1,972,188 research outputs found
Developments in target micro-doppler signatures analysis: radar imaging, ultrasound and through-the-wall radar
Get PDFTarget motions, other than the main bulk translation of the target, induce Doppler modulations around the main Doppler shift that form what is commonly called a target micro-Doppler signature. Radar micro-Doppler signatures are generally both target and action speci c and hence can be used to classify and recognise targets as well as to identify possible threats. In recent years, research into the use of micro-Doppler signatures for target classi cation to address many defence and security challenges has been of increasing interest. In this paper, we present a review of the work published in the last 10 years on emerging applications of radar target analysis using micro-Doppler signatures. Speci cally we review micro-Doppler target signatures in bistatic SAR and ISAR, through-the-wall radar and ultrasound radar. This article has been compiled to provide radar practitioners with a unique reference source covering the latest developments in micro-Doppler analysis, extraction and mitigation techniques. The paper shows that this research area is highly active and fast moving and demonstrates that micro-Doppler techniques can provide important solutions to many radar target classification challenges
Acceleration of parasitic multistatic radar system using GPGPU
No full textThis dissertation details the implementation of PMR [Parasitic Multistatic Radar] signal processing chain in the GPGPU [General Purpose Graphic Processing Units] platform. The primary objective of the project is to accelerate the signal processing chain without compromising the algorithm efficiency and to prove that GPGPUs are a promising platform for parasitic radar signal processing
The dependence of radar target detectability on array weighting function
Get PDFPresented at the IET-Radar 2007 Conference Edinburgh 15-18 October 2007This paper describes simulation work to assess the
detectability of targets by an airborne fire control radar (FCR)
operating in a medium pulse repetition frequency (PRF) mode
in the presence of strong ground clutter as a function of transmitting and receiving array weighting functions
The radar signature of the Wind Lens: a less disruptive wind turbine?
Get PDFWe study the radar signature of a new type of wind turbine, named the Wind Lens. This design includes a flanged shroud around the turbine which concentrates the wind flow past the turbine blades and hence improves the efficiency. The design also offers improved safety, and reduces acoustic noise. Furthermore, it may offer a significantly lower radar signature, which may make the design much more attractive for use in situations where conventional wind turbine designs may disturb the operation of radars. We present the results of an experimental trial, carried out in the UK, to measure the Radar Cross Section (RCS) of a 5 kW Wind Lens turbine prototype and we provide a reference database that can be used for comparing the Wind Lens RCS with that of conventional turbines. We investigate methods to further reduce the Wind Lens RCS and present the results of a time-varying Doppler analysis. Results show that the addition of a metallic mesh around the shroud obscures the rotating blades, and hence mitigates the RCS by 15 dBm2, at angles where the radar interference is highest
MIMO noise radar - matched filters and coarrays
Get PDFCopyright © 2008 IEEEThe noise radar concept can be extended to an array of K transmit antenna and M receive antenna. When independent noise sources are transmitted from each antenna the approach may be viewed as a special case of MIMO radar and matched filters may be derived. In this contribution statistical properties of matched filters for MIMO noise radar are derived. For any array the concepts of the sum and difference coarrays are useful and important tools for understanding an arraypsilas beamforming properties particularly for sparse arrays. Element space matched filters are shown to be related to the concept of the sum coarray and some examples of the advantages of this for sparse transmit/receive array geometry are provided. A variation of this result for beam space matched filters is also presented.Douglas A Gray, Amerigo Capri
Development of a MIMO Radar System Demonstrator - Calibration and Demonstration of First Results
No full textThe success of current spaceborne Synthetic Aperture Radar (SAR) is boosting the performance requirements of next generation systems. In order to cope with the evolution of SAR the design of the new systems will need to meet higher requirements for spacial resolutions and higher coverage. This tendency is recognized nearly independently of the application area and manifests itself through several study programs initiated by space agencies aiming at the design of future SAR systems. A review of several ongoing studies shows that a promising candidate for the next generation SAR systems is a multi-channel radar utilizing digital beam-forming (DBF) techniques, which allows to overcome the fundamental high resolution/wide swath limitations of the conventional SAR systems. In this context the Microwaves and Radar Institute of German Aerospace Center is conducting the research and development of the innovative concepts and advanced operational modes for the future spaceborne SAR systems. The new imaging techniques and technologies have the potential to considerably enhance the imaging performance of future systems compared to the state-of-the-art SAR sensors like TerraSAR-X/TanDEM-X, Radarsat-2 or Sentinel-1. In the framework of these activities a modular reconfigurable multi-channel DBF radar demonstrator operating at multiple frequency bands was developed in the Institute.
