US 7,688,883 B1 · Received signal correlation using a correlation scaling factor

Abstract

The present invention is a method and apparatus for generating a scaled correlation that is based on an estimate of the arrival time of a synchronization point in a received RF signal relative to a sampling clock, which is used to sample the received RF signal after down conversion. The scaled correlation may be used to validate the estimate of the arrival time of the synchronization point and, in certain embodiments of the present invention, may be used to update the estimate of the arrival times for subsequent synchronization points. Using the scaled correlation may provide arrival time estimates with a finer resolution and accuracy than the period of the sampling clock. Such arrival time estimates are important for timing-based applications, such as GPS receivers or navigation receivers.

Claims20

Dependent claims

A method comprising:

receiving a signal having a first code with a first synchronization point;
sampling the signal using a sampling clock to create a sampled signal;
correlating the first code in the sampled signal with a reference code that is associated with a reference code clock to create a correlation, wherein the reference code clock is synchronous with the sampling clock and the reference code clock has a first phase-shift with respect to the sampling clock;
creating a first scaling factor based on the first phase-shift;
and
generating a first scaled correlation based on the correlation and the first scaling factor,
wherein the first phase-shift is based on estimating an arrival time of the first synchronization point relative to the sampled signal.

4 more elements

Dependencies are inferred from the claim text.

Received signal correlation using a correlation scaling factor

Life of this patent

Received signal correlation using a correlation scaling factor

Life of this patent

Abstract

Claims20