proposed to use the push boom type

Hans Hellsten; Lars M. H. Ulander

1999-01-01

12

Effect of wind turbine micro-Doppler on SAR and GMTI signatures  

NASA Astrophysics Data System (ADS)

In this paper, we present the results of a modeling study to examine the interference effect of microDopplers caused by offshore wind farms on airborne sensors operating in the synthetic aperture radar (SAR) and ground moving target indicator (GMTI) modes. The modeling is carried out by generating CAD instantiations of the dynamic wind turbine and using the high-frequency electromagnetic code Xpatch to perform the scattering calculations. Artifacts in the resulting SAR and GMTI signatures are evaluated for interference with tracking of boats in coastal waters. Results of signal filtering algorithms to reduce the dynamic turbine clutter in both SAR images and GMTI displays are presented.

Bhalla, Rajan; Ling, Hao

2014-05-01

13

Clutter in the GMTI range-velocity map.  

SciTech Connect

Ground Moving Target Indicator (GMTI) radar maps echo data to range and range-rate, which is a function of a moving target's velocity and its position within the antenna beam footprint. Even stationary clutter will exhibit an apparent motion spectrum and can interfere with moving vehicle detections. Consequently it is very important for a radar to understand how stationary clutter maps into radar measurements of range and velocity. This mapping depends on a wide variety of factors, including details of the radar motion, orientation, and the 3-D topography of the clutter.

Doerry, Armin Walter

2009-04-01

14

Selected tendencies of modern radars and radar systems development  

Microsoft Academic Search

This paper presents modern radars and radar systems problems caused by troubles and dangers connected with actual battlefield conditions. The usefulness of the phased array radar (PAR), low probability of intercept (LPI) radar and the multi-junction radar (MFR) has been described from the point of view of the single radar using. Moreover chosen aspects of the modem radar systems development,

J. F. Pietrasinski; T. W. Brenner; C. J. Lesnik

1998-01-01

15

Radar Imaging Systems Joseph Charpentier  

E-print Network

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

16

Simultaneous SAR and GMTI using ATI/DPCA  

NASA Astrophysics Data System (ADS)

In previous work, we presented GMTI detection and geo-location results from the AFRL Gotcha challenge data set, which was collected using a 3-channel, X-band, circular SAR system. These results were compared against GPS truth for a scripted vehicle target. The algorithm used for this analysis is known as ATI/DPCA, which is a hybrid of along-track interferometry (ATI) and the displaced phase center antenna (DPCA) technique. In the present paper the use of ATI/DPCA is extended in order to detect and geo-locate all observable moving targets in the Gotcha challenge data, including both the scripted movers and targets of opportunity. In addition, a computationally efficient SAR imaging technique is presented, appropriate for short integration times, which is used for computing an image of the scene of interest using the same pulses of data used for the GMTI processing. The GMTI detections are then overlaid on the SAR image to produce a simultaneous SAR/GMTI map.

Deming, Ross; Best, Matthew; Farrell, Sean

2014-06-01

17

The Cloud Radar System  

NASA Technical Reports Server (NTRS)

Improvement in our understanding of the radiative impact of clouds on the climate system requires a comprehensive view of clouds including their physical dimensions, dynamical generation processes, and detailed microphysical properties. To this end, millimeter vave radar is a powerful tool by which clouds can be remotely sensed. The NASA Goddard Space Flight Center has developed the Cloud Radar System (CRS). CRS is a highly sensitive 94 GHz (W-band) pulsed-Doppler polarimetric radar that is designed to fly on board the NASA high-altitude ER-2 aircraft. The instrument is currently the only millimeter wave radar capable of cloud and precipitation measurements from above most all clouds. Because it operates from high-altitude, the CRS provides a unique measurement perspective for cirrus cloud studies. The CRS emulates a satellite view of clouds and precipitation systems thus providing valuable measurements for the implementation and algorithm validation for the upcoming NASA CloudSat mission that is designed to measure ice cloud distributions on the global scale using a spaceborne 94 GHz radar. This paper describes the CRS instrument and preliminary data from the recent Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE). The radar design is discussed. Characteristics of the radar are given. A block diagram illustrating functional components of the radar is shown. The performance of the CRS during the CRYSTAL-FACE campaign is discussed.

Racette, Paul; Heymsfield, Gerald; Li, Lihua; Tian, Lin; Zenker, Ed

2003-01-01

18

Goldstone solar system radar  

NASA Technical Reports Server (NTRS)

Planning, direction, experimental design, and coordination of data-acquisition and engineering activities in support of all Goldstone planetary radar astronomy were performed. This work demands familiarity with the various components of a planetary radar telescope (transmitter, receiver, antenna, computer hardware and software) as well as knowledge of how the entire system must function as a cohesive unit to meet the particular scientific objectives at hand in a given observation. Support radar data-processing facilities, currently being used for virtually all Goldstone data reduction includes: a VAX 11/780 computer system, an FPS 5210 array processor, terminals, tape drives, and image-display devices, as well as a large body of data-reduction software to accommodate the variety of data-acquisition formats and strategems. Successful 113-cm radar observation of Callisto and the near-Earth asteroid 1981 Midas and Goldstone/VLA radar observations of Saturn's rings were obtained. Quick-look verification programs from data taken with phase-coded cw (i.e., ranging) waveforms, applicable to Venus, the Moon, and small bodies were completed. Definition of scientific and engineering requirements on instrument performance, radar system configuration, and personnel, for all 1988 Goldstone radar investigations was accomplished.

Jurgens, Raymond F.

1988-01-01

19

Results from an airborne SAR GMTI experiment supporting TerraSAR-X traffic processor development  

Microsoft Academic Search

The launch of the advanced high resolution radar satellite TerraSAR-X in summer 2006 opens new possibilities for the demonstration of traffic monitoring from space. DLR is currently developing an operational traffic processor for the TerraSAR-X ground segment. The paper presents results from an airborne SAR GMTI campaign that was part of a study for algorithm development and processor design. DLR's

S. Suchandt; G. Palubinskas; R. Scheiber; F. Meyer; H. Runge; P. Reinartz; R. Horn

2005-01-01

20

Glacio RADAR system and results  

Microsoft Academic Search

Since 1997 the Istituto Nazionale di Geofisica e Vulcanologia (INGV) in Italy has been involved in the development of the airborne RES system named Glacio RADAR, which is continuously upgraded. Radio Echo Sounding (RES) techniques are widely used in glaciological measurements. They are based on the use of radar systems, to obtain information concerning ice thickness of ice sheets and

A. Zirizzotti; J. A. Baskaradas; C. Bianchi; U. Sciacca; I. E. Tabacco; E. Zuccheretti

2008-01-01

21

Venus Radar Mapper (VRM): Multimode radar system design  

NASA Technical Reports Server (NTRS)

The surface of Venus has remained a relative mystery because of the very dense atmosphere that is opaque to visible radiation and, thus, normal photographic techniques used to explore the other terrestrial objects in the solar system are useless. The atmosphere is, however, almost transparent to radar waves and images of the surface have been produced via Earth-based and orbital radars. The technique of obtaining radar images of a surface is variously called side looking radar, imaging radar, or synthetic aperture radar (SAR). The radar requires a moving platform in which the antenna is side looking. High resolution is obtained in the cross-track or range direction by conventional radar pulse encoding. In the along-track or azimuth direction, the resolution would normally be the antenna beam width, but for the SAR case, a much longer antenna (or much sharper beam) is obtained by moving past a surface target as shown, and then combining the echoes from many pulses, by using the Doppler data, to obtain the images. The radar design of the Venus Radar Mapper (VRM) is discussed. It will acquire global radar imagery and altimetry data of the surface of Venus.

Johnson, William T. K.; Edgerton, Alvin T.

1986-01-01

22

Navigation radar signal acquisition and measurement system  

Microsoft Academic Search

In the course of navigation, radar is a very important navigation aids. However, different types of radar always have different signal definition. In this paper, a kind of method on radar signal acquisition and measurement based on embedded system is proposed. The system, which could automatically detect some common radar signal parameter, is consist of CPLD, ARM micro processor, ADC

Shaowei Li; Xinqing Zhuang

2009-01-01

23

Meteorological radar facility. Part 1: System design  

NASA Technical Reports Server (NTRS)

A compilation of information regarding systems design of space shuttles used in meteorological radar probes is presented. Necessary radar equipment is delineated, while space system elements, calibration techniques, antenna systems and other subsystems are reviewed.

Brassaw, L. L., Jr.; Hamren, S. D.; Mullins, W. H.; Schweitzer, B. P.

1976-01-01

24

Obstacle penetrating dynamic radar imaging system  

DOEpatents

An obstacle penetrating dynamic radar imaging system for the detection, tracking, and imaging of an individual, animal, or object comprising a multiplicity of low power ultra wideband radar units that produce a set of return radar signals from the individual, animal, or object, and a processing system for said set of return radar signals for detection, tracking, and imaging of the individual, animal, or object. The system provides a radar video system for detecting and tracking an individual, animal, or object by producing a set of return radar signals from the individual, animal, or object with a multiplicity of low power ultra wideband radar units, and processing said set of return radar signals for detecting and tracking of the individual, animal, or object.

Romero, Carlos E. (Livermore, CA); Zumstein, James E. (Livermore, CA); Chang, John T. (Danville, CA); Leach, Jr.. Richard R. (Castro Valley, CA)

2006-12-12

25

Effect of scattering on radar system performance  

NASA Astrophysics Data System (ADS)

The effect of both forward and backward scattering effect on the performance of radar systems was investigated. It is shown that forward scatter causes considerable error in the target elevation in tracking radars. Thus, low angle tracking radars are greatly affected by specular reflection whereas airborne tracking radars are affected by forward scatter. The backscattered signal (clutter) reduces the maximum range of the pulse radar to a great extent. Finally, the radar range decreases rapidly with increasing grazing angles. This implies that the probability of detection of a target decreases as the grazing angle increases.

Vishvakarma, Babau Ram; Taha, Bazil; Al-Hafid, H. T.

26

Urbana radar systems: Possibilities and limitations  

NASA Astrophysics Data System (ADS)

The Aeronomy Laboratory Field Station of the University of Illinois at Urbana contains three different radar systems capable of probing various regions of the atmosphere below about 100 km. These are an mesosphere-stratosphere-troposphere (MST) radar, a VHF meteor radar and an MF partial-reflection radar. All three radars can measure winds and waves in the ionospheric D region. The MST radar is, in addition, capable of probing the lower stratosphere and upper troposphere. A sodium (Na) LIDAR is also located at the Field Station and provides an additional way of studing winds and waves in the mesosphere by observing temporal variations in the sodium density profile.

Royrvik, O.

1984-12-01

27

Mars Radar Observations with the Goldstone Solar System Radar  

NASA Technical Reports Server (NTRS)

The Goldstone Solar System Radar (GSSR) has successfully collected radar echo data from Mars over the past 30 years. As such, the GSSR has played a role as a specific mission element within Mars exploration. The older data provided local elevation information for Mars, along with radar scattering information with global resolution. Since the upgrade to the 70-m Deep Space Network (DSN) antenna at Goldstone completed in 1986, Mars data has been collected during all but the 1997 Mars opposition. Radar data, and non-imaging delay-Doppler data in particular, requires significant data processing to extract elevation, reflectivity and roughness of the reflecting surface. The spatial resolution of these experiments is typically some 20 km in longitude by some 150 km in latitude. The interpretation of these parameters while limited by the complexities of electromagnetic scattering, do provide information directly relevant to geophysical and geomorphic analyses of Mars. The usefulness of radar data for Mars exploration has been demonstrated in the past. Radar data were critical in assessing the Viking Lander 1 site as well as, more recently, the Pathfinder landing site. In general, radar data have not been available to the Mars exploration community at large. A project funded initially by the Mars Exploration Directorate Science Office at the Jet Propulsion Laboratory (JPL), and later funded by NASA's Mars Data Analysis Program has reprocessed to a common format a decade's worth of raw GSSR Mars delay-Doppler data in aid of landing site characterization for the Mars Program. These data will soon be submitted to the Planetary Data System (PDS). The radar data used were obtained between 1988 and 1995 by the GSSR, and comprise some 63 delay-Doppler radar tracks. Of these, 15 have yet to be recovered from old 9-track tapes, and some of the data may be permanently lost.

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

2002-01-01

28

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

29

Performance analysis of radar antenna systems  

Microsoft Academic Search

If modern airborne radar systems are to function properly, the radar antenna radiation patterns must meet certain specifications. Until recently, most radar antennas were designed and tested in a clean antenna environment, i.e., there is no near field scattering from host structures or radome effects. However, these higher order effects are the matter of increasing concern with added performance demands

J. J. Kim; O. B. Kesler

1999-01-01

30

Installed performance analysis of radar antenna systems  

Microsoft Academic Search

If modern airborne radar systems are to function properly, the radar antenna radiation patterns must meet certain specifications. Previously, most radar antennas were designed and tested in a clean antenna environment, i.e., there are no near field scattering from host structures, or radome effects. However, these higher order effects are a matter of increasing concern with added performance demands in

Jacob J. Kim; Oren B. Kesler

1998-01-01

31

Nonadaptive MIMO radar techniques for reducing clutter  

Microsoft Academic Search

Multiple-Input, Multiple-Output (MIMO) radars enhance performance by transmitting and receiving coded waveforms from multiple locations. This paper describes how MIMO techniques can be used to improve radar performance, especially in airborne GMTI applications. A previous analysis of the clutter-to-noise-ratio (CNR) for stationary, surface-based MIMO radar is extended to the airborne radar scenario. Our analysis shows that MIMO airborne radars will

Daniel J. Rabideau; Lexington MA

2008-01-01

32

Enhanced Weather Radar (EWxR) System  

NASA Technical Reports Server (NTRS)

An airborne weather radar system, the Enhanced Weather Radar (EWxR), with enhanced on-board weather radar data processing was developed and tested. The system features additional weather data that is uplinked from ground-based sources, specialized data processing, and limited automatic radar control to search for hazardous weather. National Weather Service (NWS) ground-based Next Generation Radar (NEXRAD) information is used by the EWxR system to augment the on-board weather radar information. The system will simultaneously display NEXRAD and on-board weather radar information in a split-view format. The on-board weather radar includes an automated or hands-free storm-finding feature that optimizes the radar returns by automatically adjusting the tilt and range settings for the current altitude above the terrain and searches for storm cells near the atmospheric 0-degree isotherm. A rule-based decision aid was developed to automatically characterize cells as hazardous, possibly-hazardous, or non-hazardous based upon attributes of that cell. Cell attributes are determined based on data from the on-board radar and from ground-based radars. A flight path impact prediction algorithm was developed to help pilots to avoid hazardous weather along their flight plan and their mission. During development the system was tested on the NASA B757 aircraft and final tests were conducted on the Rockwell Collins Sabreliner.

Kronfeld, Kevin M. (Technical Monitor)

2003-01-01

33

THE DEVELOPMENT AND ANALYSIS OF SCANNED PATTERN INTERFEROMETRIC RADAR  

E-print Network

THE DEVELOPMENT AND ANALYSIS OF SCANNED PATTERN INTERFEROMETRIC RADAR Karen Marais and Raymond J of Scanned Pattern Interferometric Radar by Karen Marais Submitted to the Department of Aeronautics at the Massachusetts Institute of Technology ABSTRACT A method of performing space based GMTI using radar

34

LPI Radar Systems with Spatial Feedback  

Microsoft Academic Search

The radar system with spatial feedback is considered. In this system there are self-oscillations, if the system is closed through a space of the signal radio-path and the target. When the target is absent (system is not closed), transmitter output power of the noise signal is insignificant, and that complicates detection of the radar radiation. In the report principles of

V. M. Kutuzov; S. P. Kalenichenko

2006-01-01

35

Radar Attitude Sensing System (RASS)  

NASA Technical Reports Server (NTRS)

The initial design and fabrication efforts for a radar attitude sensing system (RASS) are covered. The design and fabrication of the RASS system is being undertaken in two phases, 1B1 and 1B2. The RASS system as configured under phase 1B1 contains the solid state transmitter and local oscillator, the antenna system, the receiving system, and the altitude electronics. RASS employs a pseudo-random coded cw signal and receiver correlation techniques to measure range. The antenna is a planar, phased array, monopulse type, whose beam is electronically steerable using diode phase shifters. The beam steering computer and attitude sensing circuitry are to be included in Phase 1B2 of the program.

1971-01-01

36

29 CFR 1915.85 - Vessel radar and communication systems.  

...2014-07-01 2014-07-01 false Vessel radar and communication systems. 1915.85...Working Conditions § 1915.85 Vessel radar and communication systems. (a) The employer shall service each vessel's radar and communication systems in...

2014-07-01

37

29 CFR 1915.85 - Vessel radar and communication systems.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Vessel radar and communication systems. 1915.85...Working Conditions § 1915.85 Vessel radar and communication systems. (a) The employer shall service each vessel's radar and communication systems in...

2013-07-01

38

29 CFR 1915.85 - Vessel radar and communication systems.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Vessel radar and communication systems. 1915.85...Working Conditions § 1915.85 Vessel radar and communication systems. (a) The employer shall service each vessel's radar and communication systems in...

2012-07-01

39

Possibility of investigating star systems by radar  

Microsoft Academic Search

There is no fundamental reason why radar cannot be used in investigations of star systems. In order to detect star systems by radar it is necessary to construct an antenna with a diameter of several tens of kilometers and a transmitter whose power is commensurable with the power of all electric power stations on the Earth. Such an antenna should

O. N. Rzhiga

1986-01-01

40

Miniature synthetic-aperture radar system  

NASA Astrophysics Data System (ADS)

Loral Defense Systems-Arizona has developed a high-performance synthetic-aperture radar (SAR) for small aircraft and unmanned aerial vehicle (UAV) reconnaissance applications. This miniature radar, called Miniature Synthetic-Aperture Radar (MSAR), is packaged in a small volume and has low weight. It retains key features of large SAR systems, including high-resolution imaging and all-weather operation. The operating frequency of MSAR can optionally be selected to provide foliage penetration capability. Many imaging radar configurations can be derived using this baseline system. MSAR with a data link provides an attractive UAV sensor. MSAR with a real-time image formation processor is well suited to installations where onboard processing and immediate image analysis are required. The MSAR system provides high-resolution imaging for short-to-medium range reconnaissance applications.

Stockton, Wayne; Stromfors, Richard D.

1990-11-01

41

Knowledge Based Systems and Metacognition in Radar  

NASA Astrophysics Data System (ADS)

An airborne ground looking radar sensor's performance may be enhanced by selecting algorithms adaptively as the environment changes. A short description of an airborne intelligent radar system (AIRS) is presented with a description of the knowledge based filter and detection portions. A second level of artificial intelligence (AI) processing is presented that monitors, tests, and learns how to improve and control the first level. This approach is based upon metacognition, a way forward for developing knowledge based systems.

Capraro, Gerard T.; Wicks, Michael C.

42

ISAT - innovative space-based-radar antenna technology  

Microsoft Academic Search

ISAT is the innovative space-based-radar antenna technology program of the Defense Advanced Research Projects Agency (DARPA). The goal of the ISAT program is to develop antenna technology to enable tactical grade space-based GMTI (ground moving target indicator) radar - particularly from higher (-10,000 km) orbits which facilitate constellations with fewer satellites.

Joseph Guerci; E. Jaska

2003-01-01

43

78 FR 68861 - Certain Navigation Products, Including GPS Devices, Navigation and Display Systems, Radar Systems...  

Federal Register 2010, 2011, 2012, 2013

...Devices, Navigation and Display Systems, Radar Systems, Navigational Aids, Mapping Systems...devices, navigation and display systems, radar systems, navigational aids, mapping systems...devices, navigation and display systems, radar systems, navigational aids, mapping...

2013-11-15

44

Radar Studies in the Solar System  

NASA Technical Reports Server (NTRS)

We aid in a study of the solar system by means of ground-based radar. We have concentrated on (1) developing the ephemerides needed to acquire radar data at Arecibo Observatory and (2) analyzing the resultant data to: test fundamental laws of gravitation; determine the size, shape, topography, and spin vectors of the targets; and study the surface properties of these objects, through their scattering law and polarization characteristics.

Shapiro, Irwin I.

1996-01-01

45

Nested Radar Systems for Remote Coastal Observations  

Microsoft Academic Search

BELL, P. S., WILLIAMS, J.J., CLARK, S., MORRIS, B.D. & VILA-CONCEJO A., 2003. Nested Radar Systems for Remote Coastal Observations. Journal of Coastal Research, SI 39 (Proccendigs of the 8th International Coastal Symposium), 438 - 489. Itajaí, SC - Brazil, ISSN 0749-0208 Advances in radar technology now allow the observation of sea surface features at multiple scales, from kilometers, down

P. S. Bell; J. J. Williams; S. Clark; B. D. Morris; A. Vila-Concejo

46

Radar Studies in the Solar System  

NASA Technical Reports Server (NTRS)

We aid in study of the solar system by means of ground-based radar. We have concentrated on: (1) developing the ephemerides needed to acquire radar data at Arecibo Observatory and (2) analyzing the resultant data to: test fundamental laws of gravitation; determine the size , shape, topography, and spin vectors of the targets; and study the surface properties of these objects, through their scattering law and polarization characteristics. We are engaged in radar observations of asteroids and comets, both as systematically planned targets and as "targets of opportunity." In the course of the program, we have prepared ephemerides for about 80 asteroids and three comets, and the radar observations have been made or attempted at the Arecibo Observatory, in most cases successfully, and in some cases on more than one apparition. The results of these observations have included echo spectra for the targets and, in some cases, delay - Doppler images and measurements of the total round-trip delay to the targets. Perhaps the most dramatic of these results are the images obtained for asteroids (4179) Toutatis and 1989PB (Castalia), which were revealed to be double-lobed objects by the radar images. Besides these direct results, the radar observations have furnished information on the sizes and shapes of the targets through analysis of the Doppler width of the echoes as a function of time, and on the surface properties (such as composition, bulk density, and roughness) through analysis of the reflectivity and of the polarization state of the echoes. We have also refined the orbits of the observed asteroids as a result of the Doppler (and in some cases delay) measurements from the radar observations. Although the orbits of main-belt asteroids accessible to ground-based radar are quite well known from the available optical data, some near-Earth objects have been seen by radar very soon after their optical discovery (for example, 199OMF, just eight days after discovery). In such cases. the radar results ensure that the object in question can be anticipated and identified at the next apparition. We have also participated in radar studies of the terrestrial planets. The results of these studies have included both planetary topography profiles from the analysis of round-trip delays to points along the target Doppler equator and determinations of the target spin state. The latter is of special interest in the case of Venus, which is very close to, but not on, a multi-body spin-orbit resonance such that Venus rotates 12 times for every 8 Earth orbits and 13 Venus orbits. As a result, Venus presents nearly the same face toward Earth at each inferior conjunction. Our latest results confirm that the spin state of Venus is slightly off the resonance. The delay measurements from planetary 2 ranging have also been used in combination with other types of range data in testing general relativity with increasing accuracy. We have also been engaged in radar studies of planetary satellites. Using our ephemerides, Arecibo made radar observations of the Galilean satellites of Jupiter and of Mars' satellite Phobos during the favorable opposition seasons (1988-1992 for Jupiter and 1990 for Mars). An attempt was also made to observe Deimos, but without detecting an echo. In 1997, an attempt was made to observe Saturn's satellite Titan, using the newly upgraded Arecibo radar system for transmitting and the Goldstone radar for receiving, but no echo was detected. The study of satellites by radar is in many ways similar to that of asteroids. The results from these observations have included characterization of the surface properties from the reflectivity and polarization ratio, as well as (in the case of the large satellites of Jupiter) the variation of reflectivity with incidence angle.

Shaprio, Irwin I.

1998-01-01

47

Weather Radar Control System Seidu Ibrahim; Advisor: Eric J. Knapp  

E-print Network

Weather Radar Control System Seidu Ibrahim; Advisor: Eric J. Knapp Dept. of Electrical and Computer Engineering University of Massachusetts, Amherst Abstract Weather radar is an important part of the national radars such as the National Weather Service WSR88D Doppler radars are limited in their ability to provide

Mountziaris, T. J.

48

Design of a miniature wideband radar experimental system  

Microsoft Academic Search

Wideband radars have been found more important both in civil and military applications. Micromation is one key technology for radars mounted at missiles, unmanned aerial vehicles (UAV), satellites, etc. The scheme of a miniature wideband radar experimental system is introduced in this paper, while the design and implementation of a wideband signal generator is analyzed in detail. The radar is

Zhang Xiao-wei; Li Ming; Zuo Lei

2011-01-01

49

Vehicle lateral control system using laser radar  

Microsoft Academic Search

This paper introduces our recent research on vehicle lateral control, a component of an automated highway system (AHS). We have developed a laser radar based automatic steering control system to study the performance and feasibility of such a system in an actual highway environment. Our approach does not require significant infrastructure investment because it is based on the retroreflective road

Masahiko Nakamura; Alan Arai; Mark P. Bendett; Mitsutaka Nakamura; Roy W. Goudy; Yoshinobu Suzuki; Hideki Kusunoki

1995-01-01

50

Integrated bias removal in passive radar systems  

Microsoft Academic Search

A passive coherent location (PCL) system exploits the ambient FM radio or television signals from powerful local transmitters, which makes it ideal for covert tracking. In a passive radar system, also known as PCL system, a variety of measurements can be used to estimate target states such as direction of arrival (DOA), time difference of arrival (TDOA) or Doppler shift.

M. Subramaniam; K. Punithakumar; M. McDonald; T. Kirubarajan

2008-01-01

51

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

52

The instrumental principles of MST radars and incoherent scatter radars and the configuration of radar system hardware  

NASA Technical Reports Server (NTRS)

The principle of pulse modulation used in the case of coherent scatter radars (MST radars) is discussed. Coherent detection and the corresponding system configuration is delineated. Antenna requirements and design are outlined and the phase-coherent transmitter/receiver system is described. Transmit/receive duplexers, transmitters, receivers, and quadrature detectors are explained. The radar controller, integrator, decoder and correlator design as well as the data transfer and the control and monitoring by the host computer are delineated. Typical operation parameters of some well-known radars are summarized.

Roettger, Juergen

1989-01-01

53

System capability of air traffic control radar beacon system  

Microsoft Academic Search

The air traffic control radar beacon system problems and solutions to these problems are discussed. Residual problems, their extent, and their impact on future systems are described. The results of a system model are related to the possible fixes.

N. K. Shaw; A. A. Simolunas

1970-01-01

54

A low-power radar imaging system  

NASA Astrophysics Data System (ADS)

A near real-time radar-based imaging system is developed in this dissertation. This system uses the combination of a spatially diverse antenna array, a high sensitivity range-gated frequency-modulated continuous wave (FMCW) radar system, and an airborne synthetic aperture radar (SAR) imaging algorithm to produce near real-time high resolution imagery of what is behind a dielectric wall. This system is capable of detecting and providing accurate imagery of target scenes made up of objects as small as 6 inch tall metallic rods and cylinders behind a 4 inch thick dielectric slab. A study is conducted of through-dielectric slab imaging by the development of a 2D model of a dielectric slab and cylinder. The SAR imaging algorithm is developed and tested on this model for a variety of simulated imaging scenarios and the results are then used to develop an unusually high sensitivity range-gated FMCW radar architecture. An S-band rail SAR imaging system is developed using this architecture and used to image through two different dielectric slabs as well as free-space. All results are in agreement with the simulations. It is found that free-space target scenes could be imaged using low transmit power, as low as 5 picowatts. From this result it was decided to develop an X-band front end which mounts directly on to the S-band rail SAR so that objects as small as groups of pushpins and aircraft models in free-space could be imaged. These results are compared to previous X-band direct conversion FMCW rail SAR work. It was found that groups of pushpins and models could be imaged at transmit powers as low as 10 nanowatts. A spatially diverse S-band antenna array will be shown to be developed for use with the S-band radar; thereby providing the ability for near real-time SAR imaging of objects behind dielectric slabs with the same performance characteristics of the S-band rail SAR. The research presented in this dissertation will show that near real-time radar imaging through lossy-dielectric slabs is accomplished when using a highly sensitive radar system located at a stand-off range from the slab using a free-space SAR imaging algorithm.

Charvat, Gregory Louis

55

Tracking system for photon-counting laser radar  

E-print Network

The purpose of this thesis is to build the tracking system for a photon-counting laser radar specifically a laser radar that has the ability to perform direct and coherent detection measurement at low signal levels with ...

Chang, Joshua TsuKang

2007-01-01

56

MIMO radar systems Permanent members: F. Nadal, P. Jardin.  

E-print Network

MIMO radar systems Permanent members: F. Nadal, P. Jardin. Associated researcher: S. Middleton. Multiple-input and multiple-output (MIMO) radar systems use arrays of transmitting and receiving antennas like phased array radars but while a phased array transmits highly correlated signals which form a beam

Baudoin, Geneviève

57

Goldstone Solar System Radar Waveform Generator  

NASA Technical Reports Server (NTRS)

Due to distances and relative motions among the transmitter, target object, and receiver, the time-base between any transmitted and received signal will undergo distortion. Pre-distortion of the transmitted signal to compensate for this time-base distortion allows reception of an undistorted signal. In most radar applications, an arbitrary waveform generator (AWG) would be used to store the pre-calculated waveform and then play back this waveform during transmission. The Goldstone Solar System Radar (GSSR), however, has transmission durations that exceed the available memory storage of such a device. A waveform generator capable of real-time pre-distortion of a radar waveform to a given time-base distortion function is needed. To pre-distort the transmitted signal, both the baseband radar waveform and the RF carrier must be modified. In the GSSR, this occurs at the up-conversion mixing stage to an intermediate frequency (IF). A programmable oscillator (PO) is used to generate the IF along with a time-varying phase component that matches the time-base distortion of the RF carrier. This serves as the IF input to the waveform generator where it is mixed with a baseband radar waveform whose time-base has been distorted to match the given time-base distortion function producing the modulated IF output. An error control feedback loop is used to precisely control the time-base distortion of the baseband waveform, allowing its real-time generation. The waveform generator produces IF modulated radar waveforms whose time-base has been pre-distorted to match a given arbitrary function. The following waveforms are supported: continuous wave (CW), frequency hopped (FH), binary phase code (BPC), and linear frequency modulation (LFM). The waveform generator takes as input an IF with a time varying phase component that matches the time-base distortion of the carrier. The waveform generator supports interconnection with deep-space network (DSN) timing and frequency standards, and is controlled through a 1 Gb/s Ethernet UDP/IP interface. This real-time generation of a timebase distorted radar waveform for continuous transmission in a planetary radar is a unique capability.

Quirk, Kevin J.; Patawaran, Ferze D.; Nguyen, Danh H.; Nguyen, Huy

2012-01-01

58

TRMM precipitation radar helps address problems of ground-based weather radar systems  

Microsoft Academic Search

The launch of the first spaceborne precipitation radar (PR) aboard the Tropical Rainfall Measuring Mission (TRMM) satellite provides a unique opportunity to address the ground-based weather radar system's calibration problem. The PR measures the same variable as ground-based systems---radar reflectivity--- and is proven to be consistent with respect to calibration accuracy. PR calibration tests, conducted by the Space Agency of

Emmanouil N. Anagnostou; Carlos A. Morales

2000-01-01

59

RADAR SYSTEMS FOR INFRASTRUCTURES DIAGNOSTICS: A REVIEW Ilaria Catapano, Antonio Affinito, Lorenzo Crocco, Francesco Soldovieri  

E-print Network

RADAR SYSTEMS FOR INFRASTRUCTURES DIAGNOSTICS: A REVIEW Ilaria Catapano, Antonio Affinito, Lorenzo assessing the reconstruction capabilities of two different radar systems for subsurface imaging and civil engineering monitoring and diagnostics. In fact, Ground Penetrating Radar and Holographic Radar are well

Paris-Sud XI, Université de

60

Twin VHF radar for european space situation awareness system  

Microsoft Academic Search

The efficient space surveillance system in the current state of radar technology must be addressed in a cost-effective way. Consequently, a new twin VHF band radar concept with increased technical capabilities could partially take over these challenges. This article would like to draw the reader's attention to the potential benefits of VHF radar signal fusion, which can be extended for

Istvan Balajti

2012-01-01

61

RCS Aspects of MultiBand Radar Systems Composed of \\  

Microsoft Academic Search

An essential characteristic of any radar target is the measure of its ability to reflect energy to the receiving antenna. The parameter used to describe this ability is the radar cross section (RCS) of the target. Stealth techniques and technologies, which affect the efficiency of early warning radar systems currently in operation, are described in ref [1]. The problem is

I. Balajti

2006-01-01

62

Reconfigurable Data Acquisition System for Weather Radar Applications  

E-print Network

powerful signal processing algorithms on the raw data collected by the radars. Following processing, data, Amherst MA Abstract-- Tornado, hazardous weather and flood detection radars demand high-throughput, high-based system has been successfully integrated with a radar optimized for tornado detection and deployed

Tessier, Russell

63

The SIR-C\\/X-SAR Synthetic Aperture Radar system  

Microsoft Academic Search

The Spaceborne Imaging Radar-C\\/X-Band Synthetic Aperture Radar (SIR-C\\/X-SAR) was a joint United States\\/German\\/Italian space agency imaging radar system successfully flown aboard the shuttle Endeavor in April 1994 and again in September\\/October 1994. The multifaceted SIR-C\\/X-SAR represents a major technological step forward in radar remote sensing and is the first spaceborne multifrequency, polarimetric SAR. The United States developed SIR-C operated at

R. L. Jordan; B. L. Huneycutt; M. Werner

1995-01-01

64

The 94 GHz MMW imaging radar system  

NASA Technical Reports Server (NTRS)

The 94 GHz MMW airborne radar system that provides a runway image in adverse weather conditions is now undergoing tests at Wright-Patterson Air Force Base (WPAFB). This system, which consists of a solid state FMCW transceiver, antenna, and digital signal processor, has an update rate of 10 times per second, 0.35x azimuth resolution and up to 3.5 meter range resolution. The radar B scope (range versus azimuth) image, once converted to C scope (elevation versus azimuth), is compatible with the standard TV presentation and can be displayed on the Head Up Display (HUD) or Head Down Display (HDD) to aid the pilot during landing and takeoff in limited visibility conditions.

Alon, Yair; Ulmer, Lon

1993-01-01

65

Laser Docking System Radar flight experiment  

NASA Technical Reports Server (NTRS)

Flight experiments to verify the Laser Docking System Radar are discussed. The docking requirements are summarized, and the breadboarded hardware is described, emphasizing the two major scanning concepts being utilized: a mechanical scanning technique employing galvanometer beamsteerers and an electronic scanning technique using an image dissector. The software simulations used to apply hardware solutions to the docking requirements are briefly discussed, the tracking test bed is described, and the objectives of the flight experiment are reviewed.

Erwin, Harry O.

1986-01-01

66

Development of the Solid State X-band Radar and the Phased Array Radar System in Japan  

E-print Network

-band radar for meteorological application using the state of the art solid state amplifier and the phasedDevelopment of the Solid State X-band Radar and the Phased Array Radar System in Japan By DR. TOMOO. This is the first X-band solid-state weather radar in service in Japan, which adopted new technologies including

Droegemeier, Kelvin K.

67

Diurnal radio aurora variations at 50 MHz measured by the Bistatic Auroral Radar System radars  

Microsoft Academic Search

The Bistatic Auroral Radar System (BARS), which is a part of the Canopus program, was employed to measure typical morphological characteristics and diurnal variations in the backscatter. Mean Doppler velocity and intensity data, obtained from the normal operating mode of the BARS radars for selected intervals between March 1986 and July 1987, were used. The Canopus magnetometers at Gillam and

Dieter Andre; Allen G. McNamara; Don D. Wallis; Bruce A. McIntosh; Terry J. Hughes

1988-01-01

68

Radar altimetry systems cost analysis  

NASA Technical Reports Server (NTRS)

This report discusses the application and cost of two types of altimeter systems (spaceborne (satellite and shuttle) and airborne) to twelve user requirements. The overall design of the systems defined to meet these requirements is predicated on an unconstrained altimetry technology; that is, any level of altimeter or supporting equipment performance is possible.

Escoe, D.; Heuring, F. T.; Denman, W. F.

1976-01-01

69

Solid-state coherent laser radar wind shear measuring systems  

NASA Technical Reports Server (NTRS)

Coherent Technologies, Inc. (CTI) was established in 1984 to engage in the development of coherent laser radar systems and subsystems with applications in atmospheric remote sensing, and in target tracking, ranging and imaging. CTI focuses its capabilities in three major areas: (1) theoretical performance and design of coherent laser radar system; (2) development of coherent laser radar systems for government agencies such as DoD and NASA; and (3) development of coherent laser radar systems for commercial markets. The topics addressed are: (1) 1.06 micron solid-state coherent laser radar system; (2) wind measurement using 1.06 micron system; and flashlamp-pumped 2.09 micron solid-state coherent laser radar system.

Huffaker, R. Milton

1992-01-01

70

Automated Stokesmetric imaging laser radar system  

NASA Astrophysics Data System (ADS)

We report the design and implementation of a high-speed, automated laser radar (ladar) system with sensitivity enhanced by a polarimetric imaging technique. This ladar is able to analyze the Stokes vector of the reflected light from a target at video-rate. With a polarization state generator and a polarization state analyzer, the system is capable of performing a complete Mueller matrix imaging of the scene under observation. This polarization-sensitive ladar (pladar) is applied to various scenes and found to yield the ability to detect information that is indiscernible to a conventional, intensity-based ladar.

Liu, Xue; Tseng, Shih; Tripathi, Renu; Shahriar, Selim M.

2012-07-01

71

Detecting and mitigating wind turbine clutter for airspace radar systems.  

PubMed

It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms should be developed to mitigate the effects of wind farms on radars. Herein, one transponder-based mitigation technique is presented. The transponder is not a new concept, which has been proposed for calibrating high-resolution imaging radars. It modulates the radar signal in a manner that the retransmitted signals can be separated from the scene echoes. As wind farms often occupy only a small area, mitigation processing in the whole radar operation will be redundant and cost inefficient. Hence, this paper uses a transponder to determine whether the radar is impacted by the wind farms. If so, the effects of wind farms are then mitigated with subsequent Kalman filtering or plot target extraction algorithms. Taking airborne synthetic aperture radar (SAR) and pulse Doppler radar as the examples, this paper provides the corresponding system configuration and processing algorithms. The effectiveness of the mitigation technique is validated by numerical simulation results. PMID:24385880

Wang, Wen-Qin

2013-01-01

72

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

73

Southwest PAVE PAWS radar system: Environmental assessment  

NASA Astrophysics Data System (ADS)

This document describes the probable environmental impacts of constructing and operating a new surveillance and tracking radar that would operate between 420 and 450 MHz. Four candidate sites in the vicinity of Goodfellow Air Force Base were considered. The impact analysis found that chronic exposure of humans to the radiofrequency radiation levels outside the exclusion fence is not likely to be harmful. No hazards would be associated with fuel handling or cardiac pacemakers at ground level beyond the exclusion fence. Interference with TV reception and other home electronic systems and with UHF land mobile and amateur radios is possible, depending on the site. Handling and use of electro-explosive devices (EEDs) would be safe beyond about 1.2 miles for the basic system and about 2.4 miles for the optional, higher power system. Electromagnetic interference with radar altimeters, air navigation, and air-ground communication is not likely except at two candidate sites, where interference and EED and pacemaker hazards may exist for aircraft operating into or out of a nearby landing strip. No significant adverse biophysical impacts are expected in any location.

Everett, S. J.; Edson, W. A.; Heynick, L. N.; Pierce, S. R.; Shepherd, R. A.; Wlaklet, T. H.

1983-03-01

74

Advanced meteor radar installed at Tirupati: System details and comparison with different radars  

NASA Astrophysics Data System (ADS)

advanced meteor radar, viz, Sri Venkateswara University (SVU) meteor radar (SVU MR) operating at 35.25 MHz, was installed at Sri Venkateswara University (SVU), Tirupati (13.63°N, 79.4°E), India, in August 2013 for continuous observations of horizontal winds in the mesosphere and lower thermosphere (MLT). This manuscript describes the purpose of the meteor radar, system configuration, measurement techniques, its data products, and operating parameters, as well as a comparison of measured mean winds in the MLT with contemporary radars over the Indian region. It is installed close to the Gadanki (13.5°N, 79.2°E) mesosphere-stratosphere-troposphere (MST) radar to fill the region between 85 and 100 km where this radar does not measure winds. The present radar provides additional information due to its high meteor detection rate, which results in accurate wind information from 70 to 110 km. As a first step, we made a comparison of SVU MR-derived horizontal winds in the MLT region with those measured by similar and different (MST and MF radars) techniques over the Indian region, as well as model (horizontal wind model 2007) data sets. The comparison showed an exquisite agreement between the overlapping altitudes (82-98 km) of different radars. Zonal winds compared very well, as did the meridional winds. The observed discrepancies and limitations in the wind measurement are discussed in the light of different measuring techniques and the effects of small-scale processes like gravity waves. This new radar is expected to play an important role in our understanding of the vertical and lateral coupling of different regions of the atmosphere that will be possible when measurements from nearby locations are combined.

Rao, S. Vijaya Bhaskara; Eswaraiah, S.; Venkat Ratnam, M.; Kosalendra, E.; Kishore Kumar, K.; Sathish Kumar, S.; Patil, P. T.; Gurubaran, S.

2014-11-01

75

47 CFR 15.515 - Technical requirements for vehicular radar systems.  

Code of Federal Regulations, 2012 CFR

... Technical requirements for vehicular radar systems. 15.515 Section 15.515... Technical requirements for vehicular radar systems. (a) Operation under... (b) The UWB bandwidth of a vehicular radar system operating under the...

2012-10-01

76

47 CFR 15.515 - Technical requirements for vehicular radar systems.  

... Technical requirements for vehicular radar systems. 15.515 Section 15.515... Technical requirements for vehicular radar systems. (a) Operation under... (b) The UWB bandwidth of a vehicular radar system operating under the...

