圆走航模式下海底控制点对称差分定位模型及分析

Symmetric Difference Positioning Model and Analysis of Sailing Circle Mode of Seafloor Control Points

削弱声学定位过程中系统误差对海底控制点位坐标精度的影响是建设高精度海底控制网过程中亟待解决的关键问题。首先,分析了非差和历元间差分两种定位模型;其次,由于声速在海水中的变化受长周期误差和短周期误差的影响,声速变化引起的系统误差同样可认为具有周期性变化的特征,因此,构建了对称差分定位函数模型。模拟仿真和实测数据分析结果表明,当观测时长为系统误差变化周期的偶数倍时,对称差分定位模型可以有效削弱系统误差对定位结果的影响,但是当观测时长不足系统误差变化周期的偶数倍时,该模型将不再适用。

Objectives:The critical problem to be solved in the construction of a high-precision seafloor con-trol network is to reduce the influence of systematic errors on the coordinate accuracy of seafloor control points during acoustic positioning.Methods:First,we analyze two positioning models:Non-difference and difference between epochs.Second,due to the change of sound velocity in seawater is affected by the long period term error and the short period term error,the system error caused by the shift in sound velocity in the measurement also has the characteristics of periodic change.Results and Conclusions:Based on this premise,a symmetric epoch differential positioning model was constructed.The results of simulation analy-sis and measured data analysis show that when the observation duration is an even multiple of the system er-ror variation period,the symmetric differential positioning model can effectively reduce the influence of the system error on the positioning results.Still,when the observation duration is not an even multiple of the system error variation period,the model is no longer applicable.