Real-Time Precise Point Positioning (RT-PPP) for Positioning and Mapping

Real-Time Precise Point Positioning (RT-PPP) has started to develop among Global Positioning System (GPS) community due to some reasons, such as reference stations are required, very economical and easy to operate from everywhere. By using a dual-frequency receiver with the support from GPS precise products, RT-PPP has proven to give centimetre to decimeter positioning accuracy. Recently, the position can be obtained in real time using the real-time GPS precise products provided by many national geodetic agencies. Current real-time GPS positioning systems also allow accurate positioning by carrier phase-based double differencing approach. However, the limitation of using the differential approach is the process needs simultaneous data collection from common satellites at the reference station and the rover. Directly, the data acquisition process will become more difficult and this will decrease the suitability of this technique in other potential applications. The aim of this research is to analyse the current performance of RT-PPP technique using Hemisphere Atlas for positioning and mapping. This research also assessed the positioning accuracy between RT-PPP and static GPS techniques. Then, the reliability of RT-PPP for cadastral purposes is also evaluated. Methodologically, RT-PPP used Hemisphere Atlas, which is a dual-frequency receiver for position determination by processing raw pseudorange and carrier phase observations with the support from precise GPS orbit and clock information. The results of this research show that the coordinate for both positioning and mapping purposes using Hemisphere Atlas are within centimetre-level accuracy, i.e. below 10 cm for positioning and below 30 cm for cadastral purposes. Therefore, this study anticipates that RT-PPP has the potential to offer better operational flexibility that will guide for the full implementation of this technology particularly in surveying and mapping in the future.