捷联惯导与小视场星跟踪器构成惯性/天文组合导航系统,核心思想是利用星体跟踪器的高精度测角信息设计滤波修正算法对捷联惯导的导航姿态、方位和位置误差进行滤波估计并修正,以限制捷联惯导系统导航误差随时间的发散,最终提高系统长航时导航的导航精度。在分析小视场星体跟踪器量测量与SINS导航误差之间关系的基础上,设计了两种不同的组合导航算法:位置+方位修正算法和误差角组合导航修正算法。在此基础上对两种算法的导航精度进行了理论分析,并通过长航时仿真飞行数据进行了仿真验证。结果表明:位置+方位修正算法不受载体的位置误差的影响,更适用于星体跟踪器间断工作的情况;误差角组合算法不受载体姿态误差的影响,更适用于SINS初始位置误差得到有效修正的情况。
The core idea of inertial/celestial integrated navigation sytem composed of SINS and star tracker is to estimate and correct SINS navigation errors through a designed kalman filter by use of star' s accurate angle information measured by the star tracker. In this way, divergence of navigation errors along with time could be restricted , and thus navigation accuracy during long time flight could be improved significantly. Based on analysis of the relationship between star tracker' s measurement and SINS' s navigation errors, two integrated navigation algorithms called position plus azimuth correction algorithm and angle error integrated navigation correction algorithm are designed for the system Then, navigation accuracies of the two algorithms are analysed theoretically and validated by using a series of long time flight simulations. The results show that position plus azimuth correction algorithm not disturbed by initial position errors is more suitable when star tracker works intermittently ; while angle error integration algorithm which doesn' t disturbed by initial attitude errors is more suitable when SINS' s initial position errors are small or corrected effectively before intergation.