The Effect of Seasonal Changes on Precise Point Positioning

Precise Point Positioning (PPP) is a method that provides centimeter-level positioning accuracy using precise satellite orbit and clock products with a single GNSS receiver. Recently, this method has been the subject of many scientific studies. In this study, International GNSS Service (IGS) stations located in high latitude (KIR8 (Sweden), NYA2 (Norway)), mid-latitude (ANKR (Turkey), DLF1 (Netherlands)) and equatorial region (NKLG (Gabon), SIN1 (Singapore)) in northern hemisphere were selected to investigate the effect of seasons on position accuracy of PPP. RINEX data of 365 days 24 hours 30 seconds of selected stations were obtained to be used in solutions. The data obtained between 01.12.2019 and 30.11.2020 were evaluated with CSRS-PPP, MagicGNSS and APPS, which are web-based PPP services where solutions can be made within the specified date range. In order to investigate the precisions of the coordinates obtained from the web-based services, root mean square errors (RMSE) were calculated using the average coordinate values for each month, and then the 3D RMSE were calculated using the known coordinates of the stations obtained from IGS to reveal seasonal accuracies. The 3D RMSE obtained for the same stations and services in different seasons were compared with the Bartlett test. At the end of the comparison, it was seen that the 3D RMSE were in agreement at the other stations, except for the ANKR station, the positioning accuracy was dependent on the used services rather than seasons, and the best results were obtained with MagicGNSS.