Method and apparatus for collecting, processing and distributing differential global positioning system information using the internet

Abstract

An infrastructure for implementing DGPS virtual reference stations is disclosed. The virtual reference station infrastructure is comprised of a network of real DGPS reference stations coupled to a central computer system. The real DGPS reference stations may be coupled to the central computer by a set of radio receivers that transmit the pseudorange corrections from each real reference station to the central computer system. The central computer system processes the pseudorange corrections from all the real DGPS reference stations to generate a dynamic satellite error vector and a clock error for each satellite. The dynamic satellite error vector and satellite clock error for each satellite are transmitted to plurality of “virtual” references stations. The virtual reference stations combine the dynamic satellite error vector and the satellite clock error with a local position to generate the local pseudorange corrections (PRC) for the observable satellites. The local pseudorange corrections can be broadcast using the well known RTCM SC-104 format to mobile GPS receivers that are within the local are of the virtual reference station. The mobile GPS receivers can thus correct their position data using the pseudorange corrections broadcast the virtual reference station.