Realization and performance assessment of uncombined Multi-GNSS PPP-RTK for expressway scenarios
【摘要】：Network Real-time Kinematic(NRTK) technology performs the error corrections in the Observation Space Representation(OSR) format, thereby being regardless of the temporal characteristics of various errors, and increasing transmission rate of corrections, while PPP usually requires a long initial convergence time, which restricts real-time mass-market applications. As a result, a new method, namely PPP-RTK, that combines the advantages of the two technologies began to develop. The current PPP-RTK technology mostly uses the "wide-lane/narrow-lane" method to achieve undifferenced ambiguity resolution, however, it is easy to amplify observation noise and is not easy to extend to multi-frequency observation. To this end, this paper derives the theoretical feasibility of PPP-RTK ambiguity resolution based on the original frequency observation, and conducts GPS/Galileo/BDS PPP-RTK tests in the scene of the intercity expressway from Hangzhou to Shanghai. Taking Multi-GNSS NRTK fixed solutions as the true coordinates, the results show that the correct fixing rate of Multi-GNSS PPP-RTK is better than 90%, the positioning accuracy in horizontal and vertical direction are better than 3 cm and 5 cm, respectively, and the probability of reconvergence time less than 10 s is over than 95%, which can basically meet the requirements of mass-market applications such as automotive driving and drones.