A New Method of the Real-Time Precise Point Positioning Based on Epoch Difference of Satellite Clock Offset

The traditional real-time precise point positioning (PPP) model uses the satellite absolute clock offset products to achieve high accurate positioning. Precise satellite clock offset can be calculated by non-difference observation model and by epoch difference observation model. Non-difference observation model can directly solve the absolute satellite clock offset. While there are too many ambiguity parameters in the non-difference model which causing the dimensions of normal equation matrix are too large so that the calculation efficiency is lower. The epoch difference observation model eliminates the ambiguity parameters. Although the efficiency is much higher, while it solves the epoch difference of the satellite clock, and when restoring, the absolute clock offset of each epoch must require the initial clock offset. In this paper, a new real-time PPP method is proposed by using the epoch differential observation model, and this method can directly use the satellite clock offset products between epochs to positioning. The experimental results show that the positioning accuracy in both horizontal and elevation direction are better than 3.5 cm.