Multi-GNSS trials: a note on software comparison and campaign GNSS measurements

Determining the accuracy of position and velocity using GNSS is now on the agenda of the research community. Each unique system in the GNSS puts effort to complete its constellation of satellites, with orbits and clocks of ever-increasing quality. In order to interpret the quality of the results, we started the IGS MGEX experiment, where we, as end users, used the network and its data for evaluation. Various software has been developed to evaluate Multi-GNSS products, and researchers evaluate the results of both independent and combined systems within the framework of their experiments and have the opportunity to compare the software with each other. Succeeding JPL's 2019 experiment, we focused on the evaluation of the GIPSY-X, a multi-GNSS software, positioning results and we would like to share our initial findings with you. Unlike other studies, our focus is on the factors influencing position determination and their mathematical modeling. There is also an emphasis in our study on the campaign Multi-GNSS. In the first part of the study, we made inferences about GPS+GLONASS positioning accuracy. We modeled and compared the results of CSRS-PPP and GIPSY-X with each other. In the second part, we examined the GALILEO contribution to the GIPSY-X positioning solutions, and again we present modeling. We still see the effect of the observation session on positioning on all results and modeled it for GPS+GLONASS+GALILEO. We could not see the "geographical latitude dependence" on positioning that we noticed in the GPS-only studies in these first trials. In this presentation, we will try to examine the possible reasons for this.