Comparison of position determination accuracy conducted by PPP technique using web-based online service and dedicated scientific software

Precise Point Positioning is a relatively new technique which can be used to determine high precision 3D position by processing of observations from a single GNSS receiver. For this reason some errors that are mostly eliminated in the differential approach have to be estimated in the PPP. These errors, which are mainly related to physical phenomena, include e.g.: solid earth and ocean tides, carrierphase wind-up, relativistic effects, etc. On the other hand no base stations and no simultaneous observations are necessary to determine receiver position. In recent years, the development of PPP method and GNSS systems allows to effectively deal with the disadvantages of this technique, such as slow convergence times, problematic ambiguity resolution etc. The aim of this paper is to study the position determination accuracy obtained using PPP technique. Because current commercial software packages do not provide the processing of measurements done using PPP, it is necessary to use scientific software or one of several online services. We processed daily GNSS observations that have been made at two points characterized by different environment conditions. The post-processing of observations covered a variety of development strategies, such as different measurement intervals (0.5 h, 1 h, 2 h, 4 h) or utilization combined observations from GPS and GLONASS systems.