GNSS active control point determinations

The Royal Thai Survey Department (RTSD) is the sole organisation to establish a primary geodetic datum network across the nation to enhance precise Global Navigation Satellite Systems (GNSS) positioning applications in Thailand such as mapping, surveying and other engineering activities. The conventional geodetic surveying has been replaced by precise GNSS static positioning. This study present current GNSS surveying methodology using a network of GNSS continuously operating reference stations (CORS) operated by RTSD. These permanently installed reference stations are homogenously distributed across Thailand. It will later be part of a national network comprising of numerous networks with different agencies operating according to their responsibilities. The coordinate realisations apply geodetic products and services provided by International GNSS Service (IGS) and GNSS measurement scientific software; Bernese GNSS software version 5.2 used for post-processing this campaign dataset. The national geodetic datum has to be aligned with the global geodetic datum of International Terrestrial Reference Frame (ITRF); hence, precise coordinates and velocities of the GNSS CORS network have to be determined. This study illustrates GNSS geodetic surveying methodology and results obtained from a network of geodetic receivers; multi-frequencies and multi-constellations, and choke-ring geodetic antennas. The estimated coordinates along with their quality measures in terms of precisions and accuracies of few millimetres are discussed.