This paper describes the architecture and calibration of the system. Furthermore, the first measurement results will be presented
Examination of the effect of array weighting function on radar target detectability
Get PDFThis paper describes a methodology to assess the detectability of targets by
anairborne fire control radar operating in a medium PRF mode in the presence of
strongground clutter as a function of the transmitting and receiving antenna
array weightingfunctions and proportion of failed array elements. It describes
the radar, antenna andclutter modelling processes and the method by which target
detectability is quantified.The detectability of targets in clutter is described
using a detectability map, whichprovides a useful means of comparing target
detectability as clutter conditions change.It concludes that the best target
detectability is to be achieved using those weightingfunctions on transmit and
receive which result in the lowest average sidelobe levelsbut that the margins
between the more highly tapered weighting functions were small.Furthermore, it
concludes that target detectability degrades as the proportion of failedelements
increases. A failure of 5% of the elements gave modest, though
meaningful,degradations in target detectability and would therefore form a
suitable upper limit
Fundamental aspects of netted radar performance
No full textNetted radar employs several spatially distributed transmitters and receivers for information
retrieval. This system topology offers many advantages over traditional monostatic and bistatic
systems which use a single transmitter and a single receiver. For example, it provides better
utilization of reflected energy, more flexible system arrangement and enhanced information
retrieval capability. Therefore, the netted radar system is of emerging interests among radar
researchers.
This work investigates several fundamental aspects that determine netted radar performance.
This includes netted radar sensitivity, the netted radar ambiguity function and the
netted radar ground plane effect. Mathematical models are developed to provide a mean to
examine different aspects of netted radar performance. Software simulations examine netted
radar performance over a range of parameter variations. Simulation results show that netted
radar can offer better performance over traditional monnostatic and bistatic radar in many
cases.
Some elementary field trials have been conducted using a prototype netted radar system
developed within the UCL radar group to examine aspects of netted radar performance in practice.
The field trials are focused on netted radar range and sensitivity which are fundamental.
The field trial results show that the theoretical benefits that netted radar can offer are generally
realizable in practice
A Quality Control Concept for Radar Reflectivity, Polarimetric Parameters, and Doppler Velocity
Get PDFOver the last few years the use of weather radar data has become a fundamental part of various applications like rain-rate estimation, nowcasting of severe weather events, and assimilation into numerical weather prediction models. The increasing demand for radar data necessitates an automated, flexible, and modular quality control. In this paper a quality control procedure is developed for radar reflectivity factors, polarimetric parameters, and Doppler velocity. It consists of several modules that can be extended, modified, and omitted depending on the user requirement, weather situation, and radar characteristics. Data quality is quantified on a pixel-by-pixel basis and encoded into a quality-index field that can be easily interpreted by a nontrained end user or an automated scheme that generates radar products. The quality-index algorithms detect and quantify the influence of beam broadening, the height of the first radar echo, ground clutter contamination, return from non-weather-related objects, and attenuation of electromagnetic energy by hydrometeors on the quality of the radar measurement. The quality-index field is transferred together with the radar data to the end user who chooses the amount of data and the level of quality used for further processing. The calculation of quality-index fields is based on data measured by the polarimetric C-band Doppler radar (POLDIRAD) located in the Alpine foreland in southern Germany
A practical bistatic passive radar system for use with DAB and DRM illuminators
Get PDFDigital broadcasts provide powerful illuminators of opportunity with waveforms that produce excellent radar ambiguity functions. An experimental program to investigate the possibility of such broadcasts for target tracking radar is described. In addition, the atmospheric monitoring possibilities for such broadcasts are discussed.C.J.Coleman, R.A.Watson, and H.Yardle
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