基于惯性系的光纤寻北仪双位置寻北算法

Fiber North Finder Two Positions North Seeking Algorithm Based on Inertial System

由低精度光纤陀螺(Fiber Optical Gyroscope,FOG)组成的寻北仪具有结构简单、成本低的优点,但易受地磁和车上复杂外部环境的影响。针对低精度FOG存在地磁零位,寻北仪对外部晃动敏感的缺陷,通过对陀螺进行地磁零位补偿保证陀螺零偏稳定性,在此基础上提出了基于惯性系的双位置寻北算法。算法分别在两个对位进行惯性系寻北,利用双位置对消原理获得不受陀螺固定零偏影响的方位角并完成水平陀螺固定零偏的估计。实验结果表明,陀螺零偏稳定性0.15(°)/h,加速度计零偏稳定性150μg的惯性器件精度下,车上寻北误差1倍标准差小于4.5mil、极差小于10mil、对准时间小于5min。与传统双位置算法相比,所提算法在晃动基座条件下具有对准精度高,环境适应性强的优点。

The north finder which is composed by low accuracy fiber optical gyroscope(FOG) has a simple structure,low cost advantages except the FOG is vulnerable to external environmental conditions of geomagnetic and complex swaying of the car.In this paper,gyro geomagnetic bias compensation is used to ensure the FOG bias stability,moreover,new two position north seeking algorithm based on inertial system is presented.Algorithm respectively conduct inertial north seeking algorithm in two positions.By using the thought of cancel each other out in two positions,orientation without fixed bias effect will be obtained so as the bias estimation of the horizontal FOG.Experiments show that with gyroscope zero bias stability of 0.15(°)/h and accelerometer bias stability of 150μg,north finder error standard deviation is less than 4.5mil,the range is less than 10 mil,alignment time is less than 5min in the car.The good result in practices prove that compared with the traditional two position north seeking algorithm,new method with strong environmental adaptability can keep high alignment precision under swaying base conditions.