一种基于虚拟参考站的低轨双星时差频差精密修正方法

Method for Correcting TDOA and FDOA of Low Orbit Dual-Satellite System Based on VRS

为了解决低轨双星时差(Time difference of arrival,TDOA)、频差(Frequency difference of arrival,FDOA)定位精度低这一问题,提出了一种应用虚拟参考站(Virtual reference station,VRS)技术来实现对低轨双星TDOA/FDOA进行精密修正的方法。该方法利用合作辐射源在未知辐射源附近建立一个物理上并不存在的虚拟参考站,然后再利用此虚拟参考站修正未知辐射源的时频误差。通过仿真分析,VRS处虚拟时差构建误差比虚拟频差构建误差要小,并且VRS对未知辐射源TDOA/FDOA系统误差的修正精度分别可以达到97%和95%。利用修正后的时频差对未知辐射源定位,其定位精度相对于未修正前有极大的提高。

To improve the accuracy in positioning system of low orbit dual-satellite time difference of arrival(TDOA)and frequency difference of arrival(FDOA),an original method based on virtual reference station(VRS)to precisely correct the measured TDOA and FDOA of unknown target is advanced.VRS that doesn′t exist in physic is established nearby the unknown target by the cooperative radiation sources so that the measured TDOA and FDOA of unknown target can be corrected via utilizing the constructed TDOA and FDOA at VRS.Simulation preliminarily analyzes the method performance.It is verified that the precision of constructed virtual TDOA is more less than that of FDOA at VRS.Meanwhile the systematic error of unknown target TDOA and FDOA can be reduced by 97% and 95% separately by the proposed method.Moreover,compared with positioning accuracy using uncorrected TDOA and FDOA at unknown target,the positioning accuracy after applying corrected TDOA and FDOA is greatly improved.