Mobile positioning
First Claim
1. A mobile communication and positioning device comprising:
- a first frequency source configured to produce a temperature compensated first frequency signal;
a second frequency source configured to produce a second frequency signal having a frequency independent of the first frequency source;
a satellite positioning demodulator configured to demodulate radio signals of a satellite transmission based on the second frequency signal;
a detector configured to detect, with a resolution higher than one clock cycle of the second frequency signal, changes in the frequency difference between the first frequency signal and the second frequency signal by using interpolation; and
a decoder configured to decode the demodulated satellite radio signals while taking into account the changes in the frequency difference to compensate for errors of the demodulation caused by frequency drifts in the second frequency signal.
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Accused Products
Abstract
A dual mode device (110) comprising a communications block (120) and a satellite positioning block (130), each comprising respective Base Band (BB) blocks (123, 132) and crystals or frequency sources (122, 1312). The communications crystal (122) provides a cellular clock signal (FS1) to the satellite positioning block (130), which monitors the difference in the frequencies the crystals produce (FS1, FS2), using Vernier interpolation to gain a resolution greater than one clock cycle. The positioning crystal (1312) is used independent of the cellular crystal to demodulate satellite signals. The positioning BB (132) tracks the demodulated satellite signals compensating any errors caused by the positioning crystal signals (FS2) to the demodulation, using the information resulting from the monitoring. The communications crystal is capable to network based calibration and the positioning BB can compensate for the fluctuation thus caused in the cellular clock signal (FS1).
20 Citations
17 Claims
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1. A mobile communication and positioning device comprising:
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a first frequency source configured to produce a temperature compensated first frequency signal; a second frequency source configured to produce a second frequency signal having a frequency independent of the first frequency source; a satellite positioning demodulator configured to demodulate radio signals of a satellite transmission based on the second frequency signal; a detector configured to detect, with a resolution higher than one clock cycle of the second frequency signal, changes in the frequency difference between the first frequency signal and the second frequency signal by using interpolation; and a decoder configured to decode the demodulated satellite radio signals while taking into account the changes in the frequency difference to compensate for errors of the demodulation caused by frequency drifts in the second frequency signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of operating a mobile communication and positioning device comprising:
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producing a temperature compensated first frequency signal; producing a second frequency signal having a frequency independent of the first frequency source; demodulating radio signals of a satellite transmission based on the second frequency signal; detecting, with a resolution higher than one clock cycle of the second frequency signal, changes in the frequency difference between the first frequency signal and the second frequency signal by using interpolation; and decoding the demodulated satellite radio signals taking into account the changes in the frequency difference to compensate for errors of the demodulation caused by frequency drifts in the second frequency signal. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A memory media storing a computer program for controlling a mobile communication and positioning device, the device comprising a first frequency source configured for producing a temperature compensated first frequency signal;
- a second frequency source configured for producing a second frequency signal having a frequency independent of the first frequency source; and
a satellite positioning demodulator configured for demodulating radio signals of a satellite transmission based on the second frequency signal;
the computer program comprising;computer executable program code for causing the mobile communication device to detect, with a resolution higher than one clock cycle of the second frequency signal, changes in the frequency difference between the first frequency signal and the second frequency signal by using interpolation; and computer executable program code for causing the mobile communication device to decode the demodulated satellite radio signals configured to take into account the changes in the frequency difference to compensate for errors of the demodulation caused by frequency drifts in the second frequency signal.
- a second frequency source configured for producing a second frequency signal having a frequency independent of the first frequency source; and
Specification