High sensitivity GPS receiver and method for compensating for Doppler variation
First Claim
1. A method for compensating for Doppler variation due to user motion in a global positioning system (GPS) receiver mounted to a user terminal, comprising:
- measuring an acceleration vector of the terminal in accordance with a center of the Earth;
estimating a user Doppler variation rate of GPS satellites due to acceleration of the terminal in accordance with the measured acceleration vector;
predicting a Doppler frequency according to the estimated user Doppler variation rate and at least one different estimated Doppler variation rate; and
compensating a code frequency signal and a carrier frequency signal for use in receiving signals from GPS satellites in accordance with the predicted Doppler frequency.
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Abstract
A global positioning system (GPS) receiver and method are provided for compensating for Doppler variation to accurately detect GPS signals in an environment in which intensities of the GPS signals received from GPS satellites are very low. A user acceleration measuring unit measures an acceleration vector of the terminal with respect to a center of the Earth. A user Doppler variation rate estimator estimates a user Doppler variation rate of each GPS satellite due to acceleration of the terminal by making use of the measured acceleration vector. A Doppler predictor predicts a Doppler frequency according to the estimated user Doppler variation rate. Code and carrier frequency signal generators compensate codes and carriers of GPS satellites to be correlated with signals received therefrom by making use of the predicted Doppler frequency.
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Citations
13 Claims
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1. A method for compensating for Doppler variation due to user motion in a global positioning system (GPS) receiver mounted to a user terminal, comprising:
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measuring an acceleration vector of the terminal in accordance with a center of the Earth; estimating a user Doppler variation rate of GPS satellites due to acceleration of the terminal in accordance with the measured acceleration vector; predicting a Doppler frequency according to the estimated user Doppler variation rate and at least one different estimated Doppler variation rate; and compensating a code frequency signal and a carrier frequency signal for use in receiving signals from GPS satellites in accordance with the predicted Doppler frequency. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A global positioning system (GPS) receiver mounted to a user terminal for compensating for Doppler variation due to user motion comprising:
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a user acceleration measuring unit for measuring an acceleration vector of the terminal in accordance with a center of the Earth; a user Doppler variation rate estimator for estimating a user Doppler variation rate of GPS satellites due to acceleration of the terminal in accordance with the measured acceleration vector; a Doppler predictor for predicting a Doppler frequency according to the estimated user Doppler variation rate and at least one different estimated Doppler variation rate; and code and carrier frequency signal generators for compensating a code frequency signal and a carrier frequency signal for use in receiving signals from GPS satellites in accordance with the predicted Doppler frequency. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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Specification