Wide Area Differential GNSS in Taiwan: Development and validation testing

To provide the enhanced Global Navigation Satellite System (GNSS) service in Taiwan, a Satellite Based Augmentation System (SBAS) prototype, the Wide Area Differential GNSS (WADGNSS), is developed and tested in this work in order to facilitate the implementation and operation of a SBAS and to evaluate its services to support the land and maritime transportations in Taiwan. There are three major components of a WADGNSS, namely one Test-bed Master Station (TMS), several L1-L2 dual-frequency Test-bed Reference Stations (TRSs), and the WADGNSS user equipment. This paper will focus on the development and validation of the TMS and TRSs. In this work the e-GPS satellite tracking stations which are originally designed for the surveying and mapping purposes will be used as our TRSs; therefore, the difficulties and challenges to use them as the WADGNSS TRSs will be investigated. The data processes and communications between the TRSs and TMS will be investigated in this work, and the detailed development steps of the TMS and their validation testing will be discussed in this paper as well. Finally, the performance of the developed WADGNSS is presented by comparing the positioning results with standalone GPS measurement and that using WADGNSS correction messages. Based on the results presented in this work, the performance of the GPS users in Taiwan could be enhanced by applying the WADGNSS correction message.