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Radar, Sonar & Navigation, IET

Issue 2 • Date February 2012

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Displaying Results 1 - 6 of 6
  • Applying H/α decomposition to compact polarimetric SAR

    Publication Year: 2012 , Page(s): 61 - 70
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1171 KB)  

    This study focuses on the application of H/α decomposition to original compact polarimetric (CP) synthetic aperture radar (SAR) data. In general, the authors can extract the physical scattering mechanisms (PSMs) of targets by using pseudo fully polarimetric (FP) data that are approximately reconstructed from the original CP data. In this study, the H/α decomposition is extended to the original CP data to avoid large data volume and heavy computational burden during the reconstruction of pseudo FP data, while escaping from the possible information loss caused by the reconstruction process. The H/α plane is modified and re-plotted out to discriminate different PSMs from CP data. Two CP modes are considered in the study: the α/4 mode and the dual circular polarimetric (DCP) mode. The study shows that under the DCP mode, the modified H/α decomposition performs well to discriminate different PSMs, whereas it collapses in the α/4 mode. The feasibility and effectiveness of the new H/α decomposition for CP modes are analysed and verified by experiments with measured airborne data. View full abstract»

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  • Oblique projection polarisation filtering for interference suppression in high-frequency surface wave radar

    Publication Year: 2012 , Page(s): 71 - 80
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1051 KB)  

    Polarisation filtering is a valid approach for interference suppression in high-frequency surface wave radar (HFSWR) and other systems. Based on the fundamental principle of the oblique projection and polarised filtering, an oblique projection polarisation filter (OPPF), which can be constructed from the polarisation subspaces of the target signal and those of the interference or directly from experimental data, is proposed in this study. Generalised methods for constructing the OPPF operators (theoretical OPPF and improved OPPF) are provided and the impact on the performance caused by the estimation errors is also discussed. Numerical results from simulation and experimental data demonstrate that the proposed filter is an effective means of interference cancellation. It is proved that OPPF is an extension of the conventional polarised filter, whereas the improved OPPF is more suitable for the situation where the interference is unknown. View full abstract»

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  • C/N0 estimation: design criteria and reliability analysis under global navigation satellite system (GNSS) weak signal scenarios

    Publication Year: 2012 , Page(s): 81 - 89
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (626 KB)  

    This study provides a comprehensive theoretical analysis of a modified maximum likelihood signal-to-noise ratio (SNR) estimator and quantifies the minimum coherent integration time required to achieve a predefined level of accuracy. The SNR estimator is derived under the assumptions of perfect frequency synchronisation, data bit aiding and constant signal phase during the observation window. The probability density function (pdf) of the SNR estimator in logarithmic units is derived and used to quantify the bias and error bounds associated with the considered SNR estimator. The minimum coherent integration time is determined by requiring a desired level of accuracy with a given probability level, that is the integration time is chosen in order to make the SNR estimate lie in a predefined confidence interval. Theoretical results have been validated using GNSS software and hardware simulations. The agreement between theoretical and experimental results supports the validity of the developed theory. View full abstract»

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  • Range-spread target detection in white Gaussian noise via two-dimensional non-linear shrinkage map and geometric average integration

    Publication Year: 2012 , Page(s): 90 - 98
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (427 KB)  

    In this study, a practically efficient method is proposed to detect range-spread targets of manoeuvring flight in white Gaussian noise. High-resolution range profiles (HRRPs) from multiple consecutive pulses are stacked into a two-dimensional (2D) greyscale range-pulse image along range cells and pulses. Based on the local statistics of the images, a 2D non-linear shrinkage map is designed for reducing noise while preserving target echoes before integration. Then, a geometric average (GA) integrator, operating on filtered HRRPs, is designed for target detection. The GA integration exploits the waveform similarity of the filtered target HRRPs. Finally, the experimental results of raw radar data and comparisons with other detectors are reported, showing that the proposed detector can efficiently detect range-spread targets of manoeuvring flight in white Gaussian noise. View full abstract»

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  • Exact theoretical performance analysis of optimum detector in statistical multi-input multi-output radars

    Publication Year: 2012 , Page(s): 99 - 111
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1249 KB)  

    This study is concerned with the performance analysis of detection problem in statistical multiple-input multiple-output radars for Gaussian interference. This subject has been addressed in some publications for such special cases as white Gaussian noise and orthogonal transmission. However, theoretical performance analysis of optimum detector for general case including coloured Gaussian interference and arbitrary transmission signal has not been reported yet. In the present study, after developing the optimum detector for a general case, exact closed-form expressions are derived for the probability of detection and false alarm. As the derived expressions have complicated form, their interpretation is not tractable in the general case. Therefore lower and upper Chernoff bounds are obtained to provide better insight into the detector performance. Furthermore, the effect of various parameters on the detector performance is investigated by Monte-Carlo simulations. Numerical analysis shows a high degree of consistency between the theoretical and Monte-Carlo simulation results. View full abstract»

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  • Fifty years of instantaneous frequency measurement

    Publication Year: 2012 , Page(s): 112 - 122
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1021 KB)  

    Quadrature phase discriminators, the core of wideband instantaneous frequency measurement (IFM) receivers and multiple base-line interferometry for accurate direction finding (DF), were invented in 1957, by S.J. Robinson of Mullard Research Laboratories (MRL). Digital instantaneous frequency measurement (DIFM) receivers have been universally used operationally for wideband monitoring of radar environments in naval, airborne and ground-based electronic support measures (ESM) systems all over the world for over 50 years. Their importance is such that many countries have developed their own IFM manufacturing capability with just minor architectural changes to the original design. This study describes the invention sequence, the development history, IFM design and performance principles, its general use and limitations in modern electronic warfare (EW) systems and ends with a projection for the future. View full abstract»

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Aims & Scope

IET Radar, Sonar & Navigation covers the theory and practice of systems involving the processing of signals for radar, radiolocation, radionavigation and surveillance purposes.

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