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.     

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     

Bayesian gamma mixture model approach to radar target recognition

This paper develops a Bayesian gamma mixture model approach to automatic target recognition (ATR). The specific problem considered is the classification of radar range profiles (RRPs) of military ships. However, the approach developed is relevant to the generic discrimination problem. We model the radar returns (data measurements) from each target as a gamma mixture distribution. Several different motivations for the use of mixture models are put forward, with gamma components being chosen through a physical consideration of radar returns. Bayesian formalism is adopted and we obtain posterior distributions for the parameters of our mixture models. The distributions obtained are too complicated for direct analytical use in a classifier, so Markov chain Monte Carlo (MCMC) techniques are used to provide samples from the distributions. The classification results on the ship data compare favorably with those obtained from two previously published techniques, namely a self-organizing map and a maximum likelihood gamma mixture model classifier.     

Characterizing radar emissions using a robust countermeasurereceiver

The author presents a high-sensitivity signal processing approach for detecting and estimating the angle of arrival (AOA), frequency and pulse repetition frequency (PRF) of multiple radar emitters using broadband interferometers. Two time series are generated using information embedded in the sampled cross correlation of the signals obtained from three antenna elements (i.e. two base legs). The phase and amplitude of a complex Fourier transform of these two time series with respect to the sampling clock are used to estimate the AOA and PRF of pulsed emitters     

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     

Design and analysis of a knowledge-aided radar detector for doppler processing

In this paper we discuss the combined use of a priori information and adaptive signal processing techniques for the design and the analysis of a knowledge-aided (KA) radar receiver for Doppler processing. To this end, resorting to the generalized likelihood function (GLF) criterion (both one-step and two-step), we design and assess data-adaptive procedures for the selection of training data. Then we introduce a KA radar detector composed of three elements: a geographic-map-based data selector, which exploits some a priori information concerning the topography of the observed scene, a data-adaptive training selector which removes dynamic outliers from the training data, and an adaptive radar detector which performs the final decision about the target presence. The performance of the KA algorithm is analyzed both on simulated as well as on real radar data collected by the McMaster University IPIX radar. The results show that the new KA system achieves a satisfactory performance level and can outperform some previously proposed adaptive detection schemes     

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     

一种顾及舱内OBE干扰的改进航磁补偿方法

随着国际月球科研站计划的快速推进,针对月球基地相关技术的研究受到了广泛关注。面向月球基地场景下不同的设备间进行自主接触式交互这一应用背景展开研究。考虑不同的设备在进行自主接触式交互时,需要准确地完成相互识别,并且规划出畅行无阻且较优的行进路线以保证往返活动顺利进行,基于Webots搭建了月球基地仿真环境进行目标检测和路径规划相关实验。以前后配备高精度RGB相机的交互设备为载体实现基于TPH-YOLOv5月球基地场景下的目标检测。此外,设计并实现了交互设备在月球基地场景下基于双向快速扩展随机树（Bidirectional RTT）的路径规划算法,以保证交互设备在月球基地环境下的相关工作顺利进行。仿真结果显示,该目标检测及路径规划算法能够实现预期功能。     

A CFAR adaptive matched filter detector

An adaptive algorithm for radar target detection using an antenna array is proposed. The detector is derived in a manner similar to that of the generalized likelihood-ratio test (GLRT) but contains a simplified test statistic that is a limiting case of the GLRT detector. This simplified detector is analyzed for performance to signals on boresight, as well as when the signal direction is misaligned with the look direction     

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     

Noncoherent approach to through-the-wall radar localization

A noncoherent through-the-wall radar system approach, based on stepped-frequency signal synthesis and trilateration technique, is presented. This approach involves multiple independent monostatic radar units and as such, provides flexibility in positioning the units with various standoff distances and inter-element spacing. The performance of the proposed noncoherent localization system was demonstrated using simulated and real data. The results show that the radar is able to detect and locate multiple targets behind walls     

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 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