2014-10-01

77

47 CFR 15.515 - Technical requirements for vehicular radar systems.  

Code of Federal Regulations, 2013 CFR

... Technical requirements for vehicular radar systems. 15.515 Section 15.515... Technical requirements for vehicular radar systems. (a) Operation under... (b) The UWB bandwidth of a vehicular radar system operating under the...

2013-10-01

78

76 FR 67017 - Notice to Manufacturers of Airport Avian Radar Systems  

Federal Register 2010, 2011, 2012, 2013

...Notice to Manufacturers of Airport Avian Radar Systems AGENCY: Federal Aviation Administration...Notice to Manufacturers of Airport Avian Radar Systems...foreign manufacturers of airport avian radar systems that meet the requirements of...

2011-10-28

79

47 CFR 15.515 - Technical requirements for vehicular radar systems.  

Code of Federal Regulations, 2011 CFR

... Technical requirements for vehicular radar systems. 15.515 Section 15.515... Technical requirements for vehicular radar systems. (a) Operation under... (b) The UWB bandwidth of a vehicular radar system operating under the...

2011-10-01

80

47 CFR 15.515 - Technical requirements for vehicular radar systems.  

Code of Federal Regulations, 2010 CFR

... Technical requirements for vehicular radar systems. 15.515 Section 15.515... Technical requirements for vehicular radar systems. (a) Operation under... (b) The UWB bandwidth of a vehicular radar system operating under the...

2010-10-01

81

Radar systems for a polar mission, volume 1  

NASA Technical Reports Server (NTRS)

The application of synthetic aperture radar (SAR) in monitoring and managing earth resources is examined. Synthetic aperture radars form a class of side-looking airborne radar, often referred to as coherent SLAR, which permits fine-resolution radar imagery to be generated at long operating ranges by the use of signal processing techniques. By orienting the antenna beam orthogonal to the motion of the spacecraft carrying the radar, a one-dimensional imagery ray system is converted into a two-dimensional or terrain imaging system. The radar's ability to distinguish - or resolve - closely spaced transverse objects is determined by the length of the pulse. The transmitter components receivers, and the mixer are described in details.

Moore, R. K.; Claassen, J. P.; Erickson, R. L.; Fong, R. K. T.; Komen, M. J.; Mccauley, J.; Mcmillan, S. B.; Parashar, S. K.

1977-01-01

82

The design of China spaceborne radar altimeter control system  

Microsoft Academic Search

The control system plays a key role in the spaceborne radar altimeter, such as it should implement track function to provide the height from the satellite to the sea surface, the significant wave height (SWH) and the backscatter coefficient. In this paper, the design of the China spaceborne radar altimeter control system (RACS), which is one part of Multi-mode Microwave

Ke Xu; Jingshan Jiang; Heguang Liu

2002-01-01

83

Solar system studies with the Arecibo planetary radar system  

Microsoft Academic Search

The 305 m Arecibo telescope equipped with a 1 MW 2.38 GHz transmitter is used for studies of the terrestrial planets, planetary satellites including the Moon and small bodies in the solar system. Much of the recent program emphasis has been on astrometric and characterization observations of near-Earth objects for which the Arecibo radar system has capabilities not matched by

Donald B. Campbell; John K. Harmon; Michael C. Nolan

2011-01-01

84

78 FR 19063 - Airworthiness Approval for Aircraft Forward-Looking Windshear and Turbulence Radar Systems  

Federal Register 2010, 2011, 2012, 2013

...Forward-Looking Windshear and Turbulence Radar Systems AGENCY: Federal Aviation Administration...forward-looking windshear and turbulence radar systems. The planned advisory circular...Order (TSO)-C63d, Airborne Weather Radar Equipment. The objective is to...

2013-03-28

85

The Goldstone Solar System Radar: 1988-2003 Earth-based Mars Radar Observations  

NASA Technical Reports Server (NTRS)

The Goldstone Solar System Radar (GSSR) has successfully collected radar echo data from Mars over the past 30 years. The older data provided local elevation information for Mars, along with radar scattering information with global resolution. Since the upgrade to the 70-m DSN antenna at Goldstone completed in 1986, Mars data has been collected during all but the 1997 Mars opposition. Radar data, and non-imaging delay- Doppler data in particular, requires significant data processing to extract elevation, reflectivity and roughness of the reflecting surface. The spatial resolution of these experiments is typically some 10 km in longitude by some 150 km in latitude. The interpretation of these parameters while limited by the complexities of electromagnetic scattering, do provide information directly relevant to geophysical and geomorphic analyses of Mars.

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

2005-01-01

86

29. Perimeter acquisition radar building room #318, data processing system ...  

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

29. Perimeter acquisition radar building room #318, data processing system area; data processor maintenance and operations center, showing data processing consoles - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

87

Target Tracking in MIMO Radar Systems: Techniques and Performance Analysis  

E-print Network

]. The BCRB is derived for multi-static radar systems, an architecture based on one transmit radar, ranging from independent to fully correlated, by utilizing multiple trans- mit and receive sensors, widely frequency in the coherent case. It was further proven that optimization over the sensors' positions lowers

Haimovich, Alexander

88

Compact scalable multifunction RF payload for UAVs with FMCW radar and ESM functionality  

Microsoft Academic Search

This paper describes a concept for a scalable RF sensor payload for small UAVs that can perform multiple RF functions such as synthetic aperture radar (SAR), ground-moving target indication (GMTI) and ESM. Essential to the scalable multifunction RF payload concept is the digitization of the antenna signals on transmit and receive at the antenne element level. The architecture of a

A. G. Huizing; M. P. G. Otten; W. L. van Rossum; R. van Dijk; A. P. M. Maas; E. H. van der Houwen; R. J. Bolt

2009-01-01

89

Performance evaluations of Frequency Diversity Radar system  

Microsoft Academic Search

Frequency diversity radar combines two or more conventional transceivers through a common antenna, in a multiplex arrangement on the same RF transmission channel. It significantly improves radar detection performance and reduces false alarms under adverse weather conditions, here in case of normal distributed background clutter. Evaluations about advantages between different algorithms are discussed.

Valentina Ravenni

2007-01-01

90

Comparison of simultaneous wind measurements using colocated VHF meteor radar and MF spaced antenna radar systems  

NASA Astrophysics Data System (ADS)

Comparisons of wind velocities at heights from 80 to 98 km have been made using two different techniques. The first method involves the determination of winds using meteor drifts (e.g., Avery et al., 1990; Stubbs, 1973). This was done by observing meteors using the University of Adelaide VHF radar situated approximately 40 km north of Adelaide, Australia, at Buckland Park. The second method used to determine winds was the spaced antenna technique (e.g., Briggs, 1984) using an MF radar at the same site. The two radar systems are independent, the VHF radar operating at 54.1 MHz and the MF radar at 1.98 MHz. The spatial separation of the two radars is approximately 600 m. Simultaneous data obtained from September 10 to 20, 1993, are presented here. The agreement between the two techniques is good below 90 km, while above 90 km we find that the spaced antenna technique yields smaller wind speeds than the meteor drift technique. Several possible reasons for these discrepancies are discussed.

Cervera, Manuel A.; Reid, Iain M.

1995-07-01

91

Integrated bias removal in passive radar systems  

NASA Astrophysics Data System (ADS)

A passive coherent location (PCL) system exploits the ambient FM radio or television signals from powerful local transmitters, which makes it ideal for covert tracking. In a passive radar system, also known as PCL system, a variety of measurements can be used to estimate target states such as direction of arrival (DOA), time difference of arrival (TDOA) or Doppler shift. Noise and the precision of DOA estimation are main issues in a PCL system and methods such as conventional beam forming (CBF) algorithm, algebraic constant modulus algorithm (ACMA) are widely analyzed in literature to address them. In practical systems, although it is necessary to reduce the directional ambiguities, the placement of receivers closed to each other results in larger bias in the estimation of DOA of signals, especially when the targets move off bore-sight. This phenomenon leads to degradation in the performance of the tracking algorithm. In this paper, we present a method for removing the bias in DOA to alleviate the aforementioned problem. The simulation results are presented to show the effectiveness of the proposed algorithm with an example of tracking airborne targets.

Subramaniam, M.; Punithakumar, K.; McDonald, M.; Kirubarajan, T.

2008-04-01

92

Advanced Meteor radar at Tirupati: System details and first results  

NASA Astrophysics Data System (ADS)

An advanced meteor radar viz., Enhanced Meteor Detection Radar (EMDR) operating at 35.25 MHz is installed at Sri Venkateswara University (SVU), Tirupati (13.63oN, 79.4oE), India, in the month of August 2013. Present communication describes the need for the meteor radar at present location, system description, its measurement techniques, its variables and comparison of measured mean winds with contemporary radars over the Indian region. The present radar site is selected to fill the blind region of Gadanki (13.5oN, 79.2oE) MST radar, which covers mesosphere and lower thermosphere (MLT) region (70-110 km). By modifying the receiving antenna structure and elements, this radar is capable of providing accurate wind information between 70 and 110 km unlike other similar radars. Height covering region is extended by increasing the meteor counting capacity by modifying the receiving antenna structure and elements and hence its wind estimation limits extended below and above of 80 and 100 km, respectively. In the present study, we also made comparison of horizontal winds in the MLT region with those measured by similar and different (MST and MF radars) techniques over the Indian region including the model (HWM 07) data sets. The comparison showed a very good agreement between the overlapping altitudes (82-98 km) of different radars. Zonal winds compared very well as that of meridional winds. The observed discrepancies and limitations in the wind measurement are discussed. This new radar is expected to play important role in understanding the vertical and lateral coupling by forming a unique local network.

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

93

Calibration of polarimetric radar systems with good polarization isolation  

NASA Technical Reports Server (NTRS)

A practical technique is proposed for calibrating single-antenna polarimetric radar systems using a metal sphere plus any second target with a strong cross-polarized radar cross section. This technique assumes perfect isolation between antenna ports. It is shown that all magnitudes and phases (relative to one of the like-polarized linear polarization configurations) of the radar transfer function can be calibrated without knowledge of the scattering matrix of the second target. Comparison of the values measured (using this calibration technique) for a tilted cylinder at X-band with theoretical values shows agreement within + or - 0.3 dB in magnitude and + or - 5 degrees in phase. The radar overall cross-polarization isolation was 25 dB. The technique is particularly useful for calibrating a radar under field conditions, because it does not require the careful alignment of calibration targets.

Sarabandi, Kamal; Ulaby, Fawwaz T.; Tassoudji, M. Ali

1990-01-01

94

Integrated laser/radar satellite ranging and tracking system.  

PubMed

A laser satellite ranging system that is mounted upon and integrated with a microwave tracking radar is reported. The 1-pulse sec/ruby laser transmitter is attached directly to the radar's elevation axis and radiates through a new opening in the radar's parabolic dish. The laser photomultiplier tube receiver utilizes the radar's existing 20-cm diam f11 boresight telescope and observes through a similar symmetrically located opening in the dish. The laser system possesses separate ranging system electronics but shares the radar's timing, computer, and data handling[equation]recording systems. The basic concept of the laser[equation]radar is outlined together with a listing of the numerous advantages over present singular laser rangefinding systems. The developmental laser hardware is described along with preliminary rangefinding results and expectations. The prototype system was assembled to investigate the feasibility of such systems and aid in the development of detailed specifications for an operational system. Both the feasibility and desirability of such systems integrations have been adequately demonstrated. PMID:20134689

Hoge, F E

1974-10-01

95

Signal Processing System for the CASA Integrated Project I Radars  

SciTech Connect

This paper describes the waveform design space and signal processing system for dual-polarization Doppler weather radar operating at X band. The performance of the waveforms is presented with ground clutter suppression capability and mitigation of range velocity ambiguity. The operational waveform is designed based on operational requirements and system/hardware requirements. A dual Pulse Repetition Frequency (PRF) waveform was developed and implemented for the first generation X-band radars deployed by the Center for Collaborative Adaptive Sensing of the Atmosphere (CASA). This paper presents an evaluation of the performance of the waveforms based on simulations and data collected by the first-generation CASA radars during operations.

Bharadwaj, Nitin; Chandrasekar, V.; Junyent, Francesc

2010-09-01

96

POTENTIALITIES OF USRP-BASED SOFTWARE DEFINED RADAR SYSTEMS  

E-print Network

in which operations and components, originally implemented using dedicated hardware (i.e., mixers, filters] a measurement system making use of a hybrid radar scheme with continuous wave frequency modulation and a pseudo

Paris-Sud XI, Université de

97

The EISCAT Svalbard radar: A case study in modern incoherent scatter radar system design  

NASA Astrophysics Data System (ADS)

The EISCAT (European incoherent scatter) Svalbard radar (ESR) was officially inaugurated on August 22, 1996. This event marked the successful completion on schedule of the first phase of the EISCAT Svalbard radar project. In contrast to previous incoherent scatter radars, the ESR system design was adapted to make use of commercial off-the-shelf TV transmitter hardware, thereby reducing design risk, lead times, and cost to a minimum. Commercial hardware is also used in the digital signal processing system. Control and monitoring are performed by distributed, networked VME systems. Thanks to modern reflector antenna design methods and extreme efforts to reduce the receiver noise contribution, the system noise temperature is only 70 K, thus making the ESR about 30% faster than the much more powerful EISCAT UHF radar in F region experiments! Once the transmitter power is increased to 1 MW, it will become about 2-3 times faster than the UHF radar. State-of-the-art exciter and receiver hardware has been developed in-house to accommodate the special requirements introduced by operating the radar at the exceptionally high duty cycle of 25%. The RF waveform is generated by a system based on four switchable direct digital synthesizers. Continuous monitoring of the transmitted RF waveform by the receiver system allows removal of klystron-induced spurious Doppler effects from the data. Intermediate-frequency sampling at 7.5 MHz is employed, followed by fully digital channel separation, signal detection, and postdetection filtering in six parallel receiver channels. Radar codes for both E and F layer observation have been designed and perfected. So far, more than 40 hours of good quality ionospheric data have been collected and analyzed in terms of plasma parameters. While the tragic loss of the Cluster mission suddenly changed the plans and dispositions of a majority of the ESR user community, the radar has still been in high demand since its inauguration. It is now being operated by EISCAT staff on a campaign basis, to provide ground-based support data for a number of other magnetospheric satellites, notably Polar and FAST, and will be opened to the EISCAT user community for special program operations later in 1997.

Wannberg, G.; Wolf, I.; Vanhainen, L.-G.; Koskenniemi, K.; RöTtger, J.; Postila, M.; Markkanen, J.; Jacobsen, R.; Stenberg, A.; Larsen, R.; Eliassen, S.; Heck, S.; Huuskonen, A.

1997-11-01

98

"A Functional Design and System Architecture of a Control System for a Weather Radar"  

E-print Network

"A Functional Design and System Architecture of a Control System for a Weather Radar" Seidu Ibrahim Faculty Mentor: Eric Knapp Weather radars operate by transmitting pulses of very high microwave energy radiation through an antenna which reflects off objects such as rain drops and hail stones. As the radar

Mountziaris, T. J.

99

ECE 686: Introduction to Radar Systems Department of Electrical & Computer Engineering  

E-print Network

processes, and signals and systems. Required Text: Indroduction to Radar Systems, M.I. Skolnik, 3rd ed equation, signal-to-noise ratio, radar cross section, range and velocity ambiguity, radar clutter Sensing, Active & Passive Vol. II, Radar Remote Sensing and Surface Scattering and Emission Theory, F

Massachusetts at Amherst, University of

100

Improvement of Multiple Ground Targets Tracking with GMTI Sensor and Fusion of Identification Attributes  

Microsoft Academic Search

Multiple ground targets (MGT) tracking is a challenging problem in real environment because of partial observations, high traffic density, the maneuverability of targets, the clutter and the low target detection probabilities. Most of current MGT trackers use GMTI (Ground Moving Target Indicator) sensor, since this sensor provides the range- rate measurement (Doppler) aside classical position measurements. This helps the tracking

Benjamin Pannetier; Jean Dezert; E. Pollard

2008-01-01

101

2003 Mercury Computer Systems, Inc. Beamforming for Radar  

E-print Network

© 2003 Mercury Computer Systems, Inc. Beamforming for Radar Systems on COTS Heterogeneous ComputingHeterogeneous Computing PlatformsPlatforms Jeffrey A. Rudin Mercury Computer Systems, Inc. High Performance Embedded Computing (HPEC) Conference September 23, 2003 #12;2© 2003 Mercury Computer Systems, Inc. Outline

Kepner, Jeremy

102

A polarization diversity meteorological radar system  

Microsoft Academic Search

The AFGL 10-cm Doppler weather radar was modified to enable the measurement of the differential reflectivity between horizontal and vertical polarizations in addition to the absolute reflectivity and the Doppler mean velocity and spectrum variance. Polarization switching is achieved by means of a diplexer, which separates at the antenna the transmitted signals of two frequencies, 2710 and 2760 MHz, and

James I. Metcalf; Graham M. Armstrong; Alexander W. Bishop

1987-01-01

103

Millimeter-wave radar systems for biometric applications  

NASA Astrophysics Data System (ADS)

Millimeter-wave and terahertz radar systems can play an important role in multimodal layered sensing systems targeted at measuring both physiological and behavioral biometric data for security and medical applications. We will describe a 228 GHz heterodyne radar system that is capable of measuring respiration rates at standoff distances of up to 50 meters and simultaneously measure respiration and heartbeat rates at a distance of 10 meters. We will discuss the latest hardware and signal processing developments and a wide range of studies aimed at optimizing the performance of the system under a variety of potential field applications.

Petkie, Douglas T.; Bryan, Erik; Benton, Carla; Rigling, Brian D.

2009-09-01

104

Synthetic aperture radar: not just a sensor of last resort  

NASA Astrophysics Data System (ADS)

Modern high-performance Synthetic Aperture Radar (SAR) systems have evolved into highly versatile, robust, and reliable tactical sensors, offering images and information not available from other sensor systems. For example, real-time images are routinely formed by the Sandia-designed General Atomics (AN/APY-8) Lynx SAR yielding 4-inch resolution at 25 km range (representing better than arc-second resolutions) in clouds, smoke, and rain. Sandia's Real-Time Visualization (RTV) program operates an Interferometric SAR (IFSAR) system that forms three-dimensional (3D) topographic maps in near real-time with National Imagery and Mapping Agency (NIMA) Digital Terrain Elevation Data (DTED) level 4 performance (3 meter post spacing with 0.8-meter height accuracy) or better. When exported to 3-D rendering software, this data allows remarkable interactive fly-through experiences. Coherent Change Detection (CCD) allows detecting tire tracks on dirt roads, foot-prints, and other minor, otherwise indiscernible ground disturbances long after their originators have left the scene. Ground Moving Target Indicator (GMTI) radar modes allow detecting and tracking moving vehicles. A Sandia program known as "MiniSAR" is developing technologies that are expected to culminate in a fully functioning, high-performance, real-time SAR that weighs less than 20 lbs. The purpose of this paper is to provide an overview of recent technology developments, as well as current on-going research and development efforts at Sandia National Laboratories.

Wells, Lars M.; Doerry, Armin W.

2003-08-01

105

Protection of radar systems against nearby or direct lightning strokes  

Microsoft Academic Search

The paper deals with the characteristics of a lightning protection system (LPS) for a fixed and a mobile radars. The LPS design includes external (LPE) and internal (LPI) system as well as protection measures against lightning electromagnetic pulse (LEMP) of internal electrical and electronic systems (i.e. air terminations, down conductors, earthing arrangement, internal equipotential bonding. cable routing and shielding and

A. Annunziata; A. Dominicis; G. Antonini; A. Orlandi; F. Fiamingo; C. Mazzetti

2008-01-01

106

A fully photonics-based coherent radar system.  

PubMed

The next generation of radar (radio detection and ranging) systems needs to be based on software-defined radio to adapt to variable environments, with higher carrier frequencies for smaller antennas and broadened bandwidth for increased resolution. Today's digital microwave components (synthesizers and analogue-to-digital converters) suffer from limited bandwidth with high noise at increasing frequencies, so that fully digital radar systems can work up to only a few gigahertz, and noisy analogue up- and downconversions are necessary for higher frequencies. In contrast, photonics provide high precision and ultrawide bandwidth, allowing both the flexible generation of extremely stable radio-frequency signals with arbitrary waveforms up to millimetre waves, and the detection of such signals and their precise direct digitization without downconversion. Until now, the photonics-based generation and detection of radio-frequency signals have been studied separately and have not been tested in a radar system. Here we present the development and the field trial results of a fully photonics-based coherent radar demonstrator carried out within the project PHODIR. The proposed architecture exploits a single pulsed laser for generating tunable radar signals and receiving their echoes, avoiding radio-frequency up- and downconversion and guaranteeing both the software-defined approach and high resolution. Its performance exceeds state-of-the-art electronics at carrier frequencies above two gigahertz, and the detection of non-cooperating aeroplanes confirms the effectiveness and expected precision of the system. PMID:24646997

Ghelfi, Paolo; Laghezza, Francesco; Scotti, Filippo; Serafino, Giovanni; Capria, Amerigo; Pinna, Sergio; Onori, Daniel; Porzi, Claudio; Scaffardi, Mirco; Malacarne, Antonio; Vercesi, Valeria; Lazzeri, Emma; Berizzi, Fabrizio; Bogoni, Antonella

2014-03-20

107

Raindrop size distributions and radar reflectivity-rain rate relationships for radar hydrology Hydrology and Earth System Sciences, 5(4), 615627 (2001) EGS  

E-print Network

Raindrop size distributions and radar reflectivity-rain rate relationships for radar hydrology 615 Hydrology and Earth System Sciences, 5(4), 615­627 (2001) © EGS Raindrop size distributions and radar reflectivity­rain rate relationships for radar hydrology* Remko Uijlenhoet1 Sub-department Water Resources

Boyer, Edmond

108

Imaging subglacial water systems with coherent airborne radar sounding  

NASA Astrophysics Data System (ADS)

The remote sensing of water systems beneath ice sheets is of great interest for reasons including the role of ice sheet dynamics in sea-level change and analogues to other planetary bodies in our solar system. Radar ice sounding at VHF is well suited for the detection and classification of sub-ice interfaces. In general, radar echoes consist of both specularly reflected and diffusely scattered fields. Specular reflection results from smooth uniform interfaces, whereas diffuse scattering is a complicated function of interface roughness and the uniformity of the basal constituents. These phenomena are important to the analysis and interpretation of radar sounding experiments over subglacial water systems. Radar ice sounding is highly effective for detecting subglacial water due to the high reflectivity of any smooth water layers, and easily extends to water present within smooth saturated sediments, such as those at the basal interface of active West Antarctic ice streams. However, because of scattering considerations, there are limits to our ability to classify rough and inhomogeneous basal interfaces using incoherent radar sounding experiments. A unique radar data set was collected over the downstream portions of ice streams B and C, West Antarctica where they ultimately go afloat to join the Ross Ice Shelf. The experiment included a new data acquisition technique where both individual and ensemble averages of the radar signals were coherently recorded. The integration distance was about 40 meters and the unfocussed synthetic aperture length was about 75 meters over these 500-800 meter thick ice streams. Analysis of the complimentary individual and integrated data sets yields significantly greater information about the reflection and scattering at the subglacial interface than can be obtained solely from reflection coefficient analysis. We present reflection and scattering images of the basal interface and discuss their implications for determining small-scale roughness and the distribution of subglacial water.

Peters, M. E.; Blankenship, D. D.; Morse, D. L.

2001-05-01

109

Fiber optic coherent laser radar 3d vision system  

SciTech Connect

Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic of coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.

Sebastian, R.L.; Clark, R.B.; Simonson, D.L. [and others

1994-12-31

110

THz impulse radar for biomedical sensing: nonlinear system behavior  

NASA Astrophysics Data System (ADS)

The THz impulse radar is an "RF-inspired" sensor system that has performed remarkably well since its initial development nearly six years ago. It was developed for ex vivo skin-burn imaging, and has since shown great promise in the sensitive detection of hydration levels in soft tissues of several types, such as in vivo corneal and burn samples. An intriguing aspect of the impulse radar is its hybrid architecture which combines the high-peak-power of photoconductive switches with the high-responsivity and -bandwidth (RF and video) of Schottky-diode rectifiers. The result is a very sensitive sensor system in which the post-detection signal-to-noise ratio depends super-linearly on average signal power up to a point where the diode is "turned on" in the forward direction, and then behaves quasi-linearly beyond that point. This paper reports the first nonlinear systems analysis done on the impulse radar using MATLAB.

Brown, E. R.; Sung, Shijun; Grundfest, W. S.; Taylor, Z. D.

2014-03-01

111

Deterministic Approach for Spatial Diversity Analysis of Radar Systems Using Near-Field Radar Cross Section of a Metallic Plate  

Microsoft Academic Search

A deterministic analysis of spatial diversity is presented in connection with radar systems. A numerical technique based on physical optics is used for our analysis. Contrary to statistical models, the proposed technique takes into account accurate near-field radar cross section of the target, and radiation characteristics of transmitting and receiving antennas. The power scattered by the target and received by

Ramin Deban; Halim Boutayeb; Ke Wu; Jean Conan

2010-01-01

112

Wearable System-on-a-Chip Pulse Radar Sensors for the Health Care: System Overview  

Microsoft Academic Search

A new system-on-a-chip radar sensor for next generation wearable wireless interface applied to the human health-care and safeguard is presented. The system overview is provided and a summary of the feasibility study of the radar sensor is presented. In detail, the overall system consists of a radar sensor for detecting the heart and breath rates and a low-power IEEE 802.15.4

Domenico Zito; Domenico Pepe; Bruno Neri; Danilo De Rossi; Antonio Lanata

2007-01-01

113

UWB Microwave Monopulse Radar System for breast cancer detection  

Microsoft Academic Search

The concept of an Ultra Wideband (UWB) Monopulse Microwave Radar System for detection and location of breast cancer is described. The system uses a two-element Tapered Slot Antenna (TSA) array accompanied by a UWB 180° hybrid which scans the breast. When the breast tissue features symmetry with respect to the array axis and the hybrid enables the 180° out phase

Marek E. Bialkowski; Yifan Wang; Amin Abbosh

2010-01-01

114

DC offset reduction in phase diversity heterodyne doppler radar system  

Microsoft Academic Search

Continuous wave Doppler radar systems have been used for non-contact detection of human cardiopulmonary activity, and these functions can be used in diverse applications including health care, emergency, military, or security. For reliable and robust sensing, several schemes are applied to overcome deleterious system sensitivity associated with the periodic phase relationship between the received signal and local oscillator. In previous

Byung-Kwon Park; Dragan Samardzija; Victor M. Lubecke; Olga Boric-Lubecke; Tod Sizer

2007-01-01

115

Synthetic aperture radar simulation system based on Matlab  

Microsoft Academic Search

This paper introduces the SAR simulation system realized by using Matlab. The SAR imaging algorithm with pulse compression is discussed, and simulated radar images are also presented. It is shown that the SAR simulation system is flexible due to the easy program language and powerful signal processing tools of Matlab

Zhang Hongyuan; Zhang Yunhua; Jiang Jingshan

2000-01-01

116

Development of a Low-Cost UAV Doppler Radar Data System  

NASA Technical Reports Server (NTRS)

A viewgraph presentation on the design of a low cost unmanned aerial vehicle (UAV) doppler radar data system is presented. The topics include: 1) Science and Mission Background; 2) Radar Requirements and Specs; 3) Radar Realization: RF System; 4) Processing of RF Signal; 5) Data System Design Process; 6) Can We Remove the DSP? 7) Determining Approximate Speed Requirements; 8) Radar Realization: Data System; 9) Data System Operation; and 10) Results.

Knuble, Joseph; Li, Lihua; Heymsfield, Gerry

2005-01-01

117

Methods And System Suppressing Clutter In A Gain-Block, Radar-Responsive Tag System  

DOEpatents

Methods and systems reduce clutter interference in a radar-responsive tag system. A radar transmits a series of linear-frequency-modulated pulses and receives echo pulses from nearby terrain and from radar-responsive tags that may be in the imaged scene. Tags in the vicinity of the radar are activated by the radar's pulses. The tags receive and remodulate the radar pulses. Tag processing reverses the direction, in time, of the received waveform's linear frequency modulation. The tag retransmits the remodulated pulses. The radar uses a reversed-chirp de-ramp pulse to process the tag's echo. The invention applies to radar systems compatible with coherent gain-block tags. The invention provides a marked reduction in the strength of residual clutter echoes on each and every echo pulse received by the radar. SAR receiver processing effectively whitens passive-clutter signatures across the range dimension. Clutter suppression of approximately 14 dB is achievable for a typical radar system.

Ormesher, Richard C. (Albuquerque, NM); Axline, Robert M. (Albuquerque, NM)

2006-04-18

118

Certification methodology applied to the NASA experimental radar system  

NASA Technical Reports Server (NTRS)

The objective of the research is to apply selected FAA certification techniques to the NASA experimental wind shear radar system. Although there is no intent to certify the NASA system, the procedures developed may prove useful to manufacturers that plan to undergo the certification process. The certification methodology for forward-looking wind shear detection radars will require estimation of system performance in several FAA-specified microburst/clutter scenarios as well as the estimation of probabilities of missed and false hazard alerts under general operational conditions. Because of the near-impossibility of obtaining these results experimentally, analytical and simulation approaches must be used. Hazard detection algorithms were developed that derived predictive estimates of aircraft hazard from basic radar measurements of weather reflectivity and radial wind velocity. These algorithms were designed to prevent false alarms due to ground clutter while providing accurate predictions of hazard to the aircraft due to weather. A method of calculation of the probability of missed and false hazard alerts has been developed that takes into account the effect of the various algorithms used in the system and provides estimates of the probability of missed and false alerts per microburst encounter under weather conditions found at Denver, Kansas City, and Orlando. Simulation techniques have been developed that permit the proper merging of radar ground clutter data (obtained from flight tests) with simulated microburst data (obtained from microburst models) to estimate system performance using the microburst/clutter scenarios defined by the FAA.

Britt, Charles L.; Switzer, George F.; Bracalente, Emedio M.

1994-01-01

119

X-band Radar System for Detecting Heart and Respiration Rates  

E-print Network

X-band Radar System for Detecting Heart and Respiration Rates Jee-Hoon Lee, Yun-Taek Im, and Seong an X-band Doppler radar system to detect heart and respiration of human far away. Through the idea polarization. This bistatic radar system can be used in non-invasively sensing bio signals such as respiration

Park, Seong-Ook

120

Comparison of multifrequency phased-array and direction-finding HF radar systems during COPE3  

Microsoft Academic Search

Several HF radar systems were used to map ocean surface currents in the third Chesapeake Outflow Plume Experiment (COPE-3) conducted just outside the mouth of Chesapeake Bay, off Virginia Beach, VA during October and November 1997. A multifrequency radar system recently constructed by the University of Michigan, an Ocean Surface Current Radar (OSCR) system operated by the University of Miami,

C. C. Teague; D. M. Fernandez; K. E. Laws; J. D. Paduan; J. F. Vesecky

1998-01-01

121

Radar Cross Section measurements of small Unmanned Air Vehicle Systems in non-cooperative field environments  

Microsoft Academic Search

The growing use of unmanned air vehicle systems (UAVS) is drawing increased interest in their radar signature to search and track radars. Because it is not always possible to transport UAVS to radar cross section (RCS) measurement facilities, a portable RCS measurement system has been developed and demonstrated in non-cooperative field environments. This paper presents the portable RCS measurement system

A. Bati; D. Hilliard

2009-01-01

122

Antenna dimensions of synthetic aperture radar systems on satellites  

NASA Technical Reports Server (NTRS)

Design of a synthetic aperture radar (SAR) for a satellite must take into account the limitation in weight and dimensions of the antenna. The lower limits of the antenna area are derived from the conditions of unambiguity of the SAR system. This result is applied to estimate the antenna requirements for SARs on satellites in circular orbits of various altitudes around Earth and Venus.

Richter, K. R.

1973-01-01

123

Most people immediately recognize the importance of radar systems to  

E-print Network

a few. However, these 10- to 40-year- old systems are nearing the end of their designed lifespans. MIT An innovative design exploits dual polarization and digital beamforming to provide a radar solution board (PCB), a heat exchanger, and a backplane PCB that distributes DC power and control to the array

Reuter, Martin

124

Combined Ground Penetrating Radar and Seismic System for Detecting Tunnels  

Microsoft Academic Search

An experimental system to collect co-located ground penetrating radar (GPR) and seismic data was developed to investigate possibilities of using the sensors individually or in a cooperative manner to detect shallow tunnels. These sensors were chosen because they sense very different physical properties. The seismic sensor is sensitive to the differences between the mechanical properties of a tunnel and the

Tegan Counts; Gregg D. Larson; James H. McClellan

2006-01-01

125

Multifrequency HF radar observations of surface currents: measurements from different systems and environments  

Microsoft Academic Search

The authors present three aspects of current HF radar research. First, they examine the consistency of measurements by HF ground wave radars with different designs, but operating on the same physical principles. This is done using data from the commercially available SeaSonde (Codar Ocean Systems) and from the Multifrequency Coastal Radar (MCR), which is a research system. Data from the

John Vesecky; Jessica Drake; Michal Plume; C. Teague; L. Meadows; Y. Fernandez; Ken Davidson; Jeff Paduan

2001-01-01

126

A MIMO Radar System Approach to Target Hana Godrich, Alexander M. Haimovich, and Rick S. Blum  

E-print Network

1 A MIMO Radar System Approach to Target Tracking Hana Godrich, Alexander M. Haimovich, and Rick S performnace of MIMO radar systems with distributed antennas and non-coherent processing is studied of the radars geometric layout and the target location on tracking accuracies is analyzed. The impact

Haimovich, Alexander

127

A DDS and PLL-based X-band FMCW Radar System  

E-print Network

the quality of the received IF signals. A voltage controlled oscillator (VCO) commonly used in FMCW radar-band FMCW radar system whose VCO nonlinearity is controlled by a digitally generated reference signalA DDS and PLL-based X-band FMCW Radar System Yun-Taek Im, Jee-Hoon Lee, and Seong-Ook Park

Park, Seong-Ook

128

Doppler radar sensor positioning in a fall detection system.  

PubMed

Falling is a common health problem for more than a third of the United States population over 65. We are currently developing a Doppler radar based fall detection system that already has showed promising results. In this paper, we study the sensor positioning in the environment with respect to the subject. We investigate three sensor positions, floor, wall and ceiling of the room, in two experimental configurations. Within each system configuration, subjects performed falls towards or across the radar sensors. We collected 90 falls and 341 non falls for the first configuration and 126 falls and 817 non falls for the second one. Radar signature classification was performed using a SVM classifier. Fall detection performance was evaluated using the area under the ROC curves (AUCs) for each sensor deployment. We found that a fall is more likely to be detected if the subject is falling toward or away from the sensor and a ceiling Doppler radar is more reliable for fall detection than a wall mounted one. PMID:23365879

Liu, Liang; Popescu, Mihail; Ho, K C; Skubic, Marjorie; Rantz, Marilyn

2012-01-01

129

Time-domain compact range measurement system for radar targets  

NASA Astrophysics Data System (ADS)

Building scheme and developing procedures of a measuring system for radar targets were introduced. Theory of time domain measurement was studied. Sampling Oscilloscope was used for measurement in compact range for the first time. Structure of the system and operating flow for the measurement were presented. Programs for controlling of the oscilloscope and turntable as well as data processing were developed, based on which entire measuring software of UWB compact range was achieved, including measurement of radar cross-section, polarization scattering matrix and microwave imaging. FFT and windowing technique as well as digital filtering were used to transform data from time-domain to frequency-domain and to improve the accuracy. Idea of virtual instrument was used in the program. Finally, some data measured and processed by the system were presented, which proves performance of the system.

Li, Gaosheng; Liu, Jibin; Liu, Peiguo; He, Jianguo

2011-10-01

130

LUNARS - Lunar Unique Netted Advanced Radar System  

NASA Astrophysics Data System (ADS)

Lunar-based multi-frequency and multi-polarisation netted radio and radar facilities and observation clusters in space will be helpful to find solutions to problems in space physics and to detect long-term environmental changes and will bring new observation data of the early stage of Universe. The Moon offers an excellent platform to located the radio waves instruments for monitoring the electromagnetic emissions in near Earth environment. The innovative new radio measurements on board of satellite and the new type LOFAR-LOIS radio diagnostics, comprising wide band, and vector sensing radio receivers with full three-dimensional polarization coverage located on the Moon's surface can improve our knowledge about fundamental properties of turbulent plasma. The priority for future science experiments on the Moon is to construct low-frequency radio astronomy telescope. To understand the properties of the solar terrestrial environment and to develop a quantitative model of the near Earth environment and to monitoring the low-frequency emission of Sun, Jupiter, and Saturn and to characterize the properties of the lunar environment with respect to noise background, dielectric properties of the moon surface, and to monitoring cosmic radio sources at wavelengths not accessible from Earth it necessary to design and build new generation multi-point and multi-type sensor diagnostics.

Rothkaehl, H.; Thide, B.; Baan, W.; Falcke, H.

2009-04-01

131

Radio Aurora Explorer: Mission science and radar system  

NASA Astrophysics Data System (ADS)

The Radio Aurora Explorer (RAX) satellite is the first of several satellites funded under the NSF CubeSat-based Space Weather and Atmospheric Research Program. RAX is a ground-to-space bi-static radar remote sensing experiment designed to measure and understand the causes of meter-scale ionospheric irregularities. Also known as field-aligned irregularities (FAI), such non-thermal, coherent fluctuations of electron density occur in response to strong ionospheric flows or plasma density gradients during geomagnetic disturbances and are considered a space weather concern due to disruption to communication and navigation signals. The RAX CubeSat was launched in November 2010 and conducted a single experiment in coordination with the Poker Flat Incoherent Scatter Radar. Due to geophysical inactivity, e.g., lack of strong ionospheric electric fields and low ionospheric densities, no FAI were expected or observed. However, the radar receiver payload operation was successfully demonstrated, including the capability to sense signals as low as -110 dBm, the capability of transmitter-receiver synchronization and accurate ranging, processing of 1.2 GB of raw radar data on board in less than 1 hour, and the downlink of the science results within three-four passes. Analysis of the payload data shows that the noise level is sufficiently low. Although the interference level is a concern, it does not appear to significantly limit the measurements. Toward the end of December 2010, the solar power system gradually degraded and the mission terminated in early February 2011 after prolonged loss of contact with the satellite. Meanwhile, RAX II was launched in October 2011 to a polar orbit. This paper describes the RAX science and radar system and presents the results from the first experiment conducted.

Bahcivan, H.; Cutler, J. W.

2012-04-01

132

System-on-chip based Doppler radar occupancy sensor.  

PubMed

System-on-Chip (SoC) based Doppler radar occupancy sensor is developed through non contact detection of respiratory signals. The radio was developed using off the shelf low power RF CC2530 SoC chip by Texas Instruments. In order to save power, the transmitter sends signal intermittently at 2.405 GHz. Reflected pulses are demodulated, and the baseband signals are processed to recover periodic motion. The system was tested both with mechanical target and a human subject. In both cases Doppler radar detected periodic motion closely matched the actual motion, and it has been shown that an SoC based system can be used for subject detection. PMID:22254705

Yavari, Ehsan; Song, Chenyan; Lubecke, Victor; Boric-Lubecke, Olga

2011-01-01

133

Tropical precipitating systems observed with Indian MST radar  

NASA Astrophysics Data System (ADS)

Three campaigns are conducted with the Indian mesosphere-stratosphere-troposphere (MST) radar, located at Gadanki (13.5°N, 79.2°E), India, to study the precipitating systems in the tropics. This study mainly deals with (1) classification of precipitating clouds and the spectral characteristics of echoes associated with these cloud systems and (2) characteristics of the radar bright band. The radar gets echoes scattered both from refractive index fluctuations and precipitation particles in moderate to heavy precipitation conditions. These echoes are separated in the spectral domain to determine the vertical air motion and the Doppler velocity of hydrometeors simultaneously. The tropical precipitating systems are classified as stratiform and convective using the reflectivity and vertical velocity distribution. The echo power, spectral width, and vertical velocities of the ambient air and hydrometeors in both the cloud systems have been compared. Aspect sensitivity of the echoes from the hydrometeors and refractive index fluctuations in both stratiform and convective atmosphere is studied. A transition stage, where the stratiform precipitation is associated with the convection, is also reported. Backscattered power from precipitation particles is used to estimate the reflectivity factor (dBZ), and these values along with spectral width and vertical velocity values are used to identify the bright band structure. The reflectivity at the bright band, up to 42 dBZ, is found to be 10-12 dB more than the average value of reflectivity below the bright band. Discussion on the factors contributing to this enhancement is also included. A clear layered structure around the 0°C isotherm in the reflectivity profile of the precipitation echo confirms the presence of the bright band. The thickness of the bright band is estimated and is correlated with the peak reflectivity at the bright band. Comparison of the average terminal velocity of hydrometeors with their average Doppler velocities below the bright band shows the presence of gentle updrafts of a few cm s-1 in stratiform precipitation. These studies are made for the first time with the Indian MST radar and also demonstrate the capability of a VHF radar in studying precipitating systems in addition to the turbulence to which these radars are highly sensitive.

Rao, T. Narayana; Rao, D. Narayana; Raghavan, S.

1999-09-01

134

Interferometric aligment of the X-SAR antenna system on the space shuttle radar topography mission  

NASA Technical Reports Server (NTRS)

The on-orbit alignment of the antenna beams of both the X-band and C-band radar systems during operations of the shuttle radar topography mission/X-band synthetic aperture radar (SRTM/X-SAR)was a key requirement for achieving best interferometric performance.

Geudtner, D.; Zink, M.; Gierull, C.; Shaffer, S.

2002-01-01

135

76 FR 35176 - Operation of Radar Systems in the 76-77 GHz Band  

Federal Register 2010, 2011, 2012, 2013

...and 10-28; FCC 11-79] Operation of Radar Systems in the 76-77 GHz Band AGENCY...amend rules to enable enhanced vehicular radar technologies in the 76-77 GHz band to...avoidance and driver safety. Vehicular radars can determine the exact distance and...

2011-06-16

136

77 FR 48097 - Operation of Radar Systems in the 76-77 GHz Band  

Federal Register 2010, 2011, 2012, 2013

...RM-11555; FCC 12-72] Operation of Radar Systems in the 76-77 GHz Band AGENCY...not-in-motion distinction for vehicular radars, and instead adopting new uniform emission...side, and rear- looking vehicular radars. This will facilitate enhanced...

