A Novel Method for Detecting Maritime Moving Targets Using Bistatic Radar based on Low-Earth-Orbit Communication Satellites

With the accelerated deployment of low Earth orbit (LEO) communication satellites, the integration of distributed communication satellites with passive radar has emerged as a new research domain, offering significant application prospects and value in monitoring remote oceanic regions. However, the complex operational conditions of LEO satellites introduce multiple interference factors in the received signals, including higher-order range migration (RM), higher-order Doppler Frequency migration (DFM), and Doppler ambiguity, which severely impact the effective accumulation of echo energy. To address this issue, this paper proposes a passive radar method for detecting maritime moving targets using LEO communication satellites as the radiation source. The method first estimates the reference values and optimization intervals for the influencing factors and constructs a synchronized matched filter. It then employs a Modified Second-Order Keystone Transform (MSOKT) to process range migration and Doppler ambiguity. Subsequently, a Decoupled Fourier Transform (DcFT) is used to compensate for the remaining Doppler migration in the echo, completing the echo energy accumulation. Finally, the optimal estimates of the influencing factors are used to deduce the target's motion state. Simulation results demonstrate that this method effectively achieves target detection and perception in this scenario. This research is significant for improving the target detection performance of passive radar systems using LEO communication satellites.