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Radar, Sonar and Navigation, IEE Proceedings -

Issue 6 • Date December 2006

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Displaying Results 1 - 10 of 10
  • Range/Doppler ambiguity elimination in high-frequency chirp radars

    Page(s): 467 - 472
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    Range/Doppler ambiguity is an important problem in chirp radar operations with all the existing schemes for ambiguity elimination relying on multiple waveform switching. Now, a new method for ambiguity elimination is proposed. It is based on a single waveform and only involves a series of software computations associated with the instantaneous amplitudes of the target under consideration at adjacent range bins. Besides the ambiguity factor, the instantaneous range of the target is also estimated. The method can greatly improve the target detection and tracking capability of high-frequency chirp radars. Both simulation and real data processing results are demonstrated to validate of the method View full abstract»

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  • Statistical analysis of measured polarimetric clutter data at different range resolutions

    Page(s): 473 - 481
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (991 KB)  

    This paper deals with the statistical modelling of radar backscattering from sea surface at low-grazing angles in high resolution radar systems. High-resolution polarimetric data at different range resolutions (60, 30, 15, 9 and 3 m) are analysed to highlight the differences in clutter statistical behaviour due to changes of resolution and/or polarisation. The clutter data were recorded by the IPIX radar of McMaster University in Grimsby, Ontario, Canada View full abstract»

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  • Periodic binary codes with zero and small time sidelobe levels

    Page(s): 482 - 486
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (315 KB)  

    A periodic binary sequence that compresses a pulse to a width of several chips is proposed. In the region of relatively small compression ratios, many periodic binary sequences exist for which peak sidelobe levels are smaller than those of conventional codes such as m-sequences View full abstract»

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  • Demonstration of knowledge-aided space-time adaptive processing using measured airborne data

    Page(s): 487 - 494
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (531 KB)  

    The design and analysis of a knowledge-aided detector for airborne space-time adaptive processing (STAP) applications are addressed. The proposed processor is composed of a training data selector, which chooses secondary cells best representing the clutter statistics in the cell under test, and an adaptive processor for detection processing. The data selector is a hybrid algorithm, which pre-screens training data through the use of terrain information from the United States Geological Survey. Then, in the second stage, a data-driven selector attempts to eliminate residual non-homogeneities. The performance of this new approach is analysed using measured airborne radar data, obtained from the multi-channel airborne radar measurements program, and is compared with alternative STAP detectors proposed in the open literature View full abstract»

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  • Investigation into arc-type sideband responses in SAR and ISAR imagery

    Page(s): 495 - 501
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (346 KB)  

    Rihaczek and Hershkowitz have proposed that radar scattering from man-made targets is dominated by cavity-type reflectors that do not meet the assumptions of point scatterer theory. The effect of such dispersive scattering is to produce spurious bright responses in the radar image that can appear as a number of peaks lying along an arc. If such arc-type responses do exist in radar imagery then their removal would enhance the ability to focus moving target imagery and to perform automatic target recognition. Rihaczek and Hershkowitz have outlined a method for identifying such arc-type responses that use the image phase. Algorithms have been written to automate the outlined procedure and used to analyse a large number of synthetic and inverse synthetic aperture radar images. Arcs are present in most radar images of static and moving ground targets. To investigate whether the arcs are due to a physical mechanism or a chance occurrence, randomised target imagery was generated and also analysed. No significant differences are seen between the distributions of arc numbers obtained from randomised and real imagery. In conclusion, the arcs present in the real imagery are likely to occur by chance, rather than because of an underlying scattering mechanism View full abstract»

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  • Insect ventral radar cross-section polarisation dependence measurements for radar entomology

    Page(s): 502 - 508
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (175 KB)  

