中文摘要：

针对目标位于地球表面且高程已知的情形，首先推导了在到达时间定位体制下，接收站存在站址误差时，目标定位的克拉美罗下限；然后基于目标高度约束信息，简化定位方程，并利用加权最小二乘定位算法，实现了目标位置的定位解算．同时在理论上分析了高程信息对目标定位精度的改善效果以及所提算法的性能，证明了算法的有效性．仿真结果表明，该算法具有较好的定位精度．

英文摘要：

This paper considers the problem of locating a source on the Earth surface whose altitude is known a priori using time of arrival （TOA） measurements obtained in spatially distributed receivers. The receiver positions are subject to random errors. The Cramer-Rao lower bound （CRLB） analysis shows that exploiting the source altitude information can improve the source localization accuracy compared to the TOA-only localization system. A weighted least squares （WLS） source localization algorithm exploring both the source altitude and TOA measurements is developed. The proposed solution is shown analytically to achieve the CRLB over a small noise region. Simulation results demonstrate the good performance of the proposed method.