Motion Compensation Method of CTSR Bistatic HFSWR Using Shore-Based Transponder Signals

Abstract A Coastal Transmit Ship Receive (CTSR) scheme, which is capable of separating platform movements effects from sea echoes received by ship-born bistatic high-frequency surface wave radar (HFSWR), is proposed in this paper. It also can fully leverage the combined advantages of both bistatic and shipborne radars with the abilities of anti-interference and flexible detection capabilities. The receiving signals for moored shipborne HFSWR are modulated by 6-degree of freedom (6-DOF) motion, causing a decline in radar detecting and monitoring performance. In this paper, a 6-DOF motion compensation method for CTSR bistatic HFSWR is proposed by utilizing dual shore-based transponder signals as calibration sources. The method proposed can estimates modulation parameters, including displacements and orientation changes, using these calibration sources, and then applies these estimates to compensate 6-DOF motion modulation. The modulation parameters to be estimated include displacements and orientation changes of the radar array. Displacements can be directly estimated through dual transponder signals, whereas the orientation changes should be iteratively estimated via the displacements of each array element. These parameters are then used to compensate the signals modulated by 6-DOF motion. A simulation experiment was conducted using the proposed method to compensate for a target echo that was overlapping ocean echoes due to6-DOF motion modulation. Simulation results demonstrate that the proposed method can accurately estimate modulation parameters, allowing for the recovery of the target echo and the clarification of overlapped ocean echoes.