Global positioning system digital receiver
First Claim
1. A digital Global Positioning System (GPS) receiver for receiving a plurality of coded satellite signals from a plurality of satellites, said signals exhibiting Doppler shifting, said receiver comprising:
- means for down converting said coded satellite signals to intermediate frequency signals;
said means for down converting including;
antenna means for receiving said coded satellite signals;
mixer means connected to said antenna means, said mixer means for converting said coded satellite signals of a particular frequency to said intermediate frequency signals;
phase lock loop means connected to said mixer means, said phase lock loop means for providing a phase correcting voltage signal representing the phase error between a scaled frequency of a voltage controlled oscillator stable and a reference oscillator signal; and
voltage controlled oscillator means operating at L-band and operating in response to the phase correcting voltage signal of said phase lock loop means to produce a first mixer signal, said voltage controlled oscillator means being connected to said phase lock loop means; and
said phase lock loop means for providing a second mixer signal;
A/D means coupled to said means for converting, said A/D means for simultaneously translating said intermediate frequency signals for said plurality of coded satellite signals to a plurality of digital signals;
correlation means coupled to said A/D means, said correlation means for simultaneously separating each of said plurality of digital signals corresponding to each said satellite to provide "I" and "Q" channel information signals;
processor means coupled to said correlation means, said processor means for retrieving information transmitted from each of said satellites in response to said "I" and "Q" channel information signals.
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Accused Products
Abstract
A digital GPS (Global Positioning System) receiver for receiving a plurality of coded satellite signals. The plurality of satellite signals are transmitted by a corresponding plurality of satellites. Since these satellites are moving rapidly with respect to the receiver, Doppler shifting of the signals is exhibited. The signals are converted from analog to digital at intermediate frequency levels. The signals are then separated simultaneously into a plurality of digital signals corresponding to I and Q channel information for each transmitting satellite. A processor then converts these I and Q channel information signals to pseudo-range and broadcast data for navigation and time purposes.
132 Citations
29 Claims
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1. A digital Global Positioning System (GPS) receiver for receiving a plurality of coded satellite signals from a plurality of satellites, said signals exhibiting Doppler shifting, said receiver comprising:
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means for down converting said coded satellite signals to intermediate frequency signals; said means for down converting including; antenna means for receiving said coded satellite signals; mixer means connected to said antenna means, said mixer means for converting said coded satellite signals of a particular frequency to said intermediate frequency signals; phase lock loop means connected to said mixer means, said phase lock loop means for providing a phase correcting voltage signal representing the phase error between a scaled frequency of a voltage controlled oscillator stable and a reference oscillator signal; and voltage controlled oscillator means operating at L-band and operating in response to the phase correcting voltage signal of said phase lock loop means to produce a first mixer signal, said voltage controlled oscillator means being connected to said phase lock loop means; and said phase lock loop means for providing a second mixer signal; A/D means coupled to said means for converting, said A/D means for simultaneously translating said intermediate frequency signals for said plurality of coded satellite signals to a plurality of digital signals; correlation means coupled to said A/D means, said correlation means for simultaneously separating each of said plurality of digital signals corresponding to each said satellite to provide "I" and "Q" channel information signals; processor means coupled to said correlation means, said processor means for retrieving information transmitted from each of said satellites in response to said "I" and "Q" channel information signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A digital GPS receiver for receiving a plurality of coded satellite signals from a plurality of satellites, said signals exhibiting Doppler shifting, said digital Global Positioning System (GPS) receiver comprising:
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antenna means for receiving said coded satellite signals; mixer means coupled to said antenna means, said mixer means for converting said coded satellite signals of a particular frequency to intermediate frequency signals; said mixer means including; analog-to-digital means; phase lock loop means connected to said analog-to-digital means, said phase lock loop means for providing a phase correcting voltage signal representing the phase error between a scaled frequency of the coded satellite signals and a reference voltage oscillator signal, said phase lock loop means for providing a second mixer signal; voltage controlled oscillator means connected to said phase lock loop means, said voltage controlled oscillator means operating at L-band and in response to the phase correcting voltage signal of said phase lock loop means to produce a first mixer signal; and said analog-to-digital means coupled to said mixer means, said analog-to-digital means for simultaneously translating said intermediate frequency signals for each of said plurality of coded satellite signals to a plurality of digital signals; said digital GPS receiver means further comprising; correlation means coupled to said analog-to-digital means, said correlation means for simultaneously separating each of said plurality of digital signals corresponding to each of said satellites to provide "I" and "Q" channel information signals; said correlation means including; first phase detection means coupled to said analog-to-digital means, said first phase detection means for producing first magnitude and sign signals from a corresponding one of said plurality of digital signals; second phase detection means coupled to said analog-to-digital means and to said first phase detection means, said second phase detection means for providing second magnitude and sign signals in response to said one of said plurality of said digital signals; and processor means coupled to said correlation means, said processor means for retrieving pseudo-range and broadcast data information transmitted from each of the satellites in response to said "I" and "Q" channel information signals. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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29. A digital GPS receiver for receiving a plurality of coded, spread spectrum satellite signals from a plurality of satellites, said signals exhibiting Doppler shifting, said digital Global Positioning System (GPS) receiver comprising:
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antenna means for receiving said coded, spread spectrum satellite signals; mixer means connected to said antenna means, said mixer means for converting said coded, spread spectrum satellite signals of a particular frequency to intermediate frequency signals; a plurality of correlation means; said plurality of correlation means each including; analog-to-digital means; phase lock loop means connected to said analog-to-digital means, said phase lock loop means for providing a phase correcting voltage representing the phase error between a scaled L-band frequency and a reference voltage oscillator signal, said phase lock loop means for providing a second mixer signal; voltage controlled oscillator means connected to said phase lock loop means, said voltage controlled oscillator means operating at L-band and in response to the phase correcting voltage signal of said phase lock loop means to produce a first mixer signal; and said analog-to-digital means coupled to said mixer means, said analog-to-digital means for simultaneously translating said intermediate frequency signals for each of said plurality of coded, spread spectrum satellite signals to a plurality of digital signals; means for transmitting said plurality of digital signals to each of said plurality of correlation means, said means for transmitting being connected to said analog-to-digital conversion means and to each of correlation means; said digital GPS receiver means further comprising; said plurality of correlation means coupled to said analog-to-digital means, said plurality of correlation means for simultaneously separating each of said plurality of digital signals corresponding to each satellite to provide "I" and "Q" channel information signals; and processor means coupled to said plurality of correlation means, said processor means for retrieving information transmitted from each of the satellites in response to said "I" and "Q" channel information signals.
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Specification