Cambridge Positioning Systems Limited

David William Bartlett

Peter James Duffett-Smith

Anthony Richard Pratt

A method of and system for calibrating un-calibrated time information within a mobile terminalis disclosed. The terminal has a receivercapable of receiving signals from which calibrated time information carried by a calibrated system (a satellite positioning system) can be extracted, and a receivercapable of receiving signals from which un-calibrated time information carried by an un-calibrated stable system (a cellular communications system) may be extracted. The time offset between calibrated time information extracted from the calibrated system and un-calibrated time information extracted from the un-calibrated stable system is determined at a first terminal position where the signals from the un-calibrated stable system are available, the travel times of the signals from the un-calibrated stable system are known or determined, and the signals from the calibrated system are available. The un-calibrated time information extracted from signals of the un-calibrated stable system received at a second terminal position, is calibrated from known or determined travel times of the signals from the un-calibrated stable system at the second terminal position and the time offset which has been determined.

Growing community of inventors

Cambridge, United Kingdom

David William Bartlett