Comparison of Static PPP Performance of CSRS-PPP Float and Trimble RTX-PP Services

Abstract

Although various positioning methods are used in many engineering projects, Precise Point Positioning (PPP) technique, which enables more economical and accurate positioning, stands out among these positioning methods. The most important criteria affecting the positioning accuracy during the solution of the PPP are the quality of the precise satellite products, as well as the resolution of the phase ambiguity as fixed or float. The aim of the study is to test the static PPP performances of the online services under different satellite constellations as a function of occupation time. Within the scope of this study, PPP solutions were carried out with Canadian Spatial Reference System Precise-Point Positioning (CSRS-PPP) and Trimble CenterPoint Real Time eXtended Post-Processing (Trimble RTX-PP) web-based online GNSS processing services. The daily observations of the International GNSS Service (IGS) stations ANKR, ISTA, IZMI, MERS and KRS1, which are in Turkey, dated January 1, 2020 were used. The daily observations were divided into 1, 2, 4, 8, and 12 hour sub-sessions, and each observation session was processed with the aforementioned services using GPS-only and combination of GPS and GLONASS satellites data. As a result of the solutions, it has been shown that although CSRS-PPP provides PPP float solution, it offers a better solution than the Trimble RTX-PP, but still these two online tools were suitable for applications that require centimeter accuracy. Regarding the occupation time, the study revealed that at least 2 hours of observation period was necessary to determine the horizontal position and height with a few cm accuracies. Besides GPS and GLONASS combined PPP solutions provided more accurate results than GPS-only solutions.