Hong Kong is developing urban positioning infrastructure to support smart city applications and GNSS is the backbone of the infrastructure. In 2020, the new GNSS constellations include Chinese Beidou III and European Galieo systems will be operational. These new constellations will not only increase the number of satellites, but also further enhance the performance of positioning (i.e. Beidou III Precise Point Positioning service, the first GNSS system to provide this service), compared to the existing GPS and GLONASS systems. This project aims at enhancing Hong Kong positioning infrastructure using the enhanced functions of Chinese Beidou III, which will be operational in 2020. The objectives of the project are 1) to develop a testbed of multiple GNSS high precision service through the use of the multiple GNSS signals ; 2) to utilize Beidou III PPP data to provide better positioning service in Hong Kong, and 3) to improve the coverage of GNSS RTK service through Beidou III communication channel. The system developed in this project would be the first Beidou III augmentation system outside China. It will not only improve the positioning services in Hong Kong, but also provide useful demonstration and experience for the Beidou III technologies to the world.