非校正相位延迟参数在复杂铁路场景下GPS精密单点定位应用研究

Application research of GPS PPP in railway scene based on uncalibrated phase delay paramteters

在复杂艰险地区的铁路沿线上全球卫星导航系统(GNSS)基准站相对较少且稀疏,如何获得该场景下测站点的高精度位置信息是亟待解决的重大问题.论文以GPS系统为例,利用铁路沿线上7个GNSS测站点(14个观测时段)分别开展了卫星跟踪数和位置精度因子(PDOP)评估,观测数据的可靠性、高精度性验证以及固定解精密单点定位(PPP)技术研究.试验结果表明:1)在所有时间段内卫星平均跟踪数约分布在5.14~9.07颗,PDOP平均值约分布在2.19~5.72 cm,具有较高地定位可用性;2)模糊度固定的PPP可进一步改善铁路环境下的单点定位精度.当观测时间约为90 min时,其在水平方向和高程方向上可分别实现优于10 cm和15 cm的解算精度,且相对于浮点解,三维方向上的定位精度可提升约35.43%.该研究可为复杂铁路场景下的勘测和施工阶段提供高精度的测站位置信息.

The Global Navigation Satellite System(GNSS) reference stations along the railway in complex and dangerous areas are relatively sparse. How to obtain the high precision position information for the stations under this scenario is an important problem. Taking the single GPS system for instance, the satellite tracking number and the position dilution of precision(PDOP) are evaluation, the reliability and usability of the observation are carried out and the research of enhanced precise point positioning(PPP) technology is implemented by using 7 GNSS stations(14 observation periods) along the railway. The results show that: 1) the average numbers of tracking satellites is about 5.14 to 9.07 and the average PDOP is about 2.19 to 5.72 in all time periods, which has high localization availability;2) Enhanced PPP can further improve the accuracy of PPP in railway environment. When the observation time is about 90 min, the positioning solution can be better than 10 cm and 15 cm in horizontal and vertical direction, respectively. Compared with float solution, the positioning accuracy in 3D direction can be improved by about 35.43%. This study can provide high-precision position information in the survey and construction stage for complex railway scene.