An Extended Inverse Chirp-Z Transform Algorithm to Process High Squint Sar Data

Abstract

Abstract-This paper proposes an Extended Inverse Chirp-Z Transform (EICZT) algorithm to handle the high squint FMCW SAR data, where the conventional Inverse Chirp-Z Transform (ICZT) cannot work due to the failure in dealing with the range-variance of second-and higher-order range-azimuth coupling terms. A preprocessing operation is implemented in the azimuth-Doppler and range-time (Doppler-time) domain, where a perturbation function consisting of second-order and third-order range time variables is implemented to compensate the range variance of the second order range terms. Moreover, a new scaling factor is formulated to represent the Range Cell Migration (RCM), and further corrected by the presented EICZT approach. The proposed approach is analyzed and compared with the conventional ICZT. The simulated high squint SAR scene with nine targets is well focused by the proposed approach and the quality is greatly improved with respect the conventional ICZT. The proposed algorithm is also validated by the X-band high-resolution real SAR data.

Imaging Enhancement of Stepped Frequency Radar Using the Sparse Reconstruction Technique

“…Conventional SAR imaging schemes usually process the received signal using matched filter (MF) [9][10][11]. Although they are easy to implement, one common shortcoming of these MF based schemes is the resolution limitation to system bandwidth, which complicates localization of point scatterers for automated recognition tasks.…”