Combined Parallel and Sequential Detection for GPS Signal Acquisition

• US 20080015776A1
• Filed: 07/16/2007
• Published: 01/17/2008
• Est. Priority Date: 06/27/2000
• Status: Abandoned Application

• Current Assignee: Charles Norman, Stephen Rounds
• Original Assignee: Charles Norman, Stephen Rounds
• Inventors: Rounds, Stephen, Norman, Charles
• Application Number:
  US11/778,550
• Publication Number:
  US 20080015776A1
• Time in Patent Office: Days
• US Class Current: 701/213
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: H04B 1/70775 Multi-dwell schemes, i.e. multiple accumulation times
• CPC Class Codes: H04B 1/709 Correlator structure

Abstract

A two part signal acquisition process includes a parallel signal detection process and signal verification/false alarm rejection process. A massively parallel architecture of acquisition correlators search a large region of the time-frequency uncertainty during the parallel signal detection process to identify the most likely detections for each search dwell. Concurrent with the parallel signal detection process performed by the acquisition correlators, the current list of most likely detections is examined with additional search dwells in the verification/false alarm rejection process. The verification/false alarm rejection process is performed by a plurality of independent correlators or tracking channels. Under software control, the tracking channels perform repeated dwells on the most likely detections until they can be dismissed as false alarms or verified as the desired signal.

Claims

1. A signal acquisition process comprising:

a) performing an acquisition dwell on a plurality of cells within a time/frequency uncertainty range to detect a set of cells having the largest correlation peaks;

b) performing an initial verification dwell on the set of cells detected in step a by comparing the peak of each cell to a threshold and retaining those cells having a peak at least as great as the threshold;

c) performing an acquisition dwell on another plurality of cells within the time/frequency uncertainty range to detect another set of cells having the largest correlation peaks; and

d) performing a subsequent verification dwell on the cells retained in step b and an initial verification dwell on the set of cells detected in step c by comparing the peak of each cell to the threshold and retaining those cells having a peak at least as great as the threshold.