Abstract:
Satellite Based Augmentation System (SBAS) is the additional system that provide services for improving the accuracy of Global Navigation Satellite Systems (GNSS). The SBAS service supports wide-area and is recently developed in many countries around the world. Since Thailand is not located within the service area, Thailand can still receive the correction message from SBAS. This research, therefore, aims to study on an evaluation of positioning accuracy using the correction message from SBAS combined with standard positioning service from GPS in Thailand. Use of 40 CORS Stations operated by Royal Thai Survey Department during September 2019, December 2019, and April 2020. The results from the GPS Single Point Positioning technique (SPP) and the GPS Single Point Positioning technique (SPP) combined with SBAS messages are compared with the coordinate reference by using the GPS Precise Point Positioning technique (PPP). The research shows that Thailand can receive the correction message from 3 SBASs including SPAN, GAGAN, and BDSBAS. The above 3 SBASs cannot improve both the horizontal and vertical positioning results compared with the standard positioning service from GPS.