低精度时统的星座时差定位系统中的时差修正方法

A TDOA Correction Method for Satellite Constellation TDOA Passive Location with Low Accuracy Time System

星座型时差定位系统的定位精度受时差测量误差影响严重。为了保证较高的时差测量精度,通常需要采用能产生高精度时统和高频率准确度的时钟,但这种方案的成本非常昂贵。为了有效降低星座型时差定位系统的实现成本,提出采用低精度的时统来构建时差定位系统。而且,为了保证在低精度时统下获得较高的时差测量精度,在时差呈线性变化的基础上提出了一种低精度时统条件下的时差修正方法。经理论分析与实测数据验证,该时差修正方法可将时差测量误差由数百纳秒减小至数十纳秒。

The TDOA measuring error has extraordinary effect on the localization error of satellite constellation TDOA location system. In order to achieve high accuracy TDOA,the clock that can produce the high accuracy time and frequency must be adopted,which is extortionately expensive. In order to reduce the corresponding costs,the low accuracy time system is proposed to establish the TDOA location system. Moreover,based on the linear change tendency of the TDOA influenced by the frequency accuracy,a TDOA correction method is proposed to achieve the accurate TDOA for satellite constellation TDOA location with low accuracy time system. According to the results with the theoretical analysis and real data,the TDOA measuring error could be decreased by the proposed TDOA correction method from hundreds of nanoseconds to decades of nanoseconds.