2012-08-13

137

ECE 686: Introduction to Radar Systems Department of Electrical & Computer Engineering  

E-print Network

equation, signal-to-noise ratio, radar cross section, range and velocity ambiguity, radar clut- ter background in electromagnetic fields, probability and random processes, and signals and systems. Required., 1993, Academic Press, ISBN 0-12-221422-6. "Microwave Remote Sensing, Active & Passive Vol. II, Radar

Massachusetts at Amherst, University of

138

Considerations for integration of a physiological radar monitoring system with gold standard clinical sleep monitoring systems.  

PubMed

A design for a physiological radar monitoring system (PRMS) that can be integrated with clinical sleep monitoring systems is presented. The PRMS uses two radar systems at 2.45 GHz and 24 GHz to achieve both high sensitivity and high resolution. The system can acquire data, perform digital processing and output appropriate conventional analog outputs with a latency of 130 ms, which can be recorded and displayed by a gold standard sleep monitoring system, along with other standard sensor measurements. PMID:24110139

Singh, Aditya; Baboli, Mehran; Gao, Xiaomeng; Yavari, Ehsan; Padasdao, Bryson; Soll, Bruce; Boric-Lubecke, Olga; Lubecke, Victor

2013-01-01

139

The NASA/JPL Airborne Synthetic Aperture Radar System  

NASA Technical Reports Server (NTRS)

The NASA/JPL airborne SAR (AIRSAR) system operates in the fully polarimetric mode at P-, L- and C-band simultaneously or in the interferometric mode in both L- and C-band simultaneously. The system became operational in late 1987 and flew its first mission aboard a DC-8 aircraft operated by NASA's Ames Research Center in Mountain View, California. Since then, the AIRSAR has flown missions every year and acquired images in North, Central and South America, Europe and Australia. In this paper, we will briefly describe the instrument characteristics, the evolution of the various radar modes, the instrument performance, and improvement in the knowledge of the positioning and attitude information of the radar. In addition, we will summarize the progress of the data processing effort especially in the interferometry processing. Finally, we will address the issue of processing and calibrating the cross-track interferometry (XTI) data.

Kim, Yun-Jin; Lou, Yun-Ling; vanZyl, Jakob

1996-01-01

140

GEOS-2 C-band radar system project. Marine study using C-band radars  

NASA Technical Reports Server (NTRS)

One of the secondary objectives of the GEOS-2 C-band Systems Project is to study the feasibility of using geodetic satellites to both evaluate shipborne instrumentation and to determine ship positions in broad ocean areas. The purpose of this task is to determine whether shipborne C-band radar tracking, in conjunction with ground based tracking, is sufficiently accurate to provide instrumentation evaluation and ship position estimates. Data from several Apollo tracking ships, in particular the USNS Vanguard, was made available for this effort. A series of tests, using the USNS Vanguard, were carried out in the Port Canaveral and Bahama Acoustic Transponder Array Areas. The major portion of the analyses reported are the result of preliminary investigations using the data from these tests.

1972-01-01

141

Experimental 0.22 THz Stepped Frequency Radar System for ISAR Imaging  

NASA Astrophysics Data System (ADS)

High resolution inverse synthetic aperture radar (ISAR) imaging is demonstrated by using a 0.22 THz stepped-frequency (SF) imaging radar system. The synthesis bandwidth of the terahertz (THz) SF radar is 12 GHz, which are beneficial for high resolution imaging. The resolution of ISAR image can reach centimeter-scale with the use of Range-Doppler algorithm (RDA). Results indicate that high resolution ISAR imaging is realized by using 0.22THz SF radar coupled with turntable scanning, which can provide foundations for further research on high-resolution radar image in the THz band.

Liang, Mei Yan; Zhang, Cun Lin; Zhao, Ran; Zhao, Yue Jin

2014-09-01

142

A Foliage Penetration Imaging Radar System  

E-print Network

#12;-30 -20 -10 0 10 20 -34 -32 -30 -28 -26 -24 -22 -20 -18 -16 -14 -12 -10 Plate Area 'A' (dBsm) RCS(dBsm) 8.2 GHz Data 8.2 GHz Predicted RCS 12.4 GHz Data 12.4 GHz Predicted RCS System Linearity !! " # $$ % & = 2 2 10 4 log10 ' ( ) A dBsm·Predicted RCS ·Spot size at upper-band limits maximum dimensions

Massachusetts at Lowell, University of

143

MST radar transmitter control and monitor system  

NASA Technical Reports Server (NTRS)

A generalized transmitter control and monitor card was developed using the Intel 8031 (8051 family) microprocessor. The design was generalized so that this card can be utilized for virtually any control application with only firmware changes. The block diagram appears in Figure 2. The card provides for local control using a 16 key keypad (up to 64 keys are supported). The local display is four digits of 7 segment LEDs. The display can indicate the status of all major system parameters and provide voltage readout for the analog signal inputs. The card can be populated with only the chips required for a given application. Fully populated, the card has two RS-232 serial ports for computer communications. It has a total of 48 TTL parallel lines that can define as either inputs or outputs in groups of four. A total of 32 analog inputs with a 0-5 volt range are supported. In addition, a real-time clock/calendar is available if required. A total of 16 k bytes of ROM and 16 k bytes of RAM is available for programming. This card can be the basis of virtually any monitor or control system with appropriate software.

Brosnahan, J. W.

1983-01-01

144

How Spaceborne Radar Helps Ground Radar in Precipitation Estimation: Real-time Incorporation of TRMM PR into NOAA NMQ System  

NASA Astrophysics Data System (ADS)

The U.S. Next-Generation Radar (NEXRAD) network provides operational precipitation products for the National Weather Service. However, the effective coverage of NEXRAD at low levels is restricted in complex terrain leading to insufficient surveillance of low-level portions of the atmosphere. This problem is especially most severe in the intermountain region of the western US. Quantitative precipitation estimation (QPE) based on radar measurements at high levels above the surface can be over- or underestimated, depending on if the radar beam intercepts or overshoots the melting layer. To mitigate this problem, researchers at the University of Oklahoma (OU) have proposed a VPR Identification and Enhancement (VPR-IE) approach to improve radar-based QPE near the surface. VPR-IE applies the VPR observed by Ku-band Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) to correct the S-band NEXRAD radar reflectivity contaminated by ice-related signals such as the bright band (BB) and dry snow signals. The real-time incorporation of TRMM-PR into the NEXRAD-based National Mosaic and Multi-sensor QPE (NMQ) system faces challenges because of their big difference in temporal resolution. The current study explores how to obtain representative VPRs for the real-time implementation of VPR-IE and investigates the potential error of VPR-IE attributed to the temporal variation of precipitation. The real-time VPR-IE is tested using the archived NMQ data collected in the mountainous West region of the U.S. (southern California, Arizona, and western New Mexico). Analysis results demonstrate the great potential of real-time VPR-IE in improving radar QPE in complex terrain.

Cao, Q.; Hong, Y.; Wen, Y.; Gourley, J. J.; Qi, Y.; Zhang, J.; Kirstetter, P.

2012-12-01

145

Ambiguities in spaceborne synthetic aperture radar systems  

NASA Technical Reports Server (NTRS)

An examination of aspects of spaceborne SAR time delay and Doppler ambiguities has led to the formulation of an accurate method for the evaluation of the ratio of ambiguity intensities to that of the signal, which has been applied to the nominal SAR system on Seasat. After discussing the variation of this ratio as a function of orbital latitude and attitude control error, it is shown that the detailed range migration-azimuth phase history of an ambiguity is different from that of a signal, so that the images of ambiguities are dispersed. Seasat SAR dispersed images are presented, and their dispersions are eliminated through an adjustment of the processing parameters. A method is also presented which uses a set of multiple pulse repetition sequences to determine the Doppler centroid frequency absolute values for SARs with high carrier frequencies and poor attitude measurements.

Li, F. K.; Johnson, W. T. K.

1983-01-01

146

A Portable Low-Power Harmonic Radar System and Conformal Tag for Insect Tracking  

Technology Transfer Automated Retrieval System (TEKTRAN)

Harmonic radar systems provide an effective modality for tracking insect behavior. This paper presents a harmonic radar system proposed to track the migration of the Emerald Ash Borer (EAB). The system offers a unique combination of portability, low power and small tag design. It is comprised of a...

147

HF radar role in an integrated ocean observing system  

Microsoft Academic Search

The Australian Coastal Ocean radar Network (ACORN) is a monitoring network of HF radars which are being installed around Australia under a National Collaborative Research Infrastructure Strategy (NCRIS). It is a five-year project, at the end of which there will be five pairs of radar stations and one triplet installed and operating, enabled by the central pool of funding for

M. L. Heron; A. Prytz

2009-01-01

148

A robust tracking system for imaging radar altimeter  

Microsoft Academic Search

The capability of precise range tracking is an important characteristic for an oceanic radar altimeter, different from other tracking radars. Up to now, however, all of the operational spaceborne radar altimeters can only be applied to the ocean because their tracking algorithms are based on an assumed echo model, and usually is Brown's (1977) model. But for the land case,

Zhisen Wang; Yunhua Zhang; Jingshan Jiang

2000-01-01

149

Fiber optic coherent laser radar 3D vision system  

SciTech Connect

This CLVS will provide a substantial advance in high speed computer vision performance to support robotic Environmental Management (EM) operations. This 3D system employs a compact fiber optic based scanner and operator at a 128 x 128 pixel frame at one frame per second with a range resolution of 1 mm over its 1.5 meter working range. Using acousto-optic deflectors, the scanner is completely randomly addressable. This can provide live 3D monitoring for situations where it is necessary to update once per second. This can be used for decontamination and decommissioning operations in which robotic systems are altering the scene such as in waste removal, surface scarafacing, or equipment disassembly and removal. The fiber- optic coherent laser radar based system is immune to variations in lighting, color, or surface shading, which have plagued the reliability of existing 3D vision systems, while providing substantially superior range resolution.

Clark, R.B.; Gallman, P.G.; Slotwinski, A.R. [Coleman Research Corp., Springfield, VA (United States); Wagner, K.; Weaver, S.; Xu, Jieping [Colorado Univ., Boulder, CO (United States)

1996-12-31

150

The Goldstone Solar System Radar: Opportunities and Challenges  

NASA Astrophysics Data System (ADS)

The Deep Space Network (DSN) primarily uses the 70-m antenna at Goldstone — DSS -14 — for tracking, telemetry, and commanding National Aeronautics and Space Administration (NASA) spacecraft. However, for a small percentage of its time DSS-14 also provides NASA with the only fully steerable, high-power ground-based radar in the world. The Goldstone Solar System Radar (GSSR) has been used extensively for high-resolution radar ranging and imaging of planetary and small-body targets, including more than 160 asteroids, four comets, the Moon, Mercury, Venus, Mars, the Galilean satellites, Titan, and small orbital debris. The GSSR operates at a wavelength of 3.5 cm with a typical transmitter power of 450 kW, and provides radar imagery, surface topography, rotational information, and ice distribution on this wide variety of solar system objects. The bulk of current GSSR work centers on radar imaging, astrometry, and characterization of near-Earth asteroids (NEAs). GSSR has discovered binary and ternary NEAs (six to date); contact binary NEAs, and NEAs in non-principal axis rotation states. The GSSR has observed the following small-body mission targets: 4 Vesta (Dawn), 433 Eros (NEAR-Shoemaker), 25143 Itokawa (Hayabusa), 101955 1999 RQ36 (OSIRIS-REx), and 4179 Toutatis (Chang'e 2). Recently the highest range resolution improved by a factor of five from 18.75 meters to 3.75 meters. The first major application of this resolution increase was with imaging of 400-meter-diameter (308635) 2005 YU55 during the asteroid's 0.85 lunar distance flyby in November 2011. The images placed tens of thousands of pixels on the asteroid, and even revealed small surface boulders. The limitation to ~4-meter range resolution is driven by the bandwidth of the transmitter. However, by using chirp waveforms and klystrons with ~150 MHz bandwidth, the range resolution could be as fine as 1-meter. JPL is exploring methods of transmitting such wider bandwidths and potentially reaching 1-meter range resolution. The GSSR currently provides nearly encounter-quality imaging of NEAs a few times each year, and the potential exists for future imaging of even higher quality. Two main avenues exist to becoming a user of the GSSR. Successful proposers to the Research Opportunities in Space and Earth Sciences (ROSES) solicitations from the Planetary Science Division in the NASA Science Mission Directorate make up the majority of GSSR users. GSSR users also come via successful proposals to observing calls from the National Science Foundation for use of their Green Bank Telescope or the Extended Very Large Array that require 3.5-cm radar illumination of targets for primary science goals. In addition, any DSN-supported flight project can request GSSR observations that advance the goals of their mission. GSSR supports a wide community of scientists at many institutions. The research described above was carried out at the Jet Propulsion Laboratory, a division of the California Institute of Technology, under contract with the National Aeronautics and Space Administration. Government sponsorship acknowledged.

Slade, M. A.; Benner, L. A.; Teitelbaum, L.

2012-12-01

151

GeoSAR: A Radar Terrain Mapping System for the New Millennium  

NASA Technical Reports Server (NTRS)

GeoSAR Geographic Synthetic Aperture Radar) is a new 3 year effort to build a unique, dual-frequency, airborne Interferometric SAR for mapping of terrain. This is being pursued via a Consortium of the Jet Propulsion Laboratory (JPL), Calgis, Inc., and the California Department of Conservation. The airborne portion of this system will operate on a Calgis Gulfstream-II aircraft outfitted with P- and X-band Interferometric SARs. The ground portions of this system will be a suite of Flight Planning Software, an IFSAR Processor and a Radar-GIS Workstation. The airborne P-band and X-band radars will be constructed by JPL with the goal of obtaining foliage penetration at the longer P-band wavelengths. The P-band and X-band radar will operate at frequencies of 350 Mhz and 9.71 Ghz with bandwidths of either 80 or 160 Mhz. The airborne radars will be complemented with airborne laser system for measuring antenna positions. Aircraft flight lines and radar operating instructions will be computed with the Flight Planning Software The ground processing will be a two-step step process. First, the raw radar data will be processed into radar images and interferometer derived Digital Elevation Models (DEMs). Second, these radar images and DEMs will be processed with a Radar GIS Workstation which performs processes such as Projection Transformations, Registration, Geometric Adjustment, Mosaicking, Merging and Database Management. JPL will construct the IFSAR Processor and Calgis, Inc. will construct the Radar GIS Workstation. The GeoSAR Project was underway in November 1996 with a goal of having the radars and laser systems fully integrated onto the Calgis Gulfstream-II aircraft in early 1999. Then, Engineering Checkout and Calibration-Characterization Flights will be conducted through November 1999. The system will be completed at the end of 1999 and ready for routine operations in the year 2000.

Thompson, Thomas; vanZyl, Jakob; Hensley, Scott; Reis, James; Munjy, Riadh; Burton, John; Yoha, Robert

2000-01-01

152

Generalized radar/radiometry imaging problems  

E-print Network

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

Genève, Université de

153

EISCAT 3D - The Next Generation European Incoherent Scatter Radar System  

Microsoft Academic Search

A major new research European infrastructure will be constructed in Northern Scandinavia, combining several very large phased-array transmitters\\/receivers with multiple receiver arrays. The new EISCAT 3D radar system has a design goal of ten times higher temporal and spatial resolution than the present radars, a volumetric radar imaging capability in an extended spatial area with simultaneous full-vector drift velocities, avoiding

E. Turunen

2009-01-01

154

CEEN-4940/8946-002 Special Topics: Introduction to Antennas and Radar Systems, Fall 2008  

E-print Network

and the Yagi-Uda array 8. Slot, patch and horn antennas 9. Broadband and frequency-independent antennas 10CEEN-4940/8946-002 Special Topics: Introduction to Antennas and Radar Systems, Fall 2008 Instructor Course Description: This course will provide an introduction to antenna designs and Radar Systems

Yang, Yaoqing "Lamar"

155

Second annual progress report of the Millimeter Wave Cloud Profiling Radar System (CPRS)  

SciTech Connect

The Cloud Profiling Radar System (CPRS) is a single antenna, two frequency (33 GHz and 95 GHz) polarimetric radar which is currently under the development at the University of Massachusetts (UMASS). This system will be capable of making four dimensional Doppler and polarimetric measurements of clouds. This report gives details about the status of the various subsystems under development and discusses current research activities.

Pazmany, A.L.; Sekelsky, S.M.; McIntosh, R.E.

1992-06-07

156

The EDOP Radar System on the High-Altitude NASA ER2 Aircraft  

Microsoft Academic Search

The NASA ER-2 high-altitude ( 20 km) aircraft that emulates a satellite view of precipitation systems carries a variety of passive and active ( lidar ) remote sensing instruments. A new Doppler weather radar system at X band ( 9.6 GHz ) called the ER-2 Doppler radar ( EDOP ) has been developed and flown on the ER-2 aircraft. EDOP

Gerald M. Heymsfield; Steven W. Bidwell; I. Jeff Caylor; Syed Ameen; Shaun Nicholson; Wayne Boncyk; Lee Miller; Doug Vandemark; Paul E. Racette; Louis R. Dod

1996-01-01

157

Airborne ground-penetrating radar system to detect surface and subsurface land mines  

Microsoft Academic Search

Research progress on the design, construction, and operation of a novel, airborne ground penetrating radar system to detect surface and subsurface landmines is presented. The landmine detection system is unique in that active, electronic projectiles are shot into the ground from an airborne platform to create high power, monopulse radar signals. Intimate contact between the projectile and the ground reduces

Thomas G. Engel; William C. Nunnally; Nate B. Vankirk

1998-01-01

158

Goldstone Solar System Radar Observatory: Earth-Based Planetary Mission Support and Unique Science Results  

Microsoft Academic Search

The Goldstone Solar System Radar (GSSR) facility is the only fully steerable radar in the world for high-resolution ranging and imaging of planetary and small-body targets. These observations provide information on surface characteristics, orbits, rotations, and polar ices for a wide variety of solar system objects. The resulting data are used not just for scientific studies of these objects, but

Martin A. Slade; Lance A. M. Benner; Arnold Silva

2011-01-01

159

47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication... § 15.509 Technical requirements for ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of...

2011-10-01

160

47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication... § 15.509 Technical requirements for ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of...

2010-10-01

161

47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication... § 15.509 Technical requirements for ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of...

2013-10-01

162

47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication... § 15.509 Technical requirements for ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of...

2012-10-01

163

47 CFR 15.509 - Technical requirements for ground penetrating radars and wall imaging systems.  

...2014-10-01 false Technical requirements for ground penetrating radars and wall imaging systems. 15.509 Section 15.509 Telecommunication... § 15.509 Technical requirements for ground penetrating radars and wall imaging systems. (a) The UWB bandwidth of...

2014-10-01

164

Wuhan Atmosphere Radio Exploration (WARE) radar: System design and online winds measurements  

NASA Astrophysics Data System (ADS)

The basic configuration of the Wuhan MST (mesosphere-stratosphere-troposphere) radar, which was designed and constructed by the School of Electronic Information, Wuhan University, is preliminarily described in this paper. The Wuhan MST radar operates at very high frequency (VHF) band (53.8 MHz) by observing the real-time characteristics of turbulence and the wind field vector in the height range of 3.5-90 km (not including 25-60 km) with high temporal and height resolutions. This all-solid-state, all-coherent pulse Doppler radar is China's first independent development of an MST radar focusing on atmospheric observation. The subsystems of the Wuhan MST radar include an antenna system, a feeder line system, all-solid-state radar transmitters, digital receivers, a beam control system, a signal processing system, a data processing system, a product generation system, and a user terminal. Advanced radar technologies are used, including highly reliable all-solid-state transmitters, low-noise large dynamic range digital receivers, an active phased array, high-speed digital signal processing, and real-time graphic terminals. This paper describes the design and implementation of the radar. Preliminary online wind measurements and results of the comparison to simultaneous observations by a GPS rawinsonde are presented as well.

Zhengyu, Zhao; Chen, Zhou; Haiyin, Qing; Guobin, Yang; Yuannong, Zhang; Gang, Chen; Yaogai, Hu

2013-05-01

165

Ground-based weather radar compatibility with digital radio-relay microwave systems  

NASA Astrophysics Data System (ADS)

The potential for ground-based weather radar (meteorological radar) interference to digital microwave systems in the common carrier bands of 3700 to 4200 MHz and 5925 to 6425 MHz is examined. Reported cases of interference to microwave common carrier systems from ground-based weather radar systems have increased due to the trend towards digital modulations. Because of this interference, the National Telecommunications and Information Administration, the Federal Communications Commission and the National Spectrum Managers Association formed an informal working group to investigate and document the potential problems. The existing and planned spectrum uses by ground-based weather radars and digital microwave systems are addressed as well as regulations and policy pertaining to their electromagnetic compatibility. Methods to mitigate the interference in both the radar transmitter and microwave receiver are also provided.

Gawthrop, P. E.; Patrick, G. M.

1990-03-01

166

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

Code of Federal Regulations, 2012 CFR

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

2012-01-01

167

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

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Doppler Radar and Inertial Navigation System (INS...G Appendix G to Part 121—Doppler Radar and Inertial Navigation System (INS...applicant for authority to use a Doppler Radar or Inertial Navigation System must...

2010-01-01

168

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

Code of Federal Regulations, 2013 CFR

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

2013-01-01

169

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

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

2014-01-01

170

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

Code of Federal Regulations, 2011 CFR

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

2011-01-01

171

Application of Radar Data to Remote Sensing and Geographical Information Systems  

NASA Technical Reports Server (NTRS)

The field of synthetic aperture radar changed dramatically over the past decade with the operational introduction of advance radar techniques such as polarimetry and interferometry. Radar polarimetry became an operational research tool with the introduction of the NASA/JPL AIRSAR system in the early 1980's, and reached a climax with the two SIR-C/X-SAR flights on board the space shuttle Endeavour in April and October 1994. Radar interferometry received a tremendous boost when the airborne TOPSAR system was introduced in 1991 by NASA/JPL, and further when data from the European Space Agency ERS-1 radar satellite became routinely available in 1991. Several airborne interferometric SAR systems are either currently operational, or are about to be introduced. Radar interferometry is a technique that allows one to map the topography of an area automatically under all weather conditions, day or night. The real power of radar interferometry is that the images and digital elevation models are automatically geometrically resampled, and could be imported into GIS systems directly after suitable reformatting. When combined with polarimetry, a technique that uses polarization diversity to gather more information about the geophysical properties of the terrain, a very rich multi-layer data set is available to the remote sensing scientist. This talk will discuss the principles of radar interferometry and polarimetry with specific application to the automatic categorization of land cover. Examples will include images acquired with the NASA/JPL AIRSAR/TOPSAR system in Australia and elsewhere.

vanZyl, Jakob J.

2000-01-01

172

A survey of airborne radar systems for deployment on a High Altitude Powered Platform (HAPP)  

NASA Technical Reports Server (NTRS)

A survey was conducted to find out the system characteristics of commercially available and unclassified military radars suitable for deployment on a stationary platform. A total of ten domestic and eight foreign manufacturers of the radar systems were identified. Questionnaires were sent to manufacturers requesting information concerning the system characteristics: frequency, power used, weight, volume, power radiated, antenna pattern, resolution, display capabilities, pulse repetition frequency, and sensitivity. A literature search was also made to gather the system characteristics information. Results of the survey are documented and comparisons are made among available radar systems.

Choudhury, B. J.; Leung, K. C.

1979-01-01

173

A comparison of velocity measurements from the CUTLASS Finland radar and the EISCAT UHF system  

E-print Network

A comparison of velocity measurements from the CUTLASS Finland radar and the EISCAT UHF system J. A January 1999 Abstract. The CUTLASS Finland radar, which com- prises an integral part of the Super irregularities within a ®eld-of- view which extends over some four million square kilometres. Within the Finland

Paris-Sud XI, Université de

174

Radar and radio data fusion platform for future intelligent transportation system  

Microsoft Academic Search

We present a software-defined data fusion system which integrates both radar (sensing) function and radio (communication) function within a single transceiver platform. In the proposed architecture, the radar mode and the radio mode operate in different time slots. The required modulated waveform is generated with the help of a direct digital synthesizer (DDS) that is able to control signal parameters

Liang Han; Ke Wu

2010-01-01

175

Height Target Estimation in a Three Positioned Radar System Christo Kabakchiev, Ivan Garvanov, Vladimir Kyovtorov  

E-print Network

of the three-positioned radar in order to increase the measurement accuracy. Keywords: height target estimation108 Height Target Estimation in a Three Positioned Radar System Christo Kabakchiev, Ivan Garvanov, Vladimir Kyovtorov Institute of Information Technologies, 1113 Sofia Abstract: The target height error

Borissova, Daniela

176

Wearable system-on-a-chip UWB radar for contact-less cardiopulmonary monitoring: present status.  

PubMed

The present status of the project aimed at the realization of an innovative wearable system-on-chip UWB radar for the cardiopulmonary monitoring is presented. The overall system consists of a wearable wireless interface including a fully integrated UWB radar for the detection of the heart beat and breath rates, and a IEEE 802.15.4 ZigBee low-power radio interface. The principle of operation of the UWB radar for the monitoring of the heart wall is summarized. With respect to the prior art, this paper reports the results of the experimental characterization of the intra-body channel loss, which has been carried out successfully in order to validate the theoretical model employed for the radar system analysis. Moreover, the main building blocks of the radar have been manufactured in 90 nm CMOS technology by ST-Microelectronics and the relevant performance are resulted in excellent agreement with those expected by post-layout simulations. PMID:19163907

Zito, D; Pepe, D; Mincica, M; Zito, F; De Rossi, D; Lanata, A; Scilingo, E P; Tognetti, A

2008-01-01

177

Strapdown inertial navigation system requirements imposed by synthetic aperture radar  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to demonstrate a means of specifying strapdown inertial navigation system (INS) requirements from synthetic aperture radar (SAR) requirements. The latter include allowable levels for quadratic and cubic phase shift, and side lobe levels (i.e., peak side lobe ratio (PSLR) and integrated side lobe ratio (ISLR). When these multiple considerations produce different INS requirements, of course, the tightest governs. Results obtained constitute a technique demonstration only, and do not represent any specific mechanization. In the process of this investigation several pitfalls in common procedures were identified; these are highlighted in the discussion. A brief background description is provided in the Appendix for those unfamiliar with the analysis of SAR degradations.

Farrell, J. L.

1985-08-01

178

Simulation of synthetic aperture radar 2: Simulating SAR (Synthetic Aperture Radar) using the advanced visual technology system  

Microsoft Academic Search

The Advanced Visual Technology System (AVTS) computer image generator was modified to produce highly accurate simulations of synthetic aperture radar (SAR) reflectively and elevation effects that can be precisely correlated with corresponding visual and infrared imagery. The resulting SAR snapshot is a plan view of the selected patch area with the field-of-view corresponding to a selected scale of 0.65, 1.3,

Robert L. Ferguson; John Ellis; Steven R. French; Jeanne Ball; Lisa Spencer; Herbert H. Bell; Peter M. Crane

1989-01-01

179

Frequency Diversity Radar System: Design, Analysis and Performances  

Microsoft Academic Search

Frequency diversity (FD) is a technique that significantly improves radar detection performance in clear and under adverse weather conditions. With FD two or more conventional radar transceivers are combined through a common antenna, in a multiplex arrangement on the same RF transmission channel. Results from computer simulations show typically 40-60% improvement in terms of detection probability and 7 dB improvement

V. Ravenni; G. Pizziol

2006-01-01

180

A Digital Array Radar with a Hierarchical System Architecture Caleb Fulton, Patrick Clough, Vijay Pai, and William Chappell  

E-print Network

A Digital Array Radar with a Hierarchical System Architecture Caleb Fulton, Patrick Clough, Vijay -- A digital array radar system prototype is pre sented that makes use of a hierarchical digital backend for future radars that fully embrace the concept of lowcost inte gration in a panelized platform

181

Airborne ground-penetrating radar system to detect surface and subsurface land mines  

NASA Astrophysics Data System (ADS)

Research progress on the design, construction, and operation of a novel, airborne ground penetrating radar system to detect surface and subsurface landmines is presented. The landmine detection system is unique in that active, electronic projectiles are shot into the ground from an airborne platform to create high power, monopulse radar signals. Intimate contact between the projectile and the ground reduces the amount of reflected radar energy at the air-soil interface and ensures that maximum radar energy is propagated into the surrounding ground. The end result is that the reflected radar signal is of higher energy and possesses a higher signal-to- noise ratio allowing enhanced detectability. The high power, monopulse signal that is reflected off the landmine is received at the airborne platform via scanned antenna array. In comparison, conventional ground penetrating radar systems typically use chirped or long pulse signals and horn type antennas located close to the ground limiting their usefulness in this application. To generate electrical energy, two types of projectiles are used and are based on the principle of magnetic flux compression or by the principle of piezoelectric compression. The performance results of these two projectile types as well as the models used to predict their behavior are presented and discussed. To evaluate the overall performance of the system, a sub-scale radar test range was also constructed. The radar test range consists of a large dirt- filled tank containing a high power impulse source, several targets that simulate buried landmines, and a post scanned antenna array located above the dirt-filled tank. The high power impulse source simulates the radar signal generated when the projectiles impact the ground. The radar cross-sectional data generated in the test range is presented and discussed.

Engel, Thomas G.; Nunnally, William C.; VanKirk, Nate B.

1998-09-01

182

A system for the real-time display of radar and video images of targets  

NASA Technical Reports Server (NTRS)

Described here is a software and hardware system for the real-time display of radar and video images for use in a measurement range. The main purpose is to give the reader a clear idea of the software and hardware design and its functions. This system is designed around a Tektronix XD88-30 graphics workstation, used to display radar images superimposed on video images of the actual target. The system's purpose is to provide a platform for tha analysis and documentation of radar images and their associated targets in a menu-driven, user oriented environment.

Allen, W. W.; Burnside, W. D.

1990-01-01

183

System aspects of the Indian MST radar facility  

NASA Technical Reports Server (NTRS)

One of the major objectives of the Indian Middle Atmosphere Program is to investigate the motions of the middle atmosphere on temporal and spatial scales and the interaction between the three height regions of the middle atmosphere. Realizing the fact that radar technique has proven to be a very powerful tool for the study of Earth atmosphere, the Indian Middle Atmosphere Program has recommended establishing a mesosphere-stratosphere-troposphere (MST) radar as a national facility for atmospheric research. The major landmarks in this attempt to setup the MST radar as a national facility are described.

Viswanathan, G.

1986-01-01

184

Estimation of Microphysical and Radiative Parameters of Precipitating Cloud Systems Using mm-Wavelength Radars  

NASA Astrophysics Data System (ADS)

A remote sensing approach is described to retrieve cloud and rainfall parameters within the same precipitating system. This approach is based on mm-wavelength radar signal attenuation effects which are observed in a layer of liquid precipitation containing clouds and rainfall. The parameters of ice clouds in the upper part of startiform precipitating systems are then retrieved using the absolute measurements of radar reflectivity. In case of the ground-based radar location, these measurements are corrected for attenuation in the intervening layer of liquid hydrometers.

Matrosov, Sergey Y.

2009-03-01

185

Radar based Ground Level Reconstruction Utilizing a Hypocycloid Antenna Positioning System  

NASA Astrophysics Data System (ADS)

In this contribution we introduce a novel radar positioning system. It makes use of a mathematical curve, called hypocycloid, for a slanting movement of the radar antenna. By means of a planetary gear, a ball, and a universal joint as well as a stepping motor, a two dimensional positioning is provided by a uniaxial drive shaft exclusively. The fundamental position calculation and different signal processing algorithms are presented. By means of an 80 GHz FMCW radar system we performed several measurements on objects with discrete heights as well as on objects with continuous surfaces. The results of these investigations are essential part of this contribution and are discussed in detail.

Baer, Christoph; Musch, Thomas

2015-01-01

186

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

E-print Network

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

187

Netted radar sensing  

Microsoft Academic Search

Future radar applications are beginning to stretch monostatic radar systems beyond their fundamental sensitivity and information limits. Networks of smaller radar systems can offer a route to overcome these limitations; for example, networks of radar sensors can counter stealth technology whilst simultaneously providing additional information for improved target classification. More generally, multiple independent sensors can provide an energetically more efficient

C. J. Baker; A. L. Hume

2003-01-01

188

Radar astronomy  

Microsoft Academic Search

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

J. V. Evans

1960-01-01

189

Quasi-orthogonal wideband radar waveforms based on chaotic systems  

E-print Network

With the development of A/D converters possessing sufficiently high sampling rates, it is now feasible to use arbitrary, wideband waveforms in radar applications. Large sets of quasi-orthogonal, wideband waveforms can be ...

Willsey, Matt (Matt S.)

2007-01-01

190

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

191

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

192

Sea Clutter Reduction and Target Enhancement by Neural Networks in a Marine Radar System  

PubMed Central

The presence of sea clutter in marine radar signals is sometimes not desired. So, efficient radar signal processing techniques are needed to reduce it. In this way, nonlinear signal processing techniques based on neural networks (NNs) are used in the proposed clutter reduction system. The developed experiments show promising results characterized by different subjective (visual analysis of the processed radar images) and objective (clutter reduction, target enhancement and signal-to-clutter ratio improvement) criteria. Moreover, a deep study of the NN structure is done, where the low computational cost and the high processing speed of the proposed NN structure are emphasized. PMID:22573993

Vicen-Bueno, Raúl; Carrasco-Álvarez, Rubén; Rosa-Zurera, Manuel; Nieto-Borge, José Carlos

2009-01-01

193

FMCW radar for the sense function of sense and avoid systems onboard UAVs  

NASA Astrophysics Data System (ADS)

Rockwell Collins France (RCF) radar department is currently developing, in close collaboration with TNO in The Hague, The Netherlands, a Frequency Modulated Continuous Wave (FMCW) radar sensor dedicated to Obstacle Warning function and potentially to air traffic detection. The sensor combines flood light illumination and digital beam forming to accommodate demanding detection and coverage requirements. Performances have been evaluated in flight tests and results prove that such a radar sensor is a good candidate for the Sense Function of Sense and Avoid Systems onboard UAV.

Itcia, Eric; Wasselin, Jean-Philippe; Mazuel, Sébastien; Otten, Matern; Huizing, Albert

2013-10-01

194

Sea clutter reduction and target enhancement by neural networks in a marine radar system.  

PubMed

The presence of sea clutter in marine radar signals is sometimes not desired. So, efficient radar signal processing techniques are needed to reduce it. In this way, nonlinear signal processing techniques based on neural networks (NNs) are used in the proposed clutter reduction system. The developed experiments show promising results characterized by different subjective (visual analysis of the processed radar images) and objective (clutter reduction, target enhancement and signal-to-clutter ratio improvement) criteria. Moreover, a deep study of the NN structure is done, where the low computational cost and the high processing speed of the proposed NN structure are emphasized. PMID:22573993

Vicen-Bueno, Raúl; Carrasco-Álvarez, Rubén; Rosa-Zurera, Manuel; Nieto-Borge, José Carlos

2009-01-01

195

Dual-Frequency Airborne Scanning Rain Radar Antenna System  

NASA Technical Reports Server (NTRS)

A compact, dual-frequency, dual-polarization, wide-angle-scanning antenna system has been developed as part of an airborne instrument for measuring rainfall. This system is an upgraded version of a prior single-frequency airborne rain radar antenna system and was designed to satisfy stringent requirements. One particularly stringent combination of requirements is to generate two dual-polarization (horizontal and vertical polarizations) beams at both frequencies (13.405 and 35.605 GHz) in such a way that the beams radiated from the antenna point in the same direction, have 3-dB angular widths that match within 25 percent, and have low sidelobe levels over a wide scan angle at each polarization-and-frequency combination. In addition, the system is required to exhibit low voltage standing-wave ratios at both frequencies. The system (see figure) includes a flat elliptical scanning reflector and a stationary offset paraboloidal reflector illuminated by a common-aperture feed system that comprises a corrugated horn with four input ports one port for each of the four frequency-and-polarization combinations. The feed horn is designed to simultaneously (1) under-illuminate the reflectors 35.605 GHz and (2) illuminate the reflectors with a 15-dB edge taper at 13.405 GHz. The scanning mirror is rotated in azimuth to scan the antenna beam over an angular range of 20 in the cross-track direction for wide swath coverage, and in elevation to compensate for the motion of the aircraft. The design of common-aperture feed horn makes it possible to obtain the required absolute gain and low side-lobe levels in wide-angle beam scanning. The combination of the common-aperture feed horn with the small (0.3) focal-length-to-diameter ratio of the paraboloidal reflector makes it possible for the overall system to be compact enough that it can be mounted on a DC-8 airplane.

Hussein, Ziad A.; Green, Ken

2004-01-01

196

A general interactive system for compositing digital radar and satellite data  

NASA Technical Reports Server (NTRS)

Reynolds and Smith (1979) have considered the combined use of digital weather radar and satellite data in interactive systems for case study analysis and forecasting. Satellites view the top of clouds, whereas radar is capable of observing the detailed internal structure of clouds. The considered approach requires the use of a common coordinate system. In the present investigation, it was decided to use the satellite coordinate system as the base system in order to maintain the fullest resolution of the satellite data. The investigation is concerned with the development of a general interactive software system called RADPAK for remapping and analyzing conventional and Doppler radar data. RADPAK is implemented as a part of a minicomputer-based image processing system, called Atmospheric and Oceanographic Image Processing System. Attention is given to a general description of the RADPAK system, remapping methodology, and an example of satellite remapping.

Ghosh, K. K.; Chen, L. C.; Faghmous, M.; Heymsfield, G. M.

1981-01-01

197

LPI radar: fact or fiction  

Microsoft Academic Search

LPI radar is a system that consists of a radar and ES system. Its performance depends on both components. An LPI performance factor is derived and applied to several examples. Operational LPI radars are described. A digital LPI radar detector is described and test results presented. A recent book on LPI radar received a number of somewhat critical reviews that

D. C. Schleher

2006-01-01

198

High-resolution imaging using a wideband MIMO radar system with two distributed arrays.  

PubMed

Imaging a fast maneuvering target has been an active research area in past decades. Usually, an array antenna with multiple elements is implemented to avoid the motion compensations involved in the inverse synthetic aperture radar (ISAR) imaging. Nevertheless, there is a price dilemma due to the high level of hardware complexity compared to complex algorithm implemented in the ISAR imaging system with only one antenna. In this paper, a wideband multiple-input multiple-output (MIMO) radar system with two distributed arrays is proposed to reduce the hardware complexity of the system. Furthermore, the system model, the equivalent array production method and the imaging procedure are presented. As compared with the classical real aperture radar (RAR) imaging system, there is a very important contribution in our method that the lower hardware complexity can be involved in the imaging system since many additive virtual array elements can be obtained. Numerical simulations are provided for testing our system and imaging method. PMID:20051345

Wang, Dang-wei; Ma, Xiao-yan; Chen, A-Lei; Su, Yi

2010-05-01

199

Ultrawideband radar echoes of land mine targets measured at oblique incidence using a 250-kW impulse radar system  

NASA Astrophysics Data System (ADS)

United Nations Peacekeeping forces around the world need to transport food, personnel and medical supplies through disputed regions were land mines are in active use as road blocks and terror weapons. A method of fast, effective land mine detection is needed to combat this threat to road transport. The technique must operate from a vehicle travelling at a reasonable velocity and give warning far enough ahead for the vehicle to stop in time to avoid the land mine. There is particular interest in detecting low- metallic content land mines. One possible solutionis the use of ultra-wide-band (UWB) radar. The Australian Defence Department is investigating the feasibility of using UWB radar for land mine detection from a vehicle. A 3 GHz UWB system has been used to collect target response from a series of inert land mines and mine-like objects placed on the ground and buried in the ground. The targets measured were a subset of those in the target set described in Wong et al. with the addition of inert land mines corresponding to some of the surrogate targets in this set. The results are encouraging for the detection of metallic land mines and the larger non-metallic land mines. Smaller low-metallic- content anti-personnel land mines are less likely to be detected.

Chant, Ian J.; Staines, Geoff

1997-07-01

200

Space shuttle Ku-band integrated rendezvous radar/communications system study  

NASA Technical Reports Server (NTRS)

The results are presented of work performed on the Space Shuttle Ku-Band Integrated Rendezvous Radar/Communications System Study. The recommendations and conclusions are included as well as the details explaining the results. The requirements upon which the study was based are presented along with the predicted performance of the recommended system configuration. In addition, shuttle orbiter vehicle constraints (e.g., size, weight, power, stowage space) are discussed. The tradeoffs considered and the operation of the recommended configuration are described for an optimized, integrated Ku-band radar/communications system. Basic system tradeoffs, communication design, radar design, antenna tradeoffs, antenna gimbal and drive design, antenna servo design, and deployed assembly packaging design are discussed. The communications and radar performance analyses necessary to support the system design effort are presented. Detailed derivations of the communications thermal noise error, the radar range, range rate, and angle tracking errors, and the communications transmitter distortion parameter effect on crosstalk between the unbalanced quadriphase signals are included.

1976-01-01

201

The ElSCAT Svalbard radar: A case study in modern incoherent scatter radar system design G. Wannberg,  I. Wolf,  L.-G. Vanhainen,  K. Koskenniemi,  J. R6ttger  

Microsoft Academic Search

The EISCAT (European incoherent scatter) Svalbard radar (ESR) was officially inaugurated on August 22, 1996. This event marked the successful completion on schedule of the first phase of the EISCAT Svalbard radar project. In contrast to previous incoherent scatter radars, the ESR system design was adapted to make use of commercial off-the-shelf TV transmitter hardware, thereby reducing design risk, lead

M. Postila; J. Markkanen; R. Jacobsen; A. Stenberg; R. Larsen; S. Eliassen; S. Heck; A. Huuskonen

1997-01-01

202

Comparing Goldstone Solar System Radar Earth-based Observations of Mars with Orbital Datasets  

NASA Technical Reports Server (NTRS)

The Goldstone Solar System Radar (GSSR) has collected a self-consistent set of delay-Doppler near-nadir radar echo data from Mars since 1988. Prior to the Mars Global Surveyor (MGS) Mars Orbiter Laser Altimeter (MOLA) global topography for Mars, these radar data provided local elevation information, along with radar scattering information with global coverage. Two kinds of GSSR Mars delay-Doppler data exist: low 5 km x 150 km resolution and, more recently, high (5 to 10 km) spatial resolution. Radar data, and non-imaging delay-Doppler data in particular, requires significant data processing to extract elevation, reflectivity and roughness of the reflecting surface. Interpretation of these parameters, while limited by the complexities of electromagnetic scattering, provide information directly relevant to geophysical and geomorphic analyses of Mars. In this presentation we want to demonstrate how to compare GSSR delay-Doppler data to other Mars datasets, including some idiosyncracies of the radar data. Additional information is included in the original extended abstract.

