Global position system receiver
First Claim
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1. A global position system (GPS) receiver comprising:
- (a) a frequency synthesizer means;
(b) a fixed frequency converter means operatively connected to the frequency synthesizer means for downconverting GPS signals received from a plurality of space vehicles to baseband in-phase (I) and quadrature phase (Q) signals and forming digital words thereof of preselected bit lengths; and
(c) a signal processor means, said signal processor means including a code generator means, a plurality of space vehicle signal preprocessors and a computer means, the code generation means operatively connected to the frequency synthesizer means for receiving code clocking signals, and each of said plurality of preprocessors operatively connected to the fixed frequency converter means and code generator means for receiving the in-phase and quadrature phase digital words and selectively timed code signals for the in phase and quadrature phase signals of early (IE,QE), prompt (IP,QP) and late (IL,QL) complex responses for one space vehicle for producing early, late and prompt correlation outputs for the computer means, whereby the plurality of space vehicle signal preprocessors operate in the same I.Q base band signals for producing early, prompt and late correlations peculiar to each space vehicle for the computer means, and said computer means operatively connected to the plurality of preprocessors, code generator means and frequency synthesizer means for performing preselected fundamental GPS signal processing functions.
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Abstract
A Global Position System (GPS) receiver is disclosed which includes an RF converter and quadrature digitizer implemented in hardware and a signal processor including a computer, code generator and preprocessor. The preprocessor has a divide by 1,2,3 divider for controlling the code generator so as to provide I,Q early, prompt and late digital signals of 0.5 chip separations to the computer for tracking code phase, carrier phase/frequency and signal amplitude. This structure eliminates the need for numerically controlled oscillators implemented in hardware while maintaining accurate performance.
124 Citations
11 Claims
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1. A global position system (GPS) receiver comprising:
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(a) a frequency synthesizer means; (b) a fixed frequency converter means operatively connected to the frequency synthesizer means for downconverting GPS signals received from a plurality of space vehicles to baseband in-phase (I) and quadrature phase (Q) signals and forming digital words thereof of preselected bit lengths; and (c) a signal processor means, said signal processor means including a code generator means, a plurality of space vehicle signal preprocessors and a computer means, the code generation means operatively connected to the frequency synthesizer means for receiving code clocking signals, and each of said plurality of preprocessors operatively connected to the fixed frequency converter means and code generator means for receiving the in-phase and quadrature phase digital words and selectively timed code signals for the in phase and quadrature phase signals of early (IE,QE), prompt (IP,QP) and late (IL,QL) complex responses for one space vehicle for producing early, late and prompt correlation outputs for the computer means, whereby the plurality of space vehicle signal preprocessors operate in the same I.Q base band signals for producing early, prompt and late correlations peculiar to each space vehicle for the computer means, and said computer means operatively connected to the plurality of preprocessors, code generator means and frequency synthesizer means for performing preselected fundamental GPS signal processing functions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification