A Benefit of Multiple Carrier GNSS Signals: Regional Scale Network-Based RTK with Doubled Inter-Station Distances

This paper presents a regional scale network-based real time kinematic (RTK) positioning strategy based on the use of three carrier GNSS signals, in which the inter-station distances of the network could be doubled, that is, around 140 to 180 km instead of the current 70 to 90 km with the use of dual-frequency GPS receivers. The paper outlines the most efficient virtual observables and models that allow for resolving ambiguities of three carriers with observation of above 7 minutes for baselines of a few hundreds of kilometres. As a result, the remaining key limiting factor for implementation of the regional scale network RTK is the distance-dependent residual tropospheric bias. A reference station placement scheme of doubling the inter-station distances is then suggested based on the interpolation accuracy of the tropospheric errors within the network. A semi-simulation procedure is introduced for generation of the third GPS signal from the real CPS L1 and L2 data to allow for more realistic assessment of three carrier ambiguity resolution WAR) performance benefits in real world situations. Numerical studies performed with 24-h data sets from four US CORS stations have demonstrated the superior AR performance benefits of the outlined TCAR algorithms, providing the technical basis for the deployment of regional scale network RTK services with doubled inter-station distances. The distance-independent nature of the AR performance has significant implications for future GNSS technological evolutions and applications.