一种多标校源的高轨伴星时差频差定位算法

针对高轨伴星时差频差无源定位系统中卫星位置、速度、时差和频差等参数的测量系统误差严重影响定位精度的问题，提出了一种基于四个或四个以上已知位置的地面标校源的高斯-牛顿定位算法。该算法首先利用差分法消除星间时差、频差测量的系统误差，再利用标校源的时差频差测量方程组估计出主星和伴星的相对位置和相对速度误差，最后结合时差、频差、地球球面以确定非合作辐射源位置。理论和数字仿真均表明在时差和频差测量的随机误差较小时，本文算法的均方根误差（MSE）接近克拉美-罗下限(CRLB)。

A Method Using Multiple Calibration for High Orbit Companion Satellite TDOA and FDOA Geo-Location System

The systematic errors such as the satellite position, velocity, TDOA and FDOA measurement in the high orbit companion satellite TDOA and FDOA geolocation system are known to degrade the accuracy of geolocation seriously. A calibration method based on four or more calibrations on the earth surface is proposed in this paper. The systematic errors of TDOA and FDOA measurement are eliminated by using difference technique. Then the relative location and velocity between the main satellite and companion satellite are estimated by using multiple calibration sources. Finally the position of the uncooperative radio frequency emitter can be computed by combining the information of TDOA, FDOA and earth surface. It is proven that the mean square error(MSE) of the proposed method could approach the CramerRao lower bound(CRLB) in theory and simulation, when the random errors of TDOA and FDOA measurement are small.