Analysis of geometrical approximations in signal reconstruction methods for multistatic large along-track baseline SAR constellations

This paper investigates the impact of the geometrical approximations in signal reconstruction methods for spaceborne large along-track baseline multistatic SAR constellations operated with a pulse repetition frequency (PRF) under the Nyquist rate which is required for the proper sampling of the SAR signal with a given Doppler bandwidth. The crucial parameters impacting the accuracy of the reconstruction are discussed and an analysis of the geometrical inaccuracies of the reconstruction is given. The conclusion is that the validity of some assumptions in the literature appears compromised for the case of large along-track baselines, which has an impact in the accuracy of the reconstruction process. Finally, an improved signal reconstruction algorithm for the case of multistatic large along-track baseline configurations is presented.