Transfer of position information to a mobile terminal
First Claim
1. A method of supplying position assistance information to a receiver of a satellite positioning system, contained within a mobile terminal having a timing reference, said mobile terminal being connected to a cellular communications network and also able to communicate via a bi-directional link with one or more remote devices capable of calculating position information, the method comprising the steps of:
- (a) at a first location, where satellite signals are available, obtaining satellite position information of the mobile terminal from the satellite positioning system, storing said satellite position information within said terminal, measuring first time offsets, of the signals received by the terminal from a first plurality of transmitters of said cellular communications network, relative to each other or to the timing reference;
(b) sending said first time offset measurements to a remote device, calculating a first terminal cellular position information in the remote device using said time offset measurements, and storing said first terminal cellular position information;
(c) assigning a first time-tag to the first time offset measurements and storing said first time-tag;
(d) at a second location, where signals from the satellite positioning system are not adequately available, measuring second time offsets, of the signals received by the terminal from the first or a second plurality of the transmitters of said cellular communications network, relative to each other or to the timing reference;
(e) sending said second time offset measurements to, and calculating a second terminal cellular position information in, the or another remote device using said second time offset measurements;
(f) assigning a second time-tag to the second time offset measurements and storing said second time-tag;
(g) retrieving the first terminal cellular position information and the first time-tag and calculating a cellular average motion vector from the first and second terminal cellular position information and the first and second time-tags, and sending the cellular average motion vector to the mobile terminal;
(h) calculating in the terminal a position difference vector using said cellular average motion vector and the first and second time-tags, and adding said cellular position difference vector to the satellite position information stored within the mobile terminal and obtaining therefrom position assistance information of the mobile terminal at the second location;
(i) providing said position assistance information to the satellite receiver within the mobile terminal to aid the acquisition of satellite signals by the satellite receiver.
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Accused Products
Abstract
The invention provides a method of combining satellite positioning system signals and position information derived from such signals in a mobile terminal, when these are available at a first location, with cellular communication signals and a method, system and apparatus for determining the approximate position information for the said mobile terminal when SPS signals are not available at a second location. The approximate position is determined in the mobile terminal only using a position difference vector derived from the cellular communication signals using time offsets and associated time-tags in a method based on the observed time difference of arrival. The computations of cellular position and position difference information are made within the network infrastructure. The invention provides for the security of the user as only position difference information is communicated over the air interface, or transmission time offset measurements which require non-transmitted information to determine a solution. In a further aspect of the invention, the approximate position information is used to provide position assistance information to an SPS receiver for the purposes of (a) satellite signal acquisition with reduced search time and/or (b) initial position information for the calculation of SPS location which thereby avoids the ‘integer ambiguity’ problem resulting from the repetitive nature of the SPS ranging signals.
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Citations
24 Claims
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1. A method of supplying position assistance information to a receiver of a satellite positioning system, contained within a mobile terminal having a timing reference, said mobile terminal being connected to a cellular communications network and also able to communicate via a bi-directional link with one or more remote devices capable of calculating position information, the method comprising the steps of:
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(a) at a first location, where satellite signals are available, obtaining satellite position information of the mobile terminal from the satellite positioning system, storing said satellite position information within said terminal, measuring first time offsets, of the signals received by the terminal from a first plurality of transmitters of said cellular communications network, relative to each other or to the timing reference; (b) sending said first time offset measurements to a remote device, calculating a first terminal cellular position information in the remote device using said time offset measurements, and storing said first terminal cellular position information; (c) assigning a first time-tag to the first time offset measurements and storing said first time-tag; (d) at a second location, where signals from the satellite positioning system are not adequately available, measuring second time offsets, of the signals received by the terminal from the first or a second plurality of the transmitters of said cellular communications network, relative to each other or to the timing reference; (e) sending said second time offset measurements to, and calculating a second terminal cellular position information in, the or another remote device using said second time offset measurements; (f) assigning a second time-tag to the second time offset measurements and storing said second time-tag; (g) retrieving the first terminal cellular position information and the first time-tag and calculating a cellular average motion vector from the first and second terminal cellular position information and the first and second time-tags, and sending the cellular average motion vector to the mobile terminal; (h) calculating in the terminal a position difference vector using said cellular average motion vector and the first and second time-tags, and adding said cellular position difference vector to the satellite position information stored within the mobile terminal and obtaining therefrom position assistance information of the mobile terminal at the second location; (i) providing said position assistance information to the satellite receiver within the mobile terminal to aid the acquisition of satellite signals by the satellite receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system for supplying position assistance information to a satellite positioning system receiver adapted to obtain, where possible, satellite position information of the mobile terminal from a satellite positioning system, the satellite positioning system receiver being contained within a mobile terminal, and said system including
a mobile terminal having a timing reference a receiver for connection to a cellular communications network, a communication unit for communicating via a bi-directional link with one or more remote devices, a measuring unit for measuring first and second time offsets of the signals received by the terminal from one or more pluralities of transmitters of said cellular communications network, relative to each other or to the timing reference, at respective first and second locations of said terminal, a storage unit for storing said satellite position information, and a transmitting unit for sending said first and second time offset measurements to a remote device; -
an assigning unit for assigning first and second time-tags to the time offset measurements; a storage device for storing the first and/or second time-tags; a device for retrieving the first terminal cellular position information and the first and second time-tags, calculating a cellular average motion vector from the first and second terminal cellular position information and the first and second time-tags, and a transmitting unit for sending the cellular average motion vector to the mobile terminal, the mobile terminal further including a calculation unit for calculating a position difference vector using said cellular average motion vector and the first and second time-tags, and adding said cellular position difference vector to the satellite position information stored within the mobile terminal to obtain therefrom position assistance information of the mobile terminal at the second location; and transfer unit for transferring said position assistance information to the satellite receiver within the mobile terminal to aid the acquisition of satellite signals by the satellite receiver. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A mobile terminal satellite positioning system receiver having
a timing reference a receiver for connection to a cellular communications network, a communication unit for communicating via a bi-directional link with one or more remote devices, a measuring unit for measuring first and second time offsets of the signals received by the terminal from one or more pluralities of transmitters of said cellular communications network, relative to each other or to the timing reference, at respective first and second locations of said terminal, a storage unit for storing said satellite position information, a transmitting unit for sending said first and second time offset measurements to a remote device; -
a calculation unit for calculating a position difference vector using a cellular average motion vector received from a remote device and first and second time-tags assigned to the time offset measurements, and adding said cellular position difference vector to the satellite position information stored within the mobile terminal to obtain therefrom position assistance information of the mobile terminal at the second location; and transfer unit for transferring said position assistance information to the satellite receiver within the mobile terminal to aid the acquisition of satellite signals by the satellite receiver. - View Dependent Claims (23, 24)
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Specification