An improved network enabled extended ephemeris navigation system includes a network server able to collect ephemeris, clock, and almanac information from orbiting GPS satellites, and to use that information to build up extended ephemeris predictions that will be valid and useful for at least a week. A mobile client is able to request and use the extended ephemeris predictions to search for and track orbiting GPS satellites visible to it. The improvement is characterized by a satellite position and clock compact model construction and database unit that constructs a compact short-term satellite model to be sent first in response to a request for extended ephemeris predictions from the mobile client, and that constructs several consecutive long-term satellite models each representing a unique portion of a day in at least a seven day series.