一种椭球体模型下的方位时差联合定位算法

方位时差联合定位系统普遍应用在电子侦察领域，针对目标距离观测站较远时，地球球体模型会带来定位精度差的问题，提出了一种适用于地球椭球体模型的方位时差联合定位算法。该算法首先建立了双站方位时差联合定位数学模型，结合地球球体模型，解球面三角形，获得解析解；然后引入方位平面假设，将大地坐标系下的方位观测方程转换到地心直角坐标系下，结合地球椭球体方程和时差测量方程，从解析解出发，基于牛顿迭代法获得精确解，通过仿真验证算法性能。算法提出远距离方位时差联合定位的一种解决思路，为工程实现提供了技术参考。

A position finding method of azimuth and time difference with ellipsoid model

Position finding system with azimuth and time difference is commonly applied in electronic reconnaissance filed. In long-distance geo-location, a poor positioning accuracy would be caused by inaccurate earth model. An algorithm for azimuth and time difference joint positioning is proposed. In this method, a theoretical model of two-station azimuth and time difference joint positioning is established, and a rough analytical solution is obtained by solving the spherical triangle combining the spherical model of the earth. Then, the azimuth observation equation in the spherical coordinate system is converted into a plane equation. The earth ellipsoid model time difference measurement equation under the geocentric rectangular coordinate system is introduced. Starting from the rough solution, the exact solution is obtained based on Newton iteration method. Finally, the effectiveness of the model is verified by experimental simulation. The proposed method solving positioning finding of azimuth and time difference in long distance provides a technical reference for engineering implementation.