Phase Synchronization Techniques for Bistatic and Multistatic Synthetic Aperture Radar: Accounting for frequency offset

Bistatic synthetic aperture radar (BiSAR) and multistatic (MuSAR) systems with a separated transmitter and receiver have been widely used for remote sensing. However, frequency deviation among different oscillators will cause a modulated phase error on the echo signal. Therefore, phase synchronization is one of the most critical problems to be addressed in BiSAR/MuSAR systems. In this article, we review synchronization techniques, which include synchronization by direct signal, synchronization by synchronization module, and synchronization by autonomous estimation. Furthermore, the future development of synchronization technology is prospected.