Two-step Imaging of Bistatic SAR with Curvilinear Trajectory Based on Space-Variant Separation

doi:10.12382/bgxb.2021.0398

Abstract

Abstract: To solve the severe two-dimensional space-variant issue of different configurations of bistatic SAR with curvilinear trajectory，a two-step processing method based on space-variant separation is proposed. First，space-invariant phase compensation is performed on the echo in the range frequency domain-azimuth time domain to conduct range migration correction and Deramp processing，and achieve coarse focusing. The residual phase is the space-variant part related to the position of the point target after the first step of focusing. Then the Keystone transformation is introduced to the range direction，and the least square fitting of Doppler parameters and azimuth resampling in the azimuth direction are derived，compensating the space-variant phase error and completing precise focusing. Simulation results show that the proposed slanting distance equivalent model based on space-variable separation has high accuracy. The two-step algorithm effectively relieves two-dimensional space variation and strong coupling of the curvilinear bistatic SAR，improving the imaging performance of edge points，realizing a large imaging area，and demonstrating a wide range of scenarios.

Key words: bistaticsyntheticapertureradar, space-variantseparation, curvilinearmotion, keystonetransformation, leastsquarefitting, azimuthresampling

CLC Number:

TN957.52

XU Xiyi， TAN Gewei， LI Biao. Two-step Imaging of Bistatic SAR with Curvilinear Trajectory Based on Space-Variant Separation[J]. Acta Armamentarii, 2022, 43(6): 1365-1375.

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