Patent ID: 8193979

Claim:
An improved assisted satellite navigation system, comprising: a plurality of SBAS reference receivers for strategic location around the world to receive a corresponding SBAS message[s] from at least the WAAS, EGNOS, MSAS, and GAGAN SBAS systems; the improvement characterized by: a satellite navigation system assistance server for collecting corresponding SBAS messages from the plurality of SBAS reference receivers, and for computing satellite vehicle (SV) health, DGPS information, SBAS ephemeris and almanac, and PRN masks for different parts of the world; a PRN reconciliation process for reconciling particular PRN's that are duplicated between independent SBAS systems; and a PRN database for storing said SBAS messages collected from the plurality of SBAS reference receivers according to said SBAS reference receivers PRN's; wherein, the satellite navigation system assistance server is configured to reply to client requests that include an indication of the client's location, and if an accurate location is included in the server request, the satellite navigation system assistance server computes which particular SBAS systems are observable to the requesting client, and in this case the satellite navigation system assistance server limits replies to said request to pertinent information for a more compact response message.