重力模型误差是高精度导航系统的主要误差源之一,为提高惯性导航系统的导航精度,不仅要求陀螺和加速度计的精度很高,还要求系统的导航算法精度高。在导航系统初始对准和导航算法中都需要用到当地重力模型,为此需研究重力模型误差对导航系统的影响。首先介绍了现有重力模型的理论基础;其次利用三阶马尔科夫重力误差模型,推导垂线偏差引起的导航误差;最后通过仿真验证了重力误差模型对运动载体的姿态、速度、位置的影响。仿真结果表明垂线偏差对运动载体的姿态误差影响在角秒级,对水平方向速度误差的影响在0.1 m/s内,引起的位置误差在0.2海里量级。

Gravity model error is one of the main sources of error for high-precision navigation. To get high-accuracy navigation algorithm, exact gravity model is definitely needed. So it is necessary to study gravity model error propagation mechanism. Firstly, the theoretical basis of the existing gravity models are briefly introduced in this paper. Then the third-order Markov gravity anomaly model is used to deduce the navigation error caused by deflection of the vertical. Finally, the accuracy and validity of the gravity model and the influence on the attitude, velocity and position of the motion carrier are verified by the simulation. The results show that the influence of deflection of the vertical on the attitude error of the motion carrier is in the angular second level, and the horizontal velocity error is within 0. 1m/s, and the maximum error of the position is at 0. 2 nautical miles’ level.