An improved phase preservation imaging formation algorithm for spaceborne distributed SAR data processing

The approximate treatments in chirp scaling (CS) algorithm lead to phase errors, and unable to satisfy the requirement for height measurement accuracy of spaceborne distributed interferometric synthetic aperture radar (InSAR). In this article, on the basis of analysis for characteristics of residual phase error during pulse compression processing, a phase compensation function is derived in combination with the coherence requirements for spaceborne distributed InSAR data processing. And then an improved phase preservation chirp scaling algorithm is proposed to accurately compensate the phase errors, i.e. constant phase term, linear phase error term caused by shifting zero-frequency, residual cubic phase error term along range-direction and nonuniform sampling phase error term after range-compression. Furthermore, the improved algorithm has the capability to primarily implement registration procedure for distributed InSAR. Moreover, a method for calculating the theoretical phase function is presented. Finally, computer simulation results demonstrate the effectiveness of the proposed algorithm.