Comparison of three widely used multi‐GNSS real‐time single‐frequency precise point positioning models using the International GNSS Service real‐time service

Real‐time single‐frequency precise point positioning (RT‐SFPPP) of low‐cost has been attracting increasing attention in numerous global navigation satellite system (GNSS) applications. Nowadays, three multi‐GNSS RT‐SFPPP models are widely applied, i.e. ionosphere‐corrected (IC), ionospherefree (IF) and ionosphere‐weighted (IW) models. A comprehensive evaluation of the three models using CLK93 products is performed in the aspect of observation residuals, positioning accuracy and convergence. Data sets with quad‐system are collected from 16 multi‐GNSS experiments (MGEX) stations and are analysed in the simulated kinematic precise point positioning (PPP). Besides, kinematic PPP for a 5‐h shipborne data set is also conducted. Experimental results show that the positioning accuracy of IW model using MGEX data is better than that of both IC and IF models. Regarding the kinematic shipborne test, positioning accuracy of IF/IW model is of 0.27/0.26, 0.21/0.26 and 0.49/0.48 m for the N, E and U components, respectively, which is much better than that of IC model. As for average convergence time, IW model shows the best performance, which is at least 25% faster than the IF model. Different from both IF and IW models, the amplification of ionospheric errors has some impact on the positioning performance of the IC model at different frequencies.