Satellite ephemeris data, received from SPS satellites in view of the particular SPS reference receiver. A plurality of digital processing system are coupled to the communication network to receive the satellite ephemeris data which is transmitted through the communication network. A digital processing system receives a pseudorange data from a SPS mobile receiver and calculates position information of the SPS mobile receiver from a representation of the pseudorange data and from satellite ephemeris data received from the communication network. The digital processing system may also receive pseudorange corrections from the communication network and use these corrections to correct the pseudorange data to provide the representation of the pseudorange data. In one embodiment of this example of the invention, the mobile SPS receivers are communicatively coupled.