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

2005-01-01

203

Radar observations of the 2009 eruption of Redoubt Volcano, Alaska: Initial deployment of a transportable Doppler radar system for volcano-monitoring  

NASA Astrophysics Data System (ADS)

The rapid detection of explosive volcanic eruptions and accurate determination of eruption-column altitude and ash-cloud movement are critical factors in the mitigation of volcanic risks to aviation and in the forecasting of ash fall on nearby communities. The U.S. Geological Survey (USGS) deployed a transportable Doppler radar during the precursory stage of the 2009 eruption of Redoubt Volcano, Alaska, and it provided valuable information during subsequent explosive events. We describe the capabilities of this new monitoring tool and present data that it captured during the Redoubt eruption. The volcano-monitoring Doppler radar operates in the C-band (5.36 cm) and has a 2.4-m parabolic antenna with a beam width of 1.6 degrees, a transmitter power of 330 watts, and a maximum effective range of 240 km. The entire disassembled system, including a radome, fits inside a 6-m-long steel shipping container that has been modified to serve as base for the antenna/radome, and as a field station for observers and other monitoring equipment. The radar was installed at the Kenai Municipal Airport, 82 km east of Redoubt and about 100 km southwest of Anchorage. In addition to an unobstructed view of the volcano, this secure site offered the support of the airport staff and the City of Kenai. A further advantage was the proximity of a NEXRAD Doppler radar operated by the Federal Aviation Administration. This permitted comparisons with an established weather-monitoring radar system. The new radar system first became functional on March 20, roughly a day before the first of nineteen explosive ash-producing events of Redoubt between March 21 and April 4. Despite inevitable start-up problems, nearly all of the events were observed by the radar, which was remotely operated from the Alaska Volcano Observatory office in Anchorage. The USGS and NEXRAD radars both detected the eruption columns and tracked the directions of drifting ash clouds. The USGS radar scanned a 45-degree sector centered on the volcano while NEXRAD scanned a full 360 degrees. The sector strategy scanned the volcano more frequently than the 360-degree strategy. Consequently, the USGS system detected event onset within less than a minute, while the NEXRAD required about 4 minutes. The observed column heights were as high as 20 km above sea level and compared favorably to those from NEXRAD. NEXRAD tracked ash clouds to greater distances than the USGS system. This experience shows that Doppler radar is a valuable complement to traditional seismic and satellite monitoring of explosive eruptions.

Hoblitt, R. P.; Schneider, D. J.

2009-12-01

204

Impulse radar imaging system for concealed object detection  

NASA Astrophysics Data System (ADS)

Electromagnetic systems for imaging concealed objects at checkpoints typically employ radiation at millimetre and terahertz frequencies. These systems have been shown to be effective and provide a sufficiently high resolution image. However there are difficulties and current electromagnetic systems have limitations particularly in accurately differentiating between threat and innocuous objects based on shape, surface emissivity or reflectivity, which are indicative parameters. In addition, water has a high absorption coefficient at millimetre wavelength and terahertz frequencies, which makes it more difficult for these frequencies to image through thick damp clothing. This paper considers the potential of using ultra wideband (UWB) in the low gigahertz range. The application of this frequency band to security screening appears to be a relatively new field. The business case for implementing the UWB system has been made financially viable by the recent availability of low-cost integrated circuits operating at these frequencies. Although designed for the communication sector, these devices can perform the required UWB radar measurements as well. This paper reports the implementation of a 2 to 5 GHz bandwidth linear array scanner. The paper describes the design and fabrication of transmitter and receiver antenna arrays whose individual elements are a type of antipodal Vivaldi antenna. The antenna's frequency and angular response were simulated in CST Microwave Studio and compared with laboratory measurements. The data pre-processing methods of background subtraction and deconvolution are implemented to improve the image quality. The background subtraction method uses a reference dataset to remove antenna crosstalk and room reflections from the dataset. The deconvolution method uses a Wiener filter to "sharpen" the returned echoes which improves the resolution of the reconstructed image. The filter uses an impulse response reference dataset and a signal-to-noise parameter to determine how the frequencies contained in the echo dataset are normalised. The chosen image reconstruction algorithm is based on the back-projection method. The algorithm was implemented in MATLAB and uses a pre-calculated sensitivity matrix to increase the computation speed. The results include both 2D and 3D image datasets. The 3D datasets were obtained by scanning the dual sixteen element linear antenna array over the test object. The system has been tested on both humans and mannequin test objects. The front surface of an object placed on the human/mannequin torso is clearly visible, but its presence is also seen from a tell-tale imaging characteristic. This characteristic is caused by a reduction in the wave velocity as the electromagnetic radiation passes through the object, and manifests as an indentation in the reconstructed image that is readily identifiable. The prototype system has been shown to easily detect a 12 mm x 30 mm x70 mm plastic object concealed under clothing.

Podd, F. J. W.; David, M.; Iqbal, G.; Hussain, F.; Morris, D.; Osakue, E.; Yeow, Y.; Zahir, S.; Armitage, D. W.; Peyton, A. J.

2013-10-01

205

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

E-print Network

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

Vaidyanathan, P. P.

206

Weather Radar and Instrumentation: Laboratory Modules  

NSDL National Science Digital Library

These 16 radar education modules, developed for the Weather Radar and Instrumentation Curriculum at the University of Oklahoma, provide hands-on instruction for beginning, intermediate, or advanced students to learn about radar systems, especially weather radar. Topics include hardware, weather radar, adaptive systems, advanced hydrometeors, applications of weather radar, and atmospheric interpretations. The modules may be downloaded.

207

On the Use of Low-Cost Radar Networks for Collision Warning Systems Aboard Dumpers  

PubMed Central

The use of dumpers is one of the main causes of accidents in construction sites, many of them with fatal consequences. These kinds of work machines have many blind angles that complicate the driving task due to their large size and volume. To guarantee safety conditions is necessary to use automatic aid systems that can detect and locate the different objects and people in a work area. One promising solution is a radar network based on low-cost radar transceivers aboard the dumper. The complete system is specified to operate with a very low false alarm rate to avoid unnecessary stops of the dumper that reduce its productivity. The main sources of false alarm are the heavy ground clutter, and the interferences between the radars of the network. This article analyses the clutter for LFM signaling and proposes the use of Offset Linear Frequency Modulated Continuous Wave (OLFM-CW) as radar signal. This kind of waveform can be optimized to reject clutter and self-interferences. Jointly, a data fusion chain could be used to reduce the false alarm rate of the complete radar network. A real experiment is shown to demonstrate the feasibility of the proposed system. PMID:24577521

González-Partida, José-Tomás; León-Infante, Francisco; Blázquez-García, Rodrigo; Burgos-García, Mateo

2014-01-01

208

Radar-Derived Shape Model of Near-Earth Binary Asteroid System (285263) 1998 QE2  

NASA Astrophysics Data System (ADS)

We report on shape modeling of binary asteroid 1998 QE2, a 3.2-km asteroid with a 800-m moon. We observed this asteroid with both Arecibo Observatory planetary radar (2380 MHz, 12.6 cm) and Goldstone Solar System Radar (8560 MHz, 3.5 cm) between May 31-Jun 9, 2013. The close approach on May 31, 2013 (0.039 au) presented an outstanding opportunity for radar delay-Doppler imaging with resolutions as fine as 7.5 m of both objects. The extensive radar dataset was used for shape modeling of both components. Our SHAPE 3D modeling software (Hudson, 1993 and Magri et al., 2007) uses a constrained, weighted least-squares minimization procedure to invert radar delay-Doppler images.The rotation rate of the primary, 4.749 ± 0.002 h, was well constrained from optical lightcurves (P. Pravec, pers. comm.) and rotates prograde as determined from radar data. The primary is roughly spheroidal, showing prominent concavities and surface features, with effective diameter 3.2 ± 0.3 km.The secondary is irregularly shaped, with an effective diameter of 800 ± 80 m and significant elongation. The radar data suggest it is tidally locked, with an orbital period of 31.31 ± 0.01 h hours and a semi-major orbital axis of 6.2 ± 0.1 km. The orbit is approximately circular (e < 0.01), which is typical of most near-Earth asteroid binary system orbits. We estimate a preliminary density for the primary of 0.7 ± 0.2 g/cm^3. The low density is consistent with a "rubble pile" structure.

Springmann, Alessondra; Taylor, Patrick A.; Nolan, Michael C.; Howell, Ellen S.; Brozovi?, Marina; Benner, Lance A.; Giorgini, Jon D.; Busch, Michael W.; Margot, Jean-Luc; Lee, Clement; Jao, Joseph S.; Lauretta, Dante S.

2014-11-01

209

Capability of patch antennas in a portable harmonic radar system to track insects  

Technology Transfer Automated Retrieval System (TEKTRAN)

Monitoring technologies are needed to track insects and gain a better understanding of their behavior, population, migration and movement. A portable microwave harmonic-radar tracking system that utilizes antenna miniaturization techniques was investigated to achieve this goal. The system mainly con...

210

HF radar in French Mediterranean Sea: an element of MOOSE Mediterranean Ocean Observing System on Environment  

E-print Network

HF radar in French Mediterranean Sea: an element of MOOSE Mediterranean Ocean Observing System , Pascal Guterman2 , Karim Bernardet2 1 Mediterranean Institute of Oceanography (MIO, UM 110, USTV. In the framework of the French MOOSE project (Mediterranean Ocean Observing System on Environment

Boyer, Edmond

211

Conceptual design of a dual-use radar\\/communication system based on OFDM  

Microsoft Academic Search

The paper describes a novel system which can be used interchangeably as a radar sensor and communication device. The system is being developed at Miami University using COTS components and its digital part is based on OFDM architecture. Arbitrary waveform generator with high-speed DSP capabilities is being used to create either random or deterministic OFDM waveforms and a high-speed ADC

Dmitriy Garmatyuk; Jonathan Schuerger

2008-01-01

212

Space Shuttle thermal protection system inspection by 3D imaging laser radar  

Microsoft Academic Search

NASA has developed a sensor suite to inspect the Space Shuttle Thermal Protection System while the Shuttle is flying in orbit. When the Space Shuttle returns to flight, it will carry a 3D Imaging Laser Radar as part of the sensor suite to observe the Thermal Protection System and indicate any damages that may need to be repaired before return

James C. Lamoreux; James D. Siekierski; J. P. N. Carter

2004-01-01

213

Short Wavelength Technology and the Potential for Distributed Networks of Short-Range Radar Systems  

E-print Network

Short Wavelength Technology and the Potential for Distributed Networks of Short-Range Radar Systems's curvature and terrain-induced blockage. For example, the WSR-88D (NEXRAD) system is unable to view ~ 80 due to the Earth's curvature and improve resolution degradation caused by beam spreading. In addition

Cruz-Pol, Sandra L.

214

Primary propulsion of electrothermal, ion, and chemical systems for space-based radar orbit transfer  

NASA Technical Reports Server (NTRS)

An orbit transfer mission concept has been studied for a Space-Based Radar (SBR) where 40 kW required for radar operation is assumed available for orbit transfer propulsion. Arcjet, pulsed electrothermal (PET), ion, and storable chemical systems are considered for the primary propulsion. Transferring two SBR per shuttle flight to 1112 km/60 deg using eiectrical propulsion systems offers an increased payload at the expense of increased trip time, up to 2000 kg each, which may be critical for survivability. Trade offs between payload mass, transfer time, launch site, inclination, and height of parking orbits are presented.

Wang, S.-Y.; Staiger, P. J.

1985-01-01

215

Primary propulsion of electrothermal, ion and chemical systems for space-based radar orbit transfer  

NASA Technical Reports Server (NTRS)

An orbit transfer mission concept has been studied for a Space-Based Radar (SBR) where 40 kW required for radar operation is assumed available for orbit transfer propulsion. Arcjet, pulsed electrothermal (PET), ion, and storable chemical systems are considered for the primary propulsion. Transferring two SBR per shuttle flight to 1112 km/60 deg using electrical propulsion systems offers an increased payload at the expense of increased trip time, up to 2000 kg each, which may be critical for survivability. Trade offs between payload mass, transfer time, launch site, inclination, and height of parking orbits are presented.

Wang, S. Y.; Staiger, P. J.

1985-01-01

216

Acquisition and use of Orlando, Florida and Continental Airbus radar flight test data  

NASA Technical Reports Server (NTRS)

Westinghouse is developing a lookdown pulse Doppler radar for production as the sensor and processor of a forward looking hazardous windshear detection and avoidance system. A data collection prototype of that product was ready for flight testing in Orlando to encounter low level windshear in corroboration with the FAA-Terminal Doppler Weather Radar (TDWR). Airborne real-time processing and display of the hazard factor were demonstrated with TDWR facilitated intercepts and penetrations of over 80 microbursts in a three day period, including microbursts with hazard factors in excess of .16 (with 500 ft. PIREP altitude loss) and the hazard factor display at 6 n.mi. of a visually transparent ('dry') microburst with TDWR corroborated outflow reflectivities of +5 dBz. Range gated Doppler spectrum data was recorded for subsequent development and refinement of hazard factor detection and urban clutter rejection algorithms. Following Orlando, the data collection radar was supplemental type certified for in revenue service on a Continental Airlines Airbus in an automatic and non-interferring basis with its ARINC 708 radar to allow Westinghouse to confirm its understanding of commercial aircraft installation, interface realities, and urban airport clutter. A number of software upgrades, all of which were verified at the Receiver-Transmitter-Processor (RTP) hardware bench with Orlando microburst data to produce desired advanced warning hazard factor detection, included some preliminary loads with automatic (sliding window average hazard factor) detection and annunciation recording. The current (14-APR-92) configured software is free from false and/or nuisance alerts (CAUTIONS, WARNINGS, etc.) for all take-off and landing approaches, under 2500 ft. altitude to weight-on-wheels, into all encountered airports, including Newark (NJ), LAX, Denver, Houston, Cleveland, etc. Using the Orlando data collected on hazardous microbursts, Westinghouse has developed a lookdown pulse Doppler radar product with signal and data processing algorithms which detect realistic microburst hazards and has demonstrated those algorithms produce no false alerts (or nuisance alerts) in urban airport ground moving vehicle (GMTI) and/or clutter environments.

Eide, Michael C.; Mathews, Bruce

1992-01-01

217

Network connectivity paradigm for the large data produced by weather radar systems  

NASA Astrophysics Data System (ADS)

The traffic over Internet is constantly increasing; this is due in particular to social networks activities but also to the enormous exchange of data caused especially by the so-called "Internet of Things". With this term we refer to every device that has the capability of exchanging information with other devices on the web. In geoscience (and, in particular, in meteorology and climatology) there is a constantly increasing number of sensors that are used to obtain data from different sources (like weather radars, digital rain gauges, etc.). This information-gathering activity, frequently, must be followed by a complex data analysis phase, especially when we have large data sets that can be very difficult to analyze (very long historical series of large data sets, for example), like the so called big data. These activities are particularly intensive in resource consumption and they lead to new computational models (like cloud computing) and new methods for storing data (like object store, linked open data, NOSQL or NewSQL). The weather radar systems can be seen as one of the sensors mentioned above: it transmit a large amount of raw data over the network (up to 40 megabytes every five minutes), with 24h/24h continuity and in any weather condition. Weather radar are often located in peaks and in wild areas where connectivity is poor. For this reason radar measurements are sometimes processed partially on site and reduced in size to adapt them to the limited bandwidth currently available by data transmission systems. With the aim to preserve the maximum flow of information, an innovative network connectivity paradigm for the large data produced by weather radar system is here presented. The study is focused on the Monte Settepani operational weather radar system, located over a wild peak summit in north-western Italy.

Guenzi, Diego; Bechini, Renzo; Boraso, Rodolfo; Cremonini, Roberto; Fratianni, Simona

2014-05-01

218

Considerations for a Radar System to Detect an Ocean Underneath the Icy Shell of Europa  

NASA Technical Reports Server (NTRS)

The detection of an ocean underneath Europa is one of the primary objectives of the Jupiter Icy Moons Orbiter (JIMO) mission. An orbiting surface penetrating radar has the potential of providing that measurement thus yielding information regarding the possibility of life support on Europa. Radars in the MHz range have successfully monitored the kilometer-deep ice shelves of Greenland and Antarctica, including the detection of Lake Vostok (and others) below an ice sheet thickness of about 4 km. The performance of a radar system orbiting Europa will be subject to several potential complications and unknowns. Besides ionospheric dispersion and the actual depth of the ocean, which is estimated between 2 and 30 km, major unknowns affecting radar performance are the temperature profile, the amount of salt and other impurities within the ice crust as well as the surface roughness. These impurities can in part be produced at the highly irradiated surface by magnetospheric interactions and transported downward into the ice crust by geologic processes. The ionospheric interference must also be modeled from effects of these interactions on production of the thin neutral atmosphere and subsequent ionization of the neutrals. We investigated these uncertainties through radar simulations using different surface and ice characteristics over a frequency range from 10 to 50 MHz. The talk will present results from these simulations discussing potential limitations.

Markus, Thorsten; Gogineni, Prasad; Green, James; Cooper, John; Fung, Shing; Taylor, William; Benson, Robert; Reinisch, Bodo; Song, Paul

2004-01-01

219

Design of integrated ship monitoring system using SAR, RADAR, and AIS  

NASA Astrophysics Data System (ADS)

When we talk about for the ship detection, identification and its classification, we need to go for the wide area of monitoring and it may be possible only through satellite based monitoring approach which monitors and covers coastal as well as the oceanic zone. Synthetic aperture radar (SAR) has been widely used to detect targets of interest with the advantage of the operating capability in all weather and luminance free condition (Margarit and Tabasco, 2011). In EU waters, EMSA(European Maritime Safety Agency) is operating the SafeSeaNet and CleanSeaNet systems which provide the current positions of all ships and oil spill monitoring information in and around EU waters in a single picture to Member States using AIS, LRIT and SAR images. In many countries, a similar system has been developed and the key of the matter is to integrate all available data. This abstract describes the preliminary design concept for an integration system of RADAR, AIS and SAR data for vessel traffic monitoring. SAR sensors are used to acquire image data over large coverage area either through the space borne or airborne platforms in UTC. AIS reports should be also obtained on the same date as of the SAR acquisition for the purpose to perform integration test. Land-based RADAR can provide ships positions detected and tracked in near real time. In general, SAR are used to acquire image data over large coverage area, AIS reports are obtained from ship based transmitter, and RADAR can monitor continuously ships for a limited area. In this study, we developed individual ship monitoring algorithms using RADAR(FMCW and Pulse X-band), AIS and SAR(RADARSAT-2 Full-pol Mode). We conducted field experiments two times for displaying the RADAR, AIS and SAR integration over the Pyeongtaek Port, South Korea.

Yang, Chan-Su; Kim, Tae-Ho; Hong, Danbee; Ahn, Hyung-Wook

2013-06-01

220

Feasibility Study and Design of a Wearable System-on-a-Chip Pulse Radar for Contactless Cardiopulmonary Monitoring  

PubMed Central

A new system-on-a-chip radar sensor for next-generation wearable wireless interface applied to the human health care and safeguard is presented. The system overview is provided and the feasibility study of the radar sensor is presented. In detail, the overall system consists of a radar sensor for detecting the heart and breath rates and a low-power IEEE 802.15.4 ZigBee radio interface, which provides a wireless data link with remote data acquisition and control units. In particular, the pulse radar exploits 3.1–10.6 GHz ultra-wideband signals which allow a significant reduction of the transceiver complexity and then of its power consumption. The operating principle of the radar for the cardiopulmonary monitoring is highlighted and the results of the system analysis are reported. Moreover, the results obtained from the building-blocks design, the channel measurement, and the ultra-wideband antenna realization are reported. PMID:18389068

Zito, Domenico; Pepe, Domenico; Neri, Bruno; Zito, Fabio; De Rossi, Danilo; Lanatà, Antonio

2008-01-01

221

GNSS-based passive radar sensing using hybrid-aperture system  

NASA Astrophysics Data System (ADS)

A hybrid-aperture radar system is being developed for passive, GNSS-based sensing and imaging missions. Different from previous work, the real aperture (RA) array has excellent cross-range resolution and electronic scanning capability, and synthetic aperture processing is applied for the dimension along the UAV/aircraft flight path. The hybrid aperture thus provides real-time, combined sensing capability and multiple functions. Multi-level signal synchronization and tracking is used to ensure the signal phase coherency and integrity. The advantages of covert radar sensing and reduced onboard computing complexity of this sensor are being demonstrated through experiments.

Silver, Randy; Zhang, Yan Rockee; Suarez, Hernan; Pan, Yu; Huang, Yih-Ru

2013-05-01

222

Forth system for coherent-scatter radar data acquisition and processing  

NASA Technical Reports Server (NTRS)

A real time collection system was developed for the Urbana coherent scatter radar system. The new system, designed for use with a microcomputer, has several advantages over the old system implemented with a minicomputer. The software used to collect the data is described as well as the processing software used to analyze the data. In addition a magnetic tape format for coherent scatter data exchange is given.

Rennier, A. D.; Bowhill, S. A.

1985-01-01

223

A Bi-static Gregorian Confocal Dual Reflector Antenna for a bomb detection radar system  

Microsoft Academic Search

A bistatic Gregorian confocal dual reflector antenna for a bomb detection radar system had been presented. The beamwidth is suitable to uniquely illuminate a single human body at 50m away from the antenna. The dual reflector can be used for both transmit and receive simultaneously. The Configuration-1 behaves better than Configuration-2 in terms of directivity whereas it become worst in

J. A. Martinez-Lorenzo; C. M. Rappaport; R. Sullivan; A. G. Pino

2007-01-01

224

Data fusion alternatives for the integration of millimetre radar in airport surveillance systems  

Microsoft Academic Search

This work presents the integration of data from a network of millimeter wave sensors in the data fusion system of an A-SMGCS surveillance function. Most airport surface have multiple radar coverage, without the necessary synchronized sensors, so a data fusion scheme is essential to provide a coherent and stable output. Several alternatives are open, from the low-level image combination up

Jesús García; José M. Molina; A. Berlanga; G. de Miguel

2005-01-01

225

Radar, Passive Microwave, and Lightning Characteristics of Precipitating Systems in the Tropics  

Microsoft Academic Search

The bulk radar reflectivity structures, 85- and 37-GHz brightness temperatures, and lightning characteristics of precipitating systems in tropical Africa, South America, the east Pacific, and west Pacific are documented using data from the Tropical Rainfall Measuring Mission (TRMM) satellite during August, September, and October of 1998. The particular focus is on precipitation features (defined as a contiguous area $75 km2

E. R. Toracinta; Daniel J. Cecil; Edward J. Zipser; Stephen W. Nesbitt

2002-01-01

226

Obstacle awareness and collision avoidance radar sensor system for low-altitude flying smart UAV  

Microsoft Academic Search

In This work, the critical requirement for obstacle awareness and avoidance is assessed with the compliance of the equivalent level of safety regulation, and then the collision avoidance sensor system is presented with the key design parameters for the requirement of the smart unmanned aerial vehicle in low-altitude flight. Based on the assessment of various sensors, small-sized radar sensor is

Young K Kwag; Jung W Kang

2004-01-01

227

Flexible end-to-end system design for synthetic aperture radar applications  

NASA Astrophysics Data System (ADS)

This paper presents ARTEMIS, Inc.'s approach to development of end-to-end synthetic aperture radar systems for multiple applications and platforms. The flexible design of the radar and the image processing tools facilitates their inclusion in a variety of application-specific end-to-end systems. Any given application comes with certain requirements that must be met in order to achieve success. A concept of operation is defined which states how the technology is used to meet the requirements of the application. This drives the design decisions. Key to adapting our system to multiple applications is the flexible SlimSAR radar system, which is programmable on-the-fly to meet the imaging requirements of a wide range of altitudes, swath-widths, and platform velocities. The processing software can be used for real-time imagery production or post-flight processing. The ground station is adaptable, and the radar controls can be run by an operator on the ground, on-board the aircraft, or even automated as part of the aircraft autopilot controls. System integration takes the whole operation into account, seeking to flawlessly work with data links and on-board data storage, aircraft and payload control systems, mission planning, and image processing and exploitation. Examples of applications are presented including using a small unmanned aircraft at low altitude with a line of sight data link, a long-endurance UAV maritime surveillance mission with on-board processing, and a manned ground moving target indicator application with the radar using multiple receive channels.

Zaugg, Evan C.; Edwards, Matthew C.; Bradley, Joshua P.

2012-06-01

228

State transition storyboards: A tool for designing the Goldstone solar system radar data acquisition system user interface software  

NASA Technical Reports Server (NTRS)

Effective user interface design in software systems is a complex task that takes place without adequate modeling tools. By combining state transition diagrams and the storyboard technique of filmmakers, State Transition Storyboards were developed to provide a detailed modeling technique for the Goldstone Solar System Radar Data Acquisition System human-machine interface. Illustrations are included with a description of the modeling technique.

Howard, S. D.

1987-01-01

229

Shuttle orbiter KU-band radar/communications system design evaluation  

NASA Technical Reports Server (NTRS)

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

1979-01-01

230

Radar Observations of Convective Systems from a High-Altitude Aircraft  

NASA Technical Reports Server (NTRS)

Reflectivity data collected by the precipitation radar on board the tropical Rainfall Measuring Mission (TRMM) satellite, orbiting at 350 km altitude, are compared to reflectivity data collected nearly simultaneously by a doppler radar aboard the NASA ER-2 flying at 19-20 km altitude, i.e. above even the deepest convection. The TRMM precipitation radar is a scanning device with a ground swath width of 215 km, and has a resolution of about a4.4 km in the horizontal and 250 m in the vertical (125 m in the core swath 48 km wide). The TRMM radar has a wavelength of 217 cm (13.8 GHz) and the Nadir mirror echo below the surface is used to correct reflectivity for loss by attenuation. The ER-2 Doppler radar (EDOP) has two antennas, one pointing to the nadir, 34 degrees forward. The forward pointing beam receives both the normal and the cross-polarized echos, so the linear polarization ratio field can be monitored. EDOP has a wavelength of 3.12 cm (9.6 GHz), a vertical resolution of 37.5 m and a horizontal along-track resolution of about 100 m. The 2-D along track airflow field can be synthesized from the radial velocities of both beams, if a reflectivity-based hydrometer fall speed relation can be assumed. It is primarily the superb vertical resolution that distinguishes EDOP from other ground-based or airborne radars. Two experiments were conducted during 1998 into validate TRMM reflectivity data over convection and convectively-generated stratiform precipitation regions. The Teflun-A (TEXAS-Florida Underflight) experiment, was conducted in April and May and focused on mesoscale convective systems mainly in southeast Texas. TEFLUN-B was conducted in August-September in central Florida, in coordination with CAMEX-3 (Convection and Moisture Experiment). The latter was focused on hurricanes, especially during landfall, whereas TEFLUN-B concentrated on central; Florida convection, which is largely driven and organized by surface heating and ensuing sea breeze circulations. Both TEFLUN-A and B were amply supported by surface data, in particular a dense raingauge network, a polarization radar, wind profilers, a mobile radiosonde system, a cloud physics aircraft penetrating the overflown storms, and a network of 10 cm Doppler radars(WSR-88D). This presentation will show some preliminary comparisons between TRMM, EDOP, and WSR-88D reflectivity fields in the case of an MCS, a hurricane, and less organized convection in central Florida. A validation of TRMM reflectivity is important, because TRMM's primary objective is to estimate the rainfall climatology with 35 degrees of the equator. Rainfall is estimated from the radar reflectivity, as well from TRMM's Microwave Imager, which measures at 10.7, 19.4, 21.3, 37, and 85.5 GHz over a broader swath (78 km). While the experiments lasted about three months the cumulative period of near simultaneous observations of storms by ground-based, airborne and space borne radars is only about an hour long. Therefore the comparison is case-study-based, not climatological. We will highlight fundamental differences in the typical reflectivity profiles in stratiform regions of MCS's, Florida convection and hurricanes and will explain why Z-R relationships based on ground-based radar data for convective systems over land should be different from those for hurricanes. These catastrophically intense rainfall from hurricane Georges in Hispaniola and from Mitch in Honduras highlights the importance of accurate Z-R relationships, It will be shown that a Z-R relationship that uses the entire reflectivity profile (rather than just a 1 level) works much better in a variety of cases, making an adjustment of the constants for different precipitation system categories redundant.

Heymsfield, G.; Geerts, B.; Tian, L.

1999-01-01

231

The MDA MicroSatellite Target System (MTS) for DoD Radar Calibration  

Microsoft Academic Search

The Missile Defense Agency (MDA) Advanced Systems Directorate (MDA\\/DV) is developing the MicroSatellite Target System (MTS) to research and develop the technologies necessary to build relatively inexpensive microsatellites for calibration of terrestrial radar. MTS-1 is designed to simulate reentry vehicle (RV) dynamics using the spacecraft (SC) Attitude Control System (ACS). The Air Force Research Laboratory (AFRL) Space Vehicles Directorate is

Jason Guarnieri; Greg Hegemann; Greg Spanjers; James Winter; Martin Tolliver; Jeff Summers; Greg Cord

2007-01-01

232

Netted radar sensing  

Microsoft Academic Search

In this paper we consider a number of aspects illustrating how networks of radar sensor systems (rather than a single monostatic radar) can offer a counter to stealth technology whilst simultaneously providing more detailed information for improved target detection, classification and location. The netted radar equation is developed, coverage, detection and location performance are quantified, and the potential utility of

A. L. Hume; C. J. Baker

2001-01-01

233

An Airborne Radar System for High-Resolution Mapping of Internal Layers P. Kanagaratnam, R. Eakin and S.P. Gogineni  

E-print Network

An Airborne Radar System for High-Resolution Mapping of Internal Layers P. Kanagaratnam, R. Eakin and S.P. Gogineni The University of Kansas, Radar Systems and Remote Sensing Laboratory 2335 Irving Hill the use of high- resolution radars for mapping of near-surface internal layers and generating continuous

Kansas, University of

234

MMW radar enhanced vision systems: the Helicopter Autonomous Landing System (HALS) and Radar-Enhanced Vision System (REVS) are rotary and fixed wing enhanced flight vision systems that enable safe flight operations in degraded visual environments  

NASA Astrophysics Data System (ADS)

Sierra Nevada Corporation (SNC) has developed rotary and fixed wing millimeter wave radar enhanced vision systems. The Helicopter Autonomous Landing System (HALS) is a rotary-wing enhanced vision system that enables multi-ship landing, takeoff, and enroute flight in Degraded Visual Environments (DVE). HALS has been successfully flight tested in a variety of scenarios, from brown-out DVE landings, to enroute flight over mountainous terrain, to wire/cable detection during low-level flight. The Radar Enhanced Vision Systems (REVS) is a fixed-wing Enhanced Flight Vision System (EFVS) undergoing prototype development testing. Both systems are based on a fast-scanning, threedimensional 94 GHz radar that produces real-time terrain and obstacle imagery. The radar imagery is fused with synthetic imagery of the surrounding terrain to form a long-range, wide field-of-view display. A symbology overlay is added to provide aircraft state information and, for HALS, approach and landing command guidance cuing. The combination of see-through imagery and symbology provides the key information a pilot needs to perform safe flight operations in DVE conditions. This paper discusses the HALS and REVS systems and technology, presents imagery, and summarizes the recent flight test results.

Cross, Jack; Schneider, John; Cariani, Pete

2013-05-01

235

The MST Radar Technique  

NASA Technical Reports Server (NTRS)

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

Roettger, J.

1984-01-01

236

Noise-induced outpulsing technique for energy efficiency improvement of laser radar systems  

NASA Astrophysics Data System (ADS)

There are stringent false alarm probability demands on laser radar systems systems, although their operation is often accompanied by a complex target environment, when the signal-to-noise ratio is low. New signal processing technique for laser radar systems is suggested. The technique provides detection of a backscattered signal from a target during an interval between a receiver noise bursts A pulse shoot is matched with a trailing edge of a noise burst, and the signal presence decision is made according to leading edge of the next burst. There is a contradiction between the impulse frequency and false alarm probability demands, that is why double-threshold processing is offered. The lower level induces outpulsing while the higher one determines target detection performance. Since duration of such sophisticated time intervals is random, statistic analysis was made via numerical model. The technique is aimed at providing low false alarm probability and energy efficiency of the system at the same time.

Serikova, Maria G.; Lebedko, Evgeny G.

2011-09-01

237

System feasibility study of a microwave/millimeter-wave radar for space debris tracking  

NASA Technical Reports Server (NTRS)

A 35 GHz millimeter-wave radar system has been studied for space debris tracking. The objective is to track the particles ranging in size from 4 mm to 80 mm up to a range of 25 km. The system requires various state-of-the-art technologies including phased arrays, monopulse tracking, pulse compression, high power transmitters, low noise receivers, and pulse integration signal processing techniques.

Chang, Kai; Pollock, Michael A.; Skrehot, Michael K.; Arndt, G. Dickey; Suddath, Jerry

1989-01-01

238

HgCdTe photomixers for CO2 laser radar systems  

NASA Technical Reports Server (NTRS)

The Santa Barbara Research Center has developed a variety of high speed HgCdTe photodetectors for use in CO2 laser radar systems. These detectors have outstanding performance and can be made available in production quantities. Many of them have been employed in a variety of systems applications over the past ten years. In this paper, we briefly describe the detector technology, summarize the state-of-the-art, and indicate some practical applications.

Bratt, Peter R.

1992-01-01

239

Ice thickness data acquired using a helicopter-borne pulse radar system  

Microsoft Academic Search

Since several years the BGR Hannover is operating a 150 MHz helicopter-borne pulse radar for measuring ice thickness up to 3000 m mostly in Antarctica. Starting with a simple designed analogue system the recently used version is a digital system operated at 150 MHz with a variable pulse width of 12, 60 and 600 ns. A high-speed A\\/D 1 GS\\/s

Volkmar Damm; Dieter Eisenburger; Martin Jenett

240

Radar systems for a polar mission, volume 3, appendices A-D, S, T  

NASA Technical Reports Server (NTRS)

Success is reported in the radar monitoring of such features of sea ice as concentration, floe size, leads and other water openings, drift, topographic features such as pressure ridges and hummocks, fractures, and a qualitative indication of age and thickness. Scatterometer measurements made north of Alaska show a good correlation with a scattering coefficient with apparent thickness as deduced from ice type analysis of stereo aerial photography. Indications are that frequencies from 9 GHz upward seem to be better for sea ice radar purposes than the information gathered at 0.4 GHz by a scatterometer. Some information indicates that 1 GHz is useful, but not as useful as higher frequencies. Either form of like-polarization can be used and it appears that cross-polarization may be more useful for thickness measurement. Resolution requirements have not been fully established, but most of the systems in use have had poorer resolution than 20 meters. The radar return from sea ice is found to be much different than that from lake ice. Methods to decrease side lobe levels of the Fresnel zone-plate processor and to decrease the memory requirements of a synthetic radar processor are discussed.

Moore, R. K.; Claassen, J. P.; Erickson, R. L.; Fong, R. K. T.; Hanson, B. C.; Komen, M. J.; Mcmillan, S. B.; Parashar, S. K.

1976-01-01

241

MICROPROCESSOR-BASED DATA-ACQUISITION SYSTEM FOR A BOREHOLE RADAR.  

USGS Publications Warehouse

An efficient microprocessor-based system is described that permits real-time acquisition, stacking, and digital recording of data generated by a borehole radar system. Although the system digitizes, stacks, and records independently of a computer, it is interfaced to a desktop computer for program control over system parameters such as sampling interval, number of samples, number of times the data are stacked prior to recording on nine-track tape, and for graphics display of the digitized data. The data can be transferred to the desktop computer during recording, or it can be played back from a tape at a latter time. Using the desktop computer, the operator observes results while recording data and generates hard-copy graphics in the field. Thus, the radar operator can immediately evaluate the quality of data being obtained, modify system parameters, study the radar logs before leaving the field, and rerun borehole logs if necessary. The system has proven to be reliable in the field and has increased productivity both in the field and in the laboratory.

Bradley, Jerry A.; Wright, David L.

1987-01-01

242

Surface roughness measuring system. [synthetic aperture radar measurements of ocean wave height and terrain peaks  

NASA Technical Reports Server (NTRS)

Significant height information of ocean waves, or peaks of rough terrain is obtained by compressing the radar signal over different widths of the available chirp or Doppler bandwidths, and cross-correlating one of these images with each of the others. Upon plotting a fixed (e.g., zero) component of the cross-correlation values as the spacing is increased over some empirically determined range, the system is calibrated. To measure height with the system, a spacing value is selected and a cross-correlation value is determined between two intensity images at a selected frequency spacing. The measured height is the slope of the cross-correlation value used. Both electronic and optical radar signal data compressors and cross-correlations are disclosed for implementation of the system.

Jain, A. (inventor)

1978-01-01

243

Effect of signal path distortions on the decoding performance in a pulse compression radar system  

NASA Astrophysics Data System (ADS)

Computer simulation studies have been conducted on the range side lobe performance of a pulse compression radar system which uses a complementary biphase-coded signal transmission. Such a coding scheme is widely used in mesosphere-stratosphere-troposphere (MST) radars expecting to achieve ideally zero range side lobes to ensure unambiguous detection of signals. However, system parameters, like overall system bandwidth, delay distortion, limiting, amplitude and phase droop within the pulse, can lead to spillover of a target return into adjacent range bins by raising the range side lobe level. The results of the study indicate that a goal of 20-dB range side lobe level can be achieved with matched filter bandwidth and reasonable levels of amplitude and phase distortions in the signal path.

Patro, Y. G. K.; Suresh Nair, K. R.; Balamuralidhar, P.

1990-10-01

244

A convenient technique for polarimetric calibration of single-antenna radar systems  

NASA Technical Reports Server (NTRS)

A practical technique for calibrating single-antenna polarimetric radar systems is introduced. This technique requires only a single calibration target such as a conducting sphere or a trihedral corner reflector to calibrate the radar system, both in amplitude and phase, for all linear polarization configurations. By using a metal sphere, which is orientation independent, error in calibration measurement is minimized while simultaneously calibrating the crosspolarization channels. The antenna system and two orthogonal channels (in free space) are modeled as a four-port passive network. Upon using the reciprocity relations for the passive network and assuming the crosscoupling terms of the antenna to be equal, the crosstalk factors of the antenna system and the transmit and receive channel imbalances can be obtained from measurement of the backscatter from a metal sphere. For an X-band radar system with crosspolarization isolation of 25 dB, comparison of values measured for a sphere and a cylinder with theoretical values shows agreement within 0.4 dB in magnitude and 5 deg in phase. An effective polarization isolation of 50 dB is achieved using this calibration technique.

Sarabandi, Kamal; Ulaby, Fawwaz T.

1990-01-01

245

Comparison of soft computing systems for the post-calibration of weather radar  

NASA Astrophysics Data System (ADS)

The most usual tools to monitor rainfall events are raingauges and weather radar. Networks of raingauges provide accurate point estimates of rainfall, when appropriately set, but their usual low density restricts considerably the spatial resolution of the gathered information. Such networks, with rain gauges at distinct points, do not reflect the spatial distribution of rainfall. The quality of raingauge observations is also susceptible to some error sources, for example wind effects around the raingauges and poor raingauge reports due to hardware problems. Radar systems offer high spatial and temporal resolution observation which is much more efficient at providing the space-time evolution of a rainfall event in comparison with raingauge networks. However the radar measurements are not free of errors due to a variety of factors including ground clutter, bright bands, anomalous propagation, beam blockages, and attenuation. The effectiveness of weather radar operation is strongly linked to rigorous calibration. Various methods have been proposed to calibrate radar data. They can be classified into two main categories: deterministic and statistical. The deterministic approach involves the calibration of radar rainfall estimations against raingauge observations. The statistical approach includes multivariate analysis and cokriging. Geostatistical approaches are known as the best methods for radar-raingauge data integration but they are usually inefficient in real time, especially when dealing with the sampling rates of one hour or less necessary for urban and small watershed applications. Such methods also rely on a strong human expertise which can lead to user-dependent results. The objectives of this research are to introduce and to investigate the feasibility of soft computing systems for the post-calibration of weather radar in comparison with the best existing method based on geostatistics. In this work, the soft computing systems include artificial neural networks and Adaptive Neuro-Fuzzy Inference System (ANFIS) and the geostatistical approach includes residual kriging. The residual kriging calibration results are satisfying however this method is based on stationary hypotheses and requires variogram modeling, making it difficult in an operational context. This method has the advantage of providing a mean squared errors map based on variogram modeling for the estimations. For the artificial neural network, thirteen variants of the multilayer feedforward networks and two variants of radial basis functions are tested in this work. The neural calibration results showed that the Levenberg-Marquardt algorithm using Bayesian regularization is robust and reliable for radar-raingauge data integration. The ANFIS offers the precision and learning capability of artificial neural networks combined with the advantages of fuzzy logic. This method based on the Jackknife approach allows the use of all the available data for training and checking the neuro-fuzzy inference system, and provides a degree of reliability of the post-calibration. The training and the interpolation results of proposed methods can be obtained within just a few seconds using an ordinary personal computer, which is incomparably faster than geostatistical approaches. The proposed algorithms would be very efficient for real time post-calibration.

Hessami Kermani, Masoud Reza

246

Radar Observations of Convective System Variability in Relationship to African Easterly Waves during the 2006 AMMA Special Observing Period  

E-print Network

A radar-based analysis of the structure, motion, and rainfall variability of westward-propagating squall-line mesoscale convective systems (SLMCSs) in Niamey, Niger, during the African Monsoon Multidisciplinary Activities ...

