Associative hierarchiacl deinterleaver

• US 4,918,455 A
• Filed: 11/03/1988
• Issued: 04/17/1990
• Est. Priority Date: 11/03/1988
• Status: Expired due to Fees

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Maier, Mark W.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Hellner, Mark
• Application Number:
  US07/266,739
• Time in Patent Office: 530 Days
• Field of Search: 342/13, 328/119, 364/517
• US Class Current: 342/13
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals

Abstract

Sequential signal pulses from unknown sources are deinterleaved by clustering similar pulses into groups. The groups are used to form hypothetical pulse train models. If the hypotheticals are confirmed, they are used to deinterleave corresponding signal pulses. Unconfirmed hypotheticals are deleted.

Claims

1. A method for deinterleaving a plurality of signal pulses where each signal pulse is characterized by at least two parameters, the method comprising the steps of:

associating signal pulses having a similar value for one of the parameters into a group of signal pulses;

predicting a value for another parameter for an additional signal pulse not associated with the group;

associating signal pulses with the group which have values for the other parameter which are similar to the predicted parameter value; and

reporting an indication of at least one of the parameter values of the signal pulses associated with the group if the group has more than a threshold number of signal pulses associated with it.

2. The method of claim 1 wherein the parameters characterizing each signal pulse comprise time of arrival and frequency.

3. The method of claim 1 wherein the parameters characterizing each signal pulse comprise time of arrival and angle of arrival.

4. A method for deinterleaving a sequence of signal pulses, each signal pulse being characterized by a time of arrival and at least two other parameters, the method comprising the steps of:

associating signal pulses having a similar value for at least one of the at least two other parameters, into a group;

if more than a first threshold number of signal pulses are associated with the group, predicting at least one value for the time of arrival of subsequent signal pulses;

associating only subsequent signal pulses having both a similar value for the at least one of the at least two other parameters and a time of arrival similar to the at least one predicted time of arrival with the group; and

if more than a second threshold number of signal pulses is associated with the group, reporting an indication of at least one of the parameters of the signal pulses associated with the group.

5. The method of claim 4 comprising two additional steps to be performed after the step of associating only subsequent signal pulses, the additional steps comprising:

predicting a value for at least one additional time of arrival for subsequent pulses to be associated with the group only if a subsequent signal pulse is associated with the group; and

associating only subsequent signal pulses having both a similar value for the at least one of the at least two other parameters and a time of arrival similar to the at least one additional predicted time of arrival for the group with the cluster.

6. The method of claim 5 comprising the additional step of repeating the step of predicting at least one additional time of arrival, and the step of associating subsequent signal pulses having a similar value to the at least one additional predicted time of arrival, until more than a second threshold number of signal pulses are associated with the group for which the steps are repeated.

7. The method of claim 6 wherein the step of repeating comprises the step of ceasing to predict the time of arrival for subsequent signal pulses if more than a third threshold number of predictions have been made and no signal pulse corresponding to a prediction has been associated with the group corresponding to the predicted times of arrival.

8. The method of claim 4 wherein one of the at least two other parameters is the frequency of the pulse.

9. The method of claim 4 wherein one of the at least two other parameters is the angle of arrival of the pulse.

10. The method of claim 4 wherein the step of associating signal pulses comprises the step of associating signal pulses having a similar value for two of the at least two other parameters.

11. The method of claim 4 wherein the step of associating signal pulses comprises the step of associating signal pulses having a similar value for two of the at least two other parameters, and wherein the step of associating only subsequent signal pulses comprises the step of associating only subsequent signal pulses having both a similar value for two of the at least two other parameters and a time of arrival similar to the at least one predicted time of arrival.

12. A method for deinterleaving a sequence of radar pulse descriptor words, each word including a value for a time of arrival and at least two other parameters of a pulse, the method comprising the steps of:

associating words having similar values for at least one of the at least two other parameters in a group;

if more than a first threshold number of words are associated in a group, predicting at least one time of arrival value for subsequent words to be associated with the group;

associating only subsequent words having both a similar value for the at least one of the at least two other parameters and a time of arrival similar to the at least one predicted time of arrival with the group; and

if more than a second threshold number of words is associated with the group, reporting an indication of at least one of the parameter values of the words associated with the group.

13. The method of claim 12 comprising the additional step of deleting a group if no subsequent words are associated with the group following the prediction of at least one predicted time of arrival.

14. The method of claim 12 wherein the at least two other parameters comprise angle of arrival and frequency.

15. The method of claim 12 wherein the step of reporting comprises generating a pulse train descriptor word.

16. The method of claim 12 comprising two additional steps after the step of associating only subsequent words, the additional steps comprising:

predicting at least one additional time of arrival value for subsequent words to be associated with the group if a subsequent word is already associated with the group; and

associating only subsequent words having both a similar value for the at least one of the at least two other parameters and a time of arrival similar to the at least one additional predicted time of arrival with the group.

17. The method of claim 12 also comprising the additional step of repeating the step of predicting at least one additional time of arrival and the step of associating subsequent words having a similar value for the at least one additional time of arrival

18. The method of claim 12 also comprising the additional step of deleting a cluster if less than a threshold number of words are associated with the cluster.

