Abstract:

The limiting factor to the range resolution of frequency modulated continuous wave (FMCW) synthetic aperture radar (SAR) is the wellknown presence of nonlinearities in the transmitted signal. The impact of nonlinearities in FMCW SAR is investigated, and the characteristics of beat signal are analyzed. Based on the model of FMCW SAR echo with nonlinearities, a proper improved rangeDoppler algorithm is proposed. This algorithm solves the nonlinearities problem for the whole range profile through one nonlinear filter. With the characters of low computation load and high processing precision, it is suitable for the dechirped FMCW SAR realtime imaging. And the feasibility of the presented method is demonstrated by the simulation.