A Space Synchronization Method Based on Sea Clutter Energy

Space synchronization, as one of the three major synchronization issues of bistatic synthetic-aperture radar (BiSAR), is a prerequisite for subsequent signal processing. However, traditional space synchronization methods rely on the accuracy of positioning systems such as global positioning system (GPS) and inertial navigation system (INS), and are unable to cope with situations where positioning systems fail or accumulate significant errors. To solve the problems, a space synchronization method based on sea clutter energy has been proposed. First, by changing the azimuth and pitch angles of the receiver, the scanning echo from sea clutter is obtained. Then, after filtering to remove moving targets and strong points interference, the energy of each pulse is calculated and the energy peak is considered to be the moment when the bistatic radar achieves space synchronization. Finally, the particle swarm optimization (PSO) algorithm is used to re-estimate the relative positions of the radars, thereby achieving space synchronization for targets of interest. Compared with traditional space synchronization methods, this method does not rely on the positioning system, which can achieve azimuth and pitch angle estimation accuracy of no more than 0.5° and perform positioning within an error range of 150 m under the condition of radar position system failure.