AUV Tightly Coupled Terrain Aided Navigation Strategy Based on Isogonal MBES Modeling Method

Long-endurance, high-precision navigation and positioning of autonomous underwater vehicle (AUV) is regarded as an urgent need for marine intelligent transportation systems. However, the dead reckoning system alone cannot achieve such a task. The existing terrain aided navigation system is greatly affected by the terrain environment, and it is difficult to balance system complexity and positioning performance. Therefore, a tightly coupled terrain aided navigation strategy based on isogonal multibeam echosounder (MBES) modeling method is proposed. An integrated navigation system based on inertial navigation, MBES, and Doppler velocity log is designed, and a new isogonal multibeam echosounder modeling method based on two-step iteration is proposed, which improves the modeling problem of the system from the sensor level. Furthermore, a tightly coupled framework is proposed to realize the organic fusion of multi-sensor data, which can reduce the system scale and identify the internal errors of the system. Simulation and lake test results show that the proposed method has higher positioning accuracy, reliability, and stability. Accurate navigation and localization of the AUV can even be achieved with a lower resolution prior map, larger initial position error, and fewer particles.