Target tracking system and method with jitter reduction suitable for directed energy systems

• US 8,188,905 B2
• Filed: 05/29/2009
• Issued: 05/29/2012
• Est. Priority Date: 05/29/2008
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Gallivan, James R.
• Primary Examiner(s): GREGORY, BERNARR E
• Application Number:
  US12/474,483
• Publication Number:
  US 20120104282A1
• Time in Patent Office: 1,096 Days
• Field of Search: 342 52- 56, 342 61- 67, 342 73- 82, 342/175, 342/195, 342 13- 16, 342/27, 342/28, 342/165, 342/173, 342/174, 342/350, 342/359, 89/11.1, 382/100, 382/103, 315/32, 315/39.51, 250/200, 250/201.1, 250/201.9, 244/34.R, 244/35.R, 244/198, 244/201, 244/204, 244/205, 356/4.01
• US Class Current: 342/13
• CPC Class Codes: F41G 3/12 with means for compensating for muzzle velocity or powder temperature with means for compensating for gun vibrations
• CPC Class Codes: F41G 3/165 using a TV-monitor
• CPC Class Codes: F41H 13/00 Means of attack or defence not otherwise provided for details of radar or sonar systems G01S7/00
• CPC Class Codes: G01S 3/7864 T.V. type tracking systems

Abstract

Embodiments of a target tracking system and method with jitter reduction suitable for directed energy systems are generally described herein. In some embodiments, the directed energy system includes a target tracking system to track one or more track points on a moving target, and a beam transmission unit to maintain a directed energy beam on a selected one of the track points in response to tracking control signals provided by the target tracking system. The track points may be smaller than a spot size of the directed energy beam maintained on the target.

Claims

1. A target tracking system configured for use in a directed energy system, the target tracking system comprising:

a target identifier to receive video signals and to separate a target from a background;

a target tracker to track one or more track points on the target based on outputs of the target identifier; and

a tracking controller to generate tracking control signals based on outputs of the target tracker to control a beam transmission unit for placement of a directed energy beam on a selected one of the track points,

wherein the one or more track points are configured to be smaller than a spot size of the directed energy beam to allow the directed energy beam to cover the selected track point to compensate for target jitter and cause a desired effect within the selected track point.

2. The system of claim 1 wherein the beam transmission unit comprises one or more rate sensors configured to sense a rate-of-motion of the beam transmission unit and provide a rate-sensor signal for use by the target tracker to track the one or more track points on the target as part of a tracking control loop.

3. The system of claim 2 wherein the beam transmission unit comprises a main reflector antenna, a sub reflector, and rate sensors,

wherein the video signals are generated by a video transmission unit coupled to the main reflector antenna and directed to capture video in a transmission direction of the main reflector antenna,

wherein the tracking control signals are further configured to control the transmission direction of the main reflector antenna when tracking a target to keep the target in a field of view of the video transmission unit, and

wherein the tracking controller is configured to generate the tracking control signals to control the sub reflector for placement and focus of the directed energy beam on a selected one of the track points.

4. The target tracking system of claim 3 further comprising a fire control element configured to control an amount of time the directed energy beam is positioned on the selected track point,

wherein the amount of time is calculated to provide a surface temperature rise based on a distance to the target and the spot size on the target.

5. The target tracking system of claim 4 wherein the directed energy system further comprises a system controller,

wherein in response to a beam fire signal, the system controller is configured to cause the tracking controller to focus and direct the directed energy beam on the selected track point, and to maintain the directed energy beam on the selected track point as the target moves for the amount of time determined by the fire control element, and

wherein the fire control element is configured to inhibit the directed energy beam from being focused on the selected track point for greater periods of time to prevent a temperature rise above a predetermined maximum temperature.

6. The target tracking system of claim 5 wherein the fire control element is further configured to inhibit the directing of the directed energy beam on predetermined portions of a human body even though one or more track points may be provided on the predetermined portions.

7. The target tracking system of claim 1 wherein the target tracker comprises:

a target tracking element to track the one or more track points based on features of the target identified by the target identifier; and

a background tracking element to track a background portion of a field of view of a video transmission unit,

wherein the target tracking element is responsive to changes in the background portion to identify a target portion of the field of view.

8. The target tracking system of claim 7 wherein the target tracking element is a multi-point target tracking element configured to track two or more track points on the target.

9. The target tracking system of claim 7 wherein the target tracker further comprises:

a target dynamics processing element to process target movement and compute a dynamic error signal for the target;

a background dynamics processing element to process background movement and compute a dynamic error signal for the background;

a Kalman filter responsive to the dynamic error signals to generate the tracking control signals; and

a computed effect level processing element to compute a time, a distance, and an amount of target jitter for a fire control element,

wherein the fire control element is responsive to outputs of the computed effect level processing element to increase the time with increased amounts of target jitter to achieve a desired effect.

