US 7,010,066 B2Granted

System and method for fast code phase and carrier frequency acquisition in GPS receiver

AssigneeSkyBitz, Inc.

InventorMark C. Sullivan

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Abstract

A GPS receiver acquires carrier frequency and Gold code phase using short segments of a received GPS signal. In one embodiment, a 1-ms segment of the GPS signal is transformed to the frequency domain. This is multiplied by a frequency representation of the Gold code. The resulting product is converted to the time domain, and a peak is detected. The location of the peak corresponds to the code phase. If no peak is located, the carrier frequency is changed. Full- and half-bin steps in carrier frequency are considered. Processing gain is achieved by using longer segments of the input signal, for example 4 or 16 ms and integrating 1-ms segments. Considerations are provided for compensating for the effects of a transition, should it occur in the short segment of the GPS signal being processed. Integrations can be performed using non-coherent and coherent techniques.

Claims6

Dependent claims

A method for detecting code phase and carrier frequency in a GPS signal comprising:

a. collecting a multiple millisecond portion of a GPS signal in a GPS receiver;
b. performing a coarse acquisition of a carrier frequency and code phase of the GPS signal using non-coherent processing, wherein said non-coherent processing includes:
i. partitioning the multiple millisecond portion of the GPS signal into one millisecond segments, converting each one millisecond segment to the frequency domain;
ii. multiplying each of the converted millisecond segments by a frequency representation of a Gold code corresponding to a GPS satellite in view of the GPS receiver to generate a product;
iii. converting each product to the time domain to obtain a correlation signal between each millisecond segment and the Gold code;
and
iv. determining a location of a peak in each correlation signal;
and
c. performing a fine acquisition of said carrier frequency and code phase of the GPS signal using coherent processing.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/924,542Filed 9 Aug 2001 · us provisional application
Priority: 9 Aug 2000
Published: US 2002/0025011 A128 Feb 2002
Granted: 7 Mar 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

H04B 1/7075
Synchronisation aspects: with code phase acquisition
G01S 19/29
Acquisition or tracking or demodulation of signals transmitted by the system: carrier including Doppler, related
G01S 19/30
Acquisition or tracking or demodulation of signals transmitted by the system: code related
H04B 1/70753
Using partial detection: partial phase search