System and method for accurate downlink power control of composite QPSK modulated signals
First Claim
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1. A method for controlling code power levels of individual codes of a composite quadrature phase shift keyed (QPSK) signal, the method comprising:
- obtaining a sample of said composite QPSK signal;
separating said individual codes from said composite QPSK signal, the separating being done by using a plurality of navigation data codes;
analyzing said individual codes against corresponding commanded code power settings for said individual codes; and
determining a code power correction signal needed for each of said individual codes needed to adjust a code power for each of said individual codes to match their said corresponding commanded code power settings, to thus drive a code power error between said individual codes and their said corresponding commanded code power settings to zero.
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Abstract
A method for controlling code power levels of individual codes of a composite quadrature phase shift keyed (QPSK) signal. The method may involve obtaining a sample of the composite QPSK signal; separating the individual codes from the composite QPSK signal; analyzing the individual codes against corresponding commanded code power settings for the individual codes; and determining a code power correction signal needed for each of the individual codes needed to adjust a code power for each of the individual codes to match their corresponding commanded code power settings.
45 Citations
19 Claims
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1. A method for controlling code power levels of individual codes of a composite quadrature phase shift keyed (QPSK) signal, the method comprising:
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obtaining a sample of said composite QPSK signal; separating said individual codes from said composite QPSK signal, the separating being done by using a plurality of navigation data codes; analyzing said individual codes against corresponding commanded code power settings for said individual codes; and determining a code power correction signal needed for each of said individual codes needed to adjust a code power for each of said individual codes to match their said corresponding commanded code power settings, to thus drive a code power error between said individual codes and their said corresponding commanded code power settings to zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for controlling code power levels of four individual codes of a composite quadrature phase shift keyed (QPSK) signal being transmitted from a satellite, the method comprising:
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obtaining a sample of said composite QPSK signal; separating said sample into a first signal and a second signal, said first signal including components of said composite QPSK signal that are ninety degrees out of phase with respect to a zero degree phase, and said second signal including components of said composite QPSK signal that are in phase with said zero degree phase; phase detecting said first and second signals to produce a demodulated first signal and a demodulated second signal; further processing said demodulated first and second signals to generate four sampled, peak signals corresponding to a first navigation data code, a second navigation data code, a third navigation data code and a fourth navigation data code, said first, second, third and fourth navigation data codes being generated by a navigation data unit being used with said satellite; analyzing said four sampled, peak signals in relation to corresponding commanded code power settings for said first, second, third and fourth navigation data codes; and determining a code power correction signal needed for each of said first, second, third and fourth navigation data codes needed to adjust a code power for each of said first, second, third and fourth navigation data codes to match corresponding commanded code power settings for each of said first, second, third and fourth navigation data codes. - View Dependent Claims (13, 14, 15)
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16. A system for controlling code power levels of individual codes of a composite quadrature phase shift keyed (QPSK) signal being transmitted from a satellite, the system comprising:
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a power divider for splitting a sampled portion of said composite QPSK signal into a first signal and a second signal, said first and second signals being of equal power; a first subsystem for phase detecting, demodulating and analyzing said first signal, and analyzing a first navigation data code and a second navigation data code, said first and second navigation data codes being applied by a transmitter of said satellite in forming said composite QPSK signal, and generating a first sampled, peak signal and a second sampled, peak signal, said first and second peak signals relating to peak power levels of said first and second navigation data codes; a second subsystem for phase detecting, demodulating and analyzing said second signal, and analyzing and a third navigation data code and a fourth navigation data code, said third and fourth navigation data codes being applied by said transmitter to form said composite QPSK signal, and generating a third sampled, peak signal and a fourth sampled, peak signal, said third and fourth sample, peak signals relating to peak power levels of said third and fourth navigation data codes; and a processor for further analyzing said first, second, third and fourth peak sampled, peak signals and commanded navigation data codes, and generating power correction signals needed to adjust a power level of each one of said first, second, third and fourth navigation data codes being used to form said composite QPSK signal. - View Dependent Claims (17, 18, 19)
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Specification