The precise disposal of azimuth variance of range cell migrations and motion errors in the one-stationary bistatic very high frequency/ultrahigh frequency ultra-wideband synthetic aperture radar imaging is a real chal...
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The precise disposal of azimuth variance of range cell migrations and motion errors in the one-stationary bistatic very high frequency/ultrahigh frequency ultra-wideband synthetic aperture radar imaging is a real challenge for efficient frequency-domain algorithms, but can be precisely managed by time-domain approaches. In this study, a novel bistatic fast factorised backprojection (BFFBP) algorithm is presented, which can deal with these two effects accurately and achieve the computational performance in parity with frequency-domain algorithms. First, the imaging geometry with arbitrary motion in elliptical polar coordinate is provided, and the analytical expression of the bistatic backprojection algorithm in this coordinate system is derived, which provides a theory basis for the proposed algorithm. Then, based on the subaperture imaging geometry, the sampling requirements considering motion errors is deduced, which offers the optimal tradeoff between the imaging quality and computational speed. The advantage of using elliptical polar coordinate system for implementing the BFFBP algorithm is analysed. Finally, the implementation and computational burden of the BFFBP algorithm are discussed. Simulation results are shown to prove the correctness of the theory analysis and validity of the proposed approach.
Bistatic synthetic aperture radar (BSAR) as a way of Earth remote sensing has been developed considerably in recent years, both theoretically and practically due to its unsubstitutable services. BSAR frequency-domain ...
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Bistatic synthetic aperture radar (BSAR) as a way of Earth remote sensing has been developed considerably in recent years, both theoretically and practically due to its unsubstitutable services. BSAR frequency-domain processing algorithms are efficient ways of image formation in comparison to ideal two-dimensional matched filtering and to relatively accurate and time-consuming time-domainalgorithms. Among these frequency-domain algorithms, omega-K is the most precise. The starting and key step of frequency-domain algorithms is the derivation of bistatic spectrum. Recently, a new bistatic spectrum is reported, which is probably the latest and the most modified version of Loffeld's bistaic formula (LBF), maintaining its accuracy even in azimuth-variant configurations with high squint angles. So far, this spectrum has only been used within range-Doppler algorithm to process BSAR data. The authors investigate the possibility and results of applying this modified version of LBF as a basis for omega-K algorithm. Two approaches, based on Stolt interpolation and inverse scaled Fourier transform, are examined and their effectiveness in general azimuth-variant geometry is validated through several simulations. The proposed implementations show higher performance in terms of image quality measurements as compared to extended LBF-based implementations.
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