The Full-Parameter Shipborne Strapdown Gravimetry Method Based on State-Switching and Robust Filter

When global navigation satellite system (GNSS) is abnormal (interference or loss of lock), the result of shipborne strapdown gravimetry will diverge sharply. Based on this, first, the comparative analysis is conducted between full-parameter gravimetry method (FPGM) and conventional gravimetry method (CGM). The results indicate that FPGM has greater potential in anti-interference. Second, the improved robust Kalman filter (IRKF) based on Huber-M estimation is proposed and is introduced into FPGM to solve the jump of measurement result caused by interference. Furthermore, the state-switching mechanism is further introduced to avoid unreliable measurement results caused by loss of lock. Finally, the full-parameter shipborne strapdown gravimetry method based on IRKF and state-switching (SIR-FPGM) is proposed. The effectiveness of the proposed method is verified. The results show that IRKF has high comprehensive performance. And when GNSS is abnormal, the accuracy of SIR-FPGM is improved by at least 56.34%, which can enhance the sustainable capability of gravimetry.