Instantaneous ambiguity resolution for URTK and its seamless transition with PPP-AR

We extend the current Undifferenced network RTK (URTK) approaches by additionally using P1/CA augmentation information from reference stations. P1/CA augmentation information can shorten the convergence time and help to fix the ionosphere-free combination ambiguities in several epochs. Instantaneous and centimeter-level positioning solutions can be achieved for rovers within the coverage of regional reference network. Also, we develop an approach for seamless transition between URTK and precise point positioning with ambiguity resolution (PPP-AR) and present a new scheme to provide URTK service. Therefore, a service for a large number of rovers can be easily realized in real-time data communication for ambiguity fixing. In addition, the period when augmentation information from a particular reference station is not available can be bridged with the help of PPP-AR. Rovers can experience more operational time with fewer interruptions, which are difficult tasks for current URTK and Network Real-Time Kinematic services. More importantly, with this new scheme, URTK and PPP-AR services can be integrated into a unique PPP-AR system. The obtained convergence time only depends on whether or not the rover is receiving the regional augmentation information.