Method and apparatus for autonomous detonation delay in munitions

• US 20060107862A1
• Filed: 11/22/2004
• Published: 05/25/2006
• Est. Priority Date: 11/22/2004
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Alliant Techsystems Incorporated (Northrop Grumman Corporation)
• Inventors: Nelson, Carl, Tomes, Mark J., Davis, Martin R.
• Granted Patent: US 7,124,689 B2
• Time in Patent Office: Days
• US Class Current: 102/216
• CPC Class Codes: F42C 11/065 Programmable electronic delay initiators in projectiles
• CPC Class Codes: F42C 17/04 for electric fuzes
• CPC Class Codes: F42C 9/147 Impact fuze in combination with electric time fuze

Abstract

A detonation timing apparatus and method of determining a detonation time is disclosed. The detonation timing apparatus comprises an initiation sensor, at least one impact sensor, and at least one controller. The at least one controller may be configured for sensing an initiation event associated with the initiation sensor and sensing an impact event associated with the at least one impact sensor. The at least one controller is further configured for determining an impact velocity estimate proportional to a temporal difference between the initiation event and the impact event, using the impact velocity estimate to determine the detonation delay, and generating the detonation event at the detonation delay after the impact event. The timing apparatus and method of determining a detonation time may be incorporated in a fuze, which may be incorporated in an explosive projectile.

Claims

1. A detonation timing apparatus, comprising:

an initiation sensor;

at least one impact sensor; and

at least one controller configured for;

sensing an initiation event associated with the initiation sensor;

sensing an impact event associated with the at least one impact sensor;

determining an impact velocity estimate proportional to a combination of target characteristics and a temporal difference between the initiation event and the impact event;

determining a detonation delay correlated to the impact velocity estimate; and

generating a detonation event substantially at the detonation delay after the impact event.

2. The apparatus of claim 1, wherein the initiation sensor is an acceleration switch configured for sensing a launch event.

3. The apparatus of claim 1, wherein the at least one impact sensor comprises at least one of a graze sensor and a crush sensor.

4. The apparatus of claim 1, wherein determining the impact velocity estimate further comprises analyzing at least one predetermined parameter in relation to the target characteristics the initiation event and the impact event.

5. The apparatus of claim 4, wherein the at least one predetermined parameter is selected from the group consisting of projectile ballistic characteristics, propellant characteristics, and launch characteristics.

6. The apparatus of claim 1, further comprising a communication interface operably coupled with the at least one controller;

and

the at least one controller is further configured for receiving a command from the communication interface prior to the initiation event, the command indicating that the detonation event is to be generated in one of a point detonation mode and a velocity variable delay detonation mode.

7. The apparatus of claim 6, wherein the point detonation mode comprises generating the detonation event at a predetermined detonation delay after the impact event.

8. The apparatus of claim 7, wherein the predetermined detonation delay is substantially near zero.

9. The apparatus of claim 6, wherein the velocity variable delay detonation mode comprises generating the detonation event after the impact event at a detonation delay correlated to the impact velocity estimate.

10. The apparatus of claim 1, further comprising:

an arming module; and

a spin sensor configured for sensing a rotation of the detonation timing apparatus about an axis and generating a spin signal proportional to the rotation; and

wherein the at least one controller is further configured for;

sampling the spin signal between the initiation event and a safe separation time to develop an actual spin profile; and

enabling the arming module if the actual spin profile conforms to an acceptable spin profile.

11. The apparatus of claim 10, wherein the arming module is further configured for arming an explosive projectile at the safe separation time if the arming module is enabled.

12. The apparatus of claim 11, further comprising a firing module configured for detonating the explosive projectile as a result of the detonation event if the explosive projectile has been armed.

13. The apparatus of claim 10, wherein the acceptable spin profile and the actual spin profile incorporate at least one spin parameter selected from the group consisting of revolution count, spin rate, increase in spin rate, and spin signal amplitude.

14. The apparatus of claim 10, wherein the safe separation time occurs at a safe separation delay after the initiation event.

15. The apparatus of claim 1, wherein the at least one controller comprises a plurality of controllers.

16. The apparatus of claim 15, wherein at least two of the plurality of controllers are different types of controllers.

17. The apparatus of claim 15, further comprising a voting module, the voting module configured for generating an arming event if each controller of the plurality of controllers generates an arm signal.

