METHODS AND SYSTEMS FOR TEMPERATURE RELATED FREQUENCY DRIFT COMPENSATION
First Claim
1. A method of providing compensation for frequency drift due to temperature variation in a navigation receiver, comprising:
- generating a local frequency using a local oscillator in the receiver;
periodically calibrating the local frequency using a reference signal;
driving a plurality of counters with the calibrated local frequency; and
computing a count correction to compensate for temperature variation using count values from at least two of the counters.
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Accused Products
Abstract
Systems and methods are provided that compensate for frequency drift due to temperature variation without the need for a temperature sensor. In one embodiment, a navigation receiver with an integrated communication device receives a base station reference signal, which is used to periodically calibrate a local oscillator frequency. In another embodiment, the calibrated local oscillator frequency drives a counter that is used to provide code phase estimation at the start of satellite signal acquisition. To provide temperature compensation in one embodiment, the calibrated local frequency is used to drive one or more counters at different calibration rates (i.e., different time intervals between calibrations). Count values from these counters are used to determine compensation for frequency drift due to temperature variation based on predicted frequency drift variation patterns between calibrations. This temperature compensation does not require a temperature sensor and further improves the accuracy of the code phase estimation.
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Citations
24 Claims
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1. A method of providing compensation for frequency drift due to temperature variation in a navigation receiver, comprising:
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generating a local frequency using a local oscillator in the receiver; periodically calibrating the local frequency using a reference signal; driving a plurality of counters with the calibrated local frequency; and computing a count correction to compensate for temperature variation using count values from at least two of the counters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 21, 22, 23)
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13. A navigational receiver, comprising:
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a local oscillator for generating a local frequency; a calibration module coupled to the local oscillator for periodically calibrating the local frequency using a reference signal; a plurality of counters driven with the calibrated local frequency; and a correction module coupled to at least two of the counters, wherein the correction module computes a count correction to compensate for temperature variation using count values from the at least two counters. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 24)
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Specification