为提高小型机载光电平台的目标定位精度,提出了一种基于扩展卡尔曼滤波(EKF)的目标定位算法。根据机载光电平台锁定跟踪目标的特性,对同一目标进行多次测量。依据组合导航系统测量的载机位置、姿态信息及位置编码器测量的框架角位置信息,结合地球椭球模型确定目标的视轴指向。建立状态方程和测量方程,利用扩展卡尔曼滤波对目标的地理位置进行估计。采用蒙特卡罗法分析了测量误差对目标定位精度的影响,仿真结果显示:所提算法的精度较高,稳健性较高。采用飞行试验验证了该算法的有效性,当飞行高度为4300 m时,目标定位精度优于15 m。与基于地球椭球模型的算法相比,所提算法的目标定位精度明显提高。

To improve the target location accuracy of a small-scale airborne electro-optical platform, a target geo-location algorithm based on extended Kalman filtering (EKF) is proposed. According to the characteristics of a tracking target locked by the airborne electro-optical platform, the same target is measured repeatedly. Using the aircraft position and attitude information measured by an integrated navigation system as well as the position information of the gimbal angles from the position encoder, the direction of the line of sight for the target is determined according to the Earth ellipsoid model. The state and measurement equations are established, and the geographical position of the target is estimated using EKF. The Monte Carlo method is used to analyze the influence of the measurement error on the target geo-location accuracy. The simulation results demonstrate that the proposed algorithm is highly accurate and robust. The validity of the algorithm is verified by a flight test. At a flight height of 4300 m, the geo-location error of the target is less than 15 m. Compared with that of the algorithm based on the Earth ellipsoid model, the target geo-location accuracy of the proposed algorithm is improved obviously.