A variably trimmed mean CFAR radar detector

A variably trimmed mean (VTM) constant false alarm rate (CFAR) detector in which the threshold is determined by processing a linear combination of a group of ordered samples in each window is introduced. Unlike the trimmed mean detector, the number of ordered samples that require further processing is allowed to vary according to a data-dependent rule. It is demonstrated that the VTM detector exhibits performance characteristics that are independent of the total (stationary) noise power. Simulated performance results are presented for regions of clutter power transitions and for multiple target environments to illustrate the possible improvement over the order-statistic detector that can be obtained by using a VTM detector     

A branch-and-bound algorithm applied to optimal radar search pattern

In the article, the radar acquisition problem, e.g. the determination of a directional energy allocation sequence, is studied. The radar search pattern goal is the detection of a moving target whose initial location is approximately known. We have turned towards the general search theory where the observer allocates indivisible search efforts while the target presence probability spreads due to its dynamics. A few years ago, a Branch and Bound algorithm was proposed to determine the optimal sequence for a conditionally deterministic target. This operational research algorithm supposes a negative exponential detection function and a one over N detection logic, meaning that the target is declared detected if it has been detected once over a horizon of N looks. We have applied it to a narrow-beam tracking radar attempting to acquire a ballistic target. Non-trivial search patterns, such as expanding-contracting spirals, are obtained.     

雷达信号源计算机辅助测量系统

针对雷达信号源的计量,在检测方法、技术指标、综合快速的保证等方面,进行了深入细致的研究,提出了雷达信号源的自动检测方案.     

A non-contact lie detector using radar vital signs monitor (RVSM)technology

Traditional lie detector testing requires the subject to be physically attached to a variety of sensors. This is impractical for scenarios such as checkpoints where a large number of individuals are entering at a high rate, necessitating the employment of other methods. Currently, checkpoint officers must make a quick decision to determine if an individual is being deceptive, and if, in turn, they should be searched. The remote detection of deception (RDD) concept uses a non-contact sensor to obtain physiological information that can be used to aid the checkpoint officer's decision. Such a device must be able to sense physiological signals from the body that may indicate deception in an unobtrusive and non-contact manner     

Rank detector preprocessor for glint reduction in a tracking radar

A rank detector is used to detect instantaneous received power fades in a tracking radar. On detection of a fade, censorship of the angular position measurement is implemented in a Kalman tracking filter. It is shown that this technique can typically give a 15% angular tracking improvement on highly dynamic targets     

A neural network approach to pulse radar detection

A multilayer feedforward neural network is applied to pulse compression. The 13-element Barker code and the maximum-length sequences (m-sequences) with lengths 15, 31, and 63 b were used as the signal codes, and four networks were implemented, respectively. In each of these networks, the number of input units was the same as the signal length while the number of hidden units was three and the number of output units was one. In training each of these networks, backpropagation learning was used and the number of training epochs was 500. Using this approach, a more than 40 dB output peak signal-to-sidelobe ratio can be achieved. These fault-tolerant neural networks can provide a robust means for pulse radar detection     

A new approach to robust fault detection and identification

A methodology for instrument fault detection and identification (FDI) in linear dynamical systems subject to plant parameter variations or uncertainties is presented. At the heart of this approach is a robust estimator for which the necessary and sufficient conditions to its existence are outlined. The robust estimator can simultaneously estimate the unmeasurable state variables of the system for the purpose of control and provide necessary information for FDI purposes. A novel feature of this approach is that it can actually identify the shape and magnitude of the failures. The scheme allows for fast and accurate FDI, and can account for structural uncertainties and variations in the parameters of the dynamical model of the system. The overall fault tolerant control system strategy proposed is verified through simulation studies performed on the control of a vertical takeoff and landing (VTOL) aircraft in the vertical plane     

Intrepid digital microwave. A new approach to bistatic radar

Southwest Microwave, Inc. (SMI) introduced the world's first commercially viable bistatic microwave intrusion detection sensor in 1971. Bistatic microwave has become the paradigm for high security perimeters, and SMI products have become industry standards. With the introduction of the Intrepid Digital Microwave, SMI brings the latest in Digital Signal Processing (DSP) and power and data networking to this proven sensor technology     

A megawatt power millimeter-wave phased-array radar

This article describes the design and development of a multi-megawatt radar “Ruza,” having a large mechanically steered, millimeter-wave, phased-array antenna     

A low-cost space-based radar system concept

A space-based radar system concept is described that can provide continuous world-wide, all-weather, day-night observation and tracking of ships, aircraft, vehicles and ground facilities of interest. The system employs a constellation of radar satellites in low-earth orbit to provide continuous world-wide target access. The radars employ reflector antennas, TWT transmitters and high frequency (e.g., X band) to achieve long range with relatively low weight, complexity and cost. The radars operate in moving-target-detection (MTD) and synthetic-aperture-radar (SAR) spotlight imaging modes to observe moving and fixed targets, respectively. The system could support a wide range of military, intelligence, law-enforcement and civilian missions     

A mean track approach applied to the multidimensional assignment problem

The primary contribution of this paper is the introduction of a new preprocessing method to eliminate unlikely observation-to-track pairs with medium size target-measurement spacings before filter gating is carried out. The proposed method follows a track-oriented approach, with the different track hypotheses being contained in target trees. A mean track is computed for each target tree to capture as much variability as possible from the track hypotheses which are in the tree. Each newly received measurement is first gated with the mean track; only if the outcome of the test is positive, the measurement is gated with all the track hypotheses in the tree. The experimental results support the theoretical claims in the paper and show that a significant reduction in the number of observation-to-tracking pairing tests is achieved.     

