Real-time Precise Point Positioning (PPP) is drawing increasing attentions from both the Global Navigation Satellite System (GNSS) community and real-time users with different applications, such as offshore navigation, precise agriculture and hazard warning. To meet the rapidly increasing demand, the International GNSS Service (IGS) Real-Time Service (RTS) is currently disseminating several real-time high-frequency State Space Representation (SSR) products through the Internet under the Networked Transport of Radio Technical Commission for Maritime Services (RTCM) via the Internet Protocol (NTRIP) protocol. High availability of real-time PPP services requires high availability of precise orbit and clock corrections. Any correction outage, either due to corrupted ephemeris or loss of communication link, will degrade the availability of precise positioning using the service. Meanwhile, the communication burden is very heavy with such high update rates.

To tackle the above limitations, a new robust real-time PPP system with higher availability is proposed in this thesis. The proposed system consists of three components regarding server end, communication end and user end. For the new real-time PPP system, the satellite orbit and clock Initial Parameters (IP) products are generated at the server end and broadcast to the user end for the generation of high precision orbit and clock products, afterwards, the real-time PPP can be carried out with the IP-based high precision satellite products. With the IP products, the real-time PPP system can operate with scalable update rates according to the various accuracy requests of different applications. Furthermore, the new real-time PPP system can continue during Internet connection outages, which is not uncommon in real applications due to the Internet connection losses. The prototype of the new real-time PPP system is developed and substantially tested in real-time.