Method and apparatus for munition timing and munitions incorporating same

• US 7,926,402 B2
• Filed: 11/29/2006
• Issued: 04/19/2011
• Est. Priority Date: 11/29/2006
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Alliant Techsystems Incorporated (Northrop Grumman Corporation)
• Inventors: Pikus, Eugene C., Erdmann, David P.
• Primary Examiner(s): Carone; Michael
• Assistant Examiner(s): Weber; Jonathan C
• Application Number:
  US11/564,714
• Publication Number:
  US 20080121131A1
• Time in Patent Office: 1,602 Days
• Field of Search: 89/6, 89/65, 102/215, 102/206, 102/228, 102/232, 102/238, 102/248, 102/255, 102/257, 102/264, 102/266, 102/268, 102/276
• US Class Current: 89/6.5
• CPC Class Codes: F42C 11/065 Programmable electronic delay initiators in projectiles
• CPC Class Codes: F42C 15/40 wherein the safety or arming action is effected electrically
• CPC Class Codes: F42C 17/04 for electric fuzes

Abstract

Microcontroller apparatuses and methods of use are disclosed. An explosive projectile system contains a faze and a remote fuze setter. The fuze includes a microcontroller comprising an RC-based clock generator and is configured to sample an accurate timing event sent from a crystal-based or similarly accurate timing device. The microcontroller is then calibrated with the received timing event and results are employed in a manner appropriate for desired implementation. Implementations of the microcontroller may include sampling a detonation delay value, in the form of a time pulse, and calibrating the microcontroller to issue a fire command at delay time after an impact event. Additionally, in a setter calibration application, a microcontroller may receive a carrier signal, calibrate the faze to an accurate time base and then set frequency boundary limits for subsequent data bit transfers.

Claims

1. A timing apparatus for use within an explosive projectile, comprising:

a fuze including a microcontroller comprising an RC-based clock generator and configured for;

receiving a timing event from an accurate time-based source, wherein the timing event has a time duration between a first timing edge and a second timing edge;

executing software instructions comprising repeatedly performing iterations of an internal timing loop of instructions, each internal timing loop comprising a loop period taking a predetermined number of instruction executions at an instruction execution rate set by the RC-based clock generator, wherein a first iteration begins at the first timing edge and a last iteration ends at or within the loop period corresponding to the second timing edge to determine an iteration value comprising a number of executions of the internal timing loop; and

after the receiving the timing event, executing the internal timing loop the iteration value times to generate a calibrated time base correlated to the accurate time-based source.

2. The timing apparatus of claim 1, wherein the accurate time-based source is a crystal-based timing source.

3. The timing apparatus of claim 1, wherein the timing event comprises a time pulse.

4. The timing apparatus of claim 3, further comprising at least one controller operably connected to the microcontroller.

5. The timing apparatus of claim 4, wherein the microcontroller is further configured for:

sensing an impact event received from the at least one controller; and

generating a detonation event after executing the internal timing loop a number of times equal to the iteration value after the impact event.

6. The timing apparatus of claim 3, further comprising at least one impact sensor operably connected to the microcontroller.

7. The timing apparatus of claim 6, wherein the microcontroller is further configured for:

sensing an impact event received from the at least one impact sensor; and

generating a detonation event the calibrated time base after the impact event by executing the internal timing loop a number of times equal to the iteration value after the impact event.

8. The timing apparatus of claim 1, wherein the timing event comprises two consecutive same direction edges of an oscillating carrier signal.

9. The timing apparatus of claim 8, wherein the microcontroller is further configured for:

setting frequency boundary limits for the oscillating carrier signal;

repeatedly executing the internal timing loop the iteration value number of times to repeatedly generate the calibrated time base; and

sampling the oscillating carrier signal such that a period of the oscillating carrier signal greater than the calibrated time base is assigned a first binary value and a period of the oscillating carrier signal less than the calibrated time base is assigned a second binary value.

