Apparatus and method for acquiring spread-spectrum signals
First Claim
1. An apparatus for acquiring spread-spectrum signals, comprising:
- a decimator generating a plurality of samples based on the spread-spectrum signal;
a serial-to-parallel converter connected to the decimator, the converter grouping a plurality of samples into a word;
a first memory with a data width capable of storing the word; and
a correlation engine comprised of a plurality of partial correlation modules connected to the first memory for calculating a partial correlation between the word and a PN code segment, wherein a partial correlation module comprises;
a plurality of multipliers and an adder calculating an inner product of the word and the PN code segment to produce the partial correlation; and
an accumulator for a plurality of partial correlations to produce a complete correlation.
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Abstract
An apparatus for acquiring spread-spectrum signals includes a mixer for generating an in-phase signal and a quadrature signal from the spread-spectrum signal, a decimator for subsampling the in-phase signal and the quadrature signal, a correlation engine for producing an in-phase correlation between the subsampled in-phase signal and a PN code and producing a quadrature correlation between the subsampled quadrature signal and the PN code, a first coherent integrator for accumulating a plurality of in-phase correlations to produce an in-phase coherent integration, a second coherent integrator for accumulating a plurality of quadrature correlations to produce a quadrature coherent integration, an incoherent integrator for accumulating the in-phase coherent integrations and the quadrature coherent integrations to produce an incoherent integration, and a signal detector for checking the presence of the spread-spectrum signal based on the incoherent integration.
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Citations
20 Claims
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1. An apparatus for acquiring spread-spectrum signals, comprising:
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a decimator generating a plurality of samples based on the spread-spectrum signal;
a serial-to-parallel converter connected to the decimator, the converter grouping a plurality of samples into a word;
a first memory with a data width capable of storing the word; and
a correlation engine comprised of a plurality of partial correlation modules connected to the first memory for calculating a partial correlation between the word and a PN code segment, wherein a partial correlation module comprises;
a plurality of multipliers and an adder calculating an inner product of the word and the PN code segment to produce the partial correlation; and
an accumulator for a plurality of partial correlations to produce a complete correlation. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for acquiring spread-spectrum signals, comprising:
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a mixer generating an in-phase signal and a quadrature signal from the spread-spectrum signal;
a decimator connected to the mixer for subsampling the in-phase signal and the quadrature signal;
a correlation engine connected to the decimator producing an in-phase correlation between the subsampled in-phase signal and a PN code, and a quadrature correlation between the subsampled quadrature signal and the PN code;
a first coherent integrator connected to the correlation engine accumulating a plurality of in-phase correlations to produce an in-phase coherent integration;
a second coherent integrator connected to the correlation engine accumulating a plurality of quadrature correlations to produce a quadrature coherent integration;
an incoherent integrator connected to the first coherent integrator and the second coherent integrator accumulating a plurality of in-phase coherent integrations and the quadrature coherent integrations to produce an incoherent integration; and
a signal detector connected to the incoherent integrator checking the presence of the spread-spectrum signal based on the incoherent integration. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method for acquiring spread-spectrum signals, comprising the steps of:
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generating an in-phase signal and a quadrature signal from the spread-spectrum signal;
multiplying the in-phase signal with a PN code to produce an in-phase correlation, and multiplying the quadrature signal with the PN code so as to produce a quadrature correlation;
accumulating a plurality of in-phase correlations to produce an in-phase coherent integration and a plurality of quadrature correlations to produce a quadrature coherent integration;
accumulating a plurality of in-phase coherent integrations and quadrature coherent integrations so as to produce an incoherent integration; and
checking the presence of the spread-spectrum signal based on the incoherent integration. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification