针对地面匀速运动目标定位问题,在校正源存在条件下提出基于双星时频差序列观测量的定位算法。首先在卫星星历存在误差条件下,推导基于双星时频差序列观测量的差分校正定位公式及其理论性能,数学分析表明尽管其能有效抑制卫星星历误差所带来的定位偏置,但定位方差难以达到克拉美罗界,为此,提出一种基于两步统计最优融合的运动目标定位算法,并证明其理论定位性能可达到克拉美罗界。最后,通过数值实验验证所提算法的优越性和理论分析的有效性。
The method for locating a moving source on earth using a sequence of time difference of arrival(TDOA) and frequency difference of arrival(FDOA) measurements pairs obtained by dual-satellites was presented in the presence of calibration sources with accurate positions. First, the difference calibration(DC) location algorithm aiming to the mobile target was derived, and its theoretical performance was also analytically derived. The result demonstrates that the DC localization variance could not reach the CRB, although it could eliminate the location bias produced by the position and velocity errors of the dual-satellites. For this reason, a two-step optimal association location algorithm was proposed, and its theoretical performance was proved to be equal to the CRB. Finally, a variety of numerical experiments are performed to corroborate the superiority of the geolocation algorithms and the effectiveness of the performance analysis.