A distributed
orbit and propagation method for use in a predicted GPS or GNSS
system, which includes a predicted GPS
server (PGPS
Server), a source of high accuracy
orbit predictions (
Orbit Server), a global reference network (GRN
Server) providing real-time GPS or GNSS assistance data to the PGPS Server, a predicted GPS
client (PGPS
Client) running on a device equipped with a GPS or AGPS
chipset. In response to requests from the PGPS
Client, the PGPS Server produces and disseminates an
initial seed dataset consisting of current
satellite orbit state vectors and orbit propagation model coefficients. This seed dataset enables the PGPS
Client to locally predict and propagate
satellite orbits to a desired future time. This predictive assistance in turn helps accelerate
Time To First Fix (TTFF), optimize position solution calculations and improve the sensitivity of the GPS
chip present on, or coupled with, the device. In contrast with other conventional predicted GPS systems that forward large volumes of predicted orbits, synthetic
ephemeris or synthetic almanac data, this method optimally reduces data transfer requirements to the
client, and enables the
client to locally synthesize its own predicted assistance data as needed. This method also supports seamless notification of real-time
satellite integrity events and seamless integration of predicted assistance data with
industry standard real-time assistance data.