Impact of different GNSS data processing approaches (precise point positioning vs differenced approach) and different scientific software packages on the solutions for displacement detection

GNSS technology is one of the most useful techniques for displacements monitoring. Thanks to the time series given by permanent stations very precise and reliable results are achievable. The most usual approach for the GNSS data processing is the “differencing approach” which provides very accurate results and has been widely tested in the last decades. Many software allow the calculation of GNSS data through differenced approaches, someone are commercial software and some other are scientific packages such as Bernese or GAMIT. Precise Point Positioning (PPP) is a different technique which allows the estimation of the absolute coordinates of a single GNSS receiver without differencing observables. The PPP technique has proved to give coordinates at the same precision level obtainable through the classic differencing approach, at least if considering 24 hours data files and distances between the stations of several tens of km, that is the case of offshore permanent stations. The use of different strategies, algorithms and software for the GNSS processing should has some impact on the monitoring results. Therefore, the purpose of the future research is to compare different scientific software packages, which use different approaches and boundary conditions, and analyze the obtained accuracies. Tests will be performed basing on dataset acquired by a GNSS monitoring station located on an offshore platform.