一种改进的海底控制点非差定位函数模型

An Improved Non-differential Positioning Function Model of Seafloor Control Points

海底大地测量控制点的定位精度受复杂的海洋环境的影响,因此构建合适的、符合实际情况的函数模型显得尤为重要。本文首先提出了传统的海底控制点声学定位的函数模型,详细介绍了该定位模型的计算流程,并分析了其弊端。在传统的单程模型基础上,文中提出了改进的定位函数模型,双程模型。针对不同走航航迹的情况,利用最小二乘解算和抗差最小二乘解算对不同函数模型进行了定位解算。结果显示,改进的水下非差定位模型能有效改正由于声信号传播过程中测量船继续行进而产生的时延测距误差,提高了海底控制点的定位精度;抗差最小二乘解算可以有效克服粗差对定位精度带来的影响;在线性走航情况下,更能有效消除测距误差对水平分量的影响,水平分量的精度可达毫米级;高程分量精度稍显逊色,精度为厘米级。

The positioning accuracy of seafloor geodetic control points is affected by the complex marine environment, so it is essential to construct a suitable function model. In this paper, the traditional function model of acoustic positioning of control points on the seabed is proposed, and the calculation process of the model is introduced in detail, with its disadvantages analyzed. Based on the traditional one-way model, an improved positioning function model and a two-way model are proposed. According to different flight paths, the least square solution and robust least square solution are used to locate other function models. The results show that the improved underwater non-difference positioning model can effectively correct the ranging error caused by the continuous travel of the measuring ship in the process of acoustic pulse signal propagation and improve the positioning accuracy. A robust least square algorithm can effectively overcome the influence of gross error on positioning accuracy. Under the linear navigation condition, it can eliminate the influence of ranging error on the horizontal component and the accuracy of the horizontal element more effectively. The accuracy of the elevation component is slightly inferior to that of the centimeter level.