A Phase Synchronization Scheme for Spaceborne Multistatic SAR Based on OFDM-Chirp Signal

The phase synchronization is a necessary condition for the normal operation of spaceborne multistatic synthetic aperture radar (SAR). The research on bistatic SAR phase synchronization is relatively mature, and some phase synchronization schemes have been verified in practical systems. Because of the limitations that existing synchronization schemes extended to the case of multistatic SAR, this letter proposes a phase synchronization scheme for spaceborne multistatic SAR. As the scheme suggests, we used orthogonal frequency-division multiplexing (OFDM)-Chirp signal to be the synchronization signal and exploited the orthogonality of subcarriers to separate the mixed synchronization signal. The decomposed signals are independently compressed to extract phase error. This scheme can simultaneously achieve phase synchronization for multiple radar platforms on the basis of satisfying the high accuracy of phase synchronization, greatly improves the efficiency of phase synchronization. Furthermore, the performance prediction and phase synchronization simulation for this synchronization scheme are presented, which verifies the feasibility of the proposed scheme.