Precise Point Positioning with Ambiguity Resolution in Real-Time

We have developed and implemented a method to resolve carrier phase ambiguities in precise point positioning (PPP) mode at the satellite single difference (difference between two satellites observed from one receiver) level. The corrections needed for PPP with single difference ambiguity resolution can be generated in real-time and transmitted to static or moving dual frequency GPS client users. We call the real-time point positioning with ambiguity resolution “PPP-RTK”. We demonstrate that “PPP-RTK” has several significant advantages over PPP positioning without ambiguity resolution or standard PPP. Compared to PPP, PPP-RTK converges significantly faster to the correct position in static and kinematic applications. In kinematic applications PPP RTK provides superior positions of the moving platform compared to standard PPP. PPP-RTK has the main advantage over traditional network RTK techniques that the client user of the PPP RTK corrections can be in a highly kinematic environment like a buoy or an airplane at a significant distance (several 100 to 1000 km) from the reference network and still achieve 1-2 cm horizontal position accuracy. This paper summarizes the technique to obtain PPP and PPP RTK corrections and shows representative example results.