Abstract: GNSS satellites as an illuminator and the receiver on the ground can construct a space-surface passive bistatic radar system for maritime moving target detection. However, the GNSS reflected signals from the maritime moving targets (such as vessels) are usually very weak and submerged by the background noise and the interference. To address this issue, a target detection method is proposed, which uses the peculiarity of the target's motion for echo energy concentration. First, because the trajectory of the moving vessel is considered as a synthetic aperture, SAR imaging technique—range-Doppler algorithm (RDA) is employed to concentrate the echo energy and suppress the interference such as sea clutter. Then, phase gradient autofocus (PGA) is exploited to perform autofocusing processing for further echo energy concentration. Multiple groups of real data are collected from the field trials to validate the proposed method. The experimental results show that the proposed method can concentrate the echo energy of multiple targets, estimate the target-to-receiver range accurately, and determine the target’s moving direction.

Key words: GPS, space-surface passive bistatic radar, maritime moving target detection, SAR, RDA