Williams, Earle R.

247

Improving Ground Penetrating Radar Imaging in High Loss Environments by Coordinated System Development, Data Processing, Numerical Modeling, & Visualization  

SciTech Connect

Improving Ground Penetrating Radar Imaging in High Loss Environments by Coordinated System Development, Data Processing, Numerical Modeling, and Visualization Methods with Applications to Site Characterization EMSP Project 86992 Progress Report as of 9/2004.

Wright, David L.

2004-12-01

248

Research of Amplitude - Time Characteristic of Television Signal Reflected From a Meteoric Trail in Spased Radar System  

Microsoft Academic Search

In this paper the technique of processing the television signal reflected from a meteoric trail for research of parameters of amplitude-time characteristics of signals in the spased radar system is considered.

A. N. Oleynikov; D. M. Sosnovchik

2006-01-01

249

Comparative of signal processing techniques for micro-Doppler signature extraction with automotive radar systems  

NASA Astrophysics Data System (ADS)

In recent years, the automotive industry has experienced an evolution toward more powerful driver assistance systems that provide enhanced vehicle safety. These systems typically operate in the optical and microwave regions of the electromagnetic spectrum and have demonstrated high efficiency in collision and risk avoidance. Microwave radar systems are particularly relevant due to their operational robustness under adverse weather or illumination conditions. Our objective is to study different signal processing techniques suitable for extraction of accurate micro-Doppler signatures of slow moving objects in dense urban environments. Selection of the appropriate signal processing technique is crucial for the extraction of accurate micro-Doppler signatures that will lead to better results in a radar classifier system. For this purpose, we perform simulations of typical radar detection responses in common driving situations and conduct the analysis with several signal processing algorithms, including short time Fourier Transform, continuous wavelet or Kernel based analysis methods. We take into account factors such as the relative movement between the host vehicle and the target, and the non-stationary nature of the target's movement. A comparison of results reveals that short time Fourier Transform would be the best approach for detection and tracking purposes, while the continuous wavelet would be the best suited for classification purposes.

Rodriguez-Hervas, Berta; Maile, Michael; Flores, Benjamin C.

2014-05-01

250

Embedded DSP-Based Telehealth Radar System for Remote In-Door Fall Detection.  

PubMed

Telehealth systems and applications are extensively investigated nowadays to enhance the quality-of-care and, in particular, to detect emergency situations and to monitor the well-being of elderly people, allowing them to stay at home independently as long as possible. In this paper, an embedded telehealth system for continuous, automatic, and remote monitoring of real-time fall emergencies is presented and discussed. The system, consisting of a radar sensor and base station, represents a cost-effective and efficient healthcare solution. The implementation of the fall detection data processing technique, based on the least-square support vector machines, through a digital signal processor and the management of the communication between radar sensor and base station are detailed. Experimental tests, for a total of 65 mimicked fall incidents, recorded with 16 human subjects (14 men and two women) that have been monitored for 320 min, have been used to validate the proposed system under real circumstances. The subjects' weight is between 55 and 90 kg with heights between 1.65 and 1.82 m, while their age is between 25 and 39 years. The experimental results have shown a sensitivity to detect the fall events in real time of 100% without reporting false positives. The tests have been performed in an area where the radar's operation was not limited by practical situations, namely, signal power, coverage of the antennas, and presence of obstacles between the subject and the antennas. PMID:25291803

Garripoli, Carmine; Mercuri, Marco; Karsmakers, Peter; Jack Soh, Ping; Crupi, Giovanni; Vandenbosch, Guy A E; Pace, Calogero; Leroux, Paul; Schreurs, Dominique

2015-01-01

251

A W-Band MMIC Radar System for Remote Detection of Vital Signs  

NASA Astrophysics Data System (ADS)

In medical and personal health systems for vital sign monitoring, contact-free remote detection is favourable compared to wired solutions. For example, they help to avoid severe pain, which is involved when a patient with burned skin has to be examined. Continuous wave (CW) radar systems have proven to be good candidates for this purpose. In this paper a monolithic millimetre-wave integrated circuit (MMIC) based CW radar system operating in the W-band (75-110 GHz) at 96 GHz is presented. The MMIC components are custom-built and make use of 100 nm metamorphic high electron mobility transistors (mHEMTs). The radar system is employing a frequency multiplier-by-twelve MMIC and a receiver MMIC both packaged in split-block modules. They allow for the determination of respiration and heartbeat frequency of a human target sitting in 1 m distance. The analysis of the measured data is carried out in time and frequency domain and each approach is shown to have its advantages and drawbacks.

Diebold, Sebastian; Ayhan, Serdal; Scherr, Steffen; Massler, Hermann; Tessmann, Axel; Leuther, Arnulf; Ambacher, Oliver; Zwick, Thomas; Kallfass, Ingmar

2012-12-01

252

Precision SAW filters for a large phased-array radar system  

NASA Astrophysics Data System (ADS)

The electronically steerable radar (ELRA) at the Forschungsinstitut fuer Funk und Mathematik is an experimental S-band phased-array radar system consisting of separate transmitting and receiving arrays employing several coherent and incoherent signal-processing and data-handling techniques, incorporating multiple beam and multifunction operation for target search and tracking, adaptive interference suppression, and target resolution. This paper deals with the development and application of two types of SAW filters for the IF amplifier channel of the receiving array. Compared to conventional filters with lumped elements, these filters have some important merits. By making use of a special tuning technique, the center frequencies of all filters were adjusted, resulting in an rms deviation of less than 1 kHz. One type of the SAW filters represents an almost ideal approach of realizing a matched filter for rectangular shaped pulses. The conformity of the frequency responses of several hundred filters improved the noise suppression capability of the system.

Haydl, W. H.; Sander, W.; Wirth, W.-D.

1981-05-01

253

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

254

FCC compliant 3.1-10.6 GHz UWB Pulse Radar System using Correlation Detection  

Microsoft Academic Search

A short range 3.1-10.6 GHz single band ultra-wideband (UWB) pulse radar system is presented. The transmitter consists of a pulse generator that is connected to a broadband monopole antenna. The generated pulse shape is similar to the fifth derivative of the Gaussian bell shape and makes efficient use of the allocated FCC UWB frequency mask. The receiver is realized with

J. Dederer; B. Schleicher; F. De Andrade Tabarani Santos; A. Trasser; H. Schumacher

2007-01-01

255

Antenna design of collision avoidance radar system for the smart UAV  

Microsoft Academic Search

Geometrical parameter of 1 horn, 1 parabolic, 4 Cassegrain and 1 offset-Cassegrain antennas for collision avoidance radar system in UAV are designed for the first time and then, the radiation patterns of these single-feed antennas are generated by S\\/W and compared. The sidelobes of the parabolic and the Cassegrain antennas are smaller than the others, however, the parabolic antenna is

Hyeon-Cheol Lee; In-Kyu Kim

2004-01-01

256

The EDOP radar system on the high-altitude NASA ER-2 aircraft  

USGS Publications Warehouse

The NASA ER-2 high-altitude (20 km) aircraft that emulates a satellite view of precipitation systems carries a variety of passive and active (lidar) remote sensing instruments. A new Doppler weather radar system at X band (9.6 GHz) called the ER-2 Doppler radar (EDOP) has been developed and flown on the ER-2 aircraft. EDOP is a fully coherent Doppler weather radar with fixed nadir and forward pointing (33?? off nadir) beams that map out Doppler winds and reflectivities in the vertical plane along the aircraft motion vector. Doppler winds from the two beams can be used to derive vertical and along-track air motions. In addition, the forward beam provides linear depolarization measurements that are useful in discriminating microphysical characteristics of the precipitation. This paper deals with a general description of the EDOP instrument including the measurement concept, the system configuration and hardware, and recently obtained data examples from the instrument. The combined remote sensing package on the ER-2, along with EDOP, provides a unique platform for simulating spaceborne remote sensing of precipitation.

Heymsfield, G.M.; Bidwell, S.W.; Caylor, I.J.; Ameen, S.; Nicholson, S.; Boncyk, W.; Miller, L.; Vandemark, D.; Racette, P.E.; Dod, L.R.

1996-01-01

257

Radar investigations of the solar system objects at extremely low frequencies  

NASA Astrophysics Data System (ADS)

The first discussion on the use of a radar to study the Solar System has been introduced by F. J. Keer [14], and F. G. Bass and S. Ya. Braude [3]. The research of the Sun with a radar technique became to be of particularly king interest. The next step in this trend was made in Massachusetts Institute of Technology by El Campo array [1, 2, 4], [10]--[13]. The first results with reflected signal from the Sun were obtained on El Campo array in 1961. This program was prolonged up to 1969 and the sequence of the successful events were analyzed and interpret by I. M. Gordon and N. N. Gerasimova [5]--[8].

Abranin, E. P.; Konovalenko, A. A.; Ul'Yanov, O. M.; Zackarenko, V. V.; Belov, Y. I.; Karashtin, A. N.; Komrakov, G. P.; Tokarev, Y. V.; Rodriguez, P.; van't Klooster, K.

2000-09-01

258

An x-band radar system for bathymetry and wave field analysis in a harbour area.  

PubMed

Marine X-band radar based systems are well tested to provide information about sea state and bathymetry. It is also well known that complex geometries and non-uniform bathymetries provide a much bigger challenge than offshore scenarios. In order to tackle this issue a retrieval method is proposed, based on spatial partitioning of the data and the application of the Normalized Scalar Product (NSP), which is an innovative procedure for the joint estimation of bathymetry and surface currents. The strategy is then applied to radar data acquired around a harbour entrance, and results show that the reconstructed bathymetry compares well with ground truth data obtained by an echo-sounder campaign, thus proving the reliability of the whole procedure. The spectrum thus retrieved is then analysed to show the evidence of reflected waves from the harbour jetties, as confirmed by chain of hydrodynamic models of the sea wave field. The possibility of using a land based radar to reveal sea wave reflection is entirely new and may open up new operational applications of the system. PMID:25594601

Ludeno, Giovanni; Reale, Ferdinando; Dentale, Fabio; Carratelli, Eugenio Pugliese; Natale, Antonio; Soldovieri, Francesco; Serafino, Francesco

2015-01-01

259

A digital signal processing system for coherent laser radar  

NASA Technical Reports Server (NTRS)

A data processing system for use with continuous-wave lidar is described in terms of its configuration and performance during the second survey mission of NASA'a Global Backscatter Experiment. The system is designed to estimate a complete lidar spectrum in real time, record the data from two lidars, and monitor variables related to the lidar operating environment. The PC-based system includes a transient capture board, a digital-signal processing (DSP) board, and a low-speed data-acquisition board. Both unprocessed and processed lidar spectrum data are monitored in real time, and the results are compared to those of a previous non-DSP-based system. Because the DSP-based system is digital it is slower than the surface-acoustic-wave signal processor and collects 2500 spectra/s. However, the DSP-based system provides complete data sets at two wavelengths from the continuous-wave lidars.

Hampton, Diana M.; Jones, William D.; Rothermel, Jeffry

1991-01-01

260

METR 4624--Radar Meteorology SPRING 2014  

E-print Network

METR 4624--Radar Meteorology SPRING 2014 Dr. Michael I. Biggerstaff; drdoppler@ou.edu (best method Principles of weather radar and storm observations including: radar system design, em wave propagation, radar&Q, moments of the power spectrum, ground clutter, attenuation, rainfall measurements using radar reflectivity

Droegemeier, Kelvin K.

261

METR 4624--Radar Meteorology SPRING 2012  

E-print Network

METR 4624--Radar Meteorology SPRING 2012 Dr. Michael I. Biggerstaff; drdoppler@ou.edu (best method Principles of weather radar and storm observations including: radar system design, em wave propagation, radar&Q, moments of the power spectrum, ground clutter, attenuation, rainfall measurements using radar reflectivity

Droegemeier, Kelvin K.

262

Assimilation of radar precipitation in the DMI-HIRLAM now-casting system - methodology and preliminary results  

NASA Astrophysics Data System (ADS)

Recent episodes of heavy rain and subsequent flooding in Denmark with large economical consequences have implied increased focus on very short range high quality forecasts of precipitation. The Danish Meteorological Institute (DMI) have therefore developed a now-casting system based on a dense network of surface observations combined with radar and satellite products available every 10 and 15 minutes. The rapid update cycles are initialized from a new three dimensional variational (3dvar) analysis every hour to employ the latest observations and forecasts extends 12 hours with output every 10 minutes to enable comparison with radar and satellite input. Model precipitation fields are nudged towards radar reflectivity derived precipitation by performing a dynamical adjustment of the wind field, temperature and humidity. The talk focuses on the basic methodology of including radar precipitation in the system and shows preliminary results. An accompanying poster displays more results.

Korsholm, Ulrik; Petersen, Claus

2013-04-01

263

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

NASA Technical Reports Server (NTRS)

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

Maronde, R. G.

1980-01-01

264

Enhancements to the RADAR User Location and Tracking System  

Microsoft Academic Search

We address the problem of locating users inside buildings using a radio-frequency (RF) wireless LAN. A previous paper presented the basic design and a limited evaluation of a user-location system we have developed. In this paper, we analyze shortcomings of the basic system, and develop and evaluate solutions to address these shortcomings. Additionally, we describe several new enhancements, including a

Anand Balachandran; Venkata N. Padmanabhan

2000-01-01

265

Data reduction programs for a laser radar system  

NASA Astrophysics Data System (ADS)

The listing and description of software routines which were used to analyze the analog data obtained from LIDAR - system are given. All routines are written in FORTRAN - IV on a HP - 1000/F minicomputer which serves as the heart of the data acquisition system for the LIDAR program. This particular system has 128 kilobytes of highspeed memory and is equipped with a Vector Instruction Set (VIS) firmware package, which is used in all the routines, to handle quick execution of different long loops. The system handles floating point arithmetic in hardware in order to enhance the speed of execution. This computer is a 2177 C/F series version of HP - 1000 RTE-IVB data acquisition computer system which is designed for real time data capture/analysis and disk/tape mass storage environment.

Badavi, F. F.; Copeland, G. E.

1984-01-01

266

Advanced system model for 1574-nm imaging, scannerless, eye-safe laser radar  

NASA Astrophysics Data System (ADS)

Laser radar based on gated viewing uses narrow laser pulses to illuminate a whole scene for direct (incoherent) detection. Due to the time of flight principle and a very fast shutter with precisely controlled delay time, only light reflected in the range R (range slice ?R) is detected by a camera. Scattered light which reaches the shutter outside a given exposure time (gate) is suppressed. Hence, it is possible to "look" along the optical axis through changing atmospheric transmissions (rain, haze, fog, snow). For each laser pulse, the grey value image ES(x,y) of the camera is captured by a framegrabber for subsequent evaluation. Image sequences from these laser radar systems are ideally suited to recognize objects, because of the automatic contrast generation of the technology. Difficult object recognition problems, detection, target tracking, or obstacle avoidance at bad weather conditions are favorite applications. In this paper we discuss improvements in the system modelling and simulation of our laser radar system. Formerly the system performance was calculated for the whole system using the signal-to-noise ratio (SNR), leading to a general estimation of the maximum range of target detection. Changing to a pixel oriented approach, we are now able to study the system response for targets with arbitrary two and even three dimensional form. We take into account different kinds of target reflectivity and the Gaussian nature of the illuminating laser spot. Hence it is possible to simulate gray value images (range slices) and calculate range images. This will lead to a modulation transfer function for the system in future. Finally, the theoretical considerations are compared with experimental results from indoor measurements.

Schael, Ulrich; Rothe, Hendrik

2002-10-01

267

Scanning Laser Radar Development for Solar System Exploration Applications  

NASA Technical Reports Server (NTRS)

The Jet Propulsion Laboratory (JPL) has recently established an accelerated development initiative to enable high-resolution active optical ranging and terrain mapping capabilities for a series of upcoming Solar System exploration missions.

Tratt, D.; Menzies, R.; Bartman, R.; Hemmati, H.

2000-01-01

268

TerraSAR-X active radar ground calibrator system  

Microsoft Academic Search

In April 2006, the TerraSAR-X satellite was launched. This paper describes the development of a novel and highly integrated, digitally-controlled active SAR system calibrator (DARC). It consists of both an active transponder path for absolute radiometric calibration and a calibrated receiver chain for antenna pattern evaluation of the satellite antenna. A total of 16 active transponder and receiver systems and

R. Lenz; K. Schuler; M. Younis; W. Wiesbeck

2006-01-01

269

REVIEW ARTICLE Interferometric Synthetic Aperture Radar  

E-print Network

REVIEW ARTICLE Interferometric Synthetic Aperture Radar Christopher T. Allen Department of Electrical Engineering and Computer Science and Radar Systems and Remote Sensing Laboratory University of Kansas Abstract. This paper provides a brief review of interferometric synthetic aperture radar (In

Kansas, University of

270

The Ganged Phased Array Radar Risk Mitigation System: Atmospheric Sciences Applications  

NASA Astrophysics Data System (ADS)

Technology advances have resulted in rapid developments in unmanned aircraft systems. The widespread utilization of those systems, however, is limited by the diminished capability of these systems to "sense and avoid" other aircraft in uncontrolled air space. As a means for providing this capability, researchers at the UND John D. Odegard School of Aerospace Sciences are developing a Ganged Phased Array Radar Risk Mitigation System (GPARS-RMS), the purpose of which is to provide information that enables aircraft (manned and unmanned) deconfliction. As part of the development of such a system, potential atmospheric sciences applications are being explored. Such applications will be able to potentially take advantage of not only remotely-sensed radar data streams from the GPARS-RMS, but also in situ tropospheric data collected on-board the unmanned aircraft. Possible applications include studies of boundary-layer flow structures, local- and meso-scale moisture balances, surface fluxes, cloud and precipitation microphysics, local scale plume dispersion, and the utility of four-dimensional assimilation of such very high resolution data for improvements in short-term (1-6 hour) local- and meso-scale numerical weather prediction. As part of the development of the GPARS-RMS, a system simulation environment is being developed. The utilization of weather information in this system will be described, as will initial tests of the applications of data from such a system in multiple-Doppler and data assimilation experiments.

Askelson, M. A.; Tilley, J. S.; Theisen, C. J.; Theisen, A. K.

2008-05-01

271

Standoff concealed weapon detection using a 350-GHz radar imaging system  

NASA Astrophysics Data System (ADS)

The sub-millimeter (sub-mm) wave frequency band from 300 - 1000 GHz is currently being developed for standoff concealed weapon detection imaging applications. This frequency band is of interest due to the unique combination of high resolution and clothing penetration. The Pacific Northwest National Laboratory (PNNL) is currently developing a 350 GHz, active, wideband, three-dimensional, radar imaging system to evaluate the feasibility of active sub-mm imaging for standoff detection. Standoff concealed weapon and explosive detection is a pressing national and international need for both civilian and military security, as it may allow screening at safer distances than portal screening techniques. PNNL has developed a prototype active wideband 350 GHz radar imaging system based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed rotating conical scanner. This prototype system operates at ranges up to 10+ meters, and can acquire an image in 10 - 20 seconds, which is fast enough to scan cooperative personnel for concealed weapons. The wideband operation of this system provides accurate ranging information, and the images obtained are fully three-dimensional. During the past year, several improvements to the system have been designed and implemented, including increased imaging speed using improved balancing techniques, wider bandwidth, and improved image processing techniques. In this paper, the imaging system is described in detail and numerous imaging results are presented.

Sheen, David M.; Hall, Thomas E.; Severtsen, Ronald H.; McMakin, Douglas L.; Hatchell, Brian K.; Valdez, Patrick L. J.

2010-04-01

272

A millimetre-wave MIMO radar system for threat detection in urban environments  

NASA Astrophysics Data System (ADS)

The European Defence Agency (EDA) engages countermeasures against Improvised Explosive Devices (IEDs) by funding several scientific programs on threat awareness, countermeasures IEDs or land-mine detection, in which this work is only one of numerous projects. The program, denoted as Surveillance in an urban environment using mobile sensors (SUM), covers the idea of equipping one or more vehicles of a patrol or a convoy with a set of sensors exploiting different physical principles in order to gain detailed insights of the road situation ahead. In order to give an added value to a conventional visual camera system, measurement data from an infra-red (IR) camera, a radiometer and a millimetre-wave radar are fused with data from an optical image and are displayed on a human-machine-interface (HMI) which shall assist the vehicle's co-driver to identify suspect objects or persons on or next to the road without forcing the vehicle to stop its cruise. This paper shall especially cover the role of the millimetre-wave radar sensor and its different operational modes. Measurement results are discussed. It is possible to alter the antenna mechanically which gives two choices for a field of view and angular resolution trade-off. Furthermore a synthetic aperture radar mode is possible and has been tested successfully. MIMO radar principles like orthogonal signal design were exploited tofrom a virtual array by 4 transmitters and 4 receivers. In joint evaluation, it was possible to detect e.g. grenade shells under cardboard boxes or covered metal barrels which were invisible for optical or infra-red detection.

Kirschner, A. J.; Guetlein, J.; Bertl, S.; Detlefsen, J.

2012-10-01

273

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

274

The NASA Dual-Frequency Dual-Polarized Doppler Radar (D3R) System For GPM Ground Validation  

NASA Astrophysics Data System (ADS)

Following on the successful introduction of single-frequency (Ku-Band) weather radar onboard the Tropical Rain Measuring Mission (TRMM) satellite in 1997, the Global Precipitation Measurement (GPM) mission attempts to advance further the goal of making global scale precipitation observations by deploying the next generation of satellite-borne weather radars. The GPM satellite will carry a Ka-Ku band Dual-frequency Precipitation Radar (DPR) that can make measurements of parameters directly related to the microphysics of precipitation (such as raindrop size distribution). The Dual-Frequency Dual-Polarized Doppler Radar (D3R) is a ground validation radar, as a part of the GPM Ground Validation (GV) program, to enable both physical validation support in terms of understanding the microphysical description of the observations as well as algorithm retrieval implications. This paper provides a scientific and technical overview of the D3R system as well as major challenges. The preferred frequency bands of operation for precipitation surveillance in ground radar systems have been nearly non-attenuating frequencies (such as S-, C-band) or short-range measurements of attenuating frequencies (as in X band). However, it is not practical to use traditional ground radar frequencies for precipitation observations in space-borne radars. The GPM mission has embarked on a dual-frequency approach at Ku- and Ka-band for characterizing precipitation. Moving to higher frequencies to observe precipitation though has its own challenges namely, attenuation due to precipitation and reduced Doppler velocity Nyquist limits. Ground radar measurements enjoy the advantage of coincident microphysical observations available to interpret radar signatures but they are currently unavailable at Ku- and Ka-band. An important broader science goal of the NASA D3R is to enhance the database of dual-frequency radar observations on the ground, in conjunction with existing observations, in order to provide a dataset for physical validation basis. Another major advantage of the ground radar observations is the ability to use dual-polarization techniques to yield enhanced microphysical characterization similar to what has been done at lower frequencies. In addition, self-consistency of dual-polarization and dual-frequency observations presents an enhanced level of interpretation, while also providing independent rainfall estimates on the ground. With the ground-based D3R, an independent estimation of hydrometeor classification and drop size distribution retrievals can be done to understand the error structure of retrievals. The dual-frequency ground-based radar provides for various options, including polarimetry and Doppler capabilities. Hence, the name D3R or Dual-frequency Dual-polarized Doppler Radar. Another important engineering aspect of a dual-frequency system is the level of "integration". This can range from a design where two separate radar units operate independently to the one that employs a common reference system for dual-transmitters on a single dual-frequency aperture. The first generation version of the D3R falls somewhere in the middle, i.e., a common platform transmitter illuminating two distinct but aligned antennas. Most of the engineering challenges stem from making precipitation measurements on the ground at a highly attenuating frequency. In order to support the development, extensive numerical evaluations have been carried out to document the extinction statistics of propagation through precipitation. One of the novel aspects of this system is that it employs a solid-state transceiver which supports the deployment in different climactic locations. Thirdly, the dual-frequency dual-polarization operation at higher frequencies involves non-Rayleigh scattering mechanisms and presents different precipitation signatures compared to the conventional S- or C- band observations. The expected observations for this radar based on such scattering and precipitation models are also presented in this paper.

Chandrasekar, V.; Schwaller, Mathew; Vega, Manuel; Carswell, James; Vijay Mishra, Kumar; Nguyen, Cuong; Meneghini, Robert; Peterson, Walt

2010-05-01

275

Assimilation of radar precipitation in the DMI-HIRLAM now-casting system - initial results  

NASA Astrophysics Data System (ADS)

The pre-operational DMI now-casting system provides rapid update cycles with new forecasts every hour. Each forecast is initialized by three-dimensional variational and surface assimilation while radar precipitation and satellite derived cloud cover and cloud-top height are nudged every 10 and 15 minutes. For non-precipitating clouds nudging of temperature, humidity and cloud condensate are performed while for precipitating clouds nudging of precipitation is also included in the first two hours of each forecast. Precipitation nudging is based on a dynamical adjustment scheme of the wind field. The poster displays the general methodology and shows new results from system output.

Korsholm, Ulrik; Petersen, Claus

2013-04-01

276

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

277

Technology of polarization diversity radars for meteorology  

Microsoft Academic Search

Polarimetric techniques and their application to radar meteorology are reviewed. Four state-of-the-art radar systems are described and other dual-polarized radars and their measurement capabilities are also presented. A discussion of radar system considerations is provided. In the review of dual-polarized meteorological radar installations it was found that 21 such radars were currently or recently active, covering the frequency range 3-35

V. N. Bringi; A. Hendry

1990-01-01

278

Through-the-wall localization of a moving target by two independent ultra wideband (UWB) radar systems.  

PubMed

In the case of through-the-wall localization of moving targets by ultra wideband (UWB) radars, there are applications in which handheld sensors equipped only with one transmitting and two receiving antennas are applied. Sometimes, the radar using such a small antenna array is not able to localize the target with the required accuracy. With a view to improve through-the-wall target localization, cooperative positioning based on a fusion of data retrieved from two independent radar systems can be used. In this paper, the novel method of the cooperative localization referred to as joining intersections of the ellipses is introduced. This method is based on a geometrical interpretation of target localization where the target position is estimated using a properly created cluster of the ellipse intersections representing potential positions of the target. The performance of the proposed method is compared with the direct calculation method and two alternative methods of cooperative localization using data obtained by measurements with the M-sequence UWB radars. The direct calculation method is applied for the target localization by particular radar systems. As alternative methods of cooperative localization, the arithmetic average of the target coordinates estimated by two single independent UWB radars and the Taylor series method is considered. PMID:24021968

Kocur, Dušan; Svecová, Mária; Rov?áková, Jana

2013-01-01

279

Through-the-Wall Localization of a Moving Target by Two Independent Ultra Wideband (UWB) Radar Systems  

PubMed Central

In the case of through-the-wall localization of moving targets by ultra wideband (UWB) radars, there are applications in which handheld sensors equipped only with one transmitting and two receiving antennas are applied. Sometimes, the radar using such a small antenna array is not able to localize the target with the required accuracy. With a view to improve through-the-wall target localization, cooperative positioning based on a fusion of data retrieved from two independent radar systems can be used. In this paper, the novel method of the cooperative localization referred to as joining intersections of the ellipses is introduced. This method is based on a geometrical interpretation of target localization where the target position is estimated using a properly created cluster of the ellipse intersections representing potential positions of the target. The performance of the proposed method is compared with the direct calculation method and two alternative methods of cooperative localization using data obtained by measurements with the M-sequence UWB radars. The direct calculation method is applied for the target localization by particular radar systems. As alternative methods of cooperative localization, the arithmetic average of the target coordinates estimated by two single independent UWB radars and the Taylor series method is considered. PMID:24021968

Kocur, Dušan; Švecová, Mária; Rov?áková, Jana

2013-01-01

280

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

281

Radar in transition  

NASA Astrophysics Data System (ADS)

It is pointed out that radar engineers, at the end of 1984, find their field in transition between the conventional designs of the post War II era and the digitally controlled, solid-state systems which will be in place for the year 2000. The U.S. Navy has two major phased array radar systems in operation, including the rotating three-dimensional (3D) AN/SPS-48, and the phased-scanned AN/SPY-1 (Aegis) radars. The Aegis represents a major step beyond the conventional 3D and mechanical fire-control radars. However, it requires a special ship, dedicated to its use. Attention is given to questions regarding an extension of the application of Aegis technology to other U.S. Navy applications and to other navies, an ambitious solid-state radar program in the UK, and Army radars.

Barton, D. K.

1984-12-01

282

Phase correction system for automatic focusing of synthetic aperture radar  

DOEpatents

A phase gradient autofocus system for use in synthetic aperture imaging accurately compensates for arbitrary phase errors in each imaged frame by locating highlighted areas and determining the phase disturbance or image spread associated with each of these highlight areas. An estimate of the image spread for each highlighted area in a line in the case of one dimensional processing or in a sector, in the case of two-dimensional processing, is determined. The phase error is determined using phase gradient processing. The phase error is then removed from the uncorrected image and the process is iteratively performed to substantially eliminate phase errors which can degrade the image.

Eichel, Paul H. (Albuquerque, NM); Ghiglia, Dennis C. (Placitas, NM); Jakowatz, Jr., Charles V. (Albuquerque, NM)

1990-01-01

283

Mesovortex Circulations Seen by Airborne Doppler Radar within a Bow-Echo Mesoscale Convective System.  

NASA Astrophysics Data System (ADS)

During the spring of 1991, scientists from the National Severe Storms Laboratory conducted a field observational program to obtain a better understanding of the processes responsible for organizing and maintaining the dynamical and electrical structure of mesoscale convective systems (MCSs), as well as mechanisms acting to organize and propagate the dryline. Extensive use was made of a relatively new observing tool, the airborne Doppler radar installed on one of the NOAA P-3 research aircraft, to map the precipitation and kinematic structure of large convective systems. The radar was operated in an innovative scanning mode in order to collect pseudo dual-Doppler wind data from a straightline flight path. This scanning method, termed the fore/aft scanning technique (FAST), effectively maps out the three-dimensional wind field over mesoscale domains (e.g., 80 km× 100 km) in 15 min with horizontal data spacing of 1-2 km. Several MCSs were observed over central Oklahoma during May and June of 1991, and one such system exhibiting a "bow-echo" structure is described. Many observed features of this MCS correspond to structures seen in nonhydrostatic numerical simulations. These features include a pronounced bulge or "bow" in the convective line (convex toward the storm's direction of propagation), a strong descending rearinflow jet whose axis is aligned with the apex of the bow, and a cyclonic vortex (most pronounced at heights of 2-3 km) situated in the trailing stratiform region lateral to the axis of strongest rear inflow. Doppler-derived wind analyses reveal the likely role played by the mesoscale circulation in twisting environmental vertical shear and converging ambient vertical vorticity in maintaining and amplifying the vortex. The relatively detailed yet horizontally extensive airflow analyses also reveal the utility and advantages of airborne Doppler radar in the study of large convective systems.

Jorgensen, David P.; Smull, Bradley F.

1993-11-01

284

In-flight detection of errors for enhanced aircraft flight safety and vertical accuracy improvement using digital terrain elevation data with an inertial navigation system, global positioning system and radar altimeter  

Microsoft Academic Search

This dissertation discusses integration architectures using digital terrain elevation data (DTED) with an inertial navigation system (INS), a global positioning system (GPS) and a radar altimeter. Two integration architectures are considered: DTED with INS, GPS and radar altimeter for aircraft vertical accuracy improvement during the final approach; and DTED with kinematic GPS (KGPS) and a radar altimeter for enhanced aircraft

Robert Anthony Gray

1999-01-01

285

Surface current patterns in the Ibiza Channel with the use of High Frequency (HF) Radar system  

NASA Astrophysics Data System (ADS)

The Ibiza Channel located between the East Coast of the Iberian Peninsula, and the West Coast of Ibiza, at the Balearic Islands, is a well-known biodiversity hot spot. This area is relevant due to the interaction of water masses coming from the Atlantic Ocean - ascending through the Iberian Peninsula coast - with the older Atlantic waters descending from the Gulf of Lion. In 2012, the installation of Coastal HF Radar in the area provides valuable information for the study of the surface transport along the channel. The Coastal HF Radar operates since June 2012, and provides hourly surface current maps with a spatial resolution of approximately 3 km and a range reaching up to 70 km offshore. The instrument forms part of a monitoring multi-platform system, which is completed with satellite-derived data, gliders, modelling and fixed and lagrangian buoys. All HF Radar data are processed with standard quality control methods. Drifter velocity obtained from lagrangian buoys for two oceanographic campaigns, satellite-derived data and currentmeter data from a fixed buoy in the Ibiza Channel are used to validate the HF Radar data. All surface current data are used to perform a spectrum analysis in order to show the physical processes, at the main temporal periods. The contribution of the different temporal scales to the total Kinetic Energy has been analysed for the first time at different seasonal intervals. This served to evaluate the energetic importance of the different components of the surface currents. The inertial currents have a lower contribution to the total KE during winter, compared with the summer period. Besides, the spatial distribution of the inertial component to the total KE varies seasonally, and according to the bathymetry of the area. The low-pass (sub-inertial) filtered HF Radar currents show a predominant northern current during the summer months in the channel, and a mean southern current during the winter period. These results are discussed and related with the external forcing, and bathymetry distribution, according to coastal or open ocean data.

Lana, Arancha; Fernández, Vicente; Troupin, Charles; Pascual, Ananda; Orfila, Alejandro; Tintoré, Joaquín

2014-05-01

286

1999 IEEE radar conference  

SciTech Connect

This conference addresses the stringent radar technology demands facing the next century: target detection, tracking and identification; changing target environment; increased clutter mitigation techniques; air traffic control; transportation; drug smuggling; remote sensing, and other consumer oriented applications. A timely discussion covers how to minimize costs for these emerging areas. Advanced radar technology theory and applications are also presented. Topics covered include: signal processing; space time adaptive processing/antennas; surveillance technology; radar systems; dual use; and phenomenology.

NONE

1999-07-01

287

Radars for the eighties  

Microsoft Academic Search

The Modular Survivable Radar (MSR), proposed by the General Electric Company as the solution to the USAF's airborne attack radar requirements, is a flexible system with ECCM and low probability of intercept (LPI) protection capabilities. The system is built with standard modular line replaceable units (LRU) and is adaptable to a wide range of performance requirements. The structure of the

M. Shohat

1979-01-01

288

Digital Terrestrial Video Broadcast Interference Suppression in Forward-Looking Ground Penetrating Radar Systems  

NASA Astrophysics Data System (ADS)

In this paper we show how radio frequency interference (RFI) generated by digital video broadcasting terrestrial and digital audio broadcasting transmitters can be an important noise source for forward-looking ground penetrating radar (FLGPR) systems. Even in remote locations the average interference power sometimes exceeds ultra-wideband signals by many dB, becoming the limiting factor in the system sensitivity. The overall problem of RFI and its impact in GPR systems is briefly described and several signal processing approaches to removal of RFI are discussed. These include spectral estimation and coherent subtraction algorithms and various filter approaches which have been developed and applied by the research community in similar contexts. We evaluate the performance of these methods by simulating two different scenarios submitted to real RFI acquired with a FLGPR system developed at the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR), (GER). The effectiveness of these algorithms in removing RFI is presented using some performance indices after suppression.

Rial, F. I.; Mendez-Rial, Roi; Lawadka, Lukasz; Gonzalez-Huici, Maria A.

2014-11-01

289

Aeronomy report no. 74: The Urbana meteor-radar system; design, development, and first observations  

NASA Technical Reports Server (NTRS)

The design, development, and first observations of a high power meteor-radar system located near Urbana, Illinois are described. The roughly five-fold increase in usable echo rate compared to other facilities, along with automated digital data processing and interferometry measurement of echo arrival angles, permits unsurpassed observations of tidal structure and shorter period waves. Such observations are discussed. The technique of using echo decay rates to infer density and scale height and the method of inferring wind shear from radial acceleration are examined. An original experiment to test a theory of the Delta-region winter anomaly is presented.

Hess, G. C.; Geller, M. A.

1976-01-01

290

Instantaneous Radar Polarimetry with Multiple Dually-polarized Antennas  

Microsoft Academic Search

Fully polarimetric radar systems are capable of simultaneously transmitting and receiving in two orthogonal polarizations. Instantaneous radar polarimetry exploits both polarization modes of a dually-polarized radar transmitter and receiver on a pulse by pulse basis, and can improve the radar detection performance and suppress range sidelobes . In this paper, we extend the use of instantaneous radar polarimetry for radar

A. R. Calderbank; S. D. Howard; W. Moran; A. Pezeshki; M. Zoltowski

2006-01-01

291

Measuring the wavefront distortion of a phased-array laser radar by using a real-time optoelectronic measurement system  

NASA Astrophysics Data System (ADS)

A real-time optoelectronic measurement system is proposed to measure the wavefront distortions of scanning beams of a phased-array laser radar. This measurement system includes electric control rotating and translating platforms and a cyclic radial shearing interferometer(CRSI). CRSI is an effective interferometry to mesure the laser wavefront. A inversion algorithm is used to precisely reconstruct wavefront phase distribution from interferograms generated by the CRSI. An actual experiment of laser wavefront distortion measurement is implemented successfully. The experimental results show that this optoelectromic measurement system can measure laser wavefront distortion of a phased-array laser radar in accuracy and in real time.

Zheng, Chunyan; Wu, Jian

2009-11-01

292

HERMES: a high-speed radar imaging system for inspection of bridge decks  

SciTech Connect

Corrosion of rebar in concrete bridges causes subsurface cracks and is a major cause of structural degradation that necessitates repair or replacement. Early detection of corrosion effects can limit the location and extent of necessary repairs, while providing long-term information about the infrastructure status. Most current detection methods, however, are destructive of the road surface and require closing or restricting traffic while the tests are performed. A ground-penetrating radar imaging system has been designed and developed that will perform the nondestructive evaluation of road-bed cracking at traffic speeds; i.e., without the need to restrict traffic flow. The first-generation system (called the HERMES bridge inspector), consists of an offset-linear array of 64 impulse radar transceivers and associated electronics housed in a trailer. Computers in the trailer and in the towing vehicle control the data acquisition, processing, and display. Cross-road resolution is three centimeters at up to 30 cm in depth, while down-road resolution depends on speed; 3 cm below 20 mph up to 8 cm at 50 mph. A two-meter- wide path is inspected on each pass over the roadway. This paper, describes the design of this system, shows preliminary results, and lays out its deployment schedule.

Azevedo, S.G.

1996-10-26

293

The application of digital signal processing techniques to a teleoperator radar system  

NASA Technical Reports Server (NTRS)

A digital signal processing system was studied for the determination of the spectral frequency distribution of echo signals from a teleoperator radar system. The system consisted of a sample and hold circuit, an analog to digital converter, a digital filter, and a Fast Fourier Transform. The system is interfaced to a 16 bit microprocessor. The microprocessor is programmed to control the complete digital signal processing. The digital filtering and Fast Fourier Transform functions are implemented by a S2815 digital filter/utility peripheral chip and a S2814A Fast Fourier Transform chip. The S2815 initially simulates a low-pass Butterworth filter with later expansion to complete filter circuit (bandpass and highpass) synthesizing.

Pujol, A.

1982-01-01

294

Trilateration-based localization algorithm for ADS-B radar systems  

NASA Astrophysics Data System (ADS)

Rapidly increasing growth and demand in various unmanned aerial vehicles (UAV) have pushed governmental regulation development and numerous technology research advances toward integrating unmanned and manned aircraft into the same civil airspace. Safety of other airspace users is the primary concern; thus, with the introduction of UAV into the National Airspace System (NAS), a key issue to overcome is the risk of a collision with manned aircraft. The challenge of UAV integration is global. As automatic dependent surveillance-broadcast (ADS-B) system has gained wide acceptance, additional exploitations of the radioed satellite-based information are topics of current interest. One such opportunity includes the augmentation of the communication ADS-B signal with a random bi-phase modulation for concurrent use as a radar signal for detecting other aircraft in the vicinity. This dissertation provides detailed discussion about the ADS-B radar system, as well as the formulation and analysis of a suitable non-cooperative multi-target tracking method for the ADS-B radar system using radar ranging techniques and particle filter algorithms. In order to deal with specific challenges faced by the ADS-B radar system, several estimation algorithms are studied. Trilateration-based localization algorithms are proposed due to their easy implementation and their ability to work with coherent signal sources. The centroid of three most closely spaced intersections of constant-range loci is conventionally used as trilateration estimate without rigorous justification. In this dissertation, we address the quality of trilateration intersections through range scaling factors. A number of well-known triangle centers, including centroid, incenter, Lemoine point (LP), and Fermat point (FP), are discussed in detail. To the author's best knowledge, LP was never associated with trilateration techniques. According our study, LP is proposed as the best trilateration estimator thanks to the desirable property that the total distance to three triangle edges is minimized. It is demonstrated through simulation that LP outperforms centroid localization without additional computational load. In addition, severe trilateration scenarios such as two-intersection cases are considered in this dissertation, and enhanced trilateration algorithms are proposed. Particle filter (PF) is also discussed in this dissertation, and a simplified resampling mechanism is proposed. In addition, the low-update-rate measurement due to the ADS-B system specification is addressed in order to provide acceptable estimation results. Supplementary particle filter (SPF) is proposed to takes advantage of the waiting time before the next measurement is available and improves the estimation convergence rate and estimation accuracy. While PF suffers from sample impoverishment, especially when the number of particles is not sufficiently large, SPF allows the particles to redistribute to high likelihood areas over iterations using the same measurement information, thereby improving the estimation performance.

