Real-time and online post-processing kinematic positioning services

Abstract

The national positioning infrastructure in Thailand provides accurate positioning in real time for precise positioning applications including of precise navigation, construction, precise agriculture and rapid mobile mapping. Real-time GNSS positioning relies on GNSS measurements and coordinate information being generated from measurement processing where time delay is computed at a predicted position. Two-way internet communication between rover receivers and data-controlled centre has to be continuous because of the demand on integrity for high accuracy and reliable coordinate solutions. This study applies a network real-time kinematic positioning determination using a Virtual Reference Station (VRS) technique through the national real-time GNSS positioning service to determine coordinates in a well-bred soldier project ground in Chulachomklao Royal Military Academy. Obtained real-time coordinates are later compared with the Post-Processed Kinematic (PPK) solutions using multiple GNSS ground stations and VRS observations. Obtained results are assessed in terms of their precisions determined from root mean square errors (RMSE). Their RMSEs are 0.021 metre horizontally and 0.092 metre vertically when observations from multiple reference stations and PPK positioning are applied. They are 0.016 metre horizontally and 0.105 metre vertically obtained from VRS PPK solutions. Methods and findings from this paper bring to light how users can decide to use suitable positioning algorithms and available services from the real-time national positioning and timing infrastructure in Thailand taking accounts for eventual temporary station and network outages.