10. The timing apparatus of claim 8, wherein the oscillating carrier signal has a frequency of substantially 10 KHz.

11. An explosive projectile, comprising:

an accurate time-based source;

an encasement;

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

a fuze operably associated with the explosive material, the fuze comprising;

a housing; and

a timing apparatus disposed within the housing and comprising;

a microcontroller comprising an RC-based clock generator and configured for;

receiving a signal from the accurate time-based source, wherein the signal has an identifiable frequency and a timing event with a time duration between a first timing edge and a second timing edge;

executing software instructions comprising repeatedly performing iterations of an internal timing loop of instructions, each internal timing loop comprising a loop period taking a predetermined number of instruction executions at an instruction execution rate set by the RC-based clock generator;

measuring a number of iterations of the internal timing loop of instructions executed by the microcontroller during the time duration; and

representing the identifiable frequency with a period of the identifiable frequency determined by executing the internal timing loop a number of times corresponding to the number of iterations.

12. The explosive projectile of claim 11, wherein the accurate time-based source is a crystal-based timing source.

13. The explosive projectile of claim 11, wherein the timing event comprises a time pulse.

14. The explosive projectile of claim 13, further comprising at least one controller operably connected to the microcontroller.

15. The explosive projectile of claim 14, wherein the microcontroller is further configured for:

sensing an impact event received from the at least one controller; and

generating a detonation event by iterating through the internal timing loop a number of times equal to the measured number of iterations after the impact event.

16. The explosive projectile of claim 13, further comprising at least one impact sensor operably connected to the microcontroller.

17. The explosive projectile of claim 16, wherein the microcontroller is further configured for:

sensing an impact event received from the at least one impact sensor; and

generating a detonation event by iterating through the internal timing loop a number of times equal to the measured number of iterations after the impact event.

18. The explosive projectile of claim 11, wherein the timing event comprises two consecutive same direction edges of an oscillating carrier signal.

19. The explosive projectile of claim 18, wherein the microcontroller is further configured for:

setting frequency boundary limits for the oscillating carrier signal;

repeatedly executing the internal timing loop the number of iterations times to generate the represented identifiable frequency; and

sampling the oscillating carrier signal during a data phase such that a period of the oscillating carrier signal greater than a period of the represented identifiable frequency is assigned a first binary value and a period of the oscillating carrier signal less than the period of the represented identifiable frequency is assigned a second binary value.

20. The explosive projectile of claim 18, wherein the oscillating carrier signal has a frequency of substantially 10 KHz.

21. A method of using a timing apparatus within an explosive projectile, comprising:

receiving a timing event from an accurate time-based source, wherein the timing event has a time duration between a first timing edge and a second timing edge; and

calibrating an internal timing loop of instructions executed by a microcontroller to represent the time duration as an iteration value indicative of a number of iterations of the internal timing loop during the time duration;

wherein the internal timing loop comprises software instructions configured for repeated execution and each execution of the internal timing loop comprises a loop period taking a predetermined number of instruction executions at an instruction execution rate set by an RC-based clock generator.

22. The method of claim 21, wherein receiving the timing event from the accurate time-based source comprises receiving the timing event from a crystal-based source.

23. The method of claim 21, wherein receiving the timing event from the accurate time-based source comprises receiving a time pulse from the accurate time-based source.

24. The method of claim 23, further comprising:

sensing an impact event received from at least one controller; and

generating a detonation event after iterating through the internal timing loop a number of times equal to the iteration value after the impact event.

25. The method of claim 24, further comprising receiving a command indicating that the detonation event is to be generated in a point detonation mode.

26. The method of claim 21, wherein receiving the timing event from the accurate time-based source comprises receiving two consecutive same direction edges of an oscillating carrier signal from the accurate time-based source.

27. The method of claim 26, further comprising:

setting frequency boundary limits for the oscillating carrier signal;

repeatedly executing the internal timing loop for the number of iterations to repeatedly generate the represented time duration; and

sampling the oscillating carrier signal such that a period of the oscillating carrier signal greater than the represented time duration is assigned a first binary value and a period of the oscillating carrier signal less than the represented time duration is assigned a second binary value.

28. The method of claim 26, wherein receiving the oscillating carrier signal comprises receiving the oscillating carrier signal with a frequency of substantially 10 KHz.