Patent ID: 6768909
Filing Date: 2004-07-27
Classification: G01S,H04W

Abstract:
A method for conducting a handoff procedure between positioning systems used in determining a position for a mobile terminal in a cellular network, the method comprising:disengaging a first positioning system when said first positioning system is unable to calculate the position of said mobile terminal; instructing a second positioning system to engage and calculate the position of said mobile terminal; and monitoring said first positioning system and, when said first positioning system is able to calculate the position of said mobile terminal, instructing the second positioning system to disengage and instructing said first positioning system to engage and calculate the position of said mobile terminal; wherein one of said first positioning system and said second positioning system is an internal positioning system which calculates the position at the mobile terminal using radio signals from satellites, and the other of said first positioning system and said second positioning system is an external positioning system which calculates the position based on arrivals of a radio signal from the mobile terminal at a plurality of base stations.