Handoff between external and internal positioning systems
First Claim
1. 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.
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Accused Products
Abstract
A method and apparatus for determining the position of a mobile terminal using either an internal positioning system, such as a GPS receiver, or an external positioning system such as an external cellular positioning system. A handoff procedure is used to decide which positioning system is used to calculate the position of the mobile terminal. In one embodiment, the internal positioning system is preferred and the mobile terminal switches to the external positioning system only when the internal system is unavailable, and switches back when the internal system is functioning properly. Alternatively, the external positioning system is preferred and when it is unavailable the mobile terminal switches to the internal positioning system, but switches back to the external system when it is available. In one embodiment, the mobile terminal includes the internal positioning system, a transceiver, and a mobile terminal position controller. The mobile terminal position controller selects between the external and internal positioning systems depending on availability or other factors such as operator preference.
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Citations
29 Claims
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1. 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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A mobile terminal usable in a cellular network, said mobile terminal comprising:
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an internal positioning system which calculates, at the mobile terminal, a position of the mobile terminal using signals from satellites;
a transceiver for communicating via wireless signals with the cellular network, wherein the cellular network comprises an external positioning system which calculates, the position of the mobile terminal based on arrivals of the wireless signals at a plurality of base stations, said signals including data regarding the position of the mobile terminal as determined by at least one of the external and the internal positioning systems; and
a mobile terminal position controller, wherein said mobile terminal position controller determines the availability of one of the external and internal positioning systems, wherein said mobile terminal position controller selects the other of the positioning systems when said one positioning system is unavailable. - View Dependent Claims (20, 21, 22, 23, 24)
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25. An external cellular positioning system for a cellular network, the external cellular positioning system comprising:
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a plurality of cellular positioning receivers operable for monitoring transmissions from at least one mobile terminal, wherein the at least one mobile terminal comprises an internal positioning system which is operable to calculate, at the mobile terminal, using signals from satellites, a position for the at least one mobile terminal; and
a central positioning control site connected to the plurality of cellular positioning receivers, the central positioning control site operable to receive information regarding the transmissions from the plurality of cellular positioning receivers and calculate, at the central positioning control site, the position for the at least one mobile terminal, using the arrivals of the transmissions at the cellular positioning receivers;
wherein the external cellular positioning system is operable to receive over a channel and act on an instruction message from the at least one mobile terminal which selectively instructs the external cellular positioning system to engage and disengage based on the availability of the internal positioning system. - View Dependent Claims (26, 27, 28, 29)
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Specification