POSITION ACCURACY EVALUATION BETWEEN SBAS CORRECTION AND DIFFERENTIAL GNSS SYSTEMS IN THE MARINE NAVIGATION A CASE STUDY OF DEEP SEA PORT, SONGKHLA PROVINCE

Abstract

Nowadays, Global Navigation Satellite System is the preferred method of navigation in missions such as flight planning and maritime navigation, etc., in which maritime navigation is necessary to know the coordinates with high positional accuracy during the ship's entry into the port. Satellite-Based Augmentation System and Differential Global Navigation Satellite System have therefore been applied in the routing processing for high precision and positional accuracy. These processes are accepted among mariners. However, in Thailand, there is no agency to assess the positional validity between the two techniques in the context of maritime navigation in regions of Thailand. Therefore, this research focuses on assessing the position accuracy between the correction data from the SBAS satellite system and the DGNSS positioning technique, which use the observation data with the GNSS for 6,665 positions in the deep-sea port, Songkhla province. The reference coordinates were obtained from the Post-Processed Kinematic (PPK) method. The DGNSS positioning technique showed the RMSE values at 0.59 m and 1.17 m in horizontal and vertical components respectively, while the SBAS technique showed the RMSE values at 0.90 m and 5.10 m in horizontal and vertical components respectively. Therefore, in marine navigation in the Gulf of Thailand, The DGNSS technique produced more accurate positioning results than the SBAS technique, which is navigated by the GNSS technique only and the use of correction data from the SBAS technique provides adequate positional accuracy for restricted ocean navigation. Still, it is not appropriate for the port or waters with heavy maritime traffic requiring positional accuracy of less than 1 meter