System and method for frequency management in a communication device having a positioning device
First Claim
1. A system for generating corrective information based on a frequency reference in a hybrid communications device, comprising:
- a first clock source in a communications portion of the communications device, the first clock source generating a first clock signal at a first frequency;
a first clock correction module, communicating with the first clock source, the first clock correction module sensing a first error in the first frequency;
a second clock source in a positioning portion of the communications device, the second clock source generating a second clock signal at a second frequency;
a comparator module, communicating with the first clock source and the second clock source, the comparator module comparing the first frequency and the second frequency to determine a differential error between the first frequency and the second frequency; and
a processor, communicating with the comparator module, the processor adapting a position processing operation based upon at least the first error and the differential error.
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Accused Products
Abstract
A frequency management scheme for a hybrid cellular/GPS or other device generates a local clock signal for the communications portion of the device, using a crystal oscillator or other part. The oscillator output may be corrected by way of an automatic frequency control (AFC) circuit or software, to drive the frequency of that clock signal to a higher accuracy. Besides being delivered to the cellular or other communications portion of the hybrid device, the compensated clock signal may also be delivered to a comparator to measure the offset between the cellular oscillator and the GPS oscillator. The error in the cellular oscillator may be measured from the AFC operation in the cellular portion of the device. An undershoot or overshoot in the delta between the two oscillators may thus be deduced to be due to bias in the GPS oscillator, whose value may then be determined. That value may then be used to adjust Doppler search, bandwidth or other GPS receiver characteristics to achieve better time to first fix or other performance characteristics.
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Citations
60 Claims
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1. A system for generating corrective information based on a frequency reference in a hybrid communications device, comprising:
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a first clock source in a communications portion of the communications device, the first clock source generating a first clock signal at a first frequency;
a first clock correction module, communicating with the first clock source, the first clock correction module sensing a first error in the first frequency;
a second clock source in a positioning portion of the communications device, the second clock source generating a second clock signal at a second frequency;
a comparator module, communicating with the first clock source and the second clock source, the comparator module comparing the first frequency and the second frequency to determine a differential error between the first frequency and the second frequency; and
a processor, communicating with the comparator module, the processor adapting a position processing operation based upon at least the first error and the differential error. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for generating corrective information based on a frequency reference in a hybrid communications device, comprising:
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generating a first clock signal at a first frequency in a communications portion of the communications device;
sensing a first error in the first frequency;
generating a second clock signal at a second frequency in a positioning portion of the communications device;
comparing the first frequency and the second frequency to determine a differential error between the first frequency and the second frequency; and
adapting a position processing operation based upon at least the first error and the differential error. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A system for generating corrective information based on a frequency reference in a hybrid communications device, comprising:
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first clock means in a communications portion of the communications device, the first clock means generating a first clock signal at a first frequency;
first clock correction means, communicating with the first clock source, the first clock correction means sensing a first error in the first frequency;
second clock means in a positioning portion of the communications device, the second clock means generating a second clock signal at a second frequency;
comparator means, communicating with the first clock means and the second clock means, the comparator means comparing the first frequency and the second frequency to determine a differential error between the first frequency and the second frequency; and
processing means, communicating with the comparator means, the processor means adapting a position processing operation based upon at least the first error and the differential error. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60)
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Specification