Impact of range chirp on chirp scaling algorithm

Abstract

Chirp scaling algorithm (CSA) is considered as an efficient SAR imaging algorithm. The existence of the range-uncompressed chirp is the necessary condition for CSA to be used. However, if the range chirp is large in high squint angle case, there will be a strong coupling between the range chirp and azimuth frequency. This coupling will render the relationship between range curvature and Doppler frequency non-linear and hence make the CSA lost its precision in such case. An analysis about this couple effect and a compensating method are given in this paper. Computer simulation has confirmed the coupling effect. A possible solution to this problem is also mentioned.