多普勒测速雷达辅助捷联惯导系统空中精对准方法

A method of in-flight fine alignment for SINS aided by Dopplervelocity radar

为了提高飞行器的快速反应能力,提出在飞行器飞行过程中采用多普勒雷达的测速信息辅助捷联惯导系统实现空中精对准。对多普勒测速雷达的刻度系数误差和安装误差进行分析与建模,根据捷联惯导系统、多普勒测速雷达的误差模型,选取精对准的状态;利用多普勒雷达的速度输出与捷联惯导的姿态输出,计算得到导航坐标系下雷达等效速度输出,将该等效速度输出与捷联惯导实际速度输出之间的差值选为精对准的量测;推导精对准的量测与状态之间的关系式,建立精对准的量测方程;从而,设计获得基于卡尔曼滤波的空中精对准算法。在仿真实验中设计生成多种飞行运动轨迹,经过仿真验证表明,空中精对准的方位对准精度优于1.4′,水平对准精度优于0.3′;而在航向机动的辅助下,方位对准时间可大幅缩短,对准精度显著提高,天向失准角估计误差从载体作航向机动开始就明显快速收敛,方位对准精度可以达到0.3′。

In order to improve the rapid response capability of aircraft,a method of in-flight fine alignment for SINS with the help of Doppler velocity radar during the flight course of aircraft is proposed.The calibration coefficient error and installation error of Doppler velocity radar are analyzed and modeled,and system state of fine alignment is selected by the error models of SINS and Doppler velocity radar.The equivalent velocity output of radar in navigation coordinate system is obtained by using the attitude output of SINS and the velocity output of Doppler radar.The difference between the equivalent velocity output and the velocity output of SINS is used as the measurement of fine alignment.Then the relationship between the measurement of fine alignment and the system state is derived,and the measurement equation of fine alignment is established.Kalman filter is adopted to design the in-flight fine alignment filtering algorithm.A variety of flight trajectories are designed and generated in the simulation experiment.Simulation results showed that,the accuracy of azimuth aligning is better than 1.4′in the process of aircraft motion,and the accuracy of horizontal aligning reached 0.3′.With the help of the azimuth maneuver,the alignment time is greatly shortened and the azimuth aligning accuracy is significantly improved.The accuracy of azimuth aligning is better than 0.3′,and the estimation error of azimuth misalignment angle converged rapidly from the beginning of azimuth maneuver.