Ultra-short baseline(USBL)combined positioning method in submarine cable laying scenarios
High-precision positioning is essential for ensuring the safety and efficiency of submarine cable operations in complex underwater environments.Traditional methods of laying submarine cables rely on standalone ultra-short baseline(USBL)technology to position the cable burial plow.However,this approach often encounters challenges due to frequent data fluctuations caused by suspended sediment stirred up by the high-pressure water flow from the plow.To address these issues and enhance the stability and accuracy of underwater positioning during submarine cable laying,this paper investigates a USBL combination positioning method.Initially,we analyze the positioning stability and accuracy of both responder USBL and transponder USBL using data collected from a stationary cable burial plow.This analysis aims to determine the optimal USBL mode for combination positioning.Subsequently,based on the Kalman filter algorithm,we integrate the selected USBL mode with the inertial navigation system(INS)to achieve the USBL combination positioning,which allows us to process positioning data from the dynamic cable burial plow effectively.Finally,we conduct a comparative analysis between the designed cable route,the track of the USBL combination positioning of the cable burial plow,the track of the single USBL positioning of the cable burial plow,and the ship's GNSS navigation track,to assess the stability and accuracy of the USBL combination positioning method.The results reveal that transponder USBL static positioning outperforms responder USBL static positioning,which is often hampered by transmission cable hardware delay errors and clock synchronization errors.Transponder USBL improves the static positioning accuracy of submarine cable laying by 2.75 times(from 1.1 m to 0.4 m),providing more stable and precise static positioning results.Therefore,it is deemed the more suitable USBL mode for combination positioning.Furthermore,the combination of transponder USBL and INS addresses the issue of systematic bias present in standalone transponder USBL dynamic positioning results.This combination positioning method yields dynamic positioning results that are more aligned with actual conditions.Specifically,it improves the overall Euclidean distance metric between the buried plow beacon trajectory and the ship GNSS trajectory by 1.79 times(from 2.954 m to 1.652 m)and enhances the dynamic time warping distance metric by 2.14 times(from 206.886 m to 96.661 m).When compared to the positioning results of standalone responder USBL and transponder USBL,the combined positioning of transponder USBL and INS demonstrates a significant improvement in accuracy by approximately two times.This highlights the effectiveness and robustness of the proposed USBL combination positioning method in enhancing the precision of submarine cable laying operations.
submarine cabledeep buried plowUSBLinertial navigationdynamic time warping distance
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