18. The apparatus of claim 17, wherein the voting module is further configured for generating the detonation event if each controller of the plurality of controllers generates a fire signal.

19. A fuze for an explosive projectile, comprising:

a housing;

a detonation timing apparatus disposed within the housing, comprising;

an initiation sensor;

at least one impact sensor; and

at least one controller configured for;

sensing an initiation event associated with the initiation sensor;

sensing an impact event associated with the at least one impact sensor;

determining an impact velocity estimate proportional to a combination of a target characteristic and a temporal difference between the initiation event and the impact event;

determining a detonation delay correlated to the impact velocity estimate; and

generating a detonation event substantially at the detonation delay after the impact event; and

a safety and arming module disposed within the housing and configured for enabling and

initiating detonation of the explosive projectile responsive to the detonation event.

20. An explosive projectile, comprising:

an encasement;

an explosive material disposed within the encasement and configured for detonation; and

a fuze disposed within the encasement, comprising;

a housing;

a detonation timing apparatus disposed within the housing, comprising;

an initiation sensor;

at least one impact sensor; and

at least one controller configured for;

sensing an initiation event associated with the initiation sensor;

sensing an impact event associated with the at least one impact sensor;

determining an impact velocity estimate proportional to a combination of a target characteristic and a temporal difference between the initiation event and the impact event;

determining a detonation delay correlated to the impact velocity estimate; and

generating a detonation event substantially at the detonation delay after the impact event; and

a safety and arming module disposed within the housing and configured for enabling and

initiating detonation of the explosive material responsive to the detonation event.

21. A method of determining a detonation time of an explosive

projectile, comprising:

sensing an initiation event;

sensing an impact event;

determining an impact velocity estimate proportional to a combination of a target characteristic and a temporal difference between the initiation event and the impact event;

determining a detonation delay correlated to the impact velocity estimate;

generating a detonation event substantially at the detonation delay after the impact event.

22. The method of claim 21, wherein the initiation event is determined by sensing a launch event using an acceleration sensor.

23. The method of claim 21, wherein the impact event is sensed by at least one of a graze sensor and a crush sensor.

24. The method of claim 21, wherein determining the impact velocity estimate further comprises analyzing at least one predetermined parameter in relation to the target characteristics, the initiation event, and the impact event.

25. The method of claim 24, further comprising selecting the at least one predetermined parameter from the group consisting of projectile ballistic characteristics, propellant characteristics, and launch characteristics.

26. The method of claim 21, wherein determining the detonation delay further comprises receiving a command from a communication interface prior to the initiation event indicating that the detonation event is to be generated in one of a point detonation mode and a velocity variable delay detonation mode.

27. The method of claim 26, wherein generating the detonation event in the point detonation mode comprises generating the detonation event at a predetermined detonation delay after the impact event.

28. The method of claim 27, further comprising selecting the predetermined detonation delay to be substantially near zero.

29. The apparatus of claim 26, wherein generating the detonation event in the velocity variable delay detonation mode comprises generating the detonation event after the impact event at a detonation delay correlated to the impact velocity estimate.

30. The method of claim 21, further comprising detonating an explosive projectile responsive to the detonation event.

31. The method of claim 21, further comprising:

generating a spin signal proportional to rotation of the explosive projectile about an axis;

determining an actual spin profile by sampling the spin signal between the initiation event and a safe separation time; and

arming the explosive projectile at the safe separation time if the actual spin profile conforms to an acceptable spin profile.

32. The method of claim 31, further comprising detonating the explosive projectile responsive to the detonation event if the explosive projectile has been armed.

33. The apparatus of claim 31, wherein the acceptable spin profile and the actual spin profile incorporate at least one spin parameter selected from the group consisting of revolution count, spin rate, increase in spin rate, and spin signal amplitude.

34. The method of claim 31, wherein the safe separation time occurs at a safe separation delay after the initiation event.

35. The method of claim 21, wherein the acts of determining the impact velocity, determining the detonation delay, and generating the detonation event are performed by at least one controller.

36. The method of claim 35, further comprising selecting the at least one controller to comprise a plurality of controllers.

37. The method of claim 36, further comprising selecting at least two of the plurality of controllers to be different types of controllers.

38. The method of claim 36, further comprising generating an arming event if all the controllers of the plurality of controllers generate an arm signal.

39. The method of claim 38, further comprising generating the detonation event if all the controllers of the plurality of controllers generate a fire signal.