A Method for Ship Target Extracting from Broadened Bragg Lines in Bistatic Shipborne SWR

The Doppler frequency shifts of the sea echoes in bistatic shipborne surface wave radar (BS-SWR) are simultaneously modulated by the velocity components projected from the motion of the radar transmitter and receiver and, therefore the Doppler spectrum in BS-SWR is much more complex than it´s counterparts in monostatic mode. The characteristics of the broadened first-order bistatic Bragg lines are first analyzed in this paper and, then a model of radar return received by an arbitrary element in the receiving antenna array is proposed. Finally, a method for ship target extracting from broadened Bragg lines in BS-SWR is presented, which is based upon the azimuth differences between the Bragg waves and the moving targets whose Doppler spectrum fall into the same Doppler resolution cell. Simulation results show that the method suggested in this paper is effective in the bistatic shipborne surface wave radar applications