考虑SAR量测特性的弹载SINS/SAR组合导航滤波算法

在弹载捷联惯性导航系统(strapdown inertial navigation system, SINS)/合成孔径雷达(synthetic aperture radar, SAR)组合导航系统中, 针对量测输出时间间隔不同及SAR量测滞后的问题, 提出一种利用曲线拟合法解决量测滞后的非等间隔无迹卡尔曼滤波(unscented Kalman filter, UKF)算法。首先，在UKF的基础上, 利用系统状态转移矩阵的特性, 根据SAR有无量测输出选择是否进行量测更新, 解决了量测不同步的问题。然后，利用曲线拟合补偿法拟合SAR输出信息, 获得SAR量测信息滞后的补偿算法。最后，以弹载SINS/SAR组合导航系统为研究对象, 验证所提算法的有效性。仿真结果证明，该算法得到的东向位置误差的绝对值为5.12 m, 航向角误差绝对值为6.63″, 北向速度误差绝对值为0.08 m/s, 相比于传统UKF算法有效提升了组合导航系统滤波精度。

Filtering algorithm of missile-borne SINS/SAR integrated navigation considering SAR measurement characteristics

In the missile-borne strapdown inertial navigation system(SINS)/synthetic aperture radar(SAR)integrated navigation system,in terms of the problems of different measurement output time intervals and the SAR measurement lag,a non-equal interval unscented Kalman filter(UKF)algorithm for solving the measurement lag by using the curve fitting method is proposed.Firstly,on the basis of UKF,using the characteristics of system state transition matrix,the measurement is updated according to whether there is measurement output or not,which solves the non-synchronous problem of the measurement.Then,the curve fitting compensation method is used to fit the SAR output information to obtain the compensation algorithm of the SAR measurement information lag.Finally,the effectiveness of the proposed algorithm is verified by the missile-borne SINS/SAR integrated navigation system.The simulation results show that the absolute value of east position error,heading angle error and north velocity error are 5.12 m,6.63″and 0.08 m/s,respectively.Compared with the traditional UKF algorithm,the filtering accuracy of integrated navigation system is effectively improved.