    Radar entomology has developed such that routine long-term monitoring of insect flight through the atmospheric boundary layer is now practical. Typical entomological radars use X-band (9.4 GHz) marine transceivers with a vertical pencil beam and rotate the plane of polarisation about the beam axis. Ideally, insect species and other parameters (mass etc.) should be estimated from the measured radar cross-section variation with polarisation angle. For this, a library of known insect cross-section polarisation signatures is required. Two models are currently used to parameterise the polarisation signature: the harmonic model and a model using the scattering matrix for symmetric targets (SM3). Data from the literature and a doctoral research project are presented and analysed to obtain parameters for both the harmonic and SM3 models. Knowledge of the measurement errors allows SM3 parameter uncertainties to be quantified in most cases using a maximum likelihood approach. Results for 68 insects representing 24 species are presented. These include several economically significant species (e.g. bees and locusts), with individual insect masses ranging from 9 mg to 3 g View full abstract»

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  • Radar target identification using a likelihood ratio test and matching pursuit technique

    Page(s): 509 - 515
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (340 KB)  

    On the basis of likelihood ratio test (LRT) theory, a new method for radar target identification with matching pursuits, including the estimation method for target scattering response and the extraction technique for the reference atom dictionary to characterise the target scattering, is introduced. When compared with the generalised LRT (GLRT) target identification method, there is a very important contribution in our method that the whole scattering waveform, not only a few main poles, is used to identify targets without any prior parameterisation model hypothesis. Furthermore, the identification to candidate targets can be performed in an almost aspect-independent manner over a full aspect angle in white Gaussian noise through a finite size reference atom dictionary. Simulation results using scattered responses synthesised from weighted sums of some exponentially damped sinusoids and calculated scattering signatures of three thin wires through a time-domain electric field integral equation are presented to contrast the performance of our method to the GLRT and the best LRT target identification method as a function of signal-to-noise ratio View full abstract»

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  • Training strategies for joint domain localised-space-time adaptive processing in a bistatic environment

    Page(s): 516 - 524
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (425 KB)  

    Optimum space-time adaptive processing (STAP) requires knowledge of the true interference covariance matrix. In practice, this matrix is not known and must be estimated from training data, which must be target free and statistically homogeneous with respect to the range gate under test. These conditions are often not satisfied, which degrades the detection performance. Particularly for bistatic ground moving target indication radar, the clutter Doppler frequency depends on range for all array geometries. This range dependency leads to problems in clutter suppression through STAP techniques. The main aim in this paper is to access the relative merits of several strategies associated with STAP weight training for bistatic airborne radar applications. In particular, the issues associated with applying reduced-dimension conventional STAP and in-the-gate processing are studied. Simulation results show that, for a bistatic radar environment, in-the-gate processing approach performs better than conventional STAP approaches View full abstract»

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  • Fast-matched filters in time domain for global positioning system receivers

    Page(s): 525 - 531
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (326 KB)  

    A fast-matched filter algorithm in time domain is presented to correlate signals for optimal detection of signals in noise, to extract ranging measurements, for synchronisation, and so on. The matched filters are discussed in the context of global positioning system receivers, but the algorithms presented here can be directly used for other direct sequence spread spectrum receivers as no constraining assumptions are made in the derivations. The method proposed here outperforms the conventional time-domain method several times in arithmetic complexity. It is also competitive with transform-domain techniques based on fast Fourier transform (FFT). Unlike FFT-based methods, however, this approach is accurate and does not use rounding or scaling operations View full abstract»

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  • Synthetic aperture radar-moving target indicator processing of multi-channel airborne radar measurement data

    Page(s): 532 - 543
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1479 KB)  

    Coherent signal processing methods for combining the data that are collected via a multi-channel airborne radar system for moving target detection and image formation, are examined. Methods that convert multi-channel radar data into dual along-track monopulse synthetic aperture radar (SAR) signals of the radiated scene, are studied. A two-dimensional adaptive filtering method that projects the data in one synthesised SAR channel into the signal subspace of the other, is used for blind calibration of the monopulse SAR signals and generation of the moving target indication statistic. The merits of these algorithms are studied using the data from the multi-channel airborne radar measurement system that has been developed by the Air Force Research Laboratory at Rome, New York 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