An effect of tropospheric delay irregularity among the reference stations on precise positioning

Abstract

Network RTK generates corrections by using differenced measurements from reference stations in the network, and the corrections are then provided to a user. The user, generally, uses linear interpolation, which assumes that the corrections at each reference station are spatially correlated, to obtain a precise correction of its location. However, the tropospheric delay irregularity is a real-world factor that violates this assumption. Tropospheric delay is a result of weather conditions, such as humidity, temperature and pressure, and it can cause spatial decorrelation in corrections among reference stations when there are meteorological changes by locally. In this paper, we have defined the non-linear characteristics of the tropospheric delay among the reference stations within a network as the irregularity in tropospheric delay. Such an irregularity can negatively impact the network RTK performance. Therefore, an analysis of the effect of tropospheric delay irregularity on Network RTK is needed. For the analysis, the tropospheric delay irregularity modeling is made based on the meteorological data during the typhoon. The effect of tropospheric delay irregularity is analyzed in two parts. One is analyzing the effect of tropospheric delay irregularity on delta Carrier Phase Corrections (CPC) which are generated by comparing between master and auxiliary station by each. Another part is analyzing the effect of tropospheric delay irregularity on corrections of Network RTK user. The results of analysis conclude that tropospheric delay irregularity needs to be considered to utilize the Network RTK on precise positioning application which requires cm level accuracy. ？ 2016 by Institute of Navigation. All right reserved.