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Radar, Sonar and Navigation, IEE Proceedings -

Issue 3 • Date 3 June 2005

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Displaying Results 1 - 16 of 16
  • Editorial: Passive radar systems

    Page(s): 105 - 106
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (58 KB)  

    This IEE Special Issue on passive radar systems coincides with the seventieth anniversary of the first British radar experiment at Daventry in February 1935. The papers in this Special Issue cover the full spectrum of topics currently being researched in the area of passive radar systems. There are papers addressing the use of a variety of transmitters of opportunity -FM radio, digital audio broadcast (DAB), digital video broadcast (DVB), global navigation satellite systems and cell-phone base-stations - plus one paper that looks at detecting targets by radiometry. Other papers examine specific signal processing issues, including the problem of nearby large targets masking smaller more distant targets, improved computational performance for cross-correlation processing and the use of the probability hypothesis density (PHD) tracker to solve the problem of multistatic passive radars with non-directional antennas. Finally, a number of papers look at the issues of performance and deployment modelling and address the problems of optimally siting the radar receivers for passive radar and bearings-only systems and predicting the performance of passive radar systems. A common feature in all the systems described in this Special Issue is the extensive use of digital hardware and software processing and it seems inevitable that in the future we might see the development of passive radar systems that simultaneously exploit a wide range of different transmissions of opportunity. View full abstract»

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  • FM radio based bistatic radar

    Page(s): 107 - 115
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (832 KB)  

    An experimental bistatic radar system is described that detects and tracks targets to ranges in excess of 150 km from the receiver, using echoes from a non-cooperative FM radio transmitter. The system concept and limitations on performance are described, followed by details of the processing used to implement the system. An adaptive filter algorithm is described that is used to efficiently remove interference and strong clutter signals from the receiver channels. A computationally efficient algorithm for target detection using Doppler-sensitive cross-correlation techniques is described. A simple constant false alarm rate algorithm for target detection is described, together with a description of a Kalman filter based target association algorithm. Representative results from the system are provided and compared to truth data derived from air traffic control data. View full abstract»

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  • Passive radar using Global System for Mobile communication signal: theory, implementation and measurements

    Page(s): 116 - 123
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (686 KB)  

    Passive radars using illuminators of opportunity have attracted much attention in the international radar community. One existing radio transmission system that may be utilised for this purpose is the Global System for Mobile communication (GSM). This paper presents a study showing the feasibility of using a GSM signal for passive radar. The analysis of the GSM waveform, and any significance or influence it has with respect to the passive radar design considerations are investigated in detail. The paper describes fully the design and implementation of a low-cost GSM-based passive radar prototype in addition to the associated signal processing scheme. Numerous measurements for various ground-moving targets were investigated extensively. The preliminary processing results demonstrate the feasibility of using GSM signals as a radar waveform and have the potential capability to detect and track different types of ground-moving targets. View full abstract»

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  • Signal detectability in SS-BSAR with GNSS non-cooperative transmitter

    Page(s): 124 - 132
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (246 KB)  

    Power budget analysis is considered for signal detection in bistatic synthetic aperture radar, with global navigation satellite systems acting as non-cooperative transmitters. The signal detection is analysed against thermal noise, in addition to interference introduced by the transmitting satellites sharing the same frequency bands. Two basic radar receiver configurations are considered: on an aeroplane; stationary on the ground. View full abstract»

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  • DTV signal ambiguity function analysis for radar application

    Page(s): 133 - 142
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (591 KB)  

    Signals transmitted by digital television-terrestrial (DTV-T) stations are analysed as a non-cooperative illuminator in bistatic radar. It is shown that the original DTV-T signal contains random and some deterministic components. The use of this signal for radar applications is studied on the basis of an ambiguity function (AF). Signal processing algorithms at the reception side are then proposed to improve the AF of the DTV-T signal. View full abstract»

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  • Passive detection using digital broadcasters (DAB, DVB) with COFDM modulation

    Page(s): 143 - 152
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1358 KB)  