Huang, Ming-Shih

295

On the combined use of radar systems for multi-scale imaging of transport infrastructures  

NASA Astrophysics Data System (ADS)

Ground Penetrating Radar (GPR) systems are worth to be considered as in situ non invasive diagnostic tools capable of assessing stability and integrity of transport infrastructures. As a matter of fact, by exploiting the interactions among probing electromagnetic waves and hidden objects, they provide images of the inner status of the spatial region under test from which infer risk factors, such as deformations and oxidization of the reinforcement bars as well as water infiltrations, crack and air gaps. With respect to the assessment of concrete infrastructures integrity, the reconstruction capabilities of GPR systems have been widely investigated [1,2]. However, the demand for diagnostic tools capable of providing detailed and real time information motivates the design and the performance evaluation of novel technologies and data processing methodologies aimed not only to effectively detect hidden anomalies but also to estimate their geometrical features. In this framework, this communication aims at investigating the advantages offered by the joint use of two GPR systems both of them equipped with a specific tomographic imaging approach. The first considered system is a time domain GPR equipped with a 1.5GHz shielded antenna, which is suitable for quick and good resolution surveys of the shallower layers of the structure. As second system, the holographic radar Rascan-4/4000 [3,4] is taken into account, due to its capability of providing holograms of hidden targets from the amplitude of the interference signal arising between the backscattered field and a reference signal. The imaging capabilities of both the GPR tools are enhanced by means of model based data processing approaches, which afford the imaging as a linear inverse scattering problem. Mathematical details on the inversion strategies will be provided at the conference. The combined use of the above GPR systems allows to perform multi-resolution surveys of the region under test, whose aim is, first of all, to detect hidden anomalies and then to provide a high resolution image of their geometrical features. Therefore, reliable and efficient diagnostic surveys devoted to state the healthy state of a structure can be scheduled. Numerical examples and on field validations assessing the achievable reconstruction capabilities will be provided at the conference. [1] D. J. Daniels, Ground Penetrating Radar, in IEE Radar, Sonar and Navigation Series 15, London, U.K.: IEE, 2004. [2] M. Proto, M. Bavusi, R. Bernini et al., Transport Infrastructure Surveillance and Monitoring by Electromagnetic Sensing: The ISTIMES Project, Sensors, vol.10, n.12, pp.10620-10639, 2010. [3] S. Ivashov, I. A. Vasiliev, T. D. Bechtel, C. Snapp, Comparison between impulse and holographic subsurface radar for NDT of space vehicle structural materials, Progress In Electromagnetic Research, vol.3, pp.658-661, 2004. [4] I. Catapano. L. Crocco, A. F. Morabito, F. Soldovieri, Tomographic imaging of holographic GPR data for non-invasive structural assessment: the Musmeci Bridge investigation, submitted to Nondestructive Testing and Evaluation Acknowledgement The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement no 225663.

Catapano, I.; Bavusi, M.; Loperte, A.; Crocco, L.; Soldovieri, F.

2012-04-01

296

Shuttle synthetic aperture radar implementation study, volume 1. [flight instrument and ground data processor system for collecting raw imaged radar data  

NASA Technical Reports Server (NTRS)

Results of an implementation study for a synthetic aperture radar for the space shuttle orbiter are described. The overall effort was directed toward the determination of the feasibility and usefulness of a multifrequency, multipolarization imaging radar for the shuttle orbiter. The radar is intended for earth resource monitoring as well as oceanographic and marine studies.

Mehlis, J. G.

1976-01-01

297

REVS: a radar-based enhanced vision system for degraded visual environments  

NASA Astrophysics Data System (ADS)

Sierra Nevada Corporation (SNC) has developed an enhanced vision system utilizing fast-scanning 94 GHz radar technology to provide three-dimensional measurements of an aircraft's forward external scene topography. This threedimensional data is rendered as terrain imagery, from the pilot's perspective, on a Head-Up Display (HUD). The image provides the requisite "enhanced vision" to continue a safe approach along the flight path below the Decision Height (DH) in Instrument Meteorological Conditions (IMC) that would otherwise be cause for a missed approach. Terrain imagery is optionally fused with digital elevation model (DEM) data of terrain outside the radar field of view, giving the pilot additional situational awareness. Flight tests conducted in 2013 show that REVS™ has sufficient resolution and sensitivity performance to allow identification of requisite visual references well above decision height in dense fog. This paper provides an overview of the Enhanced Flight Vision System (EFVS) concept, of the technology underlying REVS, and a detailed discussion of the flight test results.

Brailovsky, Alexander; Bode, Justin; Cariani, Pete; Cross, Jack; Gleason, Josh; Khodos, Victor; Macias, Gary; Merrill, Rahn; Randall, Chuck; Rudy, Dean

2014-06-01

298

Two-dimensional imaging via a narrowband MIMO radar system with two perpendicular linear arrays.  

PubMed

This paper presents a system model and method for the 2-D imaging application via a narrowband multiple-input multiple-output (MIMO) radar system with two perpendicular linear arrays. Furthermore, the imaging formulation for our method is developed through a Fourier integral processing, and the parameters of antenna array including the cross-range resolution, required size, and sampling interval are also examined. Different from the spatial sequential procedure sampling the scattered echoes during multiple snapshot illuminations in inverse synthetic aperture radar (ISAR) imaging, the proposed method utilizes a spatial parallel procedure to sample the scattered echoes during a single snapshot illumination. Consequently, the complex motion compensation in ISAR imaging can be avoided. Moreover, in our array configuration, multiple narrowband spectrum-shared waveforms coded with orthogonal polyphase sequences are employed. The mainlobes of the compressed echoes from the different filter band could be located in the same range bin, and thus, the range alignment in classical ISAR imaging is not necessary. Numerical simulations based on synthetic data are provided for testing our proposed method. PMID:20040416

Wang, Dang-wei; Ma, Xiao-yan; Su, Yi

2010-05-01

299

An X-band balanced optical hybrid mixer for ?-wave optical interconnect in active phased array radar and communication systems  

Microsoft Academic Search

In the following paper an X-band hybrid electro optical mixer for a photonic microwave receiver is described. The application of balanced hybrid mixer in phased array radar, communication system and ESM receivers will reduce overall loss and hence the cumulative noise figure of the system and thus enhance the spurious free dynamic range of the receiver

S. K. Banejee; U. Goebel; P. Niichter

2000-01-01

300

The potential of bistatic HF surface wave radar system for the surveillance of water-entry area along coastline  

Microsoft Academic Search

A bistatic\\/monostatic HF surface wave radar (HFSWR) experiment was conducted using both the transmit and receive systems of the HFSWR at Cape Race, Newfoundland and the receive system of the HFSWR at Cape Bonavista, Newfoundland. While the HFSWR at Cape Race operated in the monostatic mode, the transmitter at Cape Race and the receiver at Cape Bonavista were synchronized via

H. Leong

2006-01-01

301

A System Concept for the Advanced Post-TRMM Rainfall Profiling Radars  

NASA Technical Reports Server (NTRS)

Atmospheric latent heating field is fundamental to all modes of atmospheric circulation and upper mixed layer circulations of the ocean. The key to understanding the atmospheric heating process is understanding how and where precipitation occurs. The principal atmospheric processes which link precipitation to atmospheric circulation include: (1) convective mass fluxes in the form of updrafts and downdrafts; (2) microphysical. nucleation and growth of hydrometeors; and (3) latent heating through dynamical controls on the gravitation-driven vertical mass flux of precipitation. It is well-known that surface and near-surface rainfall are two of the key forcing functions on a number of geophysical parameters at the surface-air interface. Over ocean, rainfall variation contributes to the redistribution of water salinity, sea surface temperature, fresh water supply, and marine biology and eco-system. Over land, rainfall plays a significant role in rainforest ecology and chemistry, land hydrology and surface runoff. Precipitation has also been closely linked to a number of atmospheric anomalies and natural hazards that occur at various time scales, including hurricanes, cyclones, tropical depressions, flash floods, droughts, and most noticeable of all, the El Ninos. From this point of view, the significance of global atmospheric precipitation has gone far beyond the science arena - it has a far-reaching impact on human's socio-economic well-being and sustenance. These and many other science applications require the knowledge of, in a global basis, the vertical rain structures, including vertical motion, rain intensity, differentiation of the precipitating hydrometeors' phase state, and the classification of mesoscale physical structure of the rain systems. The only direct means to obtain such information is the use of a spaceborne profiling radar. It is important to mention that the Tropical Rainfall Measuring Mission (TRMM) have made a great stride forward towards this ultimate goal. The Precipitation Radar (PR) aboard the TRMM satellite is the first ever spaceborne radar dedicated to three-dimensional, global precipitation measurements over the tropics and the subtropics, as well as the detailed synopsis of a wide range of tropical rain storm systems. In only twelve months since launch, the PR, together with other science instruments abroad the satellite have already provided unprecedented insights into the rainfall systems. It is anticipated the a lot more exciting and important rain observations would be made by TRMM throughout its mission duration. While TRMM has provided invaluable data to the user community, it is only the first step towards advancing our knowledge on rain processes and its contributions to climate variability. It is envisioned that a TRMM follow-on mission is needed in such a way to capitalize on the pioneering information provided by TRMM, and its instrument capability must be extended beyond TRMM in such a way to fully address the key science questions from microphysical to climatic time scale. In fact, a number of new and innovative mission concepts have recently put forth for this purpose. Almost all of these new concepts have suggested the utility of a more advanced, high-resolution, Doppler-enabled, vertical profiling radar that can provide multi-parameter observations of precipitation. In this paper, a system concept for a second- gene ration precipitation radar (PR-2) which addresses the above requirements will be described.

Im, Eastwood; Smith, Eric A.

1998-01-01

302

Advanced ground-based ESCAN radars  

Microsoft Academic Search

Electronically scanned radars (ESCAN radars) are key system elements of ground based military systems being developed for air and missile defense against future threats including tactical ballistic missiles, high agile and low RCS targets like drones, ARMs, UAVs. The radar design is governed on the one hand by challenging requirements on ESCAN radar performance and on the other hand by

U. Fuchs; W. Sieprath

2005-01-01

303

Decoders for MST radars  

NASA Technical Reports Server (NTRS)

Decoding techniques and equipment used by MST radars are described and some recommendations for new systems are presented. Decoding can be done either by software in special-purpose (array processors, etc.) or general-purpose computers or in specially designed digital decoders. Both software and hardware decoders are discussed and the special case of decoding for bistatic radars is examined.

Woodman, R. F.

1983-01-01

304

Aircraft radar antennas  

Microsoft Academic Search

Many changes have taken place in airborne radar antennas since their beginnings over forty years ago. A brief historical review of the advances in technology is presented, from mechanically scanned reflectors to modern multiple function phased arrays. However, emphasis is not on history but on the state-of-the-art technology and trends for future airborne radar systems. The status of rotating surveillance

Helmut E. Schrank

1987-01-01

305

Determination of the effectiveness of commercial-off-the-shelf radar in the cuing of unmanned aerial vehicle pan-tilt-zoom camera systems  

Microsoft Academic Search

This study examined the use of low-cost commercial-off-the-shelf (COTS) radar in support of the cuing of pan-tilt-zoom (PTZ) optical payload systems. Cancellation of the U.S. Navy's vertical take off and landing (VTOL) unmanned aerial vehicle (VTUAV) program left the Navy without a UAV with radar sensor capability. Using a UAV PTZ optical payload and a COTS radar, this study collected

Patrick Joseph Ford

2003-01-01

306

47 CFR 15.252 - Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz.  

...2014-10-01 2014-10-01 false Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29...Additional Provisions § 15.252 Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and...

2014-10-01

307

47 CFR 15.252 - Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29...Additional Provisions § 15.252 Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and...

2011-10-01

308

47 CFR 15.252 - Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29...Additional Provisions § 15.252 Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and...

2013-10-01

309

Characterization of Adolescent Prescription Drug Abuse and Misuse Using the Researched Abuse Diversion and Addiction-Related Surveillance (RADARS[R]) System  

ERIC Educational Resources Information Center

Objective: To describe the characteristics and health effects of adolescent (age 13-19 years) prescription drug abuse and misuse using the Researched Abuse Diversion and Addiction-Related Surveillance (RADARS[R])) System. Method: Secondary analysis of data collected from RADARS System participating poison centers was performed. Data for all…

Zosel, Amy; Bartelson, Becki Bucher; Bailey, Elise; Lowenstein, Steven; Dart, Rick

2013-01-01

310

47 CFR 15.252 - Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29...Additional Provisions § 15.252 Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and...

2012-10-01

311

Development of random signal radars  

Microsoft Academic Search

Development of random signal radar (RSR) over the past 30 years is described. Conventional methods of implementing RSR are summarized such as correlation, spectrum analysis, and anticorrelation. Some typical RSR systems are introduced, for example, noise frequency modulation CW radar, random binary phase-coded CW radar, etc., and their merits and demerits are also pointed out. Finally, RSR development trends are

Guosui Liu; Hong Gu; Weimin Su

1999-01-01

312

Performance metric development for a group state estimator in airborne UHF GMTI applications  

NASA Astrophysics Data System (ADS)

This paper describes the development and implementation of evaluation metrics for group state estimator (GSE, i.e. group tracking) algorithms. Key differences between group tracker metrics and individual tracker metrics are the method used for track-to-truth association and the characterization of group raid size. Another significant contribution of this work is the incorporation of measured radar performance in assessing tracker performance. The result of this work is a set of measures of performance derived from canonical individual target tracker metrics, extended to characterize the additional information provided by a group tracker. The paper discusses additional considerations in group tracker evaluation, including the definition of a group and group-to-group confusion. Metrics are computed on real field data to provide examples of real-world analysis, demonstrating an approach which provides characterization of group tracker performance, independent of the sensor's performance.

Elwell, Ryan A.

2013-05-01

313

High-level multifunction radar simulation for studying the performance of multisensor data fusion systems  

NASA Astrophysics Data System (ADS)

This paper presents the basic requirements for a simulation of the main capabilities of a shipborne MultiFunction Radar (MFR) that can be used in conjunction with other sensor simulations in scenarios for studying Multi Sensor Data Fusion (MSDF) systems. This simulation is being used to support an ongoing joint effort (Canada - The Netherlands) in the development of MSDF testbeds. This joint effort is referred as Joint-FACET (Fusion Algorithms & Concepts Exploration Testbed), a highly modular and flexible series of applications that is capable of processing both real and synthetic input data. The question raised here is how realistic should the sensor simulations be to trust the MSDF performance assessment? A partial answer to this question is that at least, the dominant perturbing effects on sensor detection (true or false) are sufficiently represented. Following this philosophy, the MFR model, presented here, takes into account sensor's design parameters and external environmental effects such as clutter, propagation and jamming. Previous radar simulations capture most of these dominant effects. In this paper the emphasis is on an MFR scheduler which is the key element that needs to be added to the previous simulations to represent the MFR capability to search and track a large number of targets and at the same time support a large number of (semi-active) surface-to-air missiles (SAM) for the engagement of multiple hostile targets.

Huizing, Albert G.; Bosse, Eloi

1998-07-01

314

The evolution of synthetic aperture radar systems and their progression to the EOS SAR  

NASA Technical Reports Server (NTRS)

The authors describe the evolution of the spaceborne imaging radar starting with the Seasat SAR, through the SIR-A, SIR-B, and SIR-C/X-SAR missions, to the Earth Observing System (EOS) SAR which is scheduled for launch as part of EOS in the late 1990s. A summary of the planned international missions, which may produce a permanent active microwave capability in space starting as early as 1991, is also presented, along with a description of the airborne systems which will be essential to the algorithm development and long-term calibration of the spaceborne data. A brief summary of the planetary missions utilizing SAR and a comparison of their imaging capabilities with those available on Earth are presented.

Way, Jobea; Smith, Elizabeth A.

1991-01-01

315

Binary selectable detector holdoff circuit: Design, testing, and application. [to laser radar data acquisition system  

NASA Technical Reports Server (NTRS)

A very high speed switching circuit, part of a laser radar data acquisition system, has been designed and tested. The primary function of this circuit was to provide computer controlled switching of photodiode detector preamplifier power supply voltages, typically less than plus or minus 20 volts, in approximately 10 nanoseconds. Thus, in actual use, detector and/or detector preamplifier damage can be avoided as a result of sudden extremely large values of backscattered radiation being detected, such as might be due to short range, very thin atmospheric dust layers. Switching of the power supply voltages was chosen over direct switching the photodiode detector input to the preamplifier, based on system noise considerations. Also, the circuit provides a synchronized trigger pulse output for triggering devices such as the Biomation Model 8100 100 MHz analog to digital converter.

Kadrmas, K. A.

1973-01-01

316

Modeling and performance of HF/OTH (High-Frequency/Over-the-Horizon) radar target identification systems  

NASA Astrophysics Data System (ADS)

Several Radar Target Identification (RTI) techniques have been developed at The Ohio State University in recent years. Using the ElectroScience Laboratory compact range a large database of coherent RCS measurement has been constructed for several types of targets (aircraft, ships, and ground vehicles) at a variety of polarizations, aspect angles, and frequency bands. This extensive database has been used to analyze the performance of several different classification algorithms through the use of computer simulations. In order to optimize classification performance, it was concluded that the radar frequency range should lie in the Rayleigh-resonance frequency range, where the wavelength is on the order of or larger than the target size. For aircraft and ships with general dimensions on the order of 10 meters to 100 meters it is apparent that the High Frequency (HF) band provides optimal classification performance. Since existing HF radars are currently being used for detection and tracking or aircraft and ships of these dimensions, it is natural to further investigate the possibility of using these existing radars as the measurement devices in a radar target classification system.

Strausberger, Donald J.

317

Design considerations for high-power VHF radar transceivers: The Poker Flat MST radar phase control system  

NASA Technical Reports Server (NTRS)

Sixty-four separate 50-kW peak-power transmitters are distributed throughout the 200 x 200 meter Poker Flat MST radar antenna array. The relative phase of each transmitter is automatically controlled by a 64-channel unit located in the main building at the edge of the antenna. The phase control unit is described. In operation the RF pulse from a transmitter coupler is power divided and compared with the phase reference in a mixer. The mixer output is low-pass filtered and sampled near the center of the resulting video pulse by an amplifying sample-and-hold integrated circuit. Phase control is effected by maintaining the mixer output pulse near zero volts by amplifying the sample-and-hold output which then drives the voltage-controlled phase shifter in the direction to null the mixer output. The voltage-controlled shifter achieves over 360 deg phase shift in the range from 0.7 to 24 volts. When the voltage into the shifter tracks to either voltage limit the wrap-around control resets the voltage so that the shifter is always operating within its control range.

Ecklund, W. L.; Johnson, P. E.

1983-01-01

318

Road safety alerting system with radar and GPS cooperation in a VANET environment  

NASA Astrophysics Data System (ADS)

New applications in wireless environments are increasing and keeping even more interests from the developer companies and researchers. In particular, in these last few years the government and institutional organization for road safety spent a lot of resources and money to promote Vehicular Ad-Hoc Network (VANET) technology, also car manufactures are giving a lot of contributions on this field as well. In our paper, we propose an innovative system to increase road safety, matching the requests of the market allowing a cooperation between on-board devices. The vehicles are equipped with On Board Unit (OBU) and On Board Radar Unit (OBRU), which can spread alerting messages around the network regarding warning and dangerous situations exploiting IEEE802.llp standard. Vehicles move along roads observing the environment, traffic and road conditions, and vehicles parameters as well. These information can be elaborated and shared between neighbors, Road Side Unit (RSU)s and, of course, with Internet, allowing inter-system communications exploiting an Road Traffic Manager (RTM). Radar systems task it the detection of the environment in order to increase the knowledge of current conditions of the roads, for example it is important to identify obstacles, road accidents, dangerous situations and so on. Once detected exploiting onboard devices, such as Global Position System (GPS) receiver it is possible to know the exact location of the caught event and after a data elaboration the information is spread along the network. Once the drivers are advised, they can make some precautionary actions such as reduction of traveling speed or modification of current road path. In this work the routing algorithms, which have the main goal to rapidly disseminate information, are also been investigated.

Santamaria, Amilcare Francesco; Sottile, Cesare; De Rango, Floriano; Voznak, Miroslav

2014-05-01

319

Radar Entomology  

NSDL National Science Digital Library

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

0000-00-00

320

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

321

Test report for the Direct Access Radar/National Airspace System (DARC/NAS) bi-directional interface test  

NASA Astrophysics Data System (ADS)

The results of the DARC/NAS (HOST) bi-directional interface testing are described in this report. The DARC and NAS systems were physically connected by the General Purpose Output (GPO)/General Purpose Input (GPI) lines. Controller and supervisory messages were entered automatically by time from both the DARC and NAS systems. Both systems used common simulated radar data. Results were examined by analyzing recorded data to determine the transparency of the system.

Dimeo, Robert V.; Mullany, T. C.; Tedford, A.; Grossman, L.

1989-01-01

322

Electro-optical and radar systems for disaster management: lessons and perspectives from India  

NASA Astrophysics Data System (ADS)

Using conjunctively electro-optical and radar systems has been a part of India's Earth Observation (EO) strategy for disaster management. To address the gaps in the operational systems of disaster management, increasingly improved quality of information in terms of spatial scale, temporal scale and all weather capability mapping are called for and the EO satellites have accordingly been configured. For example, CCD camera (1 km spatial resolution) in GEO orbiting INSAT satellites, which work in conjunction with polar orbiting IRS WiFS (188 m spatial resolution) for real time coarse observations of the events such as forest fire, floods etc is in operation. To address the subtle features associated with agricultural drought, Resourcesat has been configured with Advanced WiFS having 55 m spatial, 5 days repetativitity, 740 km swath and 10 bits radiometry. It is a unique mission with variety of payloads viz., AWiFS, LISS 4 (5.8 m multi-spectral; 22 days repetativitity) and PAN from the same platform. The Digital Elevation Models (DEM) emanating from Cartosat are providing valuable inputs to characterize geo-physical terrain vulnerability. Radar Imaging Satellite (RISAT), with all weather capability mission, is yet another mission configured for disaster management. Taking into account the flood dynamics as well as the river basin parameters, RISAST is being configured with multiparametric C-band SAR with 5 imaging modes; 1-2 m spatial resolution; 224 km swath; 7 days repetitivity and 8 bits quantizations. Integrating these capabilities, space based Disaster Management Support (DMS) systems, in India, has been built upon committing EO enabled products and services for disaster reduction on operational basis.

Hegde, V. S.; Srivastava, S. K.; Bandyopadhayay, S.; Manikiam, B.

2006-12-01

323

Doppler Radar Technology  

NSDL National Science Digital Library

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

324

Target position localization in a passive radar system through convex optimization  

NASA Astrophysics Data System (ADS)

This paper proposes efficient target localization methods for a passive radar system using bistatic time-of-arrival (TOA) information measured at multiple synthetic array locations, where the position of these synthetic array locations is subject to random errors. Since maximum likelihood (ML) formulation of this target localization problem is a non-convex optimization problem, semi-definite relaxation (SDR)-based optimization methods in general do not provide satisfactory performance. As a result, approximated ML optimization problems are proposed and solved with SDR plus bisection methods. For the case without position errors, it is shown that the relaxation guarantees a rank-one solution. The optimization problem for the case with position errors involves only a relaxation of a scalar quadratic term. Simulation results show that the proposed algorithms outperform existing methods and provide mean square position error performance very close to the Cramer-Rao lower bound even for larger values of noise and position estimation errors.

Chalise, Batu K.; Zhang, Yimin D.; Amin, Moeness G.; Himed, Braham

2013-05-01

325

Ground penetrating detection using miniaturized radar system based on solid state microwave sensor.  

PubMed

We propose a solid-state-sensor-based miniaturized microwave radar technique, which allows a rapid microwave phase detection for continuous wave operation using a lock-in amplifier rather than using expensive and complicated instruments such as vector network analyzers. To demonstrate the capability of this sensor-based imaging technique, the miniaturized system has been used to detect embedded targets in sand by measuring the reflection for broadband microwaves. Using the reconstruction algorithm, the imaging of the embedded target with a diameter less than 5 cm buried in the sands with a depth of 5 cm or greater is clearly detected. Therefore, the sensor-based approach emerges as an innovative and cost-effective way for ground penetrating detection. PMID:24387449

Yao, B M; Fu, L; Chen, X S; Lu, W; Guo, H; Gui, Y S; Hu, C-M

2013-12-01

326

A new approach to importance sampling for the simulation of false alarms. [in radar systems  

NASA Technical Reports Server (NTRS)

In this paper a modified importance sampling technique for improving the convergence of Importance Sampling is given. By using this approach to estimate low false alarm rates in radar simulations, the number of Monte Carlo runs can be reduced significantly. For one-dimensional exponential, Weibull, and Rayleigh distributions, a uniformly minimum variance unbiased estimator is obtained. For Gaussian distribution the estimator in this approach is uniformly better than that of previously known Importance Sampling approach. For a cell averaging system, by combining this technique and group sampling, the reduction of Monte Carlo runs for a reference cell of 20 and false alarm rate of lE-6 is on the order of 170 as compared to the previously known Importance Sampling approach.

Lu, D.; Yao, K.

1987-01-01

327

Ground penetrating detection using miniaturized radar system based on solid state microwave sensor  

NASA Astrophysics Data System (ADS)

We propose a solid-state-sensor-based miniaturized microwave radar technique, which allows a rapid microwave phase detection for continuous wave operation using a lock-in amplifier rather than using expensive and complicated instruments such as vector network analyzers. To demonstrate the capability of this sensor-based imaging technique, the miniaturized system has been used to detect embedded targets in sand by measuring the reflection for broadband microwaves. Using the reconstruction algorithm, the imaging of the embedded target with a diameter less than 5 cm buried in the sands with a depth of 5 cm or greater is clearly detected. Therefore, the sensor-based approach emerges as an innovative and cost-effective way for ground penetrating detection.

Yao, B. M.; Fu, L.; Chen, X. S.; Lu, W.; Guo, H.; Gui, Y. S.; Hu, C.-M.

2013-12-01

328

Designing a Multichannel Sense-and-Avoid Radar for Small UASs  

E-print Network

(FMCW) collision-avoidance radar for Unmanned Aircraft Systems (UASs). This radar system is being ........................................................................................................................ 9 1.2.1 Pulse and FMCW Radar Characteristics................................................................................... 10 1.3 FMCW Radar Theory

Kansas, University of

329

A radar course at undergraduate level: an approach to systems engineering  

Microsoft Academic Search

This paper describes the undergraduate radar course taught at the Escola Universitaria Politecnica del Baix Llobregat (EUPBL) of the Universitat Politecnica de Catalunya (UPC), Barcelona, Spain. At present, the EUPBL offers a three-year degree in Technical Telecommunications Engineering. This paper briefly describes the EUPBL, the organization of the degree program, the structure of the radar course, the evaluation methods, and

Adriano J. Camps

2003-01-01

330

Low probability of intercept (LPI) techniques and implementations for radar systems  

Microsoft Academic Search

After a brief overview of optimal low-probability of intercept (LPI) radar design criteria, it is shown that for a given radar signal code length, many more codes are available by using higher-order Galois fields; that is, polyphase coding will supply the required diversity. Various aspects of polyphase coding are described because Doppler compensation of the returned signal is a polyphase

E. J. Carlson

1988-01-01

331

Determination of Bragg scatter in an aircraft-generated wake vortex system for radar detection  

Microsoft Academic Search

Remote detection and tracking of wingtip generated wake vortices is important for hazard avoidance especially near airports. Aircraft that fly through these hazardous vortices experience sudden induced roll. Experiments have demonstrated that there is sufficient radar cross section for remote detection at frequencies ranging from VHF to C band (100 MHz to 5 GHz). The mechanism that yields this radar

Theodore Jon Myers

1997-01-01

332

An FPGA-based data acquisition system for a 95 GHz W-band radar  

Microsoft Academic Search

We describe a 95 GHz radar for an unmanned aerial vehicle (UAV). The radar measures vertical profiles of the reflectivity and Doppler velocity of clouds, which are then telemetered to the ground for storage. Telemetry bandwidth requires that substantial real-time data processing be done on the UAV in a low-power (less than 100 watts) and small size (less than 1

Michael Petronino; Ray Bambha; James Carswell; W. Burleson

1997-01-01

333

High Power mm-Wave Transmitter System for Radar or Telecommunications  

NASA Technical Reports Server (NTRS)

Future NASA deep space missions able to provide tens of kilo-watts of spacecraft DC power, make it feasible to employ high power RF telecommunications systems. Traditional flight systems (e.g., Cassini), constrained by limited DC power, used a single high-gain 4m Cassegrain reflector fed by a single lower power (20W) transmitter. Increased available DC power means that high power (1000 W) transmitters can be used. Rather than continue building traditional single-transmitter systems it now becomes feasible to engineer and build multi-element active arrays that can illuminate a dish. Illuminating a 2m dish with a spherical wavefront from an offset 1kW active array can provide sufficient ERP (Effective Radiated Power) when compared to a larger Cassegrain dish. Such a system has the advantage of lower mass, lower volume, improved reliability, less stringent pointing requirements, lower cost and risk. We propose to design and build a prototype Ka-band transmit antenna with an active sub-array using 125W TWTAs. The system could be applied to a telecommunications downlink or radar transmitter used for missions such as JIMO.

Stride, S. L.; McMaster, R. L.; Pogorzelski, R. J.

2003-01-01

334

Airborne laser radar: systems and methods for reconnaissance and terrain modeling  

NASA Astrophysics Data System (ADS)

Recently a number of airborne nadir scanning laser radars have been developed for both military and civilian applications. These have range resolutions on the order of 10 cm but relatively moderate area coverage rates, in the range 1000 - 10,000 m2/s (3.6 - 36 km2/h) when operating in a high resolution mode with 0.25 m spot distance. Technology development in laser sources, scanning techniques and signal processing will probably improve the area coverage substantially and lead to compact systems suitable for new applications, including the use in UAV:s. Present nadir capability could be combined with a forward looking capability for guidance and obstacle avoidance in autonomous or semi-autonomous systems. The paper will investigate the potential performance of such combined systems using state-of-the-art lasers and receiver technology. Among the applications for both military and civilian users we note the collection of 3-D data for terrain modeling and object recognition. For these functions signal processing using multiple echo and intensity information is of great value as well as adding passive senor information. Full wave form processing will further improve the information for example to characterize trees. The use of high resolution 3-D data in synthetic environments is obvious and will be discussed. Experimental data collected with a commercial laser system, TopEye, developed by Saab Dynamics, will be shown and some image examples will be discussed in relation to different applications.

Steinvall, Ove K.; Soederman, Ulf; Ahlberg, Simon; Sandberg, Martin; Letalick, Dietmar; Jungert, Erland

1999-05-01

335

Aircraft radar antennas  

NASA Astrophysics Data System (ADS)

Many changes have taken place in airborne radar antennas since their beginnings over forty years ago. A brief historical review of the advances in technology is presented, from mechanically scanned reflectors to modern multiple function phased arrays. However, emphasis is not on history but on the state-of-the-art technology and trends for future airborne radar systems. The status of rotating surveillance antennas is illustrated by the AN/APY-1 Airborne Warning and Control System (AWACS) slotted waveguide array, which achieved a significant breakthrough in sidelobe suppression. Gimballed flat plate arrays in nose radomes are typified by the AN/APG-66 (F-16) antenna. Multifunction phased arrays are presented by the Electronically Agile Radar (EAR) antenna, which has achieved significant advances in performance versatility and reliability. Trends toward active aperture, adaptive, and digital beamforming arrays are briefly discussed. Antennas for future aircraft radar systems must provide multiple functions in less aperture space, and must perform more reliably.

Schrank, Helmut E.

1987-04-01

336

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

337

High-resolution radar imagery of the Mirage III aircraft  

Microsoft Academic Search

High-resolution radar imagery has attracted increasing interest in recent years. As more radars are endowed with a high-resolution capability, target classification will become a regular system function. In order to classify an aircraft using radar, one must have an understanding of how the radar imagery relates to the physical aircraft. This paper illustrates the more important radar backscattering features on

A. Zyweck; R. E. Bogner

1994-01-01

338

On the role of waveform diversity in MIMO radar  

Microsoft Academic Search

MIMO radar employs multiple antennas to simultaneously transmit diverse waveforms, as well as multiple antennas to receive the radar returns. This paper studies the role of waveform diversity in MIMO radar as separate and distinct from the role of the multiple transmit antennas. This is done by comparing a MIMO radar system to a scanning phased-array radar which uses the

B. Friedlander

2011-01-01

339

A class of frequency hop codes with nearly ideal characteristics for use in multiple-access spread-spectrum communications and radar and sonar systems  

Microsoft Academic Search

The problem of constructing frequency hop codes for use in multiuser communication systems such as multiple-access spread-spectrum communications and multiuser radar and sonar systems is addressed. Previous frequency hopping techniques are reviewed. The construction of a new family of frequency hopping codes called hyperbolic frequency hop codes is given. The concepts of multiple-access spread-spectrum communication systems and multiuser radar and

Svetislav V. Maric; Edward L. Titlebaum

1992-01-01

340

Wearable System-on-a-Chip UWB Radar for Health Care and its Application to the Safety Improvement of Emergency Operators  

Microsoft Academic Search

A new wearable system-on-a-chip UWB radar for health care systems is presented. The idea and its applications to the safety improvement of emergency operators are discussed. The system consists of a wearable wireless interface including a fully integrated UWB radar for the detection of the heart beat and breath rates, and a IEEE 802.15.4 ZigBee radio interface. The principle of

Domenico Zito; Domenico Pepe; Bruno Neri; Danilo De Rossi; A. Lanata; A. Tognetti; E. P. Scilingo

2007-01-01

341

Determination of the effectiveness of commercial-off-the-shelf radar in the cuing of unmanned aerial vehicle pan-tilt-zoom camera systems  

NASA Astrophysics Data System (ADS)

This study examined the use of low-cost commercial-off-the-shelf (COTS) radar in support of the cuing of pan-tilt-zoom (PTZ) optical payload systems. Cancellation of the U.S. Navy's vertical take off and landing (VTOL) unmanned aerial vehicle (VTUAV) program left the Navy without a UAV with radar sensor capability. Using a UAV PTZ optical payload and a COTS radar, this study collected specific time difference measurements between PTZ optical payload searches without radar cuing and searches with radar cuing. In every test run conducted, searches with radar cuing reduced PTZ optical payload detection time. The study showed that a low-cost COTS radar mounted on a small UAV can meet some of the radar requirements lost with cancellation of the VTUAV program. The study results could have a direct impact on myriad of U.S. Navy and other U.S. government surveillance requirements, especially the monitoring of U.S. coastal waters in support of homeland security goals and objectives.

Ford, Patrick Joseph

342

The GeoSAR program: Development of a commercially viable 3-D radar terrain mapping system  

SciTech Connect

GeoSAR is joint development between the Defense Advanced Research Project Agency (DARPA) and the California Department of Conservation (CA DOC) to determine the technical and economic viability of an airborne interferometric and foliage penetration synthetic aperture radar for mapping terrain and man made objects in geographical areas obscured by foliage, urban buildings, and other concealments. The two core technology elements of this program are Interferometric Synthetic Aperture Radar (IFSAR) and Foliage Penetration Radar (FOPEN). These technologies have been developed by NASA and ARPA, principally for defense applications.

Carlisle, R.G. [Decision-Science Applications, Inc., Arlington, VA (United States); Davis, M. [Defense Advanced Research Projects Agency, Arlington, VA (United States)

1996-11-01

343

An Acoustic / Radar System for Automated Detection, Localization, and Classification of  

E-print Network

SPVA D/C/L CRH D/C/L Radar D/C/L ESM D/C/L IR D/C/L Shipboard Organic Sensors UAV Sensors Video D DFFS Data Structures SPVA D/C/L CRH D/C/L Radar D/C/L ESM D/C/L IR D/C/L Shipboard Organic Sensors UAV DFFS Data Structures SPVA D/C/L CRH D/C/L Radar D/C/L ESM D/C/L IR D/C/L Shipboard Organic Sensors UAV

Maher, Robert C.

344

Synthetic aperture radar for a crop information system: A multipolarization and multitemporal approach  

NASA Astrophysics Data System (ADS)

Acquisition of timely information is a critical requirement for successful management of an agricultural monitoring system. Crop identification and crop-area estimation can be done fairly successfully using satellite sensors operating in the visible and near-infrared (VIR) regions of the spectrum. However, data collection can be unreliable due to problems of cloud cover at critical stages of the growing season. The all-weather capability of synthetic aperture radar (SAR) imagery acquired from satellites provides data over large areas whenever crop information is required. At the same time, SAR is sensitive to surface roughness and should be able to provide surface information such as tillage-system characteristics. With the launch of ERS-1, the first long-duration SAR system became available. The analysis of airborne multipolarization SAR data, multitemporal ERS-1 SAR data, and their combinations with VIR data, is necessary for the development of image-analysis methodologies that can be applied to RADARSAT data for extracting agricultural crop information. The overall objective of this research is to evaluate multipolarization airborne SAR data, multitemporal ERS-1 SAR data, and combinations of ERS-1 SAR and satellite VIR data for crop classification using non-conventional algorithms. The study area is situated in Norwich Township, an agricultural area in Oxford County, southern Ontario, Canada. It has been selected as one of the few representative agricultural 'supersites' across Canada at which the relationships between radar data and agriculture are being studied. The major field crops are corn, soybeans, winter wheat, oats, barley, alfalfa, hay, and pasture. Using airborne C-HH and C-HV SAR data, it was found that approaches using contextual information, texture information and per-field classification for improving agricultural crop classification proved to be effective, especially the per-field classification method. Results show that three of the four best per-field classification accuracies (\\ K=0.91) are achieved using combinations of C-HH and C-VV SAR data. This confirms the strong potential of multipolarization data for crop classification. The synergistic effects of multitemporal ERS-1 SAR and Landsat TM data are evaluated for crop classification using an artificial neural network (ANN) approach. The results show that the per-field approach using a feed-forward ANN significantly improves the overall classification accuracy of both single-date and multitemporal SAR data. Using the combination of TM3,4,5 and Aug. 5 SAR data, the best per-field ANN classification of 96.8% was achieved. It represents an 8.5% improvement over a single TM3,4,5 classification alone. Using multitemporal ERS-1 SAR data acquired during the 1992 and 1993 growing seasons, the radar backscatter characteristics of crops and their underlying soils are analyzed. The SAR temporal backscatter profiles were generated for each crop type and the earliest times of the year for differentiation of individual crop types were determined. Orbital (incidence-angle) effects were also observed on all crops. The average difference between the two orbits was about 3 dB. Thus attention should be given to the local incidence-angle effects when using ERS-1 SAR data, especially when comparing fields from different scenes or different areas within the same scene. Finally, early- and mid-season multitemporal SAR data for crop classification using sequential-masking techniques are evaluated, based on the temporal backscatter profiles. It was found that all crops studied could be identified by July 21.

Ban, Yifang

345

The NASA radar entomology program at Wallops Flight Center  

NASA Technical Reports Server (NTRS)

NASA contribution to radar entomology is presented. Wallops Flight Center is described in terms of its radar systems. Radar tracking of birds and insects was recorded from helicopters for airspeed and vertical speed.

Vaughn, C. R.

1979-01-01

346

A Tower-based Prototype VHF/UHF Radar for Subsurface Sensing: System Description and Data Inversion Results  

NASA Technical Reports Server (NTRS)

Knowledge of subsurface characteristics such as permittivity variations and layering structure could provide a breakthrough in many terrestrial and planetary science disciplines. For Earth science, knowledge of subsurface and subcanopy soil moisture layers can enable the estimation of vertical flow in the soil column linking surface hydrologic processes with that in the subsurface. For planetary science, determining the existence of subsurface water and ice is regarded as one of the most critical information needs for the study of the origins of the solar system. The subsurface in general can be described as several near-parallel layers with rough interfaces. Each homogenous rough layer can be defined by its average thickness, permittivity, and rms interface roughness assuming a known surface spectral distribution. As the number and depth of layers increase, the number of measurements needed to invert for the layer unknowns also increases, and deeper penetration capability would be required. To nondestructively calculate the characteristics of the rough layers, a multifrequency polarimetric radar backscattering approach can be used. One such system is that we have developed for data prototyping of the Microwave Observatory of Subcanopy and Subsurface (MOSS) mission concept. A tower-mounted radar makes backscattering measurements at VHF, UHF, and L-band frequencies. The radar is a pulsed CW system, which uses the same wideband antenna to transmit and receive the signals at all three frequencies. To focus the beam at various incidence angles within the beamwidth of the antenna, the tower is moved vertically and measurements made at each position. The signals are coherently summed to achieve focusing and image formation in the subsurface. This requires an estimate of wave velocity profiles. To solve the inverse scattering problem for subsurface velocity profile simultaneously with radar focusing, we use an iterative technique based on a forward numerical solution of the layered rough surface problem. The layers are each defined in terms of a small number of unknown distributions as given above. An a priori estimate of the solution is first assumed, based on which the forward problem is solved for the backscattered measurements. This is compared with the measured data and using iterative techniques an update to the solution for the unknowns is calculated. The process continues until convergence is achieved. Numerical results will be shown using actual radar data acquired with the MOSS tower radar system in Arizona in Fall 2003, and compared with in-situ measurements.

Moghaddam, Mahta; Pierce, Leland; Tabatabaeenejad, Alireza; Rodriguez, Ernesto

2005-01-01

347

Real-time signal processing system for high resolution CWLFM millimeter-wave radars  

Microsoft Academic Search

An FPGA-based real-time signal processing unit has been developed to perform Doppler processing in a high resolution CWLFM (continuous wave linear frequency modulated) millimeter-wave radar demonstrator. The article focuses on the strategies followed in order to achieve the required throughput as well as on the measures taken to guarantee coherency. Doppler processing is accomplished to output Range-Doppler radar images and

Javier Carretero Moya; Wang Zongbo; Álvaro Blanco del Campo; Javier Gismero Menoyo; Alberto Asensio López

2008-01-01

348

Radar cross-section measurements and simulation of a tethered satellite. The small expendable deployer system end-mass payload  

NASA Technical Reports Server (NTRS)

The first Small Expendable Deployer System (SEDS-1), a tethered satellite system, was developed by NASA and launched March 29, 1993 as a secondary payload on a United State Air Force (USAF) Delta-2 launch vehicle. The SEDS-1 successfully deployed an instrumented end-mass payload (EMP) on a 20-km nonconducting tether from the second stage of the Delta 2. This paper describes the effort of NASA Langley Research Center's Antenna and Microwave Research Branch to provide assistance to the SEDS Investigators Working Group (IWG) in determining EMP dynamics by analyzing the mission radar skin track data. The radar cross section measurements taken and simulations done for this study are described and comparisons of the measured data with the simulated data for the EMP at 6 GHz are presented.

