Detection and identification of stable PRI patterns using multiple parallel hypothesis correlation algorithms

• US 7,657,588 B2
• Filed: 07/20/2006
• Issued: 02/02/2010
• Est. Priority Date: 08/08/2003
• Status: Expired

• Current Assignee: Callahan Cellular LLC (Intellectual Ventures LLC)
• Original Assignee: Wisterium Development LLC (Intellectual Ventures LLC)
• Inventors: Sirois, Joseph A
• Primary Examiner(s): Mai; Tan V
• Application Number:
  US11/458,963
• Publication Number:
  US 20060284755A1
• Time in Patent Office: 1,293 Days
• Field of Search: 708422-426, 342/189
• US Class Current: 708/422
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals
• CPC Class Codes: G06F 17/15 Correlation function computation including computation of convolution operations arithmetic circuits for sum of products per se, e.g. multiply-accumulators G06F7/5443; digital filters, e.g. FIR, IIR, adaptive filters H03H17/00

Abstract

A linear detection method for determining correlation values associated with an estimated Pulse Repetition Interval (PRI) executed by a linear detection module of a correlation mask disposed on a digital signal processor is provided comprising: determining a correlation spread associated with a vector of Times-of-Arrival (TOA) data; determining a delta spread associated with the correlation spread; determining a first/next estimated PRI associated with the vector of TOA data; determining a first/next estimated PRI vector based on the first/next estimated PRI; determining a delta vector based on the first/next estimated PRI vector; determining a correlation weights vector based on the delta vector; determining a first/next correlation value based on the correlation weights vector; and in response to there being no additional PRIs to estimate, searching the correlation values for a highest correlation.

Claims

1. A linear detection method for determining correlation values associated with an estimated Pulse Repetition Interval (PRI) executed by a linear detection module of a correlation mask disposed on a digital signal processor, comprising:

determining a correlation spread associated with a vector of Times-of-Arrival (TOA) data;

determining a delta spread associated with the correlation spread;

determining a first/next estimated PRI associated with the vector of TOA data;

determining a first/next estimated PRI vector based on the first/next estimated PRI;

determining a delta vector based on the first/next estimated PRI vector;

determining a correlation weights vector based on the delta vector;

determining a first/next correlation value based on the correlation weights vector; and

in response to there being no additional PRIs to estimate, searching the correlation values for a highest correlation.

2. The method of claim 1 further comprising:

receiving the vector of TOA data;

normalizing the vector of TOA data, thereby providing a normalized vector of TOA data; and

determining a seed PRI associated with the vector of TOA data.

3. The method of claim 2 wherein determining the seed PRI includes dividing each element of the normalized vector by m−

1, where m=the number of pulses in the vector of TOA data.

4. The method of claim 2 wherein determining the correlation spread includes dividing the seed PRI by a correlation bandwidth percentage that defines a percentage bandwidth for searching for the estimated PRI.

5. The method of claim 2 wherein determining the first/next estimated PRI includes subtracting (correlation spread /2) from the seed PRI.

6. The method of claim 2 wherein determining the delta vector includes subtracting the estimated PRI vector from the normalized vector of TOA data.

7. The method of claim 2 wherein determining the first/next correlation value includes dividing the sum of the correlation weights by the square of the seed PRI.

8. The method of claim 1 wherein determining the delta spread includes dividing the correlation spread by a number of point (npts)−

1, where npts defines the number of points to search for the estimated PRI.

9. The method of claim 1 wherein determining a correlation weights vector includes squaring the delta vector.

10. The method of claim 1 further comprising repeating the determining steps for additional PRIs.

11. The method of claim 1 further comprising comparing the highest correlation value to a pass/fail threshold to determine a pass/fail status.

12. The method of claim 11 further comprising determining a second pass/fail status for a correlation value associated with an estimated PRI using a linear regression algorithm and setting a final pass/fail status if said pass/fail status is passing and said second pass/fail status is passing.

13. The method of claim 1 further comprising providing a linear detection report that includes at least one of a pass/fail status, the highest correlation value, a PRI estimate that corresponds to the highest correlation value, or pulses associated with the PRI estimate.

14. The method of claim 1 wherein said method is run in a multiple correlation processor, and wherein said method is run on one of the group consisting of a set of pulses, a mask set, and a singular fashion for all pulses of a pulse train.

15. The method of claim 1 wherein the correlation values are assessed by at least one of the group consisting of the linear detection method, linear regression method, and dual vote method.

16. The method of claim 1 further comprising processing in an operation mode selected from at least one of the group consisting of batch mode, stream mode, loop back mode, and tracker mode.