    For some years, 'coded orthogonal frequency division multiplexing' (COFDM) has been emerging in many European countries. This waveform is used for digital audio broadcasting (DAB) with 1.5 MHz bandwidth and for terrestrial digital video broadcasting (DVB) with 7.6 MHz bandwidth. The objective of the study is to prove the feasibility of target detection using such COFDM broadcasters. After a description of COFDM modulation, the adaptive filter required for zero-Doppler paths cancellation (clutter contributors and transmitters in a single frequency network, SFN, configuration, where all transmitters are identical) is described and applied to experimental data. View full abstract»

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  • Passive coherent location radar systems. Part 1: performance prediction

    Page(s): 153 - 159
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    Passive coherent location (PCL) systems are a variant of bistatic radar that exploit 'illuminators of opportunity' as their sources of radar transmission. Dispensing with the need for a dedicated transmitter makes PCL inherently low cost, and hence attractive for a broad range of applications. Although a number of experimental and development examples exist, relatively little has been reported on the detailed performance of these systems and the resulting effects that these will have on the interpretation of backscatter and exploitation of derived information. In this paper, a bistatic form of the radar range equation, specifically tailored to PCL systems, is developed. Realistic examples are used to examine and compare variations in sensitivity and coverage for three candidate transmitters of opportunity. These are analogue FM radio, cellular phone base stations and digital audio broadcast (DAB). These examples show that a wide and extremely useful set of detection ranges are achievable and also highlight some of the key issues underpinning more detailed aspects of predicting detection performance. View full abstract»

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  • Passive coherent location radar systems. Part 2: waveform properties

    Page(s): 160 - 168
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (844 KB)  

    Resolution and ambiguity in both range and Doppler are parameters of fundamental importance in the design and subsequent performance of any radar system. In this paper, practical measurements of transmitted waveforms are reported and used to illustrate their effects on the resulting system design and performance. In particular, the 'self-ambiguity' which enables the limits on range and Doppler resolution to be evaluated is computed. The bistatic form of the ambiguity function is subsequently presented and used to illustrate how these best case parameters vary as a function of transmitter, receiver and target locations. Understanding the forms that these functions can take and subsequently the implications for system performance is most important if this type of radar is to be used effectively. It is shown that the radar designer does in fact have some limited freedoms to improve system performance. Finally, the implications of transmitter waveform and bistatic geometry on target detection, location and imaging are discussed. View full abstract»

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  • Multi-static entirely passive detection of moving targets and its limitations

    Page(s): 169 - 173
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (319 KB)  

    The concept of fully passive detection of moving targets based on thermal radiation in the microwave range is presented. The classical approach for target detection, based on a single receiver, allows detection of the target in the case when its temperature is significantly higher than the background. The fundamental problem, i.e., distinction between stationary and moving targets, may be solved using a multilateral system, and examining the range-Doppler correlation function among signals obtained from diverse sensor localisation in the multi-static constellation. The range equation and some limitations of the presented method are discussed. View full abstract»

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  • Masking effect and its removal in PCL radar

    Page(s): 174 - 178
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (399 KB)  

    Nowadays, passive coherent location (PCL) radar technology has become a subject of intensive investigation owing to its unique features, such as the absence of range and velocity ambiguity, low probability of interception (LPI), small size and low price. A study of PCL radar performance for the case when a distant, weak target echo is shadowed by strong echoes is presented. The presented method increases PCL radar performance in the distant zone by adaptive removal of strong echoes from the received signal. View full abstract»

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  • Improved computational performance for distributed passive radar processing through channelised data

    Page(s): 179 - 184
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (254 KB)  

    Passive radars provide excellent Doppler spectral estimates for deep, fluctuating targets. Because the radar illumination is unpredictable, a full lag-profile or cross-ambiguity analysis must be performed to extract the scatterer power spectrum as a function of range. Two techniques (coherent integration and channelisation), that may be used to achieve significant speed improvements, are demonstrated. Coherent integration reduces the data bandwidth. While this step reduces the computational burden to an effort readily achievable by modern desktop computers for observing FM broadcasts from a single receiver, the load increases when observing more transmitters, using more antennas in interferometric analysis, and using a larger bandwidth source such as DTV. A further improvement is developed; it works by 'channelising' the illuminating and scattered signals, and splitting the spectral bandwidth by an integer factor, resulting in a computational reduction. The initial coherent integration method is presented, then a variety of implementations of the channelised improvements are shown. Properly implemented, these methods produce significant speed increases on ordinary desktop workstations. Channelised methods work nicely with transmitters whose spectral content is not white, permitting the elimination of noise power which lies outside the transmitter bandwidth, as well as beyond the decimation filter bandwidth of digital receivers. View full abstract»

