System and method for receiving and decoding global positioning satellite signals
AssigneeAvion Systems, Inc.
InventorJohn Abaunza
Life of this patent
Estimating the term…
Abstract
A system receives and demodulates spread spectrum positional signals such as those generated by a GPS satellite by frequency shifting the signals substantially to baseband and utilizing digital signal processing techniques. The digital signal processing techniques utilized can be implemented by a standard audio digital signal processor due to the circuit design. The spread spectrum signal is frequency shifted substantially to baseband, forming in-phase and quadrature components which are processed substantially in parallel. Pseudo-range, carrier phase and doppler frequency, and the underlying data are thereby derived.
Claims57
A method of deriving information from spread spectrum positional signals modulated on a carrier frequency comprising:
- a) frequency shifting said spread spectrum positional signals to shift said carrier frequency substantially to baseband;
- and
- b) deriving said information from frequency shifted spread spectrum positional signals using said standard audio digital signal processing techniques.
A system of deriving information from spread spectrum positional signals modulated on a carrier frequency comprising:
- mixing means for shifting the carrier frequency of said spread spectrum positional signals substantially to baseband;
- demodulating means, responsive to said mixing means, for processing said spread spectrum positional signals to derive information therefrom.
A method of deriving information from spread spectrum positional signals comprising:
- frequency shifting said spread spectrum positional signals to a lower frequency range;
- separating said spread spectrum positional signals from the radio frequency environment using only lowpass filtering;
- and
- deriving information from said frequency shifted spread spectrum positional signals using said standard audio digital signal processing techniques.
A system of deriving information from spread spectrum positional signals modulated on a carrier frequency comprising:
- mixing means for shifting the carrier frequency of said spread spectrum positional signals to a lower frequency range;
- means for separating said spread spectrum positional signals, received from said mixing means, from the radio frequency environment, said means for separating consisting essentially of means for low pass filtering;
- demodulating means, responsive to said means for separating, for processing said spread spectrum positional signals to derive information therefrom.
A method of deriving information from spread spectrum positional signals, said spread spectrum positional signals having a carrier frequency and an information bandwidth BW.sub.T comprising:
- frequency shifting said spread spectrum positional signals by shifting said carrier frequency to a new frequency less than BW.sub.T /2;
- deriving said information from said frequency shifted spread spectrum positional signals using said standard audio digital signal processing techniques.
A system of deriving information from spread spectrum positional signals having a carrier frequency and an information bandwidth BW.sub.T comprising:
- mixing means for shifting the carrier frequency of said spread spectrum positional signals to a new frequency less than BW.sub.T /2;
- demodulating means, responsive to said mixing means, for processing said spread spectrum positional signals to derive information therefrom.
Dependencies are inferred from the claim text.