Cravey, Robin L.; Fralick, Dion T.; Vedeler, Erik

1995-01-01

349

Numerical techniques for electromagnetic applications in microelectronic and radar imaging systems  

NASA Astrophysics Data System (ADS)

In this thesis, the application of numerical techniques to electromagnetic problems in microelectronic and radar imaging systems are investigated. In particular the following problems are studied: (1) Dielectric rib waveguide discontinuities are analyzed with the Finite Difference Time Domain (FDTD) method. The application of Berenger's Perfectly Matched Layer to multi-layered dielectrics is analyzed and the specific conditions needed to successfully match the multiple dielectric layers are determined and justified. An FDTD method to find the fundamental mode's spatial distribution is used to excite the discontinuity problem. It is shown that the computational domain can be reduced by twenty percent over Gaussian excitations. The effects of rib waveguide bend discontinuities and the effects of the rib geometry to the bend loss are presented. (2) An Impedance Boundary Condition (IBC) for two dimensional FDTD simulations containing thin, good conductor sheets is developed. The IBC uses a recursive convolution scheme based on approximating the conductor's impedance as a sum of exponentials. The effects of FDTD parameters such as grid size and time step on simulation accuracy are presented. The IBC is shown to accurately model the conductor loss over a wide frequency range. The verification is performed by comparing the quality factors of rectangular resonant structures determined by the FDTD simulation and analytical methods. (3) Phase unwrapping techniques for the inversion of terrain height using Synthetic Aperture Radar Interferometry (InSAR) data are analyzed. The weighted least squares and branch cut phase unwrapping techniques are specifically studied. An optimal branch cut method and a hybrid least squares/branch cut method are presented and used to unwrap the phase of both simulated and real SAR interferograms. When used to invert terrain height, these new SAR phase unwrapping methods offer over fifty percent reduction in root mean square (rms) height error compared to the straight least squares method and over thirty-five percent reduction in rms height error compared to the weighted least squares method based on coherence data weighting schemes. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253- 1690.)

Akerson, Jerome J.

1998-12-01

350

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

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

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

351

Installation of a Permanent Doppler Radar Monitoring System at Colima Volcano, Mexico, and its use for Eruption Cloud Modelling  

NASA Astrophysics Data System (ADS)

In February 2007 we installed a standalone Doppler radar monitoring station at Colima volcano, Mexico. During that time, a new episode of dome growth was underway with daily Vulcanian eruptive events occurring. These were continuously recorded with the Doppler radar. In December 2008 we upgraded the monitoring station with a second Doppler radar, a network video camera, and a direct WLAN connection to the 28.5km distant Colima University, which allows us to remotely reconfigure the whole system in times of volcanic crises. A custom made data logger collects and stores all data at the station before transmitting data in packages to the office. The entire system is powered by solar panels. The camera is triggered by the Doppler radar that is aimed at the vent. In case an eruption is detected, the camera switches from taking pictures at arbitrary intervals to continuous video recording until the end of the eruption. Similarly the Doppler radar switches to a high sampling rate (15Hz). In 2007 we recorded 92 events during six months with durations of 20 to 200 seconds. The velocity spectra clearly show two regimes: (a) buoyant updraft with 20 to 60 seconds of constant velocities and a maximum of 20 m/s (vertical) and (b) series of pulses of intense jetting where every pulse lasts about 20s and starts with vertical velocities up to 85 m/s (measured ~75m above vent). Our deployment at Colima volcano is the first investigation of Vulcanian eruption column dynamics using Doppler radar. The data provide particle velocities and a proxy of the particles mass ~75m above the vent, which allows us to define the activity status in near real time during an eruption. Here we focus on the dynamic processes during the early stages of eruption cloud formation. Using (1) a simple ballistic model for particle transport and (2) the active tracer high-resolution atmospheric model (ATHAM) we model the first 100 m of cloud formation in 2D (axis-symmetric) and 3D. We constrain the initial conditions for both models trying to reproduce the dynamics measured by the radars. For this comparison synthetic Doppler radar data are calculated from the numerical models by converting particle properties (size, velocity, and backscatter-efficiency) into synthetic velocity spectra. First results show that pure ballistic transport of particles in a gas jet cannot reproduce the measured spectra. Eruption clouds are a major hazard to aviation. Hence real-time tracking and forecasting of ash clouds are increasingly important tasks in volcanology. In-situ measurements of the dynamics inside the developing cloud are needed to constrain the input parameters of the Volcanic Ash Advisory Center's (VAAC) numerical ash cloud dispersion models. Our aim is to directly deduce the initial conditions for an eruption column model or ash dispersal model from the radar data in near-real time.

Scharff, L.; Hort, M. K.; Varley, N. R.; Herzog, M.

2011-12-01

352

Transmitter and receiver antenna gain analysis for laser radar and communication systems  

NASA Technical Reports Server (NTRS)

A comprehensive and fairly self-contained study of centrally obscured optical transmitting and receiving antennas is presented and is intended for use by the laser radar and communication systems designer. The material is presented in a format which allows the rapid and accurate evaluation of antenna gain. The Fresnel approximation to scalar wave theory is reviewed and the antenna analysis proceeds in terms of the power gain. Conventional range equations may then be used to calculate the power budget. The transmitter calculations, resulting in near and far field antenna gain patterns, assumes the antenna is illuminated by a laser operating in the fundamental cavity mode. A simple equation is derived for matching the incident source distribution to a general antenna configuration for maximum on-axis gain. An interpretation of the resultant gain curves allows a number of auxiliary design curves to be drawn which display the losses in antenna gain due to pointing errors and the cone angle of the outgoing beam as a function of antenna size and central obscuration. The use of telescope defocusing as an approach to spreading the beam for target acquisition is compared to some alternate methods.

Klein, B. J.; Degnan, J. J.

1973-01-01

353

MIDAS-W: a workstation-based incoherent scatter radar data acquisition system  

NASA Astrophysics Data System (ADS)

The Millstone Hill Incoherent Scatter Data Acquisition System (MIDAS) is based on an abstract model of an incoherent scatter radar. This model is implemented in a hierarchical software system, which serves to isolate hardware and low-level software implementation details from higher levels of the system. Inherent in this is the idea that implementation details can easily be changed in response to technological advances. MIDAS is an evolutionary system, and the MIDAS hardware has, in fact, evolved while the basic software model has remained unchanged. From the earliest days of MIDAS, it was realized that some functions implemented in specialized hardware might eventually be implemented by software in a general-purpose computer. MIDAS-W is the realization of this concept. The core component of MIDAS-W is a Sun Microsystems UltraSparc 10 workstation equipped with an Ultrarad 1280 PCI bus analog to digital (A/D) converter board. In the current implementation, a 2.25 MHz intermediate frequency (IF) is bandpass sampled at 1 µs intervals and these samples are multicast over a high-speed Ethernet which serves as a raw data bus. A second workstation receives the samples, converts them to filtered, decimated, complex baseband samples and computes the lag-profile matrix of the decimated samples. Overall performance is approximately ten times better than the previous MIDAS system, which utilizes a custom digital filtering module and array processor based correlator. A major advantage of MIDAS-W is its flexibility. A portable, single-workstation data acquisition system can be implemented by moving the software receiver and correlator programs to the workstation with the A/D converter. When the data samples are multicast, additional data processing systems, for example for raw data recording, can be implemented simply by adding another workstation with suitable software to the high-speed network. Testing of new data processing software is also greatly simplified, because a workstation with the new software can be added to the network without impacting the production system. MIDAS-W has been operated in parallel with the existing MIDAS-1 system to verify that incoherent scatter measurements by the two systems agree. MIDAS-W has also been used in a high-bandwidth mode to collect data on the November, 1999, Leonid meteor shower.

Holt, J. M.; Erickson, P. J.; Gorczyca, A. M.; Grydeland, T.

2000-09-01

354

Use of the X-Band Radar to Support the Detection of In-Flight Icing Hazards by the NASA Icing Remote Sensing System  

NASA Technical Reports Server (NTRS)

The Alliance Icing Research Study-II (AIRS-II) field program was conducted near Montreal, Canada during the winter of 2003. The NASA Icing Remote Detection System (NIRSS) was deployed to detect in-flight icing hazards and consisted of a vertically pointing multichannel radiometer, a ceilometer and an x-band cloud radar. The radiometer was used to derive atmospheric temperature soundings and integrated liquid water, while the ceilometer and radar were used only to define cloud boundaries. The purpose of this study is to show that the radar reflectivity profiles from AIRS-II case studies could be used to provide a qualitative icing hazard.

Serke, David J.; Politovich, Marcia K.; Reehorst, Andrew L.; Gaydos, Andrew

2009-01-01

355

Reconfigurable L-Band Radar  

NASA Technical Reports Server (NTRS)

The reconfigurable L-Band radar is an ongoing development at NASA/GSFC that exploits the capability inherently in phased array radar systems with a state-of-the-art data acquisition and real-time processor in order to enable multi-mode measurement techniques in a single radar architecture. The development leverages on the L-Band Imaging Scatterometer, a radar system designed for the development and testing of new radar techniques; and the custom-built DBSAR processor, a highly reconfigurable, high speed data acquisition and processing system. The radar modes currently implemented include scatterometer, synthetic aperture radar, and altimetry; and plans to add new modes such as radiometry and bi-static GNSS signals are being formulated. This development is aimed at enhancing the radar remote sensing capabilities for airborne and spaceborne applications in support of Earth Science and planetary exploration This paper describes the design of the radar and processor systems, explains the operational modes, and discusses preliminary measurements and future plans.

Rincon, Rafael F.

2008-01-01

356

RF MEMS on the radar  

Microsoft Academic Search

This article gives an overview of applications of radio frequency (RF) microelectromechanical system (MEMS) technology in radio detection and ranging (radar). RF MEMS components for radar include attenuators, limiters, (true-time-delay) phase shifters, transmit\\/receive (T\\/R) switches and tunable matching networks. Radar subsystems that benefit from RF MEMS technology include active electronically scanned arrays (T\\/R modules), passive electronically scanned arrays (lenses, reflect

Koen Van Caekenberghe

2009-01-01

357

Ten Methods to Fuse GMTI and HRRR Measurements For Joint Tracking and Identification  

Microsoft Academic Search

Mutual-aided target tracking and identification (ID) schemes are described by exploiting the couplings between the target tracking and object ID systems, which are typically implemented separately. A hybrid state space approach is formulated to deal with continuous-valued kinematics, discrete-valued target type, and discrete-valued target pose (inherently continuous but quantized). We identify ten possible mutual aiding mechanisms with different complexity in

Erik P. Blasch; Chun Yang

358

Waveform diversity in distributed radar  

Microsoft Academic Search

The desire to anticipate actions before they occur is a goal within the military. Cognitive sensor and communications systems along with distributed radar systems are key enablers to meet this need. Close in sensing examples are provided showing the value of waveform diversity in distributed radar. The use of waveform diversity presents a challenge to the electromagnetic compatibility (EMC) community.

G. T. Capraro; I. Bradaric; M. C. Wicks

2009-01-01

359

Frequency diversity in multistatic radars  

Microsoft Academic Search

This paper presents the model and analysis of a frequency-diverse radar system. Multistatic radar systems provide an inherent spatial diversity by processing signals from different platforms which view a potential target from different aspect angles. By using different frequencies at each platform, an additional diversity gain can be obtained on top of the advantages of spatial diversity. Here, since platforms

Byung Wook Jung; R aviraj S. Adve; Joohwan Chun

2008-01-01

360

MST radar data-base management  

NASA Technical Reports Server (NTRS)

Data management for Mesospheric-Stratospheric-Tropospheric, (MST) radars is addressed. An incoherent-scatter radar data base is discussed in terms of purpose, centralization, scope, and nature of the data base management system.

Wickwar, V. B.

1983-01-01

361

Progress in existing and planned MST radars  

NASA Astrophysics Data System (ADS)

Radar systems are described which use two different wind measuring techniques: the partial-reflection drift technique and the mesosphere-stratosphere-troposphere (MST) or Doppler beam-swing radar technique. The advantages and disadvantages of each technique are discussed.

Vanzandt, T. E.

1986-06-01

362

Progress in existing and planned MST radars  

NASA Technical Reports Server (NTRS)

Radar systems are described which use two different wind measuring techniques: the partial-reflection drift technique and the mesosphere-stratosphere-troposphere (MST) or Doppler beam-swing radar technique. The advantages and disadvantages of each technique are discussed.

Vanzandt, T. E.

1986-01-01

363

Remote profiling of lake ice thickness using a short pulse radar system aboard a C-47 aircraft  

NASA Technical Reports Server (NTRS)

Description of the design and operation of two new short-pulse radar systems developed for use aboard aircraft for remote profiling of lake ice thickness. The principle of operation is based on the fact that the return signal is composed of a pulse return from the top of the ice and another, delayed in time, from the ice-water interface. The delay time between these two pulses directly gives the ice thickness when allowance is made for the slower RF propagation through the ice. The two systems are the S band and the C band systems, and their comparative merits are discussed.

Cooper, D. W.; Heighway, J. E.; Shook, D. F.; Jirberg, R. J.; Vickers, R. S.

1974-01-01

364

Agricultural and hydrological applications of radar  

Microsoft Academic Search

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,

F. T. Ulaby

1976-01-01

365

APPLICATION OF SENSOR SCHEDULING CONCEPTS TO RADAR  

E-print Network

Chapter 10 APPLICATION OF SENSOR SCHEDULING CONCEPTS TO RADAR William Moran University of Melbourne time illustrating the ideas on sensor schedul- ing in a specific context: that of a radar system. A typical pulse radar system operates by illuminating a scene with a short pulse of electromagnetic energy

Nehorai, Arye

366

Removing interfering clutter associated with radar pulses that an airborne radar receives from a radar transponder  

DOEpatents

Interfering clutter in radar pulses received by an airborne radar system from a radar transponder can be suppressed by developing a representation of the incoming echo-voltage time-series that permits the clutter associated with predetermined parts of the time-series to be estimated. These estimates can be used to estimate and suppress the clutter associated with other parts of the time-series.

Ormesher, Richard C. (Albuquerque, NM); Axline, Robert M. (Albuquerque, NM)

2008-12-02

367

Australian Weather Watch Radar Home Page  

NSDL National Science Digital Library

The Commonwealth Bureau of Meteorology's Weather Watch Radar website provides up-to-date radar images of the locations of rain in Australia in relation to local features such as coast lines. The newly developed Loops provide four consecutive radar images so that users can view how the weather has been changing in the last forty to fifty minutes. The website provides radar images of past cyclone events as well as updates on severe weather throughout Australia. Those interested in radar systems can discover how the weather radars work and how to interpret the maps. [RME

368

Software Radar Technology and the Open Radar Initiative  

NASA Astrophysics Data System (ADS)

We have recently implemented a Software Radar System as the production data taking and control system for the Millstone Hill Incoherent Scatter Radar. In a Software Radar the traditional real-time hardware control and signal processing elements of a radar system are replaced by software systems running on general purpose computer systems and interconnected by a high speed and low latency multicast network. From our efforts to develop this system we have identitified a number of architectural patterns which are important for achieving performance, modularity, and scalability in distributed systems for managing experimental instrumentation and the many terabytes of information that are produced. The most important of these patterns concern information organization and management in the system and they are general far beyond their application to ionospheric radar systems. After discussing our system and these patterns we will describe the Open Radar Initiative. This effort is an open source project to make Software Radar technology widely available and to ready it for use as the foundation of a ground based Global Space Weather Network.

Lind, F. D.; Grydeland, T.; Erickson, P. J.; Rideout, B.; Holt, J.

2002-12-01

369

AEGIS - Advanced Multi-Function Array Radar  

NASA Astrophysics Data System (ADS)

The AMFAR (Advanced Multi-Function Array Radar), a radar system technology developed in the late 1960s, has demonstrated automatic detection and tracking of all air targets plus inherent resistance to natural and man-made clutter with computer control of the radar. The major elements of the AMFAR - a high-power radar frequency transmitter, a phased-array antenna, a signal processor system, a computer control system, and an automated test system - are described in detail. The capabilities of the radar are demonstrated in a series of pictures showing processing steps to provide automatic target detection and track in both ground clutter zones and rain clutter. The success of AMFAR laid the foundation of Radar System AN/SPY-1A, the Weapon Control Radar System now being produced as a major element of the AEGIS Weapon System for the U.S. Navy guided missile cruiser Ticonderoga.

Phillips, C. C.

1981-12-01

370

Infrared, microwave, and spaceborne radar simulations of a deep convective system using a 3-D cloud ensemble method  

NASA Technical Reports Server (NTRS)

A 3D cloud model is used to simulate the storm structure, and the results are linked to microwave and infrared radiative transfer models for simulation of aircraft observations. Spaceborne radar data are also simulated along the aircraft flight track. The cloud and radiative model simulations are studied and compared with aircraft observations. The initial results indicate that the 3D cloud model is capable of simulating the major features of observed storm systems when given a representative atmospheric sounding to initialize the convective systems. The simulations of infrared and microwave radiances provide reasonably good comparisons with the observations.

Yeh, H.-Y. M.; Prasad, N.; Tao, W.-K.; Jones, J. A.; Meneghini, R.; Adler, R. F.

1992-01-01

371

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

372

Numerical study of a low permeability microporous heat sink for cooling phased-array radar systems  

Microsoft Academic Search

Microporous media is being used to develop an improved forced convection cold plate device for removing waste heat from high frequency phased-array radar apertures. The waste heat, generated by transmit and receive microwave functions mounted in separate electronic modules, is conducted to the surfaces of a thin rectangular enclosure (cold plate) through which coolant flows. The performance of the phased-array

R. M. Weber

1996-01-01

373

A Virtual Antenna Beamforming (VAB) Approach for Radar Systems by Using Orthogonal Coding Waveforms  

Microsoft Academic Search

An innovative approach is introduced to form virtual transmitting and receiving radar antenna beams simultaneously by transmitting orthogonal coding waveforms from the antenna elements and digitally processing of their echoes at the receiver. Multiple virtual transmitting-receiving beams can be formed simultaneously by employing an equal number of beamforming filters without increasing transmitting power or antenna gain or resolution loss. The

Hai Deng; Braham Himed

2009-01-01

374

Remote sensing of precipitation by weather radar system at space station  

Microsoft Academic Search

A space station is considered as the ideal vehicle for a spaceborne weather radar, in virtue of its ability to accomodate an exceptionally large aperture X-band antenna and supply the power levels required for adequate operation. The space station envisioned will orbit at an altitude of 500 km, and can be developed in two distinct stages. The first stage will

K. Okamoto

1983-01-01

375

Millimeter wave, solid-state amplifiers in radar and communication systems  

Microsoft Academic Search

Two different designs of millimeter wave, high-power, solid-state amplifiers are presented here, one each for use in missile radar and satellite communication applications. Details of each design are given along with the tradeoffs which led to the specific solid-state designs over other alternative solid-state and tube amplifier designs

M. Russell; A. Marinilli; F. Sullivan

1996-01-01

376

Decorrelation in interferometric radar echoes  

Microsoft Academic Search

A radar interferometric technique for topographic mapping of surfaces, implemented utilizing a single synthetic aperture radar (SAR) system in a nearly repeating orbit, is discussed. The authors characterize the various sources contributing to the echo correlation statistics, and isolate the term which most closely describes surficial change. They then examine the application of this approach to topographic mapping of vegetated

Howard A. Zebker; John Villasensor

1992-01-01

377

CURRENT APPLICATIONS OF IMAGING RADAR  

Microsoft Academic Search

This paper discusses the current status of imaging radar systems deployed on spacecraft and airborne platforms, such as aircraft and unmanned airborne vehicles (UAVs). Imaging radar technology has advanced considerably over the last twenty years, and the user can now be fairly certain of finding a sensor ideal for a specifi c application. The objective of the paper is to

M. R. Inggs; R. T. Lord; WG VII

378

46 CFR 169.726 - Radar reflector.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Radar reflector. 169.726 Section 169...Systems, and Equipment § 169.726 Radar reflector. Each nonmetallic vessel less than 90 feet in length must exhibit a radar reflector of suitable size and design...

2012-10-01

379

EISCAT Radar School, Kiruna, 2005 Outrigger in  

E-print Network

EISCAT Radar School, Kiruna, 2005 LOFAR Outrigger in Scandinavia Physics in Space Programme LOFAR Centre, Växjö University #12;Bo Thidé EISCAT Radar School, Kiruna,, 20052 LOFAR Low Frequency Array (10 radio system for space radio #12;Bo Thidé EISCAT Radar School, Kiruna,, 20053 Hydrogen radiates at 1420

380

46 CFR 184.404 - Radars.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Radars. 184.404 Section 184.404 Shipping... Navigation Equipment § 184.404 Radars. (a) A vessel must be fitted with...Commission (FCC) type accepted general marine radar system for surface navigation with...

2011-10-01

381

46 CFR 108.717 - Radar.  

...2014-10-01 2014-10-01 false Radar. 108.717 Section 108.717 Shipping...Miscellaneous Equipment § 108.717 Radar. Each self-propelled unit of 1...coastwise service must have— (a) A marine radar system for surface navigation; and...

2014-10-01

382

46 CFR 108.717 - Radar.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Radar. 108.717 Section 108.717 Shipping...Miscellaneous Equipment § 108.717 Radar. Each self-propelled unit of 1...coastwise service must have— (a) A marine radar system for surface navigation; and...

2013-10-01

383

46 CFR 108.717 - Radar.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Radar. 108.717 Section 108.717 Shipping...Miscellaneous Equipment § 108.717 Radar. Each self-propelled unit of 1...coastwise service must have— (a) A marine radar system for surface navigation; and...

2011-10-01

384

46 CFR 108.717 - Radar.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Radar. 108.717 Section 108.717 Shipping...Miscellaneous Equipment § 108.717 Radar. Each self-propelled unit of 1...coastwise service must have— (a) A marine radar system for surface navigation; and...

2010-10-01

385

46 CFR 121.404 - Radars.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Radars. 121.404 Section 121.404 Shipping... Navigation Equipment § 121.404 Radars. (a) Except as allowed by paragraph...Commission (FCC) type accepted general marine radar system for surface navigation with...

2010-10-01

386

46 CFR 121.404 - Radars.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Radars. 121.404 Section 121.404 Shipping... Navigation Equipment § 121.404 Radars. (a) Except as allowed by paragraph...Commission (FCC) type accepted general marine radar system for surface navigation with...

2011-10-01

387

46 CFR 169.726 - Radar reflector.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Radar reflector. 169.726 Section 169...Systems, and Equipment § 169.726 Radar reflector. Each nonmetallic vessel less than 90 feet in length must exhibit a radar reflector of suitable size and design...

2011-10-01

388

46 CFR 169.726 - Radar reflector.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Radar reflector. 169.726 Section 169...Systems, and Equipment § 169.726 Radar reflector. Each nonmetallic vessel less than 90 feet in length must exhibit a radar reflector of suitable size and design...

2013-10-01

389

46 CFR 167.40-40 - Radar.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Radar. 167.40-40 Section 167.40-40...Equipment Requirements § 167.40-40 Radar. All mechanically propelled vessels...coastwise service must be fitted with a marine radar system for surface navigation....

2012-10-01

390

46 CFR 169.726 - Radar reflector.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Radar reflector. 169.726 Section 169...Systems, and Equipment § 169.726 Radar reflector. Each nonmetallic vessel less than 90 feet in length must exhibit a radar reflector of suitable size and design...

2010-10-01

391

46 CFR 121.404 - Radars.  

...2014-10-01 2014-10-01 false Radars. 121.404 Section 121.404 Shipping... Navigation Equipment § 121.404 Radars. (a) Except as allowed by paragraph...Commission (FCC) type accepted general marine radar system for surface navigation with...

2014-10-01

392

46 CFR 121.404 - Radars.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Radars. 121.404 Section 121.404 Shipping... Navigation Equipment § 121.404 Radars. (a) Except as allowed by paragraph...Commission (FCC) type accepted general marine radar system for surface navigation with...

2013-10-01

393

46 CFR 167.40-40 - Radar.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Radar. 167.40-40 Section 167.40-40...Equipment Requirements § 167.40-40 Radar. All mechanically propelled vessels...coastwise service must be fitted with a marine radar system for surface navigation....

2011-10-01

394

46 CFR 167.40-40 - Radar.  

...2014-10-01 2014-10-01 false Radar. 167.40-40 Section 167.40-40...Equipment Requirements § 167.40-40 Radar. All mechanically propelled vessels...coastwise service must be fitted with a marine radar system for surface navigation....

2014-10-01

395

46 CFR 167.40-40 - Radar.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Radar. 167.40-40 Section 167.40-40...Equipment Requirements § 167.40-40 Radar. All mechanically propelled vessels...coastwise service must be fitted with a marine radar system for surface navigation....

2010-10-01

396

46 CFR 184.404 - Radars.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Radars. 184.404 Section 184.404 Shipping... Navigation Equipment § 184.404 Radars. (a) A vessel must be fitted with...Commission (FCC) type accepted general marine radar system for surface navigation with...

2013-10-01

397

46 CFR 184.404 - Radars.  

...2014-10-01 2014-10-01 false Radars. 184.404 Section 184.404 Shipping... Navigation Equipment § 184.404 Radars. (a) A vessel must be fitted with...Commission (FCC) type accepted general marine radar system for surface navigation with...

2014-10-01

398

46 CFR 184.404 - Radars.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Radars. 184.404 Section 184.404 Shipping... Navigation Equipment § 184.404 Radars. (a) A vessel must be fitted with...Commission (FCC) type accepted general marine radar system for surface navigation with...

2010-10-01

399

46 CFR 121.404 - Radars.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Radars. 121.404 Section 121.404 Shipping... Navigation Equipment § 121.404 Radars. (a) Except as allowed by paragraph...Commission (FCC) type accepted general marine radar system for surface navigation with...

2012-10-01

400

Synthetic aperture radar calibration using reference reflectors  

Microsoft Academic Search

A simple expression for the terrain backscatter coefficient is derived in terms of the integrated power of an adjacent known radar reflector in a synthetic aperture radar (SAR) image. It is shown that this technique for SAR image calibration is independent of the radar system focus or partial coherence and thereby possesses an important advantage over the usual technique, which

A. L. Gray; P. W. Vachon; C. E. Livingstone; T. I. Lukowski

1990-01-01

401

46 CFR 167.40-40 - Radar.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Radar. 167.40-40 Section 167.40-40...Equipment Requirements § 167.40-40 Radar. All mechanically propelled vessels...coastwise service must be fitted with a marine radar system for surface navigation....

2013-10-01

402

46 CFR 184.404 - Radars.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Radars. 184.404 Section 184.404 Shipping... Navigation Equipment § 184.404 Radars. (a) A vessel must be fitted with...Commission (FCC) type accepted general marine radar system for surface navigation with...

2012-10-01

403

46 CFR 169.726 - Radar reflector.  

...2014-10-01 2014-10-01 false Radar reflector. 169.726 Section 169...Systems, and Equipment § 169.726 Radar reflector. Each nonmetallic vessel less than 90 feet in length must exhibit a radar reflector of suitable size and design...

2014-10-01

404

Noise modulated multistatic surveillance radar concept  

Microsoft Academic Search

Noise modulated surveillance radars have many desirable properties. However, practical problems with signal processing and system design have inhibited noise modulated radars to become common. Fast improving signal processing will probably change this in future. We have studied what kind of noise modulated radar might be realistic in 15 years. Advantages are good LPI, good ECCM, good ARM avoidance, good

Vesa-Jukka Salminen; Timo Lensu; Pekka Eskelinen; Simo Mertanen

2006-01-01

405

CWLFM Radar for Ship Detection and Identification  

Microsoft Academic Search

Continuous wave lineal frequency modulated (CWLFM) radar presents some interesting advantages for coast surveillance and control as well as low probability of interception (LPI). This paper presents real results obtained with a radar prototype and processed with ISAR techniques. Also, results of an automatic ship identification system applied to simulated ISAR images are exposed. Moreover, radar behavior with unfavorable meteorological

C. C. Duarte; B. P. Dorta Naranjo; A. A. Lopez; A. B. del Campo

2007-01-01

406

Autonomous deployment of the UAVSAR radar instrument  

Microsoft Academic Search

The UAVSAR program was formed to provide repeat pass radar interferometry on an uninhabited aircraft platform. The UAVSAR imaging radar system is housed in an external unpressurized pod that may be attached to an Uninhabited Aerial Vehicle (UAV), although initial flight tests were performed aboard a Gulfstream-III aircraft with flight test personnel on-board. Since the radar science missions are to

K. Vines; R. Chao

2010-01-01

407

UAV Collision Avoidance Radar - Build and Test  

Microsoft Academic Search

This paper describes an experimental radar and data recording system designed to provide the 'sense and avoid' capability required by UAV's to fly in uncontrolled airspace. The radar incorporates the MIMO technique, forming multiple staring beams giving wide angular protection. Algorithms for detection in clutter, tracking, and miss-distance estimation for this radar have been developed, based on synthesised data only,

Benjamin J. Shannon; Ashoka Halappa; Ian D. Longstaff

408

Spaceborne radar remote sensing: Applications and techniques  

Microsoft Academic Search

The operation and applications of spaceborne radars for terrestrial and planetary remote sensing are described in an introduction for advanced students and practicing scientists. Chapters are devoted to imaging radars, wave-surface interactions and geoscientific applications, real- and synthetic-aperture radars, end-to-end system design, SAR data processing, altimeters, and scatterometers. Extensive diagrams, drawings, graphs, photographs, and sample radar images are provided.

Charles Elachi

1988-01-01

409

Short vertical-wavelength inertia-gravity waves generated by a jet-front system at Arctic latitudes - VHF radar, radiosondes and numerical modelling  

NASA Astrophysics Data System (ADS)

Inertia-gravity waves with very short vertical wavelength (?z?1000 m) are a very common feature of the lowermost stratosphere as observed by the 52 MHz radar ESRAD (Esrange MST radar) in northern Scandinavia (67.88° N, 21.10° E). The waves are seen most clearly in radar-derived profiles of buoyancy frequency (N). Here, we present a case study of typical waves from 21 February to 22 February 2007. Good agreement between N2 derived from radiosondes and by radar shows the validity of the radar determination of N2. Large-amplitude wave signatures in N2 are clearly observed by the radar and the radiosondes in the lowermost stratosphere, from 9 km to 14-16 km height. Vertical profiles of horizontal wind components and potential temperature from the radiosondes show the same waves. Mesoscale simulations with the Weather Research and Forecasting (WRF) model are carried out to complement the analysis of the waves. Good agreement between the radar and radiosonde measurements and the model (except for the wave amplitude) shows that the model gives realistic results and that the waves are closely associated to the upper-level front in an upper-troposphere jet-front system. Hodographs of the wind fluctuations from the radiosondes and model data show that the waves propagate upward in the lower stratosphere confirming that the origin of the waves is in the troposphere. The observations and modelling all indicate vertical wavelengths of 700 ± 200 m. The radiosonde hodograms indicate horizontal wavelengths between 40 and 110 km and intrinsic periods between 6 and 9 h. The wave amplitudes indicated by the model are however an order of magnitude less than in the observations. Finally, we show that the profiles of N2 measured by the radar can be used to estimate wave amplitudes, horizontal wavelengths, intrinsic periods and momentum fluxes which are consistent with the estimates from the radiosondes.

Réchou, A.; Kirkwood, S.; Arnault, J.; Dalin, P.

2014-07-01

410

Extended target recognition in cognitive radar networks.  

PubMed

We address the problem of adaptive waveform design for extended target recognition in cognitive radar networks. A closed-loop active target recognition radar system is extended to the case of a centralized cognitive radar network, in which a generalized likelihood ratio (GLR) based sequential hypothesis testing (SHT) framework is employed. Using Doppler velocities measured by multiple radars, the target aspect angle for each radar is calculated. The joint probability of each target hypothesis is then updated using observations from different radar line of sights (LOS). Based on these probabilities, a minimum correlation algorithm is proposed to adaptively design the transmit waveform for each radar in an amplitude fluctuation situation. Simulation results demonstrate performance improvements due to the cognitive radar network and adaptive waveform design. Our minimum correlation algorithm outperforms the eigen-waveform solution and other non-cognitive waveform design approaches. PMID:22163464

Wei, Yimin; Meng, Huadong; Liu, Yimin; Wang, Xiqin

2010-01-01

411

German Radar Observation Shuttle Experiment (ROSE)  

NASA Technical Reports Server (NTRS)

The success of radar sensors in several different application areas of interest depends on the knowledge of the backscatter of radar waves from the targets of interest, the variance of these interaction mechanisms with respect to changing measurement parameters, and the determination of the influence of he measuring systems on the results. The incidence-angle dependency of the radar cross section of different natural targets is derived. Problems involved by the combination of data gained with different sensors, e.g., MSS-, TM-, SPOTand SAR-images are analyzed. Radar cross-section values gained with ground-based radar spectrometers and spaceborne radar imaging, and non-imaging scatterometers and spaceborne radar images from the same areal target are correlated. The penetration of L-band radar waves into vegetated and nonvegetated surfaces is analyzed.

Sleber, A. J.; Hartl, P.; Haydn, R.; Hildebrandt, G.; Konecny, G.; Muehlfeld, R.

1984-01-01

412

Intermediate photovoltaic system application experiment operational performance report. Volume 5 for Mt. Laguna Radar Station, Mt. Laguna, CA  

SciTech Connect

For the month of November, 1981, performance data are given for a photovoltaic power supply at a California radar station. Data given include: daily and monthly electric energy production; daily and monthly solar energy incident; daily and monthly array efficiency; electric energy production vs. power level, voltage, cell temperature, and hour of the day; power conditioning system input, output, and efficiency; daily and monthly electric energy provided by the photovoltaic system to the load; photovoltaic system efficiency; capacity factor; system availability; heating and cooling degree days; daily and hourly insolation, ambient temperature, and wind speed; wind direction distribution; hourly cell temperature; number of freeze-thaw cycles; and system efficiency. Also included is a brief narrative section to provide information not easily included in the computer-generated modules. (LEW)

Not Available

1981-12-01

413

Optimization of a 50 MHz Frequency Modulated Continuous Wave Radar system for the study of auroral E-region coherent backscatter  

NASA Astrophysics Data System (ADS)

A 50 MHz Frequency Modulated Continuous Wave (FMCW) radar system has been developed at the University of Saskatchewan to provide excellent spatial and temporal resolution measurements of auroral E-region plasma processes. An undesirable feature of the otherwise highly effective FMCW system is the introduction of ambiguous spectral information, due to spectral ghosting, for scattering events in which multiple radar echoes are detected. The use of two Linearly Frequency Modulated (LFM) waveforms which extract the range and Doppler frequency information from the radar echoes, is the source of a data association problem, causing the spectral ghosting feature. An alternative frequency coded-CW radar waveform with noise-like properties is investigated as a replacement for the LFM waveforms. The proposed waveform, which is known as a composite Costas waveform, maintains the spatial and temporal resolutions of the FMCW system and prevents data association problems. The implementation of the proposed waveform with state-of-the-art signal generation hardware presents opportunities for the development of a coded-CW mono-static radar system for auroral E-region studies.

Perry, G. W.; Hussey, G. C.

2010-12-01

414

Millimeter wave radar system on a rotating platform for combined search and track functionality with SAR imaging  

NASA Astrophysics Data System (ADS)

Ground based millimeter wave radar sensors offer the potential for a weather-independent automatic ground surveillance at day and night, e.g. for camp protection applications. The basic principle and the experimental verification of a radar system concept is described, which by means of an extreme off-axis positioning of the antenna(s) combines azimuthal mechanical beam steering with the formation of a circular-arc shaped synthetic aperture (SA). In automatic ground surveillance the function of search and detection of moving ground targets is performed by means of the conventional mechanical scan mode. The rotated antenna structure designed as a small array with two or more RX antenna elements with simultaneous receiver chains allows to instantaneous track multiple moving targets (monopulse principle). The simultaneously operated SAR mode yields areal images of the distribution of stationary scatterers. For ground surveillance application this SAR mode is best suited for identifying possible threats by means of change detection. The feasibility of this concept was tested by means of an experimental radar system comprising of a 94 GHz (W band) FM-CW module with 1 GHz bandwidth and two RX antennas with parallel receiver channels, placed off-axis at a rotating platform. SAR mode and search/track mode were tested during an outdoor measurement campaign. The scenery of two persons walking along a road and partially through forest served as test for the capability to track multiple moving targets. For SAR mode verification an image of the area composed of roads, grassland, woodland and several man-made objects was reconstructed from the measured data.

Aulenbacher, Uwe; Rech, Klaus; Sedlmeier, Johannes; Pratisto, Hans; Wellig, Peter

2014-10-01

415

A highly capable arbitrary waveform generator for next generation radar systems  

NASA Technical Reports Server (NTRS)

We are developing an Arbitrary Waveform Generator (AWG) to provide enhanced capability for radar applications. The current design will accommodate two waveform generators on a single unit for dual frequency operation. The basic architecture of this unit employs a Field Programmable Gate Array (FPGA) and a high speed and high precision Digital to Analog Converter (DAC) for direct digital synthesis. This AWG will be capable of up to 450 MHz bandwidth with ability for frequency notching. Phase fidelity of less than 1.2(sup o) deviation RMS is also achievable. This AWG operates with lower power consumption as compared with other waveform generators, which is advantageous for future spaceborne applications. This will enable radars to return higher precision data, to be reduced in complexity, and to operate in any band without interfering with dedicated bandwidths.

Chuang, Ernie; Hensley, Scott; Wheeler, Kevin

2006-01-01

416

Detection of aquifer system compaction and land subsidence using interferometric synthetic aperture radar, Antelope Valley, Mojave Desert, California  

USGS Publications Warehouse

Interferometric synthetic aperture radar (InSAR) has great potential to detect and quantify land subsidence caused by aquifer system compaction. InSAR maps with high spatial detail and resolution of range displacement (??10 mm in change of land surface elevation) were developed for a groundwater basin (~103 km2) in Antelope Valley, California, using radar data collected from the ERS-1 satellite. These data allow comprehensive comparison between recent (1993-1995) subsidence patterns and those detected historically (1926-1992) by more traditional methods. The changed subsidence patterns are generally compatible with recent shifts in land and water use. The InSAR-detected patterns are generally consistent with predictions based on a coupled model of groundwater flow and aquifer system compaction. The minor inconsistencies may reflect our imperfect knowledge of the distribution and properties of compressible sediments. When used in conjunction with coincident measurements of groundwater levels and other geologic information, InSAR data may be useful for constraining parameter estimates in simulations of aquifer system compaction.

Galloway, D.L.; Hudnut, K.W.; Ingebritsen, S.E.; Phillips, S.P.; Peltzer, G.; Rogez, F.; Rosen, P.A.

1998-01-01

417

The DEFENSE (debris Flows triggEred by storms - nowcasting system): An early warning system for torrential processes by radar storm tracking using a Geographic Information System (GIS)  

NASA Astrophysics Data System (ADS)

Debris flows, responsible for economic losses and occasionally casualties in the alpine region, are mainly triggered by heavy rains characterized by hourly peaks of varying intensity, depending on the features of the basin under consideration. By integrating a recent classification of alpine basins with the radar storm tracking method, an innovative early warning system called DEFENSE (DEbris Flows triggEred by storms - Nowcasting SystEm) was developed using a Geographical Information System (GIS). Alpine catchments were classified into three main classes based on the weathering capacity of the bedrock into clay or clay-like minerals, the amount of which, in unconsolidated material, directly influences the debris flow rheology, and thus the sedimentary processes, the alluvial fan architecture, as well as the triggering frequency and seasonal occurrence probability of debris flows. Storms were identified and tracked by processing weather radar observations; subsequently, rainfall intensities and storm severity were estimated over each classified basin. Due to rainfall threshold values determined for each basin class, based on statistical analysis of historical records, an automatic corresponding warning could be issued to municipalities.

Tiranti, Davide; Cremonini, Roberto; Marco, Federica; Gaeta, Armando Riccardo; Barbero, Secondo

2014-09-01

418

Instantaneous Radar Polarimetry with Multiple Dually-polarized Antennas  

E-print Network

1 Instantaneous Radar Polarimetry with Multiple Dually-polarized Antennas A. R. Calderbank,1 S. D radar systems are capable of simultaneously transmitting and receiving in two orthogonal polarizations. Instantaneous radar polarimetry exploits both polarization modes of a dually-polarized radar transmitter

Pezeshki, Ali

419

Sparsity-based MIMO Noise Radar for Multiple Target Estimation  

E-print Network

in radar applications since they provide a low probability of intercept (LPI) [10]. Recently, there hasSparsity-based MIMO Noise Radar for Multiple Target Estimation Sandeep Gogineni, Student Member using a colocated multiple-input multiple-output (MIMO) radar system. Each antenna of the radar array

Nehorai, Arye

420

Use of ground-penetrating radar technology in construction of the Los Angeles MetroRail subway system  

NASA Astrophysics Data System (ADS)

State-of-the-art ground penetrating radar (GPR) technology was used successfully in tunneling through the former L.A. City Oil Field to search for uncharted, abandoned oil wells. A magnetometer probe was previously used for this purpose, because it was felt abandoned oil wells with steel casings may exist ahead of tunneling. These wells were suspected to contain methane gases which could be released into the tunnels. Studies revealed the abandoned wells could be wooden-cased or uncased open holes, indicating they would not be detected using a magnetometer probe. GPR was therefore selected as a geophysical technique more capable of detecting both steel-cased and uncased oil wells. After some initial testing from inside the tunnel, a commercially available GPR system was selected. Procedures were developed for conducting the surveys and evaluating the data profiles for possible oil wells. The profiles were obtained by moving the radar antenna across the smoothed tunnel face. During tunnelling of the oil field area abandoned oil wells were not encountered. However, the GPR surveys did detect anomalous radar reflections that the machine operator was alerted to as possible oil wells. Review of the data indicates that other changes in ground conditions were detected, such as transitions from soft- to hard-ground conditions and zones of oil bearing sands. These results suggest GPR could be useful for other exploratory applications during mining. GPR was also used as an investigative tool to check for possible shallow subsurface voids from the ground surface. Air-filled cavities or voids beneath city streets can sometimes be formed as a result of deeper tunneling-induced ground movements, resulting in dangerous sink-hole forming conditions. The GPR surveys were conducted from the street surface above the tunnels in areas where geotechnical data measured greater ground movements. These surveys helped rule out the possibility of voids beneath the street pavement in an area where over nine inches of ground settlement was measured.

