Method for self-calibration of frequency offsets
First Claim
1. A method for self-calibration of frequency offsets in measurement equipment of an interference monitoring system, wherein the measurement equipment has a measurement antenna of a known position, the method comprising the steps of:
- a) sampling I/Q data using the interference monitoring system measurement equipment;
b) acquiring a satellite navigation signal from the I/Q data by correlating the sampled I/Q data with replica signals of different code phases and different carrier frequencies;
c) said acquisition of step b) providing an estimate of a carrier frequency of the satellite navigation signal of a satellite;
d) calculating visibility of the satellite from ephemeris or almanac data and determining an expected carrier frequency of the satellite navigation signal from satellite orbit data and the known position of the measurement antenna;
e) comparing the expected carrier frequency of the satellite navigation signal with the estimated carrier frequency of the satellite navigation signal and calculating a frequency offset value as the difference between the expected and estimated carrier frequencies of the satellite navigation signal;
f) storing the frequency offset value in a memory; and
g) using the stored frequency offset value to compensate the frequency offset of at least one subsequent measurementwherein steps a)-g) are performed in alphabetical order.
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Accused Products
Abstract
A method for self-calibration of frequency offsets in a measurement equipment of an interference monitoring system is provided. The method involves sampling I/Q data using the interference monitoring system measurement equipment and acquiring satellite navigation signals from the I/Q data. A carrier frequency of the satellite navigation signal is estimated and an expected carrier frequency of the satellite navigation signal is calculated. The expected carrier frequency of the satellite navigation signal is compared with the estimated carrier frequency of the satellite navigation signal and a frequency offset value is calculated as the difference between the expected and estimated carrier frequencies of the satellite navigation signal. The frequency offset value is stored in a memory and used to compensate the frequency offset of at least one subsequent measurement.
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Citations
13 Claims
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1. A method for self-calibration of frequency offsets in measurement equipment of an interference monitoring system, wherein the measurement equipment has a measurement antenna of a known position, the method comprising the steps of:
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a) sampling I/Q data using the interference monitoring system measurement equipment; b) acquiring a satellite navigation signal from the I/Q data by correlating the sampled I/Q data with replica signals of different code phases and different carrier frequencies; c) said acquisition of step b) providing an estimate of a carrier frequency of the satellite navigation signal of a satellite; d) calculating visibility of the satellite from ephemeris or almanac data and determining an expected carrier frequency of the satellite navigation signal from satellite orbit data and the known position of the measurement antenna; e) comparing the expected carrier frequency of the satellite navigation signal with the estimated carrier frequency of the satellite navigation signal and calculating a frequency offset value as the difference between the expected and estimated carrier frequencies of the satellite navigation signal; f) storing the frequency offset value in a memory; and g) using the stored frequency offset value to compensate the frequency offset of at least one subsequent measurement wherein steps a)-g) are performed in alphabetical order. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Self-calibration device for calibrating frequency offsets in a measurement equipment of an interference monitoring system, wherein the measurement equipment has a measurement antenna of a known position, and wherein the device executes instructions stored on a non-transitory computer-readable medium causing the device to:
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a) sample I/Q data using the interference monitoring system measurement equipment; b) acquire a satellite navigation signal from the I/Q data by correlating the sampled I/Q data with replica signals of different code phases and different carrier frequencies; c) said acquisition of step b) providing an estimate of a carrier frequency of the satellite navigation signal of a satellite; d) calculate visibility of the satellite from ephemeris or almanac data and determining an expected carrier frequency of the satellite navigation signal from satellite orbit data and the known position of the measurement antenna; e) compare the expected carrier frequency of the satellite navigation signal with the estimated carrier frequency of the satellite navigation signal and calculate a frequency offset value as the difference between the expected and estimated carrier frequencies of the satellite navigation signal; f) store the frequency offset value in a memory; and g) use the stored frequency offset value to compensate the frequency offset of at least one subsequent measurement, wherein steps a)-g) are performed in alphabetical order. - View Dependent Claims (8, 9, 10, 11, 12)
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13. An interference monitoring system comprising measurement equipment provided with a self-calibrating device that executes instructions stored on a non-transitory computer-readable medium causing the device to:
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a) sample I/Q data using the interference monitoring system measurement equipment; b) acquire a satellite navigation signal from the I/Q data by correlating the sampled I/Q data with replica signals of different code phases and different carrier frequencies; c) said acquisition of step b) providing an estimate of a carrier frequency of the satellite navigation signal of a satellite; d) calculate visibility of the satellite from ephemeris or almanac data and determining an expected carrier frequency of the satellite navigation signal from satellite orbit data and the known position of the measurement antenna; e) compare the expected carrier frequency of the satellite navigation signal with the estimated carrier frequency of the satellite navigation signal and calculate a frequency offset value as the difference between the expected and estimated carrier frequencies of the satellite navigation signal; f) store the frequency offset value in a memory; and g) use the stored frequency offset value to compensate the frequency offset of at least one subsequent measurement, wherein steps a)-g) are performed in alphabetical order.
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Specification