Improving the estimation of fractional-cycle biases for ambiguity resolution in precise point positioning
Improving the estimation of fractional-cycle biases for ambiguity resolution in precise point positioning
复制标题
改进精确单点定位中模糊度解析的分数周期偏差估计
DOI：
10.1007/s00190-011-0537-0
复制
发表时间：
2012-08-01
影响因子：
4.4
通讯作者：
Liu, Jingnan
中科院分区：
文献类型：
--
作者：
Geng, Jianghui;Shi, Chuang;Liu, Jingnan
专用于单个全球定位系统（GPS）站的模糊度解算可以提高精密单点定位的精度。在此过程中，窄巷分数周期偏差（FCB）的估计精度对整周模糊度定位精度至关重要，它破坏了无差模糊度的整数性质。因此，在这项研究中，我们提出了改进的窄巷FCB来自模糊度固定的GPS网络解决方案，而不是原来的（即先前提出的）FCB来自模糊度浮动网络解决方案。改进后的FCB的性能优于原来的FCB，因为改进后的FCB确保了所得到的模糊度固定的每日位置在性质上与国际全球导航卫星系统服务产生的最新位置相吻合。为了验证这一改进，对分布在全球各地的约350个台站进行了为期一年的全球定位系统测量。我们发现，当较少的站点参与FCB估计时，特别是当站点数量小于20时，原始FCB与改进的FCB的差异更大。此外，当通过Helmert变换将248个站的模糊度固定的日位置与IGS周位置进行比较时，对于东分量，我们发现在一年中的359天，基于改进的FCB的变换残差的日RMS比基于原始FCB的变换残差的日RMS小0.8 mm，年平均均方根值福尔斯从2.6 mm明显下降到2.2 mm。同时，当使用改进的，而不是原来的FCB，转换残差的RMS为东分量的239个站（即96.4%的所有248个站）明显减少了高达1.6毫米，特别是对于站位于稀疏的GPS网络。因此，我们建议，窄车道FCB应确定模糊度固定，而不是模糊度浮动，GPS网络的解决方案。
Ambiguity resolution dedicated to a single global positioning system (GPS) station can improve the accuracy of precise point positioning. In this process, the estimation accuracy of the narrow-lane fractional-cycle biases (FCBs), which destroy the integer nature of undifferenced ambiguities, is crucial to the ambiguity-fixed positioning accuracy. In this study, we hence propose the improved narrow-lane FCBs derived from an ambiguity-fixed GPS network solution, rather than the original (i.e. previously proposed) FCBs derived from an ambiguity-float network solution. The improved FCBs outperform the original FCBs by ensuring that the resulting ambiguity-fixed daily positions coincide in nature with the state-of-the-art positions generated by the International GNSS Service (IGS). To verify this improvement, 1 year of GPS measurements from about 350 globally distributed stations were processed. We find that the original FCBs differ more from the improved FCBs when fewer stations are involved in the FCB estimation, especially when the number of stations is less than 20. Moreover, when comparing the ambiguity-fixed daily positions with the IGS weekly positions for 248 stations through a Helmert transformation, for the East component, we find that on 359 days of the year the daily RMS of the transformed residuals based on the improved FCBs is smaller by up to 0.8 mm than those based on the original FCBs, and the mean RMS over the year falls evidently from 2.6 to 2.2 mm. Meanwhile, when using the improved rather than the original FCBs, the RMS of the transformed residuals for the East component of 239 stations (i.e. 96.4% of all 248 stations) is clearly reduced by up to 1.6 mm, especially for stations located within a sparse GPS network. Therefore, we suggest that narrow-lane FCBs should be determined with ambiguity-fixed, rather than ambiguity-float, GPS network solutions.