基于电网GNSS站的区域对流层延迟改正建模研究

Research on Regional Tropospheric Delay CorrectionModeling Based on GNSS Stations in Power Grid

基于全球卫星导航系统(global navigation satellite system, GNSS)的高精度定位技术是实现无人机自动巡检的基础条件。广东省地处南方沿海地区,大气水汽含量丰富,导致对流层天顶总延迟(zenith total delay, ZTD)在该地区短期变化剧烈;且常规ZTD经验模型在该区域精度较差,导致无人机自动巡检经常出现偏航等情况。对此基于广东电网自建地基增强系统,结合ERA5再分析资料和GNSS-ZTD解算结果,充分考虑ZTD在不同高程范围内的变化,通过分段函数对ERA5再分析资料进行拟合;并考虑年、半年和日周期变化的傅里叶级数来对分段拟合函数的系数进行时序分析,提出新区域ZTD格网模型;最后,使用96个广东电网GNSS站2023年1—3月的数据对所提出的模型进行验证,以其中31个站点作为基准站,以65个站点作为验证站进行模型验证。结果表明所提出的模型定位均方根误差为1.12 cm,远优于常规经验模型。

The high-precision positioning technology based on the global navigation satellite system(GNSS)is one of the fundamental conditions to realize automatic inspection of UAVs.However,since Guangdong province locates in the southern coastal area of China,it is rich in atmospheric water vapor content,leading to drastic short-term changes in the zenith total delay(ZTD)and the poor accuracy of the traditional ZTD empirical model.Therefore,frequent yawing often occurs during automatic UAV inspection.Based on the self-built ground-based augmentation system of Guangdong power grid,this paper proposes a new regional ZTD grid model by combining with the ERA5 reanalysis data and GNSS-ZTD solving results.The model uses a segmented function to fit the ERA5 reanalysis data,and the coefficients in the function are analyzed on a time-series basis,taking into account the Fourier series of the annual,semi-annual,and daily cycle variations.Finally,the paper uses the data from 96 GNSS reference stations of the Guangdong power grid from January to March in 2023 to verify the proposed model.31 stations are used as the base stations and 65 stations are used as the validation stations for model verification.The result shows that the mean square error of the positioning accuracy of the proposed model is 1.12 cm,which is much better than the traditional empirical models.