High sensitivity GPS receiver
First Claim
1. A method of tracking a Global Positioning Satellite (GPS) signal, the method comprising:
- executing a pull-in stage by setting a center frequency of a phase-locked loop (PLL) having an initial bandwidth to a Doppler frequency of the GPS signal;
determining whether the PLL has converged in a first occurrence over an initial integration time;
determining whether the PLL has false convergence by comparing a power of an in-phase component to a power of a quadrature component of the GPS signal if the PLL has converged in the first occurrence;
executing a transition stage by decreasing the initial bandwidth and increasing the initial integration time if the PLL does not have false convergence;
determining whether the PLL has converged in a second occurrence after execution of the transition stage; and
executing a tracking stage by fixing a decreased bandwidth for the PLL and an increased integration time if the PLL has converged in the second occurrence.
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Accused Products
Abstract
A high sensitivity GPS receiver includes an acquisition engine and a tracking engine. The acquisition engine processes GPS satellite data at data rate that is substantially equal to twice the coarse acquisition (CA) code chip rate. This data rate advantageously enables the acquisition engine to process GPS satellite data with relatively less hardware area than traditional GPS acquisition approaches. In one embodiment, the high efficiency acquisition engine may be over-clocked, thereby allowing different phases of a CA code to be correlated quickly. The tracking engine can advantageously process GPS satellite data at a data rate that does not have an integer relationship to the CA code chip rate.
30 Citations
21 Claims
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1. A method of tracking a Global Positioning Satellite (GPS) signal, the method comprising:
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executing a pull-in stage by setting a center frequency of a phase-locked loop (PLL) having an initial bandwidth to a Doppler frequency of the GPS signal; determining whether the PLL has converged in a first occurrence over an initial integration time; determining whether the PLL has false convergence by comparing a power of an in-phase component to a power of a quadrature component of the GPS signal if the PLL has converged in the first occurrence; executing a transition stage by decreasing the initial bandwidth and increasing the initial integration time if the PLL does not have false convergence; determining whether the PLL has converged in a second occurrence after execution of the transition stage; and executing a tracking stage by fixing a decreased bandwidth for the PLL and an increased integration time if the PLL has converged in the second occurrence. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A tracking engine for tracking a Global Positioning Satellite (GPS) signal, the tracking engine comprising:
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means for executing a pull-in stage by setting a center frequency of a phase-locked loop (PLL) having an initial bandwidth to a Doppler frequency of the GPS signal; means for determining whether the PLL has converged in a first occurrence over an initial integration time; means for determining whether the PLL has false convergence by comparing a power of an in-phase component to a power of a quadrature component of the GPS signal if the PLL has converged in the first occurrence; means for executing a transition stage by decreasing the initial bandwidth and increasing the initial integration time if the PLL does not have false convergence; means for determining whether the PLL has converged in a second occurrence after execution of the transition stage; and means for executing a tracking stage by fixing a decreased bandwidth for the PLL and an increased integration time if the PLL has converged in the second occurrence. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A Global Positioning Satellite (GPS) receiver for tracking a GPS signal, the GPS receiver comprising:
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an antenna to receive the GPS signal; and a tracking engine to; execute a pull-in stage by setting a center frequency of a phase-locked loop (PLL) having an initial bandwidth to a Doppler frequency of the GPS signal; determine whether the PLL has converged in a first occurrence over an initial integration time; determine whether the PLL has false convergence by comparing a power of an in-phase component to a power of a quadrature component of the GPS signal if the PLL has converged in the first occurrence; execute a transition stage by decreasing the initial bandwidth and increasing the initial integration time if the PLL does not have false convergence; determine whether the PLL has converged in a second occurrence after execution of the transition stage; and execute a tracking stage by fixing a decreased bandwidth for the PLL and an increased integration time if the PLL has converged in the second occurrence. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification