应用双向时间传递的重力卫星时标误差自主测量

星间时标误差的自主测量对于中国自主研发地球重力卫星具有重要意义. 提出利用双向时间传递法实现重力卫星时标误差的自主测量, 设计了测量方案, 建立了包含卫星运动导致的链路非对称、电离层效应、设备零值以及随机测时误差在内的测量模型. 结合地球重力卫星相关特性, 分析了时标误差测量中各误差源的影响及相应的误差校正方法. 以GRACE重力卫星为例, 利用提出的方法和校正措施, 星间时标误差自主测量精度可以达到0.62ns, 其中误差主要来自系统零值标定误差和随机测时误差.

Autonomous Time-tag Error Measurement Applying Two Way Time Transfer for Earth Gravity Satellites

Autonomous time-tag error measurement is of importance for development of Chinese Earth gravity satellites. In this paper, Two Way Time Transfer (TWTT) method is introduced for the autonomous time-tag error measurement of gravity satellites. A measurement scenario is presented, and a model which includes satellite-motion-induced path asymmetry, ionosphere effect, instrument delay, and random time measurement error is built. Combining the characteristics of Earth gravity satellites adopting TWTT, the influences of above mentioned error sources are analyzed and the relevant correction methods are proposed. Take GRACE (Gravity Recovery And Climate Experiment) system for example, based on the TWTT method with correction means, the achieved measurement precision of autonomous time-tag error can be better than 0.62ns, most of which is induced by the calibration error of instrument delay and the random time measurement error.