Ground Moving Target Imaging for the Geosynchronous-Low Earth orbit Bi-Static Multi-channel SAR System

In this paper, an effective moving target imaging approach is proposed for the geosynchronous-low earth orbit (GEO-LEO) bi-static multi-channel SAR system, which is robust for the fast moving target with Doppler centroid ambiguity. We discover that the baseline can be approximately regarded as a constant in chirp Fourier transform domain for the GEO-LEO bi-static multi-channel SAR system. Hence, the corresponding baseline compensation can be achieved in the azimuth chirp Fourier transform domain for the clutter. Then, the clutter can be well-suppressed and the moving target is extracted. After that, the moving target imaging approach is developed with the baseband Doppler centroid estimation and Doppler ambiguity number estimation. Finally, the theoretical investigations and the proposed approach in this paper is validated by experiments.