高速铁路CP0基线解算中天顶对流层参数估计研究

Research on Estimation of Parameters of Zenith Troposphere with CP0 Baseline Resolution for High-speed Railway

对流层延迟是GPS测量的重要误差源之一，对模糊度解算及基线精度均有较大影响。高速铁路 CP0框架控制网基线解算中采用 PWL 分段线性法估计天顶对流层湿延迟参数的方法提高对流层折射改正精度，因此研究PWL 分段线性法中参数估计的时间间隔对CP0基线解算的影响是十分必要的。介绍GPS对流层延迟的改正原理，通过设计不同解算方案采用工程测量数据对天顶对流层湿延迟参数估计的合理时间间隔进行研究。结果表明，每4-6h估计一个天顶对流层湿延迟参数效果较好，能真实反映出对流层折射影响随时间变化的趋势，从而提高基线解的精度。

The refraction of the tropospheric delay on radio signals, which is one of the important error sources in GPS surveying, has great influences on the accuracy of ambiguity and baseline resolution. The method to estimate zenith tropospheric wet delay parameters of PWL model, which may be applied to CP0 baseline resolution of high-speed railway, improves the accuracy of the tropospheric delay correction effectively. Thus, it is necessary to conduct a research on the time interval selection of zenith tropospheric wet delay parameters of PWL model. In this paper, the principle of GPS tropospheric delay correction is introduced, and then surveying data in different resolution schemes are analyzed to determine a reasonable time interval of zenith tropospheric wet delay parameters of PWL model. The results show that the estimation of zenith tropospheric wet delay parameter every 4 to 6 hours has better baseline resolution effect, which truly indicates the trend of changes of the tropospheric refraction effect with time, and, thereby, improves the accuracy of baseline resolution.