Hebert, Christopher D.; Olson, Mark G.

1995-05-01

421

Rain radar instrument definition  

Microsoft Academic Search

As a result of a pre-phase a study, founded by ESA, this paper presents the definition of a spaceborne Rain Radar, candidate instrument for earth explorer precipitation mission. Based upon the description of user requirements for such a dedicated mission, a mission analysis defines the most suitable space segment. At system level, a parametric analysis compares pros and cons of

N. Vincent; J. Chenebault; Noel Suinot; P. L. Mancini

1996-01-01

422

The impact of reflectivity correction and accounting for raindrop size distribution variability to improve precipitation estimation by weather radar for an extreme low-land mesoscale convective system  

NASA Astrophysics Data System (ADS)

Between 25 and 27 August 2010 a long-duration mesoscale convective system was observed above the Netherlands, locally giving rise to rainfall accumulations exceeding 150 mm. Correctly measuring the amount of precipitation during such an extreme event is important, both from a hydrological and meteorological perspective. Unfortunately, the operational weather radar measurements were affected by multiple sources of error and only 30% of the precipitation observed by rain gauges was estimated. Such an underestimation of heavy rainfall, albeit generally less strong than in this extreme case, is typical for operational weather radar in The Netherlands. In general weather radar measurement errors can be subdivided into two groups: (1) errors affecting the volumetric reflectivity measurements (e.g. ground clutter, radar calibration, vertical profile of reflectivity) and (2) errors resulting from variations in the raindrop size distribution that in turn result in incorrect rainfall intensity and attenuation estimates from observed reflectivity measurements. A stepwise procedure to correct for the first group of errors leads to large improvements in the quality of the estimated precipitation, increasing the radar rainfall accumulations to about 65% of those observed by gauges. To correct for the second group of errors, a coherent method is presented linking the parameters of the radar reflectivity-rain rate (Z - R) and radar reflectivity-specific attenuation (Z - k) relationships to the normalized drop size distribution (DSD). Two different procedures were applied. First, normalized DSD parameters for the whole event and for each precipitation type separately (convective, stratiform and undefined) were obtained using local disdrometer observations. Second, 10,000 randomly generated plausible normalized drop size distributions were used for rainfall estimation, to evaluate whether this Monte Carlo method would improve the quality of weather radar rainfall products. Using the disdrometer information, the best results were obtained in case no differentiation between precipitation type (convective, stratiform and undefined) was made, increasing the event accumulations to more than 80% of those observed by gauges. For the randomly optimized procedure, radar precipitation estimates further improve and closely resemble observations in case one differentiates between precipitation type. However, the optimal parameter sets are very different from those derived from disdrometer observations. It is therefore questionable if single disdrometer observations are suitable for large-scale quantitative precipitation estimation, especially if the disdrometer is located relatively far away from the main rain event, which was the case in this study. In conclusion, this study shows the benefit of applying detailed error correction methods to improve the quality of the weather radar product, but also confirms the need to be cautious using locally obtained disdrometer measurements.

Hazenberg, Pieter; Leijnse, Hidde; Uijlenhoet, Remko

2014-11-01

423

Paleodrainages of the Eastern Sahara - The radar rivers revisited (SIR-A/B implications for a mid-tertiary Trans-African drainage system)  

NASA Technical Reports Server (NTRS)

The images obtained by the Shuttle Imaging Radar (SIR)-A and -B systems over the southwestern Egypt and northwestern Sudan were coregistered with the Landsat images and the existing maps to aid in extrapolations of the buried paleodrainages ('radar rivers'), first discovered by SIR-A. Field observations explain the radar responses of three types of radar rivers, RR-1 (broad, aggraded valleys filled with alluvium), RR-2 (braided channels inset in the RR-1 valleys), and RR-3 (narrow, long, bedrock-incised channels). A generalized model of the radar rivers, based on field studies and regional geologic relations, shows inferred changes in river regimen since the large valleys were established during the later Paleogene-early Neogene. It is suggested that a former Trans-African master stream system may have flowed from headwaters in the Red Sea Hills southwestward across North Africa, discharging into the Atlantic at the Paleo-Niger delta, prior to the Neogene domal uplifts and building of volcanic edifices across the paths of these ancient watercourses.

Mccauley, J. F.; Breed, C. S.; Schaber, G. G.; Mchugh, W. P.; Haynes, C. C.

1986-01-01

424

Solar Radar  

NASA Astrophysics Data System (ADS)

Radar echoes from the Sun were first detected in 1959 at 25 MHz and an extensive set of measurements was made at 38 MHz between 1960 and 1969. The results were unexpected and could not be explained at the time. Interest in the technique waned and radar astronomy evolved to the use of higher frequencies so it became impossible to repeat the measurements. The early observations can be explained in the light of our present understanding of the corona. New radar observations, with correlative optical, UV, and soft X-ray observations, would be very useful in probing the corona near the origin of the solar wind. Radar measures the range to the reflection point and the plasma velocity at the reflection point. Reflection occurs where the dielectric constant goes to zero, which is polarization dependent. Thus dual polarization observations provide estimates of the electron density, magnetic field, and velocity at the reflection point. Solar echoes can be observed at frequencies between 18 MHz and 100 MHz, corresponding to reflection heights between (roughly) 1.8 Rs and 1.15 Rs. It may be possible to operate up to 200 MHz and probe to the edge of the transition region. Here we will review the early observations; explain their basic features; outline existing and potential opportunities for new observations; and speculate on the future development of the technique.

Coles, W. A.

2002-12-01

425

L-band radar scattering from grass  

NASA Technical Reports Server (NTRS)

A radar system based on a network analyzer has been developed to study the backscatter from vegetation. The radar is operated at L-band. Radar measurements of a grass field were made in 1991. The radar returns from the grass were measured at three incidence angles. Ground truth and canopy parameters such as blade and stem dimensions, moisture content of the grass and the soil, and blade and stem density, were measured. These parameters are used in a distorted Born approximation model to compute the backscatter coefficients from the grass layer. The model results are compared with the radar data.

Chauhan, N.; O'Neill, P.; Le Vine, D.; Lang, R.; Khadr, N.

1992-01-01

426

Comet Radar Explorer  

NASA Astrophysics Data System (ADS)

Comet Radar Explorer (CORE) is a low cost mission that uses sounding radar to image the 3D internal structure of the nucleus of Jupiter-family comet (JFC) Tempel 2. Believed to originate in the Kuiper Belt, JFCs are among the most primitive bodies in the inner solar system. CORE operates a 5 and 15 MHz Radar Reflection Imager from close orbit about the nucleus of Tempel 2, obtaining a dense network of echoes that are used to map its interior dielectric contrasts to high resolution (? m) and resolve the dielectric constants to ? m throughout the 16x8x9 km nucleus. The resulting clear images of internal structure and composition reveal how the nucleus was formed and how it has evolved. Radiometric tracking of the spacecraft orbit results in an interior mass distribution that constrains the radar-based models of interior composition. High-resolution visible and infrared color images provide the surface and exterior boundary conditions for interior models and hypotheses. They present the geology and morphology of the nucleus surface at meter-scales, and also the time-evolving activity, structure and composition of the inner coma. By making deep connections from interior to exterior, the data CORE provides will answer fundamental questions about the earliest stages of planetesimal evolution and planet formation, and lay the foundation for a comet nucleus sample return mission. CORE is led by Prof. Erik Asphaug of the University of California, Santa Cruz and is managed by JPL. It benefits from key scientific and payload contributions by ASI and CNES. The international science team has been assembled on the basis of their key involvement in past and ongoing missions to comets, and in Mars radar missions, and for their expertise in radar data analysis.

Asphaug, Erik; CORE Science Team

2010-10-01

427

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

428

Polar mesospheric summer echoes at 78°N, 16°E, 2008: First results of the refurbished sounding system (SOUSY) Svalbard radar  

NASA Astrophysics Data System (ADS)

The second-generation sounding system (SOUSY) 53.5-MHz mesosphere-stratosphere-troposphere (MST) radar at 78°N, 16°E on Svalbard has recently completed its inaugural summer, 2008, of polar mesospheric summer echoes (PMSE) observations. Here PMSE observations have been assembled in order to identify dates of the earliest and latest occurrences and how the frequency of PMSE occurrence correlates with dynamics and temperature, which are available from the collocated Nippon/Norway Svalbard Meteor 31-MHz Radar (NSMR). We find strong correlations between preferred PMSE altitude and low temperature, and between equatorward flow and occurrence rate. Temperature drops cause increases in PMSE occurrence: for the height interval 82-92 km, a drop of around 7 K increases the occurrence, typically by 1-2% d-1 and similarly for a 1 m s-1 increase in equatorward wind. A temperature drop of 5 K at 90 km altitude results in a lowering of the underlying preferred PMSE altitude by 1 km. This study therefore qualifies, at least for 78°N, 16°E and 2008, the dependence of PMSE occurrence rates and preferred heights on 90 km temperature and dynamics.

Hall, C. M.; RöTtger, J.; Kuyeng, K.; Tsutsumi, M.; Dyrland, M.; Chau, J. L.

2009-06-01

429

RONSARD Radar: Implementation of Dual Polarization on a C-Band Doppler Weather Radar  

Microsoft Academic Search

The French C-band meteorological Doppler radar Recherche sur les Orages et Nuages par un Systeme Associe de Radars Doppler (RONSARD) was recently equipped with dual polarization. This modification required, on the one hand, an additional receiver and, on the other hand, a new design for the antenna geometry in order to decrease strongly the sidelobe level. This new radar configuration

Georges Scialom; Jacques Faroux; Manuel Giraud; Richard Ney; Raquel Evaristo; Yvon Lemaitre; Nicolas Viltard

2009-01-01

430

Calibration of radar reflectivity measurements from the KMA operational radar network  

Microsoft Academic Search

A systematic procedure for calibrating system gain bias (so-called “calibration error”) of radar reflectivity measurements\\u000a from the Korea Meteorological Administration (KMA) operational radar network is presented. First, the RJNI radar located at\\u000a Jindo Island is calibrated by comparing with radar reflectivities simulated theoretically by a scattering algorithm using\\u000a drop spectra collected by a disdrometer from June 19 to 29, 2009.

S.-G. Park; Gyuwon Lee

2010-01-01

431

Simulation of orbital radar images  

NASA Technical Reports Server (NTRS)

The operating parameters for spaceborne synthetic aperture imaging radar systems was addressed in the cost effective manner by using simulation techniques. The use of airborne images, Seasat images, and computer simulation were the first computer simulation of spaceborne radar imagery was analyzed for system definition studies. Analysis of the simulation indicates that incidence angles as small as 30 are useful for general terrain geomorphologic analysis.

Saunders, R. S.; Holtzman, J. C.; Elachi, C.

1980-01-01

432

Using doppler radar images to estimate aircraft navigational heading error  

DOEpatents

A yaw angle error of a motion measurement system carried on an aircraft for navigation is estimated from Doppler radar images captured using the aircraft. At least two radar pulses aimed at respectively different physical locations in a targeted area are transmitted from a radar antenna carried on the aircraft. At least two Doppler radar images that respectively correspond to the at least two transmitted radar pulses are produced. These images are used to produce an estimate of the yaw angle error.

Doerry, Armin W. (Albuquerque, NM); Jordan, Jay D. (Albuquerque, NM); Kim, Theodore J. (Albuquerque, NM)

2012-07-03

433

A Cloud and Precipitation Radar System Concept for the ACE Mission  

NASA Technical Reports Server (NTRS)

One of the instruments recommended for deployment on the Aerosol/Cloud/Ecosystems (ACE) mission is a new advanced cloud profiling radar. In this paper, we describe such a radar design, called ACERAD, which has 35- and 94-GHz channels, each having Doppler and dual-polarization capabilities. ACERAD will scan at Ka-band and will be nadir-looking at W-band. To get a swath of 25-30 km, considered the minimum useful for Ka-band, ACERAD needs to scan at least 2 degrees off nadir; this is at least 20 beamwidths, which is quite large for a typical parabolic reflector. This problem is being solved with a Dragonian design; a scaled prototype of the antenna is being fabricated and will be tested on an antenna range. ACERAD also uses a quasi-optical transmission line at W-band to connect the transmitter to the antenna and antenna to the receiver. A design for this has been completed and is being laboratory tested. This paper describes the current ACERAD design and status.

Durden, S. L.; Tanelli, S.; Epp, L.; Jamnejad, V.; Perez, R.; Prata, A.; Samoska, L.; Long, E; Fang, H.; Esteban-Fernandez, D.; Lee, C.

2011-01-01

434

A Bistatic Parasitical Radar (BIPAR)  

NASA Astrophysics Data System (ADS)

After decades of remote sensing from aircraft and satellites with cameras and other optical sensors, earth observation by imaging radars becomes more and more suitable because of their night and day and all weather operations capability and their information content being complementary to those of optical sensors. The major problem with microwave sensors (radars) is that there are not enough of them presently in operation and therefore not enough data available for effective radar signature research for civil applications. It is shown that airborne bistatic real aperture radar receivers can be operated with spaceborne transmitters of opportunity. Famous candidates for those systems are high power communications or direct TV satellites illuminating the earth surface with a power denisty of more than 10(-12) Watt/sq meter. The high sophisticated status of signal processing technology today allows the realization of receivers correlating the received direct path signal from a communications satellite with its avoidable reflection on the ground. Coherent integration can improve the signal to noise ratio up to values where the radiometric resolution can satisfy users needs. The development of such parasitic radar receivers could even provide a cost effective way to open up new frequency bands for radar signature research. Advantages of these quiet systems for the purpose of classical radar reconnaissance are evident.

Hartl, Philipp; Braun, Hans Martin

1989-01-01

435

Electromagnetic approaches to wall characterization, wall mitigation, and antenna design for through-the-wall radar systems  

NASA Astrophysics Data System (ADS)

Through-the-wall imaging (TWI) is a topic of current interest due to its wide range of public safety, law enforcement, and defense applications. Among the various available technologies such as, acoustic, thermal, and optical imaging, which can be employed to sense and image targets of interest, electromagnetic (EM) imaging, in the microwave frequency bands, is the most widely utilized technology and has been at the forefront of research in recent years. The primary objectives for any Through-the-Wall Radar Imaging (TWRI) system are to obtain a layout of the building and/or inner rooms, detect if there are targets of interest including humans or weapons, determine if there are countermeasures being employed to further obscure the contents of a building or room of interest, and finally to classify the detected targets. Unlike conventional radar scenarios, the presence of walls, made of common construction materials such as brick, drywall, plywood, cinder block, and solid concrete, adversely affects the ability of any conventional imaging technique to properly image targets enclosed within building structures as the propagation through the wall can induce shadowing effects on targets of interest which may result in image degradation, errors in target localization, and even complete target masking. For many applications of TWR systems, the wall ringing signals are strong enough to mask the returns from targets not located a sufficient distance behind the wall, beyond the distance of the wall ringing, and thus without proper wall mitigation, target detection becomes extremely difficult. The results presented in this thesis focus on the development of wall parameter estimation, and intra-wall and wall-type characterization techniques for use in both the time and frequency domains as well as analysis of these techniques under various real world scenarios such as reduced system bandwidth scenarios, various wall backing scenarios, the case of inhomogeneous walls, presence of ground reflections, and situations where they may be applied to the estimation of the parameters associated with an interior wall. It is demonstrated through extensive computer simulations and laboratory experiments that, by proper exploitation of the electromagnetic characteristics of walls, one can efficiently extract the constitutive parameters associated with unknown wall(s) as well as to characterize and image the intra-wall region. Additionally, it is possible, to a large extent, to remove the negative wall effects, such as shadowing and incorrect target localization, as well as to enhance the imaging and classification of targets behind walls. In addition to the discussion of post processing the radar data to account for wall effects, the design of antenna elements used for transmit (Tx) and receive (Rx) operations in TWR radars is also discussed but limited to antennas for mobile, handheld, or UAV TWR systems which impose design requirements such as low profiles, wide operational bands, and in most cases lend themselves to fabrication using surface printing techniques. A new class of wideband antennas, formed though the use of printed metallic paths in the form of Peano and Hilbert space-filling curves (SFC) to provide top-loading properties that miniaturize monopole antenna elements, has been developed for applications in conformal and/or low profile antennas systems, such as mobile platforms for TWRI and communication systems. Additionally, boresight gain enhancements of a stair-like antenna geometry, through the addition of parasitic self-similar patches and gate like ground plane structures, are presented.

Thajudeen, Christopher

436

Space Radar Images of Earth  

NSDL National Science Digital Library

Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR), part of NASA's Mission to Planet Earth, is studying how our global environment is changing. From the unique vantage point of space, the radar system observes, monitors and assesses large-scale environmental processes with a focus on climate change. The spaceborne data, complemented by aircraft and ground studies, gives scientists highly detailed information that will help them distinguish natural environmental changes from those that are the result of human activity. The images are divided into nine categories for easier viewing.

437

Middle Atmosphere Program. Handbook for MAP. Volume 30: International School on Atmospheric Radar  

NASA Technical Reports Server (NTRS)

Broad, tutorial coverage is given to the technical and scientific aspects of mesosphere stratosphere troposphere (MST) meteorological radar systems. Control issues, signal processing, atmospheric waves, the historical aspects of radar atmospheric dynamics, incoherent scatter radars, radar echoes, radar targets, and gravity waves are among the topics covered.

Fukao, Shoichiro (editor)

1989-01-01

438

Preliminary data on the nature of the planetary system of lineaments observed on Venera 15 and 16 radar images of Venus  

NASA Astrophysics Data System (ADS)

The paper presents a detailed description of the planetary system of lineaments observed on Venera 15 and 16 radar images of Venus. The results suggest that the rotation of Venus was more rapid in the past, and that rotational forces might have made a substantial contribution to the formation of the structural and tectonic character of the planet.

Sliuta, E. N.; Kudrin, L. V.; Sinilo, V. P.

1989-11-01

439

A 77 GHz Transceiver for Automotive Radar System Using a120nm In AlAs/In GaAs Metamorphic HEMTs  

E-print Network

A 77 GHz Transceiver for Automotive Radar System Using a120nm 0.4 0.35 In AlAs/In GaAs Metamorphic. Compared with this, Metamorphic HEMT (MHEMT) has higher gain and lower noise characteristics at high

Kwon, Youngwoo

440

Rain radar instrument definition  

NASA Astrophysics Data System (ADS)

As a result of a pre-phase a study, founded by ESA, this paper presents the definition of a spaceborne Rain Radar, candidate instrument for earth explorer precipitation mission. Based upon the description of user requirements for such a dedicated mission, a mission analysis defines the most suitable space segment. At system level, a parametric analysis compares pros and cons of instrument concepts associated with rain rate retrieval algorithms in order to select the most performing one. Several trade-off analysis at subsystem level leads then to the definition of the proposed design. In particular, as pulse compression is implemented in order to increase the radar sensitivity, the selected method to achieve a pulse response with a side-lobe level below--60 dB is presented. Antenna is another critical rain radar subsystem and several designs are com pared: direct radiating array, single or dual reflector illuminated by single or dual feed arrays. At least, feasibility of centralized amplification using TWTA is compared with criticality of Tx/Rx modules for distributed amplification. Mass and power budgets of the designed instrument are summarized as well as standard deviations and bias of simulated rain rate retrieval profiles. The feasibility of a compliant rain radar instrument is therefore demonstrated.

Vincent, Nicolas; Chenebault, J.; Suinot, Noel; Mancini, Paolo L.

1996-12-01

441

Inverse problems arising in different synthetic aperture radar imaging systems and a general Bayesian approach for them  

NASA Astrophysics Data System (ADS)

Synthetic Aperture Radar (SAR) imaging systems are nowadays very common technics of imaging in remote sensing and environment survey. There are different acquisition modes: spotlight, stripmap, scan; different geometries: mono-, bi- and multi-static; and varieties of specific applications: interferometric SAR (InSAR), polarimetric SAR etc. In this paper, first a common inverse problem framework for all of them is given, and then basics of SAR imaging and the classical deterministic inversion methods are presented. Aiming at overcoming the inadequacies of deterministic methods, a general probabilistic Bayesian estimation method is pioneered for solving image reconstruction problems. In particular, two priors which simply allow the automated determination of the hyperparameters in a Type-II likelihood framework are considered. Finally, the performances of the proposed methods on synthetic data.

Zhu, Sha; Mohammad-Djafari, Ali; Li, Xiang; Mao, Junjie

2011-03-01

442

The development of a power spectral density processor for C and L band airborne radar scatterometer sensor systems  

NASA Technical Reports Server (NTRS)

A real-time signal processor was developed for the NASA/JSC L-and C-band airborne radar scatterometer sensor systems. The purpose of the effort was to reduce ground data processing costs. Conversion of two quadrature channels of data (like and cross polarized) was made to obtain Power Spectral Density (PSD) values. A chirp-z transform (CZT) approach was used to filter the Doppler return signal and improved high frequency and angular resolution was realized. The processors have been tested with record signals and excellent results were obtained. CZT filtering can be readily applied to scatterometers operating at other wavelengths by altering the sample frequency. The design of the hardware and software and the results of the performance tests are described in detail.

Harrison, D. A., III; Chladek, J. T.

1983-01-01

443

Intermediate photovoltaic system application experiment operational performance report. Volume 3 for Mt. Laguna Radar Station, Mt. Laguna, California  

SciTech Connect

Performance data are given for a photovoltaic power supply at a California radar station for the month of August, 1981. The daily and monthly electric energy production, insolation, and efficiency are given. Energy production is graphed as a function of power level, array field voltage, cell temperature, and hour of the day. The input, output and efficiency of the power conditioner are given. The daily system availability is graphed. Heating and cooling loads, average ambient temperature, and average wind speed are given for the month, and cell temperature, ambient temperature, wind speed and insolation are graphed as a function of the hour of the day. Also the number of occurrences of winds at different azimuth angles is graphed. (LEW)

Not Available

1981-10-01

444

An Integrated Navigation System using GPS Carrier Phase for Real-Time Airborne Synthetic Aperture Radar (SAR)  

SciTech Connect

A Synthetic Aperture Radar (SAR) requires accu- rate measurement of the motion of the imaging plat- form to produce well-focused images with minimal absolute position error. The motion measurement (MoMeas) system consists of a inertial measurement unit (IMU) and a P-code GPS receiver that outputs corrected ephemeris, L1 & L2 pseudoranges, and L1 & L2 carrier phase measurements. The unknown initial carrier phase biases to the GPS satellites are modeled as states in an extended Kalman filter and the resulting integrated navigation solution has po- sition errors that change slowly with time. Position error drifts less than 1- cm/sec have been measured from the SAR imagery for various length apertures.

Fellerhoff, J. Rick; Kim, Theodore J.; Kohler, Stewart M.

1999-06-24

445

In-flight icing hazard detection radar  

Microsoft Academic Search

Technology Service Corporation (TSC) is developing a prototype dual-frequency airborne radar system for remotely sensing hazardous in-flight icing conditions. The system, which is based on integrating a Ka-band radar into a commercial X-band weather radar, will be used to demonstrate the feasibility of the differential attenuation technique used to remotely measure cloud liquid water content (LWC). This paper provides an

R. J. Lefevre; Charles A. Shipley; Donald N. Woods; Randy F. van Daden Wetters

2000-01-01

446

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

447

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

448

From Bursts to Back-Projection: Signal Processing Techniques for Earth and Planetary Observing Radars  

NASA Technical Reports Server (NTRS)

Discusses: (1) JPL Radar Overview and Historical Perspective (2) Signal Processing Needs in Earth and Planetary Radars (3) Examples of Current Systems and techniques (4) Future Perspectives in signal processing for radar missions

Rosen, Paul A.

2012-01-01

449

The Arecibo Observatory as an MST radar  

NASA Technical Reports Server (NTRS)

The radars and other systems at the Arecibo Observatory were designed and built, originally, for incoherent-scatter and radio-astronomy research. More recently, important additions have been made for planetary radar and artificial RF heating of the ionosphere. Although designed and built for a different application, these systems have shown to be very powerful tools for tropospheric, stratospheric and mesospheric research. The Observatory at present has two main radars: one at 430 and the other at 2380 MHz. In addition, 50-MHz MST radar work has been done using portable transmitters brought to the Observatory for this purpose. This capability will become permanent with the recent acquisition of a transmitter at this frequency. Furthermore, control and data processing systems have been developed to use the powerful HF transmitter and antennas of the HF-heating facility as an HF bistatic radar. A brief description of the four radars available at the Observatory is presented.

Woodman, R. F.

1983-01-01

450

The NASA Polarimetric Radar (NPOL)  

NASA Technical Reports Server (NTRS)

Characteristics of the NASA NPOL S-band dual-polarimetric radar are presented including its operating characteristics, field configuration, scanning capabilities and calibration approaches. Examples of precipitation science data collections conducted using various scan types, and associated products, are presented for different convective system types and previous field campaign deployments. Finally, the NASA NPOL radar location is depicted in its home base configuration within the greater Wallops Flight Facility precipitation research array supporting NASA Global Precipitation Measurement Mission ground validation.

Petersen, Walter A.; Wolff, David B.

2013-01-01

451

Development of dual-polarization radar in an active and passive dual-wavelength (X\\/Ka) microwave remote sensing system  

Microsoft Academic Search

In order to enhance the sensing power of precipitating clouds, a dual-polarization radar is developed to be added in an active and passive microwave dual-wavelength (X\\/Ka band) remote sensing system. After this upgrading of dual-polarization function addition, the advanced properties of the principle of the former remote sensing system are augmented. This upgraded system becomes a new capability of synthetically

Shu Duan; Ling Zhang; Jinli Liu

2003-01-01

452

New law enforcement applications of millimeter-wave radar  

NASA Astrophysics Data System (ADS)

Recent advances in millimeter-wave (MMW) radar technologies provide new applications for law enforcement use over-and- above the venerable speed timing radar. These applications include the potential to detect weapons under clothing and to conduct surveillance through walls. Concealed Weapon Detection and covert surveillance are of high interest to both the Department of Defense in support of Small Unit Operations and the Justice Department for civilian law enforcement applications. MMW sensors are under development which should provide the needed capabilities including radiometric sensors at 95 GHz, active 95 GHz real aperture radars, active focal plane array (FPA) radars, and holographic radars. Radiometric sensors include 2D FPA systems, 1D FPA, scanned systems, and single element scanned sensors. Active FPA radars include illuminated radiometric systems and coherent radar systems. Real aperture MMW radar systems include raster scanned and conical scanned sensors. Holographic systems ruse mechanical scanners to collect coherent data over a significant solid angular sector.

Currie, Nicholas C.; Ferris, David D., Jr.; McMillan, Robert W.; Wicks, Michael C.

1997-06-01

453

Design of intelligent testing device for airplane navigation radar  

Microsoft Academic Search

Modern airborne radar systems are very complex electronic equipment systems, high reliability is demanded, and fine functions of automatic detect is needed for guarantee. In this dissertation, we have studied the detect method of a new kind of airborne radar systems. With Embed machinery control as its core, adoption unit wooden blocks type construction, examining the faults of radar one

ZENG Xianlin; LI Lizhen

2008-01-01

454

Nonlinear trajectory generation for unmanned air vehicles with multiple radars  

Microsoft Academic Search

The problem of finding a real time optimal trajectory to minimize the probability of detection of unmanned air vehicles by opponent radar detection systems is investigated. This paper extends our preliminary results on low observable trajectory generation in three ways. First, trajectory planning in the presence of detection by multiple radar systems, rather than a single radar system, is considered.

Tamer Inanc; Kathy Misovec; Richard M. Murray

2004-01-01

455

High-resolution vertical imaging of the troposphere and lower stratosphere using the new MU radar system  

NASA Astrophysics Data System (ADS)

In the present paper, a new application of the range imaging technique called Frequency Interferometry Imaging (FII) or Range Imaging (RIM), performed in April 2005, is shown using the new 46.5-MHz Middle and Upper (MU) atmosphere radar system (Shigaraki, Japan). Height-time images of brightness distribution have been computed at the highest resolution ever obtained for imaging with VHF radars in the troposphere and, for the very first time, in the lower stratosphere, up to about 22 km. The images were produced by processing signals obtained with an initial range-resolution of ?r=150 m and five equally-spaced frequencies within ?f=1.0 MHz, with the adaptive Capon method. These values represent an improvement of a factor 2 over all the previous published experiments at VHF, which were performed with ?r=300 m and ?f=0.5 MHz. The Capon images present realistic and self-consistent features, and reveal many more organized structures than the height-time SNR plots at the initial range-resolution. For example, the Capon images show persistent enhanced brightness layers significantly thinner than 150 m in the stratosphere, which are impossible to track with the standard single-frequency mode owing to a lack of range resolution. These observations thus support the idea of strong stratification even at vertical scales much smaller than 100 m, as suggested by recent high-resolution temperature observations by balloons (Dalaudier et al., 1994). We also present comparisons of Capon images with patterns obtained from the dual-FDI technique and two parametric methods (the MUSIC algorithm and the newly-introduced Maximum Entropy Method based on an auto-regressive (AR) model). The comparisons confirm the insufficiencies of the dual-FDI technique and indicate that parametric methods such as MEM and the MUSIC algorithm can help to validate the Capon images when the parametric methods provide similar patterns.

Luce, H.; Hassenpflug, G.; Yamamoto, M.; Fukao, S.

2006-05-01

456

TerraSAR-X high-resolution radar remote sensing: an operational warning system for Rift Valley fever risk.  

PubMed

In the vicinity of the Barkedji village (in the Ferlo region of Senegal), the abundance and aggressiveness of the vector mosquitoes for Rift Valley fever (RVF) are strongly linked to rainfall events and associated ponds dynamics. Initially, these results were obtained from spectral analysis of high-resolution (~10 m) Spot-5 images, but, as a part of the French AdaptFVR project, identification of the free water dynamics within ponds was made with the new high-resolution (down to 3-meter pixels), Synthetic Aperture Radar satellite (TerraSAR-X) produced by Infoterra GmbH, Friedrichshafen/Potsdam, Germany. During summer 2008, within a 30 x 50 km radar image, it was found that identified free water fell well within the footprints of ponds localized by optical data (i.e. Spot-5 images), which increased the confidence in this new and complementary remote sensing technique. Moreover, by using near real-time rainfall data from the Tropical Rainfall Measuring Mission (TRMM), NASA/JAXA joint mission, the filling-up and flushing-out rates of the ponds can be accurately determined. The latter allows for a precise, spatio-temporal mapping of the zones potentially occupied by mosquitoes capable of revealing the variability of pond surfaces. The risk for RVF infection of gathered bovines and small ruminants (~1 park/km(2)) can thus be assessed. This new operational approach (which is independent of weather conditions) is an important development in the mapping of risk components (i.e. hazards plus vulnerability) related to RVF transmission during the summer monsoon, thus contributing to a RVF early warning system. PMID:21080318

Vignolles, Cécile; Tourre, Yves M; Mora, Oscar; Imanache, Laurent; Lafaye, Murielle

2010-11-01

457

Range ambiguity suppression for multiple-input, multiple-output synthetic aperture radar system using azimuth phase coding technique  

NASA Astrophysics Data System (ADS)

For synthetic aperture radar (SAR), range ambiguity causes a great deterioration in imaging performance. To suppress range ambiguity, the azimuth phase coding (APC) technique stands out for its effectiveness with a low implementation complexity among the available approaches. With proper phase modulation and demodulation, the position of an ambiguous signal is shifted in Doppler spectrum and then part of the ambiguity can be filtered out by an azimuth filter. However, since the suppression performance heavily depends on the system oversampling rate, the APC technique cannot achieve the same suppression performance for a multichannel SAR system compared with a single-channel SAR system. A method to suppress the range ambiguity for multiple-input, multiple-output (MIMO) SAR system based on APC technique is presented. By taking advantage of more phase centers of the MIMO SAR, a proper azimuth beamformer weight vector can be computed to null out the ambiguity position in the azimuth frequency domain and reconstruct the useful signal; thus most of the ambiguity components can be significantly suppressed. Finally, the simulation results validate the effectiveness of the proposed method.

Guo, Lei; Wang, Robert; Deng, Yunkai; Wang, Wei; Luo, Xiulian

2014-01-01

458

Ground penetrating radar antenna system analysis for prediction of earth material properties  

USGS Publications Warehouse

The electrical properties of the ground directly beneath a ground penetrating radar (GPR) antenna very close to the earth's surface (ground-coupled) must be known in order to predict the antenna response. In order to investigate changing antenna response with varying ground properties, a series of finite difference time domain (FDTD) simulations were made for a bi-static (fixed horizontal offset between transmitting and receiving antennas) antenna array over a homogeneous ground. We examine the viability of using an inversion algorithm based on the simulated received waveforms to estimate the material properties of the earth near the antennas. Our analysis shows that, for a constant antenna height above the earth, the amplitude of certain frequencies in the received signal can be used to invert for the permittivity and conductivity of the ground. Once the antenna response is known, then the wave field near the antenna can be determined and sharper images of the subsurface near the antenna can be made. ?? 2005 IEEE.

Oden, C.P.; Wright, D.L.; Powers, M.H.; Olhoeft, G.

2005-01-01

459

Structural aspects of meteoroid streams observed by a forward scatter radar system  

NASA Astrophysics Data System (ADS)

Forward scatter (FS) continuous wave (CW) meteor radar observations carried out during 1992-96 over the long baseline Bologna-Lecce in Italy, enable us to investigate the structure of the main meteoroid streams and of the sporadic background by the cumulative distributions vs durations of the recorded echoes. The trends of the mass-distribution of particles belonging to the quoted meteor complexes are discussed in terms of variations of the mass index s against echo durations and in terms of steady-state conditions for each meteor population. The mass index values of the sporadic background are generally higher than for meteor showers in the duration range of 0.1? T?10 s. Observational evidence indicates that the combined cumulative distributions of meteor trails vs peak signal amplitudes and vs durations represent a more sensitive indicator of the meteoroid stream activity, and consequently, of the mass-index variation. The unexpected high proportion of short-lived echoes which produce very faint meteors is interpreted in terms of fragmenting particles which form filaments younger than those present in other parts of the stream. The effects of non-gravitational forces as the solar radiation pressure, the Poynting-Robertson (P-R) effect, mutual collisions, etc., are taken into account to justify the observed widespread radiants and unstable populations of particles.

Cevolani, G.; Gabucci, M. F.; Grassi, G.; Trivellone, G.

1998-08-01

460

RF MEMS technology for radar sensors  

Microsoft Academic Search

An overview of applications of radio frequency microelectromechanical system (RF MEMS) technology in radio detection and ranging (radar) sensors is given. RF MEMS components for radars include attenuators, limiters, (true-time-delay) phase shifters, transmit\\/receive (T\\/R) switches and tunable matching networks. Radar subsystems which benefit from RF MEMS technology include active electronically scanned arrays (T\\/R modules), passive electronically scanned arrays (lenses, reflect

Koen Van Caekenberghe; Sherwood Rangers

2009-01-01

461

Clutter free synthetic aperture radar correlator  

NASA Technical Reports Server (NTRS)

A synthetic aperture radar correlation system including a moving diffuser located at the image plane of a radar processor is described. The output of the moving diffuser is supplied to a lens whose impulse response is at least as wide as that of the overall processing system. A significant reduction in clutter results is given.

Jain, A.

1977-01-01

462

Monostatic Coherent Radar Sea Clutter Doppler Analysis Matthew Ritchie  

E-print Network

covering grazing angles from 7° to Monostatic Coherent Radar Sea Clutter Doppler Analysis Matthew Ritchie University College London & Thales Aerospace UK Abstract: Sea clutter is the backscatter returned to a radar system from the sea

Haddadi, Hamed

463

All-digital radar architecture  

NASA Astrophysics Data System (ADS)

All digital radar architecture requires exclude mechanical scan system. The phase antenna array is necessarily large because the array elements must be co-located with very precise dimensions and will need high accuracy phase processing system for aggregate and distribute T/R modules data to/from antenna elements. Even phase array cannot provide wide field of view. New nature inspired all digital radar architecture proposed. The fly's eye consists of multiple angularly spaced sensors giving the fly simultaneously thee wide-area visual coverage it needs to detect and avoid the threats around him. Fly eye radar antenna array consist multiple directional antennas loose distributed along perimeter of ground vehicle or aircraft and coupled with receiving/transmitting front end modules connected by digital interface to central processor. Non-steering antenna array allows creating all-digital radar with extreme flexible architecture. Fly eye radar architecture provides wide possibility of digital modulation and different waveform generation. Simultaneous correlation and integration of thousands signals per second from each point of surveillance area allows not only detecting of low level signals ((low profile targets), but help to recognize and classify signals (targets) by using diversity signals, polarization modulation and intelligent processing. Proposed all digital radar architecture with distributed directional antenna array can provide a 3D space vector to the jammer by verification direction of arrival for signals sources and as result jam/spoof protection not only for radar systems, but for communication systems and any navigation constellation system, for both encrypted or unencrypted signals, for not limited number or close positioned jammers.

Molchanov, Pavlo A.

2014-10-01

464

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

465

Thermal structure and drainage system of a small valley glacier (Tellbreen, Svalbard), investigated by ground penetrating radar  

NASA Astrophysics Data System (ADS)

Proglacial icings accumulate in front of many High Arctic glaciers during the winter months, as water escapes from englacial or subglacial storage. Such icings have been interpreted as evidence for warm-based subglacial conditions, but several are now known to occur in front of cold-based glaciers. In this study, we investigate the drainage system of Tellbreen, a 3.5 km long glacier in central Spitsbergen, where a large proglacial icing develops each winter, to determine the location and geometry of storage elements. Digital elevation models (DEMs) of the glacier surface and bed were constructed using maps, differential GPS and ground penetrating radar (GPR). Rates of surface lowering indicate that the glacier has a long-term mass balance of -0.6 ± 0.2 m/year. Englacial and subglacial drainage channels were mapped using GPR, showing that Tellbreen has a diverse drainage system that is capable of storing, transporting and releasing water year round. In the upper part of the glacier, drainage is mainly via supraglacial channels. These transition downglacier into shallow englacial "cut and closure" channels, formed by the incision and roof closure of supraglacial channels. Below thin ice near the terminus, these channels reach the bed and contain stored water throughout the winter months. Even though no signs of temperate ice were detected and the bed is below pressure-melting point, Tellbreen has a surface-fed, channelized subglacial drainage system, which allows significant storage and delayed discharge.

Bælum, K.; Benn, D. I.

2011-03-01

466

Classification of radar clutter in an air traffic control environment  

Microsoft Academic Search

The results of an experimental study aimed at the classification of radar clutter encountered on ground-based coherent scanning radar systems used for air traffic control are presented. The clutter signals of interest are primarily those due to birds and to clouds and weather systems. A historical perspective on the radar clutter classification problem is given, and related issues are discussed.

SIMON HAYKIN; WOLFGANG STEHWIEN; CONG DENG; PETER WEBER; RICHARD MANN

1991-01-01

467

A 24GHz CMOS RF Transceiver for Car Radar Applications  

E-print Network

System Design 2.1 Overall Architecture In FMCW radar system, detection range and minimum detectable is critical to detect close object in FMCW modulation. Generally, passive mixer has lower NF characteristic and mid range automotive radar. Especially, frequency modulated continuous wave (FMCW) radar has been

Nam, Sangwook

468

Polarization radar processing technology  

NASA Astrophysics Data System (ADS)

A comprehensive effort involving measurements and performance evaluation for the detection of scatterers immersed in a background of natural and man-made clutter using polarization diverse waveforms is presented. The effort spans evaluation from the initial stages of theoretical formation to processor performance evaluation using real-world data. The theoretical approach consists of determining polarimetric statistical properties of the backscatter waveform and these properties to derive the optimum dual-polarized S-band radar system with selectable polarization on both transmit and receive. Several processors utilizing optimum and suboptimum algorithms were evaluated using simulated and live radar data, and performance results are compared. The processor types include fully adaptive algorithms designed to operate on polarimetric spectral spread waveforms, and several combinations of single channel and polarization diverse receivers with both single and dual transmit polarization. Results are plotted and evaluated by displaying probability of detection as a function of signal-to-noise ratio with processor type as a parameter.

Wicks, Michael C.; Vannicola, Vincent C.; Stiefvater, Kenneth C.; Brown, Russell D.

469

Analysis of synthetic aperture radar imagery  

NASA Technical Reports Server (NTRS)

Some problems faced in applications of radar measurements in hydrology are: (1) adequate calibration of the radar systems and direct digital data will be required in order that repeatable data can be acquired for hydrologic applications; (2) quantitative hydrologic research on a large scale will be prohibitive with aircraft mounted synthetic aperture radar systems due to the system geometry; (3) spacecraft platforms appear to be the best platforms for radar systems when conducting research over watersheds larger than a few square kilometers; (4) experimental radar systems should be designed to avoid use of radomes; and (5) cross polarized X and L band data seem to discriminate between good and poor hydrologic cover better than like polarized data.

Blanchard, B. J.

1977-01-01

470

An MSK Radar Waveform  

NASA Technical Reports Server (NTRS)

The minimum-shift-keying (MSK) radar waveform is formed by periodically extending a waveform that separately modulates the in-phase and quadrature- phase components of the carrier with offset pulse-shaped pseudo noise (PN) sequences. To generate this waveform, a pair of periodic PN sequences is each passed through a pulse-shaping filter with a half sinusoid impulse response. These shaped PN waveforms are then offset by half a chip time and are separately modulated on the in-phase and quadrature phase components of an RF carrier. This new radar waveform allows an increase in radar resolution without the need for additional spectrum. In addition, it provides self-interference suppression and configurable peak sidelobes. Compared strictly on the basis of the expressions for delay resolution, main-lobe bandwidth, effective Doppler bandwidth, and peak ambiguity sidelobe, it appears that bi-phase coded (BPC) outperforms the new MSK waveform. However, a radar waveform must meet certain constraints imposed by the transmission and reception of the modulation, as well as criteria dictated by the observation. In part