A wide area solution that takes advantage of the existing radio broadcast and national geodetic network infrastructure

This paper discusses the implementation and operation of a wide-area differential GPS (WADGPS) system that uses existing networks. This WADGPS system was launched in commercial service on 5 December 1994 and has been operating since. This paper describes: SWEPOS- a Swedish network of reference stations for GPS; FM and the RDS subcarrier channel; Epos, the Swedish solution of nationwide access to DGPS; trials with WADGPS; experiences of a year of operation of the WADGPS system; and future developments.