Method and apparatus for receiving GPS/GLONASS signals
First Claim
1. A method of processing received L1 and L2 spread spectrum signals, wherein each of the signals includes a unique frequency carrier with a known pseudo-random code modulated thereon, each L1 and L2 signal being converted into a plurality of digital signals, the method comprising:
- locally generating a single replica of the known code;
making the code replica available at different relative phases;
first demodulating the converted L1 and L2 signals with the single replica of the known code without any substantial delay, the first demodulated signal being associated with the L1 signal;
second demodulating the converted L1 and L2 signals with the generated replica of the known code from one of the taps of the delay line, the second demodulated signal being associated with the L2 signal;
selectably switching the converted L1 and L2 signals for the first demodulation and selectably switching the converted L1 and L2 signals for the second demodulation;
repetitively and separately integrating the demodulated L1 and L2 signals over a time period; and
adjusting the phases of the locally generated code replicas relative to the incoming L1 and L2 signals in order to maximize the power of the integrated demodulated L1 and L2 signals.
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Abstract
A method of processing received L1 and L2 spread spectrum signals is disclosed. In one embodiment, the method comprises i) locally generating replicas of a known P-code, wherein each of the received signals includes a unique frequency carrier with the known pseudo-random P-code and an unknown code modulated thereon, ii) making the code replicas available at different relative phases, iii) demodulating the received L1 and L2 signals with replicas of the P-code, iv) repetitively and separately integrating the demodulated L1 and L2 signals over time periods related to the unknown code, and v) correlating an integration result for one of the L1 and L2 signals with an integration result for the other of the L1 and L2 signals.
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Citations
19 Claims
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1. A method of processing received L1 and L2 spread spectrum signals, wherein each of the signals includes a unique frequency carrier with a known pseudo-random code modulated thereon, each L1 and L2 signal being converted into a plurality of digital signals, the method comprising:
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locally generating a single replica of the known code;
making the code replica available at different relative phases;
first demodulating the converted L1 and L2 signals with the single replica of the known code without any substantial delay, the first demodulated signal being associated with the L1 signal;
second demodulating the converted L1 and L2 signals with the generated replica of the known code from one of the taps of the delay line, the second demodulated signal being associated with the L2 signal;
selectably switching the converted L1 and L2 signals for the first demodulation and selectably switching the converted L1 and L2 signals for the second demodulation;
repetitively and separately integrating the demodulated L1 and L2 signals over a time period; and
adjusting the phases of the locally generated code replicas relative to the incoming L1 and L2 signals in order to maximize the power of the integrated demodulated L1 and L2 signals. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for processing received L1 and L2 spread spectrum signals, wherein each of the signals includes a unique frequency carrier with a known pseudo-random P-code and an unknown code modulated thereon, the apparatus comprising:
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a generator of replicas of the known P-code;
a delay line configured to make the known P-code replicas available at different relative phases;
a first demodulator, connected to the generator, configured to demodulate one of the received L1 and L2 signals with one of the known P-code replicas;
a second demodulator configured to demodulate the other of the received L1 and L2 signals with one of the known P-code replicas;
a first integrator configured to repetitively and separately integrate the demodulated one of the L1 and L2 signals over time periods related to the unknown code;
a second integrator configured to repetitively and separately integrate the demodulated other of the L1 and L2 signals over time periods related to the unknown code; and
a correlator configured to correlate the first integrator output with the second integrator output. - View Dependent Claims (7, 8, 9, 10, 11)
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12. An apparatus for processing received L1 and L2 spread spectrum signals, wherein each of the signals includes a unique frequency carrier with a known pseudo-random code modulated thereon, each L1 and L2 signal being converted into a plurality of digital signals, the apparatus comprising:
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a generator configured to locally generate a single replica of the known code;
a delay line wherefrom the known P-code replicas are available at different relative phases thereof, wherein the single replica of the known code is applied to the delay line;
a first demodulator configured to first demodulate the converted L1 and L2 signals with the single replica of the known code without any substantial delay, the first demodulated signal being associated with the L1 signal;
a second demodulator configured to second demodulate the converted L1 and L2 signals with the generated replica of the known code from one of the taps of the delay line, the second demodulated signal being associated with the L2 signal;
a switch configured to selectably switch the converted L1 and L2 signals for the first demodulation and selectably switch the converted L1 and L2 signals for the second demodulation;
an integrator configured to repetitively and separately integrate the demodulated L1 and L2 signals over a time period; and
a phase adjuster configured to adjust the phases of the locally generated code replicas relative to the incoming L1 and L2 signals in order to maximize the power of the integrated demodulated L1 and L2 signals.
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13. A method of processing received L1 and L2 spread spectrum signals, wherein each of the signals includes a unique frequency carrier with a known pseudo-random P-code and an unknown code modulated thereon, the method comprising:
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locally generating replicas of the known P-code;
making the code replicas available at different relative phases;
demodulating the received L1 and L2 signals with replicas of the P-code;
repetitively and separately integrating the demodulated L1 and L2 signals over time periods related to the unknown code; and
correlating an integration result for one of the L1 and L2 signals with an integration result for the other of the L1 and L2 signals. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A system for processing received L1 and L2 spread spectrum signals, wherein each of the signals includes a unique frequency carrier with a known pseudo-random code modulated thereon, each L1 and L2 signal being converted into a plurality of digital signals, the system comprising:
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means for locally generating a single replica of the known code;
means for making the code replica available at different relative phases;
means for first demodulating the converted L1 and L2 signals with the single replica of the known code without any substantial delay, the first demodulated signal being associated with the L1 signal;
means for second demodulating the converted L1 and L2 signals with the generated replica of the known code from one of the taps of the delay line, the second demodulated signal being associated with the L2 signal;
means for selectably switching the converted L1 and L2 signals for the first demodulation and selectably switching the converted L1 and L2 signals for the second demodulation;
means for repetitively and separately integrating the demodulated L1 and L2 signals over a time period; and
means for adjusting the phases of the locally generated code replicas relative to the incoming L1 and L2 signals in order to maximize the power of the integrated demodulated L1 and L2 signals.
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Specification