A Novel Azimuth Doppler Signal Reconstruction Approach for the GEO-LEO Bi-Static Multi-Channel HRWS SAR System

• Published in: IEEE access 2019, Vol.7, p.39539-39546
• Main Authors: Zhang, Shuang-Xi, Li, Shaojie, Liu, Yanyang, Xing, Meng-Dao, Chen, Junli
• Format: Article
• Language: English
• Subjects: Algorithms; Approximation; Azimuth; bistatic; Cell adhesion & migration; Chirp; Domains; Doppler effect; Doppler signal reconstruction; Fourier transforms; Image reconstruction; Low earth orbits; multi-channel in azimuth high-resolution and wide-swath (MC-HRWS); Signal reconstruction; Synthetic aperture radar; Synthetic aperture radar (SAR); the geosynchronous-low earth orbit (GEO-LEO)
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2019.2904653

For the geosynchronous-low earth orbit (GEO-LEO) bi-static multi-channel high-resolution and wide-swath synthetic aperture radar (HRWS SAR) system, a novel azimuth Doppler signal reconstruction algorithm is developed based on an equivalent baseline approximating in the azimuth Doppler chirp Fourier transform domain. The main difficulty for the GEO-LEO bistatic multi-channel HRWS SAR system is that the baseline is variant with the scene in the conventional Doppler Fourier transform domain during azimuth signal reconstruction. The developed approach first employs the linear range cell migration correction and chirp Fourier transform to obtain the coarse-focused ambiguity SAR image. More importantly, the baseline component can be approximated a uniform baseline length for the whole image scene and the ambiguous Doppler spectrum can be reconstructed using the available Doppler signal reconstruction approach. Finally, the experimental results for a simulation GEO-LEO bi-static multi-channel HRWS SAR system are employed to validate the theoretical investigations and the proposed approach.