Method and apparatus for estimating GPS time
First Claim
1. A method of providing an estimate of GPS time from non-GPS timing information present in communications signals transmitted from a base station to a first mobile communications device, the method comprising the steps of:
- (i) in a second mobile communications device, receiving corresponding non-GPS timing signals present in communications signals transmitted by the base station (ii) in a GPS receiver of the second mobile communications device, obtaining at least one pseudorange to a GPS satellite and obtaining an first estimate of GPS time;
(iii) deriving a relationship between the receipt of timing signals received in step (i) and the estimate of GPS time obtained in step (ii); and
(iv) from the non-GPS timing information received by the first mobile communications device and the relationship derived in step (iii), calculating a second estimate of GPS time.
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Accused Products
Abstract
A method of providing an estimate of GPS time from non-GPS timing information present in communications signals transmitted from a base station (BS1) to a first mobile communications device (MS1) is provided comprising the steps of (i) in a second mobile communications device (MS2), receiving corresponding non-GPS timing signals present in communications signals transmitted by the base station; (ii) in a GPS receiver (23, 24) of the second mobile communications device (MS2), obtaining at least one pseudorange to a GPS satellite (GPS SV) and obtaining an first estimate of GPS time; (iii) deriving a relationship between the receipt of timing signals received in step (i) and the estimate of GPS time obtained in step (ii); and (iv) from the non-GPS timing information received by the first mobile communications device (MS1) and the relationship derived in step (iii), calculating a second estimate of GPS time.
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Citations
29 Claims
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1. A method of providing an estimate of GPS time from non-GPS timing information present in communications signals transmitted from a base station to a first mobile communications device, the method comprising the steps of:
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(i) in a second mobile communications device, receiving corresponding non-GPS timing signals present in communications signals transmitted by the base station (ii) in a GPS receiver of the second mobile communications device, obtaining at least one pseudorange to a GPS satellite and obtaining an first estimate of GPS time;
(iii) deriving a relationship between the receipt of timing signals received in step (i) and the estimate of GPS time obtained in step (ii); and
(iv) from the non-GPS timing information received by the first mobile communications device and the relationship derived in step (iii), calculating a second estimate of GPS time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 28)
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14. A system comprising a base station and first and second mobile communications devices wherein the system is configured to derive a relationship between non-GPS timing signals present in communications signals transmitted by the base station to the second mobile communications device and a first estimate of GPS time obtained from a GPS receiver of the second mobile communications device, and using said relationship and non-GPS timing information received by the first mobile communications device, to obtain a second estimate of GPS time.
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26. A mobile communications device comprising a GPS receiver and adapted to transmit to a corresponding communications base station information describing the relationship between the receipt of non-GPS timing signals present in communications signals transmitted by the base station and received by the device and an estimate of GPS time obtained using the GPS receiver.
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27. A mobile communications device comprising a communications receiver adapted to receive from a corresponding communications base station information describing the relationship between the GPS timing signals present in communications signals transmitted by the base station and GPS time, and a processor for using the relationship to obtain an estimate of GPS time at the mobile communications device;
- wherein the mobile communications device is able to communicate the base station being one of several such basestations of a cellular telephone network where are not synchronized using GPS receivers.
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29. A mobile communications device comprising a communications receiver adapted to receive from a corresponding communications base station information describing the relationship between the GPS timing signals present in communications signals transmitted by the base station and GPS time, and a processor for using the relationship to obtain an estimate of GPS time at the mobile communications device;
- wherein the mobile communications device does not comprise a GPS receiver.
Specification