INS/SAR组合导航量测信息不同步的滤波算法

Filtering Algorithm with Asynchronous Measurement Information for INS/SAR Integrated Navigation System

在惯性导航系统/合成孔径雷达(Inertial navigation system/synthetic aperture radar,INS/SAR)组合导航系统中,传统的SAR只提供位置和航向角信息,本文引入SAR图像测速系统,实现对INS速度信息的补偿修正。同时,建立了该组合导航滤波的数学模型。针对图像匹配耗时较大、产生信息不同步的现象,本文利用INS信息增量来对SAR导航信息延迟、非等间隔以及SAR量测不在INS滤波离散间隔上所带来的误差进行修正,并进行了仿真。经过1 500s后,本导航系统导航信息没有出现发散,在飞行器出现加速、爬升、转弯等机动时,位置误差绝对值不超过36.8m,高度误差绝对值不超过18.1m,航向角误差绝对值不超过5.3′,速度误差绝对值不超过0.5m/s,并与曲线拟合法作对比,仿真结果表明本文算法能够有效提高INS/SAR组合导航系统的精度,并为其他组合导航系统提供参考。

In inertial navigation system/synthetic aperture radar （INS/SAR） integrated navigation system, the traditional SRA only provides the position and heading angle. In this paper, the SAR velocity measurement system is introduced to realize the compensation for INS velocity information. A mathe- matical model is established for the integrated navigation filtering. In the view of the long-time image matching and asynchronous information, INS increment information is used to correct errors of SAR navigation delay, unequal information interval, unaligned time interval between SAR measurement and INS filtering. After 1 500 s simulation, navigation information does not appear to diverge in this naviga- tion system. When the aircraft is accelerating, climbing and turning, the absolute value of the position error is less than 36.8 m, height error is less than 18.1 m, heading error is less than 5.3＇, and velocity error is less than 0.5 m/s. The results of curve fitting methods are also analyzed and compared with the simulation results. The simulation results show that the algorithm can effectively improve the accuracy of the INS/SAR integrated navigation system, and provide reference for other integrated navigation system.