高低轨双星时频差无源定位精度

高低轨卫星联合定位是提高地面辐射源无源定位精度的有效方法。从时差基线、速度差增加方面分析了高低轨双星定位精度相对同轨卫星定位精度高的原因,推导出高低轨双星时频差定位误差分布表达式,分析了高低轨联合定位适用的时频差测量方法及其测量精度。仿真分析结果表明:在低轨卫星星下点附近较大范围内,定位精度达到百米量级。验证了双星相对位置变化、时频差测量误差、高低轨卫星自身位置速度测量误差等因素对高低轨双星定位精度的影响。

Geolocation Accuracy of High and Low Orbit Satellites by Using TDOA and FDOA

Combined geolocation by high and low orbit satellites is an effective way to significantly improve the passive geolocation performance of ground emitter. The reason why geolocation accuracy of high and low orbit satellites is better than that of same orbit satellites is analyzed from two aspects of the TDOA (time difference of arrival) baseline and velocity difference increase. The expression of GDOP (geometric dilution of precision) of high and low orbit dual satellites is deduced. The TDOA/ FDOA measurement method which can be used for combined geolocation by high and low orbit satellites and its accuracy are introduced. The simulation results show that the geolocation accuracy can reach 100 meters on a large scale under the low orbit satellite. The influence of relative positions of dual satellites, measurement error of TDOA and FDOA, measurement error of satellite position and velocity on the geolocation accuracy of high and low orbit dual satellites is demonstrated.