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  • Region-enhanced passive radar imaging

    Page(s): 185 - 194
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1508 KB)  

    The authors adapt and apply a recently-developed region-enhanced synthetic aperture radar (SAR) image reconstruction technique to the problem of passive radar imaging. One goal in passive radar imaging is to form images of aircraft using signals transmitted by commercial radio and television stations that are reflected from the objects of interest. This involves reconstructing an image from sparse samples of its Fourier transform. Owing to the sparse nature of the aperture, a conventional image formation approach, based on direct Fourier transformation, results in quite dramatic artefacts in the image, as compared with the case of active SAR imaging. The region-enhanced image formation method considered is based on an explicit mathematical model of the observation process; hence, information about the nature of the aperture is explicitly taken into account in image formation. Furthermore, this framework allows the incorporation of prior information or constraints about the scene being imaged, which makes it possible to compensate for the limitations of the sparse apertures involved in passive radar imaging. As a result, conventional imaging artefacts, such as sidelobes, can be alleviated. Experimental results using data based on electromagnetic simulations demonstrate that this is a promising strategy for passive radar imaging, exhibiting significant suppression of artefacts, preservation of imaged object features, and robustness to measurement noise. View full abstract»

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  • Probability hypothesis density-based multitarget tracking with bistatic range and Doppler observations

    Page(s): 195 - 205
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1639 KB)  

    R.P.S. Mahler's probability hypothesis density (PHD) provides a promising framework for the passive coherent location of targets observed via multiple bistatic radar measurements. A particle filter implementation of the Bayesian PHD filter is applied to target tracking using both range and Doppler measurements from a simple non-directional receiver that exploits non-cooperative FM radio transmitters as its 'illuminators of opportunity'. Signal-to-noise ratios, probabilities of detection and false alarm and bistatic range and Doppler variances are incorporated into a realistic two-target scenario. Bistatic range cells are used in calculating the birth particle proposal density. The tracking results are compared to those obtained when the same tracker is used with range-only measurements. This is done for two different probabilities of false alarm. The PHD particle filter handles ghost targets well and has improved tracking performance when incorporating Doppler measurements along with the range measurements. This improved tracking performance, however, comes at the cost of requiring more particles and additional computation. View full abstract»

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  • Determining possible receiver locations for passive radar

    Page(s): 206 - 214
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (684 KB)  

    The authors present a methodology to determine the effects of real environments on the selection of possible receiver locations for a passive radar (PR) system. Considered are: specific terrain and atmospheric information; available signal sources; coverage needs, especially for low altitudes. Resolving all possible receiver locations allows for analysis from different operational and technical viewpoints. Since the realm of operational applications and technical constraints on a PR system are wide, an optimal receiver location is not determined because an optimal solution varies for each specific requirement. View full abstract»

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  • Constellation of multisensors in bearing-only location system

    Page(s): 215 - 218
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    The constellation of multisensors in a bearing-only location system is studied. Through mathematical calculation, the paper gives the optimal cut angle with the condition that the circular probable error is minimum in the whole detection region. At the same time, the minimum area of the error trapezium is given. The relationship between the circular probable error and the bearing measurements of passive sensors or the cut angle is shown in simulation results, and a positioning error distribution figure is plotted. Some conclusions are drawn that can be used for reference in collocating passive sensors to improve location precision. View full abstract»

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  • TDOA and T2/R radar based target location method and performance analysis

    Page(s): 219 - 223
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (543 KB)  

    A target location method based on time difference of arrival (TDOA) sequences with a two-transmitter/one-receiver (T2/R) passive radar is presented. After demonstrating the observability of the system, the authors obtain two group nonlinear equations about TDOA in the Cartesian system of co-ordinates. Using measured TDOA data and linearising the equations, the target object is located by solving linear equations with the total least squares method. The performance of this method can approach the Cramer-Rao bound with moderate computational burden. The performance of this location method is analysed together with its geometric dilution of precision. View full abstract»

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Aims & Scope

IEE Proceedings Radar, Sonar and Navigation covers the theory and practice of systems involving the processing of signals for radar, radio location, radio navigation and surveillance purposes.

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