三星编队TDOA定位精度分析

Analyzing the geolocation precision of TDOA using formation-flying cluster of three microsatellites

利用低轨微纳卫星编队测定地面无线电发射源位置是全球范围内监视非合作无线电信号源的高效手段。采用星基TDOA测量实现无源定位是其中关键技术。本文分析了影响星基TDOA定位误差的主要因素。针对三星编队监测卫星,给出了基于高程约束的单历元定位方法及多历元距离差定位方法,利用仿真数据对上述定位方法精度进行了试验分析。结果表明,采用等边三角形编队卫星,对海面非合作信号源,TDOA单历元定位精度约为510 m,多历元定位精度可提高到110 m,高低配置三角形编队卫星在星下点轨迹附近定位误差较大。

Geolocating of the radio-frequency(RF)emitters with formation-flying cluster of microsatellite has become an efficient means to monitor the non-cooperative RF targets on the earth s surface,and the key technique involved is to geolocate the emitters with space-based TDOA measurement.The main factor impacting the space-based TDOA measurement is analyzed in this paper.Two TDOA geolocation methods,namely the single epoch geolocation with the constraint of geodetic height and multi-epoch geolocation are presented for the formation-flying cluster of three microsatellites,and the precisions are validated by simulation test.The results show that the precision of the single epoch geolocation method of TDOA and the multi-epoch geolocation can meet 510 and 110 m,respectively,when the non-cooperative targets on sea surface are monitored by the equilateral triangular formation-flying microsatellites.The geolocation error becomes more remarkable for targets near the satellite ground-track when the equilateral triangular formation satellites adopt the combined configuration with one satellite at a higher latitude and the other two at lower ones.