Patent ID: 8629803

Claim:
A positioning system comprising: a subset of transmitters of a terrestrial transmitter network, the subset of transmitters comprising a plurality of transmitters that broadcast positioning signals comprising at least ranging signals and positioning system information, wherein a ranging signal comprises information used to measure a distance to a transmitter broadcasting the ranging signal; a remote receiver that acquires at least one of the positioning signals and satellite signals, wherein the satellite signals are signals of a satellite-based positioning system, wherein a first operating mode of the remote receiver comprises terminal-based positioning in which the remote receiver computes a position of the remote receiver from at least one of the positioning signals and the satellite signals; and a server coupled to the remote receiver, wherein a second operating mode of the remote receiver comprises network-based positioning in which the server computes a position of the remote receiver from information derived from at least one of the positioning signals and the satellite signals, wherein the remote receiver receives and transfers to the server information derived from at least one of the positioning signals and the satellite signals, wherein the plurality of transmitters are synchronized to a time reference, wherein synchronization comprises coarse synchronization of the plurality of transmitters to a common time base and fine synchronization correction that is determined autonomously at the plurality of transmitters, wherein the fine synchronization correction is provided to the remote receiver via at least one of a broadcast positioning system information and data sent from the server through another communication medium.