A Novel Frequency-Scanning (F-SCAN) Phase Synchronization Scheme for Bistatic/Mutistatic SAR

Bistatic/multistatic synthetic aperture radar (BiSAR/MuSAR) systems have attracted significant attention in Earth science and environmental monitoring due to their flexible baseline configurations and high-resolution imaging capabilities. However, phase synchronization remains a critical challenge for these systems. Existing synchronization schemes predominantly use wide-beam antennas, which are highly vulnerable to radio frequency interference (RFI) and suffer from significant fluctuations in the signal-to-noise ratio (SNR) of synchronization signals during orbital operations. In addition, existing synchronization schemes face difficulties related to complex timing design and decreased synchronization rate when applied to MuSAR. To address these challenges, a phase synchronization scheme based on frequency-scanning (F-SCAN) is proposed for BiSAR and MuSAR. Narrow-beam dynamic scanning technology is introduced in the proposed scheme. This enables three key advancements to be achieved. First, it achieves superior interference resistance compared to the LuTan-1 (LT-1) synchronization system. Second, it significantly increases the minimum SNR over the entire orbital period through maximum gain transmission and reception of synchronization signals. Third, it maintains high synchronization rates even in challenging MuSAR scenarios. The conclusions are rigorously verified through comprehensive simulation experiments. These results demonstrate the robustness and effectiveness of the proposed scheme.