Optimal AUV Trajectories for Bearings-Only Tracking

In order to enhance the AUV (autonomous underwater vehicle) capability in bearings-only target tracking, the AUV trajectory optimization needs to be studied. A piecewise trajectory optimization method based on distance is proposed. In the initial phase of target tracking, GDOP (geometrical dilution of precision) matrix of positioning errors is taken as the objective function in optimization, in order to achieve optimal positioning precision at each time. Then, an AUV trajectory optimization method based on short-term prediction is proposed for the cases that the estimation of target navigation parameters (position, velocity and heading) converges. AUV predicts its own and the target's possible future states according to physical limits, and calculates its every state income according to the characteristics of the tracking trend. Based on the income, one of its own states is evaluated, and the consolidated income of every prediction state is estimated. At last, a proper state with the maximum consolidated income is chosen as its shot-term target, and the action leading to the target is executed. The extended Kalman filter algorithm is used to estimate the navigation parameters of the target. Finally, the proposed method and the GDOP based trajectory optimization method are compared through simulation, and the result shows that the AUV using the proposed method can capture the target as soon as possible.