US 6,806,827 B2 · Using FFT engines to process decorrelated GPS signals to establish frequencies of received signals

Abstract

The correlation circuitry of the present invention operates in communication with a controller and transform circuitry to concurrently search a range of frequencies by correlating a received signal from the global positioning system (GPS) with a generated frequency and a generated code at a plurality of time offsets. The output of the correlation circuitry is provided to the transform circuitry, such as fast Fourier transform (FFT) circuitry, that transforms the output of the correlation circuitry. The results from the transformation circuitry are used by a GPS receiver to determine a frequency of the received GPS signal and a time offset associated with a ranging code carried in the received GPS signal.

Claims19

Dependent claims

A GPS receiver comprising:

correlation circuitry adapted to provide data corresponding to a correlation of a signal with a generated frequency and a generated code at a plurality of time offsets, said correlation circuitry comprising a plurality of correlators each adapted to provide a subset of said data corresponding to a correlation of said signal with said generated frequency and said generated code at a one of said plurality of offsets;
circuitry adapted to provide said generated frequency and said generated code at said plurality of time offsets to said correlation circuitry;
and
transform circuitry adapted to receive said data and transform each subset of said data into a frequency domain to produce transformed data, which is used by the GPS receiver to determine a frequency of said signal and a time offset associated with a ranging code carried in said signal.

1 more element

A GPS receiver comprising:

a receiver frontend adapted to receive a radio-frequency signal and provide a baseband signal based on said radio-frequency signal;
correlation circuitry adapted to provide data corresponding to a correlation of said baseband signal with a generated frequency and a generated code at a plurality of time offsets, said correlation circuitry comprising a plurality of correlators each adapted to provide a subset of said data corresponding to a correlation of said baseband signal with said generated frequency and said generated code at a one of said plurality of offsets;
circuitry adapted to provide said generated frequency and said generated code at said plurality of time offset to said correlation circuitry;
and
transform circuitry adapted to receive said data and transform each subset of said data into a frequency domain to produce transformed data, which is used by the GPS receiver to determine a frequency of said baseband signal and a time offset associated with a ranging code carried in said baseband signal.

2 more elements

Dependencies are inferred from the claim text.

Using FFT engines to process decorrelated GPS signals to establish frequencies of received signals

Life of this patent

Using FFT engines to process decorrelated GPS signals to establish frequencies of received signals

Life of this patent

Abstract

Claims19