水下单信标导航航路规划和最优航路接近方法

相比于传统的长基线和超短基线等导航方式，水下单信标导航具有布放简单的优点，但其导航精度有待进一步提高。为此，提出了单信标导航的航路规划方案，通过泰勒级数展开推导了水平位置精度因子的表达式，并分析了导航点和声信标的相对几何位置关系对导航精度的影响，最终提出了航路规划方案。在此基础上，还提出了自主水下航行器(autonomous underwater vehicle，AUV)从其他位置接近最优航路的方法，包括两部分：一是建立以时延为观测量的滤波模型，利用滤波算法实时获取AUV的位置估计值；二是基于可观测度分析结果对最优航路接近过程的轨迹进行了设计。二者的结合使得AUV高效率且高精度地逼近最优航路。仿真证明了采用所提出的航路规划方案和最优航路接近方法可以提高导航精度，航路规划方案使得AUV位置估计的均方根误差近似为2 m。

Path planning and path approaching for underwater single beacon navigation

Compared with the traditional long baseline (LBL) and ultra-short baseline (USBL) navigation methods, single beacon navigation has the advantages of simple deployment and low cost. However, its navigation accuracy needs to be further improved, thus, a single beacon navigation path planning method is proposed. The expression of horizontal dilution of precision (HDOP) factor is derived by Taylor series expansion, and the influence of relative geometric position relationship of navigation point and acoustic beacon on navigation precision is analyzed. Finally, the path planning method is given. On this basis, a method for the autonomous underwater vehicle (AUV) to effectively and accurately approach the optimal path from other locations is also proposed, which includes two parts. One is to establish a filter model with time delay as the observed quantity, and the AUV position estimate is obtained in real time by the filter algorithm; the other is to design the trajectory of the optimal path approaching process according to the results of observability degree analysis. The combination of the two makes the AUV approach the optimal path with high efficiency and high precision. Several simulations are implemented to validate the effectiveness of the proposed methods, and the path planning makes the root mean square error (RMSE) of the estimated position of AUV approximately equal to 2 m.