19. An apparatus for deinterleaving a plurality of signal pulses, each signal pulse having at least two parameters comprising:

means for associating pulses for which a first parameter value is substantially similar into a group;

means for predicting a value for a second parameter for an additional signal pulse not associated with the group;

means for associating signal pulses having (parameter values substantially similar to the predicted parameter value with the group; and

means for reporting an indication of at least one of the parameter values of the signal pulses associated with the group if the group has more than a threshold number of signal pulses associated with it.

20. The apparatus of claim 19 wherein the parameters characterizing each signal pulse comprise time of arrival.

21. The apparatus of claim 19 wherein the parameters characterizing each signal pulse comprise frequency.

22. An apparatus for deinterleaving a sequence of radar pulse descriptor words, each word including a value for a time of arrival and at least two other parameters of a pulse, comprising:

means for associating words having similar values for at least one of the at least two other parameters in a group;

means for predicting at least one time of arrival value for subsequent words to be associated with the group, if more than a first threshold number of words are associated with the group;

means for associating only subsequent words having both a similar value for the at least one of the at least two other parameters and a time of arrival similar to the at least one predicted time of arrival with the group; and

means for reporting an indication of at least one of the parameter values of the words associated with the group if more than a second threshold number of words is associated with the cluster.

23. The apparatus of claim 22 also comprising means for deleting a group if no subsequent words are associated with the group following the prediction of the at least one predicted time of arrival.

24. The apparatus of claim 22 also comprising means for deleting a group of less than a threshold number of words are associated with the group.

25. The apparatus of claim 22 wherein the at least two other parameters comprise angle of arrival and frequency.

26. The apparatus of claim 22 wherein the reporting means comprises means for generating a pulse train descriptor word.

27. A method for deinterleaving a plurality of signal pulses, wherein each signal pulse has at least two parameters, and at least some of the signal pulses are associated into groups, the signal pulses in a group having similar values for at least one parameter, the method comprising:

predicting a value for another of the at least two parameters for signal pulses to be associated with a group;

associating signal pulses having a value for the other parameter similar to the predicted value for the other parameter with the group; and

reporting an indication of at least one of the parameter values of the signal pulses associated with the group if the group has more than a threshold number of signal pulses associated with it.

28. The method of claim 27 wherein the parameters comprise time of arrival and frequency.

29. The method of claim 27 wherein the parameters comprise time of arrival and angle of arrival.

30. A method for deinterleaving a sequence of signal pulses, wherein each signal pulse is characterized by a time of arrival and at least two other parameters, and at least some of the signal pulses are associated into groups, the signal pulses in a group having similar values for at least one parameter, the method comprising:

predicting a time of arrival for subsequent signal pulses;

associating signal pulses having both a time of arrival similar to the predicted time of arrival and a similar value for at least one of the two other parameters with the group; and

reporting an indication of at least one of the parameter values of the signal pulses associated with the group.

31. The method of claim 30 comprising two additional steps to be performed after the step of associating, the additional steps comprising:

predicting at least one additional time of arrival for subsequent signal pulses to be associated with the group; and

associating subsequent signal pulses having both a time of arrival similar to the predicted additional time of arrival and a similar value for at least one of the two other parameters with the group.

32. The method of claim 31 comprising the additional steps of repeating the step of predicting at least one additional time of arrival, and the step of associating subsequent signal pulses having a time of arrival similar to the predicted additional time of arrival until at least a threshold number of signal pulses are associated with the group.

33. The method of claim 32 wherein the step of repeating comprises the step of ceasing to predict additional times of arrival for subsequent signal pulses if at least a second threshold number of predictions have been made and no signal pulse corresponding to a prediction has been associated with the group.

34. The method of claim 30 wherein one of the at least two other parameters is the frequency of the pulse.

35. The method of claim 30 wherein one of the at least two other parameters is the angle of arrival of the pulse.

36. An apparatus for deinterleaving a sequence of signal pulses, wherein each signal pulse is characterized by a time of arrival and at least two other parameters, and at least some of the signal pulses are associated into groups, the signal pulses in a group having similar values for at least one parameter, the apparatus comprising:

means for predicting a time of arrival for subsequent signal pulses;

means for associating signal pulses having both a time of arrival similar to the predicted time of arrival and a similar value for at least one of the two other parameters with the group; and

means for reporting an indication of at least one of the parameter values of the signal pulses associated with the group.

37. The apparatus of claim 36 also comprising means for predicting at least one additional time of arrival for subsequent signal pulses to be associated with the group and means for associating subsequent signal pulses having both a time of arrival similar to the predicted additional time of arrival and a similar value for at least one of the two other parameters with the group.

38. The apparatus of claim 37 also comprising means for repeatedly predicting at least one additional time of arrival, and means for repeatedly associating subsequent signal pulses having a time of arrival similar to the predicted additional time of arrival until at least a threshold number of signal pulses are associated with the group.

39. The apparatus of claim 38 also comprising means for ceasing to predict additional times of arrival for subsequent signal pulses if at least a second threshold number of predictions have been made and no signal pulse corresponding to a prediction has been associated with the group.

40. The apparatus of claim 36 wherein one of the at least two other parameters is the frequency of the pulse.

41. The apparatus of claim 36 wherein one of the at least two other parameters is the angle of arrival of the pulse.