Modified range migration algorithm integrated with motion compensation for FMCW SAR

Frequency-modulated continuous-wave (FMCW) synthetic aperture radar (SAR) is a new kind of imaging radar. Unlike traditional pulsed SAR, the FMCW signal is continuously transmitted at all times and, hence, the radar can no longer be considered as stationary during the signal transmission and reception, i.e. the “stop-and-go” approximation is not valid. This leads to the effect of Doppler frequency shift. This paper proposes a modified range migration algorithm (RMA) for FMCW SAR. The Doppler frequency shift is analyzed in detail and is corrected in the range time and azimuth Doppler domain. The algorithm maintains the high precision of RMA and motion compensation can be integrated in it conveniently. Simulation results are presented to show the validity of the proposed algorithm.