不同基准钟对BDS实时钟差估计的影响分析

Analysis of Influence of Different Reference Clocks on BDS Real-Time Clock Offset Estimation

BDS原始观测量是站星之间的相对时间延迟,在实时卫星钟差估计过程中需要引入一个基准钟,求解该基准约束下的钟差产品。基于两种不同的基准约束条件实时估计BDS卫星钟差,并从实时钟差的估计精度、钟差频率特性(频率漂移率、频率准确度、频率稳定度)及钟差预报精度等方面分析其对BDS实时钟差估计的影响。算例结果表明,在两种不同的基准模式下,估计得到的BDS实时卫星钟差性能基本一致,在实际使用中可根据情况采用不同的基准钟进行钟差估计,为BDS实时卫星钟差估计时基准钟的选择提供了参考。

The BDS raw observation is the relative time delay between stations and satellites. One clock offset datum should be applied when estimating real-time clock offset, and then the clock offset products can be estimated under the constraint of this datum. In this study, the BDS satellite clock offset is estimated based on two different datums constraint. The impact of two datums on clock offset estimation is analyzed in terms of clock offset accuracy, clock frequency characteristics(frequency drift, frequency accuracy and frequency stability), clock offset prediction. The experimental results show that the BDS satellite clock offset performance is almost the same based on two different clock offset datums. In practice, different clock offset datum can be selected to estimate clock offset under different circumstances. This study can provide a reference for datum selection when estimating real-time satellite clock offset.