A Time-Frequency Synchronization Method Using Dual-Channel Processing For GNSS-Based Passive Radar Moving Target Detection

The Global Navigation Satellite System (GNSS), as an illumination source with broad coverage capabilities, is considered for passive radar target detection. Due to the low signal power, long-time integration is required for improving the energy of moving targets. However, the receivers often use independent local oscillators, and the bistatic configuration brings challenges to signal synchronization. This paper proposes a time-frequency synchronization method based on dual-channel processing for GNSS-based PR. Firstly, the direct channel data is used to construct the range delay and Doppler phase compensation factors. Then the time-frequency synchronization error in the reflect echo is eliminated using the compensation factors. Finally, direct wave suppression is performed for the subsequent energy integration and target detection. A ship detection experiment has been conducted using GPS L1 signal. The results show that the synchronization errors caused by satellite motion and receiver local oscillator drift are eliminated and direct wave is effectively suppressed. The container ship is successfully detected in the range Doppler (RD) domain.