基于正逆向滤波的四位置对准

Four-Position Initial Alignment Based on Forward and Reverse Filtering

为实现捷联惯导初始对准的快速性和高精度,提出一种基于正逆向滤波的四位置初始对准算法。与传统的先粗对准再精对准的两段式对准法不同,所提出的方案将整个对准过程分为3个阶段:粗对准、回溯对准、精对准。在第一阶段进行粗对准并采集存储数据;在第二阶段使用无迹卡尔曼滤波(Unscented Kalman filter,UKF)对系统状态进行回溯对准;在第三阶段采用KF进行精对准。整个过程中采样四位置数据。用所提方案进行初始对准,在保证快速对准的基础上,实现了高精度对准效果。仿真实验表明:该对准方案可以快速完成初始对准,并达到较高的对准精度,天向失准角误差在10″以内。

In order to achieve fast and high accuracy of strapdown initial alignment,a four-position initial alignment algorithm based on forward and reverse filtering is proposed.The proposed scheme divides the whole alignment process into three stages:Coarse alignment,backtracking alignment and fine alignment.In the first stage,coarse alignment is performed,and data are collected and stored.In the second stage,the unscented Kalman filter(KF)is used for backtracking alignment.In the third stage,the KF is used for fine alignment.Four-position data are sampled in the whole process.The proposed scheme is used for initial alignment,and high precision alignment is achieved on the basis of ensuring fast alignment.The simulation results show that the alignment scheme can quickly complete the initial alignment and achieve a high alignment accuracy,and the sky misalignment error is within 10″.