10. The target tracking system of claim 1 wherein the target identifier is configured to identify a human target within the video signals and to identify the one or more track points on the human target.

11. A directed energy system comprising:

a target tracking system to track one or more track points on a target as the target moves; and

a beam transmission unit to maintain a directed energy beam on a selected one of the track points in response to tracking control signals provided by the target tracking system,

wherein the track points are smaller than a spot size of the directed energy beam maintained on the target to allow the directed energy beam to cover the selected track point to compensate for target jitter and cause a desired effect within the selected track point.

12. The directed energy system of claim 11 wherein the target tracking system comprises:

a target identifier to receive video signals and to separate the target from a background;

a target tracker to track the one or more track points on the target based on outputs of the target identifier and based on a rate-sensor signal from the beam transmission unit; and

a tracking controller to generate the tracking control signals based on outputs of the target tracker to control the beam transmission unit for placement of a directed energy beam on the selected track point.

13. The system of claim 12 wherein the beam transmission unit comprises one or more rate sensors configured to sense a rate-of-motion of the beam transmission unit and provide the rate-sensor signal for use by the target tracker to track the one or more track points on the target as part of a tracking control loop.

14. The system of claim 13 wherein the beam transmission unit comprises a main reflector antenna, a sub reflector, and rate sensors,

wherein the video signals are generated by a video transmission unit coupled to the main reflector antenna and directed to capture video in a transmission direction of the main reflector antenna,

wherein the tracking control signals are further configured to control the transmission direction of the main reflector antenna when tracking the target to keep the target in a field of view of the video transmission unit, and

wherein the tracking controller is configured to generate the tracking control signals to control the sub reflector for placement and focus of the directed energy beam on a selected one of the track points.

15. The system of claim 14 further comprising a fire control element configured to control an amount of time the directed energy beam is positioned on a selected one of the track points,

wherein the amount of time is calculated to provide a surface temperature rise based on a distance to the target and the spot size on the target.

16. The system of claim 15 wherein the system is a hand-held directed energy weapon.

17. The system of claim 13 wherein the beam transmission unit further comprises a millimeter-wave amplifier,

wherein the millimeter-wave amplifier is a solid state amplifier configured to generate a high-power millimeter-wave signal having a frequency between 94 and 96 GHz, and

wherein the main reflector antenna comprises a flat parabolic surface antenna having a geometrically flat surface with an array of elements to allow the main antenna to operate electromagnetically as a parabolic reflector to generate a focused beam on the target.

18. A method for deterring a target comprising:

optically tracking one or more track points on the target as the target moves;

using a rate-of-motion of a beam transmission unit to maintain a directed energy beam on a selected one of the track points with a tracking control loop; and

maintaining the directed energy beam on the selected track points for a period of time to cause a deterring effect by raising surface temperature within the selected track point,

wherein the one or more track points are configured to be smaller than a spot size of the directed energy beam to allow the directed energy beam to cover the selected track point to compensate for target jitter and cause the deterring effect within the selected track point.

19. The method of claim 18 wherein the beam transmission unit is configured to generate the directed energy beam, and

wherein the method further comprises reducing effects of target jitter and target movement using the rate-of-motion and by optically tracking track points selected to be smaller than the spot size of the directed energy beam maintained on the target.

20. A method for operating a directed energy system comprising:

enabling operation of the directed energy system when a calibration and a location are verified; and

disabling operation of the directed energy system when the calibration or the location is not verified, and

wherein the directed energy system is configured to maintain a directed energy beam on a selected track point for a period of time to cause a deterring effect by raising surface temperature within the selected track point,

wherein the selected track point is smaller than a spot size of the directed energy beam to allow the directed energy beam to cover the selected track point to compensate for target jitter and cause the deterring effect within the selected track point.

21. The method of claim 20 further comprising disabling operation of the directed energy system after a target exposure time is exceeded.

22. The method of claim 21 wherein enabling comprises enabling operation of the directed energy system when a user is authenticated, and

wherein disabling comprises disabling operation of the directed energy system when the user is not able to be authenticated.

23. The method of claim 21 further comprising:

verifying operational rules of engagement based on the calibration and the location; and

disabling operation of the directed energy system when the operational rules of engagement are not met.

24. The method of claim 23 wherein the location is verified based on GPS location information, and

wherein the directed energy system comprises a target tracking system to track one or more track points on a target as the target moves, and a beam transmission unit to maintain a directed energy beam on a selected one of the track points in response to tracking control signals provided by the target tracking system, and

wherein the track points are smaller than the spot size of the directed energy beam maintained on the target.