GNSS positioning analysis of different positioning modes using open- source tools - A comparative study

GNSS (Global Navigation Satellite System) with its advanced and efficient augmentation techniques such as SPP (Single Point Positioning) and PPP (Precise Point Positioning) can provide precise positioning with accuracy between centimeters and millimeters. In this study, GNSS Positioning is conducted and analyzed using the open-source software RTKLIB and OPUS. Ten days data was taken for the positioning and investigation of analysis was carried. This paper evaluates the change in accuracy of SPP when the elevation mask angle is increased from five degrees to fifteen degrees. Furthermore, the performance of SPP and PPP is analyzed, and also the IGS (final), IRS (rapid), IRU (ultra-rapid) clock corrections and GPS constellation precise orbit’s data are compared to the reference coordinates of IISC, Bangalore. Finally, it was proved that the Precise Point Positioning is the best positioning technique with centimeter level accuracy. Single Point Positioning can also be used for positioning where accuracy is not mandatory and when there is no availability of satellite and clock correction data. In all the cases, the data from IGS (final) showed better result and had higher accuracy compared to that of IGR and IGU. OPUS software can be used even without expertise in GNSS positioning whereas RTKLIB requires knowledge of GNSS positioning for handling the software.