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Radar, Sonar and Navigation, IEE Proceedings -

Issue 4 • Date Aug 1997

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Displaying Results 1 - 10 of 10
  • Novel high range resolution approach in microwave imaging

    Page(s): 177 - 180
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (364 KB)  

    The authors propose a method of gaining range superresolution in a microwave imaging system. After frequency domain deconvolution of the echo to the transmitted signal, the signal model is proved to be of the same form as that of DOA estimation. Hence, as in the case of DOA estimation, a nonlinear spectrum estimation algorithm can be applied to improve range resolution. Numerical simulation and experiments have shown the method to be cost-effective View full abstract»

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  • VSAR: a high resolution radar system for detection of moving targets

    Page(s): 205 - 218
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1828 KB)  

    The velocity SAR (VSAR) is a conceptual radar imaging system capable of reconstructing the three-dimensional range/azimuth/velocity image for a scene that contains moving objects. It combines the high resolution imaging capability of SAR with the clutter rejection capability of MTI systems. The clutter rejection and motion estimation capabilities of VSAR make it potentially useful for a variety of missions. The system concept is described, the basic signal-processing algorithms are developed, and a performance analysis of the VSAR system in the context of detecting low-RCS ground targets is provided. The VSAR system is able to estimate the speed of moving targets, down to slow speeds of the order of 0.5 m/s View full abstract»

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  • Simultaneous signals in IFM receivers

    Page(s): 181 - 185
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    The problem of frequency measurement by an IFM receiver when there are two or more simultaneous signals is considered. The problem is different from other frequency estimation problems considered in the literature since the IFM receiver is an extremely wideband device and reliable estimation is required for short pulse signals. A fast algorithm for estimating the frequencies of all the simultaneous signals is proposed. Computer simulations of the technique are compared with performance analyses View full abstract»

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  • Two subspace-based methods for frequency estimation of sinusoidal signals with random amplitude

    Page(s): 169 - 176
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (700 KB)  

    Sinusoidal signals with time-varying amplitude show up in many signal processing applications, such as in radar applications when the target is spatially dispersed. Amplitude modulation results in an enlargement of the signal subspace, i.e. the signal subspace corresponding to one amplitude-modulated sinusoid is no longer spanned by a single vector. The authors propose two subspace-based techniques to estimate the centre frequency of a sinusoidal signal with random ARMA amplitude. The proposed techniques are obtained by using the principles behind the ESPRIT and MODE approaches of frequency estimation and by appropriate adaptations and simplifications following careful considerations of the specifics of the problem considered. Numerical simulations illustrate the good performance of the methods. A robustified version of the proposed methods is described and successfully applied to real radar data View full abstract»

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  • Simulation and analysis of synthetic sidescan sonar images

    Page(s): 219 - 226
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (996 KB)  

    The sidescan sonar process produces a representation in image form of the seabed; however, no closed-form analytic expression or direct modelling technique exists to represent this complex process. The basic principle is presented for a model for the simulation of sidescan sonar, which produces as its output a qualitative image of the form generated by the actual sidescan. The model considers the underlying physical processes including the effects of the refractive water medium, the scattering from the seabed and the transducer motion and directivity characteristics. The statistical and visual techniques that have been applied to attempt to overcome the resulting problems of testing and verifying the images output by the sonar simulation model are then discussed View full abstract»

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  • Adaptive update rate tracking using IMM nearest neighbour algorithm incorporating rapid re-looks

    Page(s): 195 - 204
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (948 KB)  

    The paper describes an adaptive update rate tracking algorithm for use with electronically steered phased array surveillance radar, and presents results obtained from computer simulations which demonstrate available performance improvements. The update rate is varied to maintain, as closely as possible constant tracker validation region size during target nonmanoeuvre and manoeuvre phases and when missed detections occur, with the aim of improving tracker performance in clutter. The tracker combines the interactive multiple model estimator with nearest neighbour data association and incorporates rapid re-looks when required. The computer simulations demonstrate the ability of the algorithm to control the validation region size and to improve track maintenance in a cluttered environment View full abstract»

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  • Microwave intercept receiver sensitivity estimation

    Page(s): 186 - 193
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    The author applies probability and correlation analysis methods to predict the RF sensitivity and measurement accuracy of wideband automatic electronic warfare (EW) systems. The effects of system noise on the accuracy and fidelity of the main EW parameter estimators, pulse width, frequency and bearing in the critical threshold region are investigated. The sensitivity analysis technique is suitable for use in modern software spreadsheets to generate accurate and realistic system budgets and covers receiver systems driven by RF channels exhibiting large scale gain variations. The method divides the RF band into a number of subbands and derives equations for the analysis of multiplier-based demodulators used in instantaneous frequency measurement (IFM) and interferometer systems. Common receiver demodulators are compared in terms of signal-to-noise performance and include the square law detector, the coherent detector, delay line discriminators and the interferometer or homodyne. The article also compares the design and performance of some example receiver types View full abstract»

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  • Comment on “Advances in aircraft-height estimation using distance-measuring equipment“ [and reply]

    Page(s): 235 - 236
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    The author comments that in the paper of Manolakis and Dounis (see ibid., vol.143, no.1, p. 47-52, 1996) equation 17 consists of too many terms and, while deriving the various terms, s1 and S2 are not defined, leaving no scope to cross-check the solution. Later, while deriving equation 19, s1 and s2 are defined and these may hold good in equation 17 as well. It is true that equation 19 offers less computational burden than that required while considering equation 17. However, the terms required to obtain each component are enormously large in number. A simpler procedure is proposed for height computation. Manolakis et al. reply that their main purpose was to derive an efficient algorithm (not the more efficient one). In addition, they would like a mathematically tractable algorithm to facilitate the performance analysis with respect to the mean value and the standard deviation of the estimation errors. Both these objectives are accomplished by the simple formula presented View full abstract»

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  • Direction-of-arrival and frequency estimations for narrowband sources using two single rotation invariance algorithms with the marked subspace

    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (76 KB)  

    The authors comment that the basic assumption used in the approach of Chen and Chen (1992) that Cs=AHVs is a diagonal matrix is incorrect. They prove that Cs is a column permutation of a diagonal matrix View full abstract»

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  • PC-based real-time active sonar simulator

    Page(s): 227 - 233
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (732 KB)  

    To provide the data needed for testing sonar signal processing schemes, it is desirable to simulate the sonar environment and the received signals. The paper gives a description of a simulator developed for this purpose. The simulator runs on a personal computer, which makes it an attractive alternative to more expensive machines, both for system evaluation and for training purposes. It consists of two parts, the environmental part (consisting of the target, reverberation and propagation models) and the system part (providing appropriate signal processing functions). The simulator employs a novel target echo model 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.

Full Aims & Scope