The network RTK is considered as a candidate solution for cm-level service because it provides high-accuracy position to user in real-time with fast ambiguity resolution. However, the network RTK require a lot of reference stations to cover a wide-area for national or continental scales and require high-speed data bandwidth for broadcasting their scalar-type corrections. In this paper, we introduce a new concept called “Compact Wide-Area RTK (WARTK)” which provides centimeter-level positioning service on national or continental scales to overcoming the limitation of the legacy network RTK methods. Using the network of multiple reference stations whose distance is 400-1000 km, the Compact WARTK system generates three types of high-precision corrections: satellite orbit correction, satellite code/phase clock (CPC) correction, tropospheric correction. Separating each GPS error component into vector-type corrections, it is possible to broadcast their corrections over a wide-area using geosynchronous satellite with very low-speed data link. This paper mainly focuses on a correction generation algorithm for satellite clock error and code/phase biases. In order to evaluate the performance of the Compact WARTK system, a preliminary test was conducted on mid-west and south USA with six reference station, which is managed by the NOAA’s national geodetic survey. Their baseline distance are 198 km to 921 km. As a result, the Compact WARTK system can provide the centimeter-level position on the target service area within 1 minute after the receiving the WARTK corrections. In conclusion, the Compact WARTK system can provide centimeter-level positioning service to wide-area user while maintaining the hardware infrastructure of Satellite-Based Augmentation System (SBAS).

Keywords: compact RTK, network RTK, wide-area RTK, SBAS