GPS receiving apparatus and GPS satellite signal receiving method
First Claim
1. A global positioning system receiving apparatus comprising:
- a synchronous acquisition unit which detects a correlation between a spread code of a received signal from a global positioning system satellite and a spread code provided by the apparatus in order to detect a phase of the spread code of said received signal for synchronous acquisition of said spread code of said received signal, said synchronous acquisition unit further detecting a carrier frequency of said received signal when said spread code of said received signal is acquired synchronously; and
a synchronous hold unit which has a plurality of channels and which allocates one of said channels to one of a plurality of global positioning system satellites when a spread code of the received signal from the global positioning system satellite in question is synchronously acquired and a carrier frequency of the received signal from the global positioning system satellite in question is detected, said synchronous hold unit further establishing initial values based on the spread code phase of said received signal following detection by said synchronous acquisition unit as well as on the likewise-detected carrier frequency of said received signal, before starting synchronous hold of said spread code and said carrier frequency regarding the signal from the global positioning system satellite in question while decoding the signal from said global positioning system satellite.
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Accused Products
Abstract
Disclosed is a GPS receiving apparatus including a synchronous acquisition unit and a synchronous hold unit. The synchronous acquisition unit detects a correlation between a spread code of a received signal from a GPS satellite and a spread code provided by the apparatus in order to detect a phase of the spread code of the received signal and a carrier frequency of the received signal. The synchronous hold unit has a plurality of channels and allocates one of the channels to one of a plurality of GPS satellites. The synchronous hold unit also establishes initial values based on the spread code phase of the received signal following detection by the synchronous acquisition unit as well as on the likewise-detected carrier frequency of the received signal, before starting synchronous hold of the spread code and the carrier frequency regarding the signal from the GPS satellite in question while decoding the signal from the GPS satellite.
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Citations
40 Claims
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1. A global positioning system receiving apparatus comprising:
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a synchronous acquisition unit which detects a correlation between a spread code of a received signal from a global positioning system satellite and a spread code provided by the apparatus in order to detect a phase of the spread code of said received signal for synchronous acquisition of said spread code of said received signal, said synchronous acquisition unit further detecting a carrier frequency of said received signal when said spread code of said received signal is acquired synchronously; and
a synchronous hold unit which has a plurality of channels and which allocates one of said channels to one of a plurality of global positioning system satellites when a spread code of the received signal from the global positioning system satellite in question is synchronously acquired and a carrier frequency of the received signal from the global positioning system satellite in question is detected, said synchronous hold unit further establishing initial values based on the spread code phase of said received signal following detection by said synchronous acquisition unit as well as on the likewise-detected carrier frequency of said received signal, before starting synchronous hold of said spread code and said carrier frequency regarding the signal from the global positioning system satellite in question while decoding the signal from said global positioning system satellite. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A global positioning system receiving apparatus comprising:
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a preprocessing unit which, given a received signal with a carrier modulated by a signal having data spread-spectrum-encoded by a spread code, preprocesses the data that span M periods of said spread code in order to obtain a number of data spanning one period of said spread code, M being at least 2 to the n-th power, n being an integer;
fast Fourier transformation means for performing a fast Fourier transform of the received signal data spanning one period of said spread code following the preprocessing;
a first memory to which to write the result of the fast Fourier transform sent from said fast Fourier transformation means;
a second memory which stores the result of the fast Fourier transform of said spread code used in said received signal;
multiplying means for multiplying the result of the fast Fourier transform retrieved from said first memory, by the result of the fast Fourier transform of said spread code following retrieval from said second memory;
inverse fast Fourier transformation means for performing an inverse fast Fourier transform of the result of the multiplication from said multiplying means in order to output a correlation detected between said received signal and said spread code; and
correlation point detecting means for detecting a correlation point between said received signal and said spread code by searching for a peak of correlation between said received signal and said spread code based on the output of correlation detection from said inverse fast Fourier transformation means. - View Dependent Claims (20, 21)
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22. A global positioning system satellite signal receiving method comprising the steps of:
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performing synchronous acquisition by detecting a correlation between a spread code of a received signal from a global positioning system satellite and a spread code provided by a receiving side in order to detect a phase of the spread code of said received signal for synchronous acquisition of said spread code of said received signal, said synchronous acquisition step further detecting a carrier frequency of said received signal when said spread code of said received signal is acquired synchronously; and
performing synchronous hold by allocating one of a plurality of channels to any one of a plurality of global positioning system satellites when a spread code of the received signal from the global positioning system satellite in question is synchronously acquired and a carrier frequency of the received signal from the global positioning system satellite in question is detected, said synchronous hold step further establishing initial values based on the spread code phase of said received signal following detection in said synchronous acquisition step as well as on the likewise-detected carrier frequency of said received signal, before starting synchronous hold of said spread code and said carrier frequency regarding the signal from the global positioning system satellite in question while decoding the signal from said global positioning system satellite. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A global positioning system satellite signal receiving method comprising the steps of:
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given a received signal with a carrier modulated by a signal having data spread-spectrum-encoded by a spread code, preprocessing the data that span M periods of said spread code in order to obtain a number of data spanning one period of said spread code, M being at least 2 to the n-th power, n being an integer;
performing a fast Fourier transform of the received signal data spanning one period of said spread code following the preprocessing;
writing to a first memory the result of the fast Fourier transform sent from said fast Fourier transformation step;
writing to a second memory the result of the fast Fourier transform of said spread code used in said received signal;
multiplying the result of the fast Fourier transform retrieved from said first memory, by the result of the fast Fourier transform of said spread code following retrieval from said second memory;
performing an inverse fast Fourier transform of the result of the multiplication from said multiplying step in order to output a correlation detected between said received signal and said spread code; and
detecting a correlation point between said received signal and said spread code by searching for a peak of correlation between said received signal and said spread code based on the output of correlation detection from said inverse fast Fourier transformation step. - View Dependent Claims (39, 40)
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Specification