Synthesized profile

• US 10,082,563 B2
• Filed: 12/17/2014
• Issued: 09/25/2018
• Est. Priority Date: 12/17/2014
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Inventors: Mesecher, David K., Hajo, Zyad
• Primary Examiner(s): Bythrow, Peter M
• Application Number:
  US14/573,776
• Publication Number:
  US 20180067193A1
• Time in Patent Office: 1,378 Days
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/582 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/726 Multiple target tracking
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence
• CPC Class Codes: G01S 7/412 based on a comparison between measured values and known or stored values

Abstract

A target identifier can be configured to determine a synthesized profile for a target based on active sensor data that characterizes a radio frequency (“RF”) signal reflected by the target and received at an active sensor system. The synthesized profile can characterize an estimated Line of Bearing (“LoB”) and a radial speed (“Rdot”) of the target relative to a passive sensor system. The target identifier can also be configured to match the synthesized profile with a measured profile that is determined based on RF signals received at the passive sensor system. The measured profile characterizes a measured LoB and a measured Rdot of the target.

Claims

1. A target identifier comprising one or more computing devices having machine readable instructions, the target identifier being configured to:

determine a synthesized profile for a target based on active sensor data that characterizes a radio frequency (“

RF”

) signal transmitted by an active sensor system and reflected by the target and received at the active sensor system, wherein the synthesized profile characterizes an estimated Line of Bearing (“

LoB”

) and a radial speed (“

Rdot”

) of the target relative to a passive sensor system; and

match the synthesized profile with a measured profile that is determined based on RF signals that are transmitted by the target or RF signals broadcast by a communication system that are reflected by the target and the RF signals are received at the passive sensor system, wherein the measured profile characterizes a measured LoB and a measured Rdot of the target.

2. The target identifier of claim 1, wherein the active sensor system and the passive sensor system are remotely located from each other.

3. The target identifier of claim 1, wherein the synthesized profile is further based on kinematics of the passive sensor system.

4. The target identifier of claim 3, wherein the kinematics of the passive sensor system comprises data characterizing a position and a velocity of the passive sensor system.

5. The target identifier of claim 1, wherein the matching comprises executing a statistical analysis comparing the synthesized profile with the measured profile.

6. The target identifier of claim 5, wherein the statistical analysis comprises calculating a Mahalanobis distance between the measured profile and the target profile.

7. The target identifier of claim 6, wherein:

D_i²=(m_i−

s_i)^TS_i<sup>−

1</sup>(m_i−

s_i);

wherein;

8. The target identifier of claim 7, wherein the statistical analysis comprises calculating a cumulative Mahalanobis distance between the measured profile and the target profile.

9. The target identifier of claim 8, wherein:

10. The target identifier of claim 9, wherein the statistical analysis comprises calculating a total cumulative Mahalanobis distance for a combination of pairings of measured profiles and synthesized profiles, wherein the total cumulative Mahalanobis distance is equal to a sum of cumulative Mahalanobis distances within the combination, wherein each of the cumulative Mahalanobis distances corresponds to a cumulative Mahalanobis distance between a given measured profile of the measured profiles and a given synthesized profile of the synthesized profiles.

11. The target identifier of claim 1, further comprising generating a combined target data set for the target based on the matching.

12. The target identifier of claim 11, wherein the combined target data set comprises:

a target identification for the target;

an Rdot of the target over a given time period;

an LoB of the target over the given time period;

a position of the target; and

a track of the target.

13. A system comprising:

an active sensor system configured to measure radio frequency (“

RF”

) signals transmitted by the active sensor system and reflected from a plurality of targets, wherein reflected RF signals characterize a range and azimuth for each of the plurality of targets;

a passive sensor system configured to passively receive RF signals transmitted by the plurality of targets or RF signals broadcast by a communication system and reflected by the plurality of targets;

a passive sensor analyzer configured to generate a measured profile for each of the plurality of targets based on the passively received RF signals, wherein each measured profile characterizes a measured Line of Bearing (“

LoB”

) and a measured Radial speed (“

Rdot”

) over a time period of a corresponding target of the plurality of targets relative to the passive sensor system; and

an active sensor analyzer configured to;

determine a position and a track for each of the plurality of targets; and

determine a synthesized profile for each of the plurality of targets based on the reflected RF signals, wherein the synthesized profile characterizes an estimated LoB and an estimated Rdot over the time period for each of the plurality of targets; and

a profile matcher configured to match each of the measured profiles with a corresponding synthesized profile.

14. The system of claim 13, wherein the matching by the profile matcher further comprises executing a statistical analysis comparing each synthesized profile for each of the plurality of targets with each measured profile for each of the plurality of targets.

15. The system of claim 14, wherein the statistical analysis comprises calculating a total cumulative Mahalanobis distance for each possible combination of the measured profiles and the synthesized profiles for the plurality of targets.

16. The system of claim 14, wherein the statistical analysis comprises calculating a Mahalanobis distance between each measured profile and each synthesized profile for each of the plurality of targets.

17. The system of claim 16, wherein the profile matcher is further configured to generate a combined target data set for each of the plurality of targets based on the matching.

18. The system of claim 17, wherein each combined target data set for each of the plurality of targets comprises:

a target identification for the target;

an Rdot of the target over the time period;

an LoB of the target over the time period;

a position of the target; and

a track of the target.

19. A method comprising:

determining a measured profile for each of a plurality of targets based on passive measurements of RF signals transmitted by the plurality of targets or RF signals broadcast by a communication system and reflected by the plurality of targets, each measured profile characterizing a measured Line of Bearing (“

LoB”

) and a measured radial speed (“

Rdot”

) over a time period relative a passive sensor system that determines the passive measurements;

generating a synthesized profile for each of the plurality of targets based on data that characterizes RF signals transmitted from an active sensor system and reflected from the plurality of targets, wherein each synthesized profile characterizes an estimated LoB and an estimated Rdot over the time period for a corresponding target; and

matching each measured profile with a corresponding synthesized profile based on a statistical analysis.

20. The method of claim 19, further comprising generating a combined target data set for each of the plurality of targets in response to the matching.