A novel method to eliminate the azimuth phase induced by along-track baseline for DSS-SAR interferometric height measurement

There are both across-track and along-track baselines in Distributed Small Satellite Synthetic Aperture Radar (DSS- SAR). Across-track baseline is necessary for interferometric height measurement of DSS-SAR, but along-track baseline decreases the terrain height precision. According to the relationship between correlation and the phase difference of the DSS-SAR image pair, it is proposed that the along track baseline induces the azimuth phase which leads to the decreasing of the absolute accuracy of terrain elevation measurement of DSS-SAR dramatically. Therefore, a procedure targeted to eliminate the azimuth phase should be introduced to the interferometric SAR data processing in DSS-SAR. Based on deducing the expression of azimuth phase, a novel method to remove the azimuth phase is presented. It is implemented in time field and contains four main steps. The implementation of every step is described. The computer simulation is given and the results are obtained to validate the analysis in the end of the paper.