A survey of radar ECM and ECCM

Radar electronic countermeasure (ECM) and electronic counter-countermeasures (ECCM) form the principal conflicting pair in modern electronic warfare. The technical history and state of art of both the radar ECM and ECCM are surveyed and their development trends are predicted. The classification of ECCM techniques, compatibility of various ECCM devices in a radar system and effectiveness evaluation of radar ECM and ECCM systems are also discussed     

SIR-C/X-SAR: A multifaceted radar

The multifaceted Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) was successfully flown twice in 1994 aboard the Shuttle Endeavour as part of an international imaging radar mission. The United States SIR-C operated at L- and C-band, each with multiple polarization, utilizing an active phased array antenna. The German/Italian X-SAR operated at X-band with a single polarization. SIR-C and X-SAR operated synchronously to collect data over common sites. Data were collected for repeat-track interferometric processing at all three frequencies. A total of 143 hours (93 terabits) of SAR data were digitally recorded on tape over the two flights for subsequent processing in the U.S., Germany, and Italy. This advanced multifrequency/multipolarization system has produced a rich radar data set for Earth scientific investigation and demonstration of spaceborne radar remote sensing capabilities     

Comment on “A new approach to robust fault detection andidentification”

In the paper by M. Saif and Y. Guan (see ibid., vol. 3, no 29, p. 685-695), a necessary and sufficient condition is given for the existence of an asymptotically stable observer in the case of p=m. The objective of this note is to point out a critical mistake in the main theorem of the paper     

A novel range-Doppler imaging algorithm with OFDM radar

Traditional pulse Doppler radar estimates the Doppler frequency by taking advantage of Doppler modulation over different pulses and usually it requires a few pulses to estimate the Doppler frequency. In this paper, a novel range-Doppler imaging algorithm based on single pulse with orthogonal frequency division multiplexing(OFDM) radar is proposed, where the OFDM pulse is composed of phase coded symbols. The Doppler frequency is estimated using one single pulse by utilizing Doppler modulation over different symbols, which remarkably increases the data update rate. Besides, it is shown that the range and Doppler estimations are completely independent and the well-known range-Doppler coupling effect does not exist. The effects of target movement on the performances of the proposed algorithm are also discussed and the results show that the algorithm is not sensitive to velocity. Performances of the proposed algorithm as well as comparisons with other range-Doppler algorithms are demonstrated via simulation experiments.     

A multipath data association tracker for over-the-horizon radar

A new algorithm, multipath probabilistic data association (MPDA), for initiation and tracking in over-the-horizon radar (OTHR) is described. MPDA is capable of exploiting multipath target signatures arising from discrete propagation modes that are resolvable by the radar. Nonlinear measurement models exhibiting multipath target signatures in azimuth, slant range, and Doppler are used. Tracking is performed in ground coordinates and therefore depends on the provision of estimates of virtual ionospheric heights to achieve coordinate registration. Although the propagation mode characteristics are assumed to be known, their correspondence with the detections is not required to be known. A target existence model is included for automatic track maintenance. Numerical simulations for four resolvable propagation modes are presented that demonstrate the ability of the technique to initiate and maintain track at probabilities of detection of 0.4 per mode in clutter densities for which conventional probabilistic data association (PDA) has a high probability of track loss, and suffers from track bias. A nearest neighbor version of MPDA is also presented     

A baseband Doppler simulator for radar system development

Elementary electronics building blocks can be configured as a low-cost baseband Doppler simulator for developing the post-detector processing parts such as MTIs and MTDS of millimeter wave pulsed radars employing amplitude and phase channels. The challenge of narrow pulses in conjunction to low Doppler frequencies is handled here by CMOS switches and normal function generator ICs. Test noise is generated with an off-the-shelf radio RF/IF circuit. Wideband video amplifiers are not required. Typical performance figures include pulse widths from 50 ns, target ranges from 0 to ambiguity maximum, target velocities from 0.5 m/s to 500 m/s and PRFs up to 100 kflz. Virtual target RCS can be adjusted as needed in a straightforward way.     

A high performance automotive radar for automatic AICC

The paper describes a recent effort to design, build, and test a 77 GHz radar to be used for “intelligent” cruise control of automobiles. An analysis of requirements is given, design trade-offs are accounted for, and main features of prototypes in manufacturing are detailed. The radar has been thoroughly tested and evaluated both under “controlled” conditions and on roads, also in dense traffic. Results so far are very promising     

A model for target detection with over-the-horizon radar

The effects of including Faraday rotation and multipath on the probability of detecting low-flying, distant, fluctuating and nonfluctuating targets immersed in Rayleigh noise plus clutter are studied. The effect of ionospheric fluctuations is also considered. It is found that both multipath and Faraday rotation strongly influence the detection statistics, with the effect being greatest for linearly polarized targets and less marked for symmetric targets