First-Order Ocean Surface Echo Model for Shipborne HFSWR Based on Fusion Estimation of Antenna Displacement

The echo from shipborne high-frequency surface wave radar (HFSWR) is significantly influenced by the movement of the shipborne platform, and the accurate estimation of antenna displacement on the shipborne platform is a key factor in reflecting the echo model for shipborne HFSWR. However, the existing echo models for shipborne HFSWR mainly use ideal periodic motion to estimate the antenna displacement, which cannot meet the actual requirements. In this letter, a modified first-order ocean surface echo model for shipborne HFSWR in the time domain is proposed based on fusion estimation of multiple antenna displacements, which fuses the attitude and global navigation satellite system (NSS) information to improve the accuracy of the estimation of antenna displacement. Simulations were conducted in both anchor and navigation states to validate the effectiveness of the proposed modified model. The simulation results demonstrate that the proposed fusion method can more accurately estimate antenna displacement than the method using only attitude information. The modified echo model can more accurately reconstruct the first-order ocean surface echo spectrum, making it easier to accurately distinguish motion-induced peaks and extract echo spectrum information. This helps to facilitate the application of shipborne HFSWR for ocean state inversion and target detection.