Forward-scatter Doppler-only Distributed Passive Covert Radar (original) (raw)
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Journal of Communications Software and Systems
Passive radar is a bistatic radar that detects and tracks targets by processing reflections from non-cooperative transmitters. Due to the bistatic geometry for this radar, a target can be localized in Cartesian coordinates by using one of the following bistatic geometries: multiple non-cooperative transmitters and a single receiver, or a single non-cooperative transmitter and multiple receivers, whereas the diversity of receivers or non-cooperative transmitters leads to extra signal processing and a ghost target phenomenon. To mitigate these two disadvantages, we present a new method to estimate Cartesian coordinates of a target by a passive radar system with a single non-cooperative transmitter and a single receiver. This method depends on the ability of the radar receiver to analyze a signal-to-noise ratio (SNR) and estimate two arrival angles for the target’s echo signal. The proposed passive radar system is simulated with a Digital Video Broadcasting-Terrestrial (DVB-T) transmit...
Localization Capability of Cooperative Anti-Intruder Radar Systems
EURASIP Journal on Advances in Signal Processing, 2008
System aspects of an anti-intruder multistatic radar based on impulse radio ultrawideband (UWB) technology are addressed. The investigated system is composed of one transmitting node and at least three receiving nodes, positioned in the surveillance area with the aim of detecting and locating a human intruder (target) that moves inside the area. Such systems, referred to also as UWB radar sensor networks, must satisfy severe power constraints worldwide imposed by, for example, the Federal Communications Commission (FCC) and by the European Commission (EC) power spectral density masks. A single transmitter-receiver pair (bistatic radar) is considered at first. Given the available transmitted power and the capability of the receiving node to resolve the UWB pulses in the time domain, the surveillance area regions where the target is detectable, and those where it is not, are obtained. Moreover, the range estimation error for the transmitter-receiver pair is discussed. By employing this analysis, a multistatic system is then considered, composed of one transmitter and three or four cooperating receivers. For this multistatic system, the impact of the nodes location on area coverage, necessary transmitted power and localization uncertainty is studied, assuming a circular surveillance area. It is highlighted how area coverage and transmitted power, on one side, and localization uncertainty, on the other side, require opposite criteria of nodes placement. Consequently, the need for a system compromising between these factors is shown. Finally, a simple and effective criterion for placing the transmitter and the receivers is drawn.
Analysis of Chosen Results Based on Trials with Distributed and Collocated Passive-Active Radars
2018 International Conference on Radar (RADAR), 2018
In the course of NATO SET-195 RTG work, a field trial with active and passive PCL sensors was conducted. The aim of the trial was to compare experimental results with DMPAR (Deployable Multiband Passive-Active Radar) simulations. Although DMPAR has been devised as collocated receiver system, trials were planned with collocated as well as distributed receiver configurations. Received data has shown that distributed configuration can and will fill in the gaps in the radar coverage created by terrain shadowing or multipath propagation. Also, the overall score in terms of Track Visibility (TV) and Probability of detection (Pd) have been improved in the collocated configuration. Results of the trials have confirmed operational properties of passive-active sensor proposed by SET-195. In this paper a short introduction summing up SET-152 and SET-195 work will be presented. Next, received results of collocated and distributed DMPAR will be shown, analyzed, compared and commented. Now, using...
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In this study, we propose a range detection (RD) ability by a continuous wave (CW) bistatic Doppler radar (RDCWB) of small and fast targets with very high range resolution. The target’s range and velocity are detected simultaneously. The scheme is based on the transmission of a continuous wave (CW) at millimeter wavelength (MMW) and the measurement of the respective Doppler shifts associated with target movements in different directions. The range resolution in this method is determined by the Doppler resolution only, without the necessity to transmit the modulated waveforms as in frequency modulation continuous wave (FMCW) or pulse radars. As the Doppler resolution in CW depends only on the time window required for processing, a very highrange resolution can be obtained. Most other systems that perform target localization use the transmission of wide-band waveforms while measuring the delay of the received signal scattered from the target. In the proposed scheme, the range resoluti...
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The goal of this work is to propose a distributed detection method for a network of radars interchanging their measurements through pulse-position modulation. The proposed approach does not need the presence of a fusion center and it is then fully decentralized. The approach is robust against node failures, as the only requirement to get the network gain is that the whole network remains connected, i.e., for every pair of nodes, there is a path, possibly composed of multiple hops, joining them. The decentralized approach is based on a distributed consensus mechanism. However, when conventional consensus algorithms are implemented over realistic channels, the receiver noise gives rise to an error on the final decision statistic that linearly increases with time. We avoid this inconvenient by properly modifying the consensus algorithm to make it suitable for communications over noisy channels. We analyze the performance of the proposed system considering the presence of both observation and communication noise present in the interaction among the radars. In particular, we show that even with a non-coherent integration, the whole system is able to achieve a sensitivity gain equal to the number of radars.
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ABSTRACT Multisensor applications rely on effectively managing sensor resources. In particular, next-generation multifunctional agile radars demand innovative resource management techniques to achieve a common sensing goal while satisfying resource constraints. We consider an active sensing platform where multiple waveform-agile radars scan a hostile surveillance area for targets. A central controller adaptively selects which transmitters should be active and which waveforms should be transmitted.
Experimental evaluation of passive radar approach for homeland security applications
2011 IEEE International Symposium on Antennas and Propagation (APSURSI), 2011
By using the transmitters of opportunity, passive radar systems allow target detection and tracking without transmitting any RF energy. This approach ensures covert operation of the radar thus decreasing the risks of enemy detection and electronic countermeasures. In a nutshell, the passive radar utilizes the existing broadcast signals from multiple FM radio and TV transmitters, detects backscattered signals from targets, and employs advanced DSP algorithms to provide real time target position/speed estimation and tracking. In the first part of this work, the problem of estimating the true target position from three bi-static ranges is formulated and its solution is implemented using non-linear optimization tools. In the second part, the feasibility of using the passive radar approach for accurate target position detection is experimentally evaluated at 2.4 GHz. It is shown that the target range can be estimated with 50 feet resolution when a 6 MHz wide broadcast signal is used.
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International Journal of Wireless Information Networks, 2009
We study a diversity scheme based on waveform design and space-time adaptive processing to improve the detection performance of radar sensor networks in the presence of certain types of interference. To reduce the interference between radar sensors and maximize the signalto-interference-plus-noise ratio, we use an orthogonality criterion to design waveforms for radar sensors. Besides, performance of radar sensor networks depends largely on clutter which is extended in both angle and range and is spread in Doppler frequency. By using the space-time adaptive processing, effects of clutter can be suppressed. We also propose a receiver for diversity combining and, as an application example, we investigate the detection performance of radar sensor networks using the proposed diversity scheme. Simulation results for both non-fluctuating targets and fluctuating targets show that the performance of the proposed scheme is superior to that of the single radar with the spatial-temporal diversity only.
Cooperative Target Detection in a Network of Single-Channel Radar Sensors
2019 12th German Microwave Conference (GeMiC), 2019
In automotive sensor networks the spatial distribution of the radar sensors allows to unveil additional information about the target objects. For example, the different angles to a target provide an increased robustness, and the wide sensor distances allow for a single snapshot motion estimation. This is even possible with single-channel radar sensors, but the reliability of the output highly depends on the condition that single scattering points are jointly detected. This paper presents an algorithm which associates single detections of a target over multiple sensors by utilizing the ego-motion of the vehicle. Further, it is shown how all target detections can be assessed and how reliable detections can be identified to improve subsequent processing steps like target localization. The proposed processing is validated by radar measurements at 77 GHz.