Analyze the Sea Clutter Frequency of Multi-receiving Ships for Distributed Shipborne HF Hybrid Sky-Surface Wave Radar

The distributed shipborne HF hybrid sky-surface wave radar contains two or more receiving ships. To combine multi-receiving data for signal processing, this paper analyzes the relationship of the Bragg frequency in the same sea area between different shipborne receivers. As the observation mode is multi-receivers received signal from one transmitter located inland, the skywave transmitting paths are the same between receivers. Therefore, the spatial difference for the same sea area to each receiving ship is the dominant factor for the Bragg frequency difference. The spatial geometry distribution of the first-order sea clutter for different shipborne receivers is derived under the uniform coordinate system. Moreover, the space-time distribution and the range-Doppler distribution of the signal from the same sea area are analyzed based on a two-ship formation pattern. Simulation results indicate that the space-time distribution and the range-Doppler distribution of two receiving ships vary in horizontal formation, while only the range-Doppler distribution differs in trail formation.