水下垂向运动目标的海底多基站声定位方法及精度分析

针对水下垂向运动目标具有瞬变运动特性、难以对其轨迹进行高精度和高帧率测量的问题,提出一种有水声信标的海底多基站声定位模型,基于高斯-牛顿法给出求解算法,证明了算法满足局部线性收敛条件。数值仿真和精度分析表明,基站站址误差、声速误差和信号时延估计误差通过测量斜距传播到目标位置参数,误差传播过程受接收基阵几何构型、目标相对位置及水声学约束条件等因素影响。在多个海底基站共面条件下,补充海面基站可改进垂向测量能力。利用该方法对全区域进行精度估计,获取了定位性能在空间分布上的细节特征。以水平范围1 km×1 km、水深60 m的海区计算,对于由13个海底基站和1个海面基站构成的14元测量阵,目标运动深度范围为35~60 m,在x,y,z三个方向的均方根误差(RMSE)平均值分别为0.30 m,1.47 m,0.34 m。本文工作为水下垂向运动目标定位提供了一种技术途径,可为测量系统的论证设计提供参考。 

Acoustic localization scheme and accuracy analysis for underwater vertical motion target using multi-stations in the seabed

According to the difficulty of trajectory measurement with high accuracy and high frame rate for UVMT(Underwater Vertical Motion Target) in transient motion, an acoustic localization model using multi-stations in the seabed with the acoustic beacon was presented, and solving algorithm based on Gauss-Newton method was derived,which was proved to be satisfying the local linear convergence condition. The results of numerical simulation and accuracy analysis indicated that station location errors, sound velocity errors and signal time delay estimation errors were propagated to position parameters through measuring slant ranges, and this process was effected by geometry of receiving array, relative position of the target and acoustic constraint conditions. Furthermore, the vertical measuring ability was improved by adding a surface station on the basis of coplanar multi-stations in the seabed. A full-area coverage accuracy estimation was applied and its detailed distribution characteristics were available. Demonstrated by a sea area of 1 km × 1 km coverage and 60 m in depth, in the condition of 14-receivers array which was composed of 13 seabed stations and 1 surface station, the range of UVMT motion depth was 35-60 m, the average RMSE(Root Mean Square Error) in the x, y and z direction was 0.30 m, 1.47 m and 0.34 m respectively. The present work provides a technical approach for UVMT localization, which is useful for designing the measuring system.