A Mixture Distribution-Based Robust SINS/USBL Integration Navigation with Time-varying Delays

Ultra-short baseline (USBL) systems play a crucial role in underwater navigation and localization. However, the positioning accuracy is susceptible to acoustic outliers and time-varying delays. To ensure the accuracy of measurements, acoustic results from the previous cycle are transmitted to the host computer at the beginning of the subsequent cycle. Localization errors induced by time-varying delays accumulate with the increasing acoustic period. To address these challenges, modified state and measurement equations are derived, compensating quickly and accurately for delays. Besides, a robust filter algorithm is proposed for time-varying non-Gaussian noise. The simulations demonstrate that the proposed algorithm can effectively suppress time-varying delays, and horizontal errors do not increase with the acoustic period. The horizontal positioning accuracy is improved by at least 68% compared to the other algorithms. Furthermore, the algorithm also shows excellent performance in the trial test and a 20% improvement in 3-axis positioning errors. The proposed algorithm offers the advantage of improved localization accuracy and robustness, which makes it a valuable solution for addressing acoustic outliers and time-varying delays in USBL-based underwater navigation systems.