Method of despreading GPS signals
First Claim
1. A method of despreading a target GPS spread spectrum signal containing pseudorandom noise (PRN) code sequences and received by a GPS receiver, the method comprising the steps of:
- providing Doppler information relating to an estimate of the variation in Doppler shift as observed on the target signal received by the GPS receiver and which is attributable to the motion of the GPS satellite;
correlating the target signal with a reference signal containing corresponding PRN code sequences, andin the midst of a single dwell, modifying the correlation as a function of the Doppler information to compensate for the variation in Doppler shift in the course of the dwell.
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Accused Products
Abstract
A method of despreading GPS spread spectrum signals containing pseudorandom noise (PRN) code sequences and received by a GPS receiver (24) is disclosed together with a GPS receiver (24) and a mobile communications device (MS1) (especially a mobile cellular telephone) for the same. The method comprises the steps of providing Doppler information relating to an estimate of the variation in Doppler shift as observed on the target signal by the GPS receiver and which is attributable to the motion of the GPS satellite; and correlating the target signal with a reference signal containing corresponding PRN code sequences, wherein, in the course of a single dwell, the correlation is modified as a function of the Doppler information.
19 Citations
7 Claims
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1. A method of despreading a target GPS spread spectrum signal containing pseudorandom noise (PRN) code sequences and received by a GPS receiver, the method comprising the steps of:
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providing Doppler information relating to an estimate of the variation in Doppler shift as observed on the target signal received by the GPS receiver and which is attributable to the motion of the GPS satellite; correlating the target signal with a reference signal containing corresponding PRN code sequences, and in the midst of a single dwell, modifying the correlation as a function of the Doppler information to compensate for the variation in Doppler shift in the course of the dwell. - View Dependent Claims (2, 3, 4, 5)
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6. A GPS receiver for despreading a GPS spread spectrum signal received by the GPS receiver comprising:
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means for providing Doppler information relating to an estimate of the variation in Doppler shift as observed on the target signal by the GPS receiver and which is attributable to the motion of the GPS satellite; means for correlating the target signal with a reference signal containing corresponding PRN code sequences, and means for, in the midst of a single dwell, modifying the correlation as a function of the Doppler information to compensate for the variation in Doppler shift in the course of the dwell.
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7. A mobile telephone comprising a GPS receiver comprising:
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means for providing Doppler information relating to an estimate of the variation in Doppler shift as observed on the target signal by the GPS receiver and which is attributable to the motion of the GPS satellite; means for correlating the target signal with a reference signal containing corresponding PRN code sequences, and means for, in the midst of a single dwell, modifying the correlation as a function of the Doppler information to compensate for the variation in Doppler shift in the course of the dwell.
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Specification