基于北斗星间链路闭环残差检测的星间钟差平差改正

利用“闭环检测”思想检测和修正系统测量累积误差，是工程科学中的常用和有效手段。本文指出了北斗三号系统全球星间链路中所存在的有利闭环条件，并提出一种利用其进行闭合残差检测与分析的方法。在此基础上，构建了闭合残差整网平差模型，实现了对北斗三号卫星星间相对钟差的误差修正。基于在轨实测数据的计算表明，北斗三号系统全球星间链路中确实存在着明显的常数性或周期性非零闭合残差。通过对星间链路闭环残差的平差修正，基本消除了卫星星间钟差不闭合的现象，减少星间钟差随机噪声30%~50%，有效提高了星间相对钟差测定的精度，有利于提升北斗系统服务能力。

Inter-satellite clock offsets adjustment based on closed-loop residual detection of BDS inter-satellite link

It is a common and effective method in engineering science to use the "closed-loop detection" idea to detect and correct the cumulative error of system measurement. This paper indicates the favorable closed-loop conditions in the global inter-satellite link (ISL) of BeiDou-3 navigation satellite system (BDS-3), and proposes to detect and analyze the closed residuals. On this basis, a network adjustment model of the closed residuals is constructed by which the correction of inter-satellite clock offsets is realized. Calculations based on the on-orbit measured data indicate that the obvious constant or periodic non-zero closed residuals really exist in the global ISL of BDS-3. Attributed to the correction of the closed-loop residuals of the ISL, the non-closed inter-satellite clock corrections are basically eliminated, the random noise of the inter-satellite clock corrections is reduced by 30% to 50% and the accuracy of the inter-satellite clock corrections are effectively improved. It is helpful forthe service capability of BeiDou.