Impact Analysis and Compensation Method of Frequency Synchronization Error in Distributed SAR

Synchronization is an inevitable technical challenge in distributed synthetic aperture radar (DiSAR). Current work is mainly focused on configuration with the separated transmitter and receiver. In this paper, another configuration with multi-monostatic SARs is proposed to address the issue of frequency synchronization error. Combined with the system characteristic and mechanism of frequency error, the frequency synchronization error model is established first. The analysis shows that frequency synchronization error can lead to phase error, which in turn results in image degradation. Then, to compensate for the phase error, the paper uses an autofocus algorithm combined with the back projection (BP) algorithm. This algorithm adopts the coordinate descent method and iteratively adjusts the phase error estimation until the image reaches its maximum sharpness. Finally, simulations are carried out to validate the effectiveness of the algorithm. The results show that the used method can improve the imaging quality of the multi-monostatic DiSAR system.