基于空间目标异步观测的惯导误差快速确定

Fast determination of inertial navigation error based on asynchronous observation of space targets

针对惯性/天文组合导航系统中大的初始状态误差影响惯导误差收敛速度的问题,在星相机观测具有先验位置信息的有限空间目标的辅助下,提出一种基于目标-恒星角距异步测量的惯导误差在线快速确定方法。首先,在星相机光轴旋转角度和视场角大小受限的情况下,设计了通过异步照相观测方式获取有效空间目标参考信息的方案;其次,在利用惯导误差状态传播模型实现异步测量信息同步处理的基础上,构建基于空间目标与恒星之间角距的非线性最小二乘优化模型,避免了星相机的光轴扰动和安装误差对测量精度的影响;最后,基于高斯牛顿法设计了两轮迭代优化估计惯导位置误差和速度误差的方法。蒙特卡洛仿真结果表明,所提方法利用对空间目标和恒星的有限观测信息,可以有效估计惯导位置误差和速度误差,在初始位置误差约十千米量级的情况下,可以估计补偿约97.73%的位置误差以及66.25%的速度误差,优化求解误差参数的计算耗时为0.0160 s。

Aiming at the problem that large initial state error will affect the convergence rate of inertial navigation error in the inertial/celestial navigation system,assisted by star camera observing limited space target with prior position information,a kind of online fast determination method of inertial navigation error based on asynchronous measurement of target-star angular distance is proposed.Firstly,under the condition that rotation angle of optical axis and field of view of star camera are limited,the scheme of acquiring effective reference information of space target through asynchronous photographic observation is designed.Secondly,on the basis of synchronization processing of asynchronous measurement by exploiting state propagation model of inertial navigation error,nonlinear least square optimization model based on angular distance between target and star is constructed which can avoid influence of optical axis disturbance and installation error.Finally,a two-round iterative optimization method is designed to estimate the position error and velocity error of inertial navigation.Monte Carlo simulation results show that the proposed method can effectively estimate the position error and velocity error of inertial navigation by exploiting the limited observation information of space targets and stars,and can compensate the initial position error by 97.73%and the initial velocity error by 66.25%when the initial position error is about ten kilometers.The computation time of the optimization solution error parameter is 0.0160 s.