Deramping-Based Imaging Method for Bistatic Forward-Looking SAR

Abstract

Abstract With the ability to resolve the ambiguity and higher azimuth resolution, bistatic forward-looking synthetic aperture radar (BFLSAR) imaging is strongly desirable in both navigation and safety landing for small platforms. However, due to the Doppler centroid variation along the range direction, azimuth spectrum will cross into the neighboring pulse repetition frequency (PRF) band causing severe azimuth ambiguity. Conventional frequency focusing method cannot directly used in this case. In this paper, deramping technique is employed to realize the coarse focusing and reduce the azimuth bandwidth, thus spectrum folding is mitigated. Incorporated secondary range compression, fine focusing is obtained. Simulation results validate the effectiveness of the proposed method.