Programmable munitions device

A programmable munitions device (10) includes a transponder unit (12), a digital interface (18), and munitions unit (20). The transponder unit (12) receives a radio frequency signal from an interrogation unit (22). The transponder unit (12) decodes the radio frequency signal to obtain the digital data representing the transmitted information from the interrogation unit (22). The information is stored within a memory (14) and initiates the start of a time period within a timing unit (16). Upon activation, the munitions unit (20) reads the information within the memory (14) and a timing flag within the timing unit (16) through the digital interface (18). If the timing flag is set, indicating that the information within memory (14) is still fresh, munitions unit (20) causes the detonation of explosive material if the recognized event corresponds to the triggering event programmed within the memory (14). If the timing flag is cleared, indicating that the information programmed within the memory (14) is stale, the munitions unit ( 20) reverts to default settings within the digital interface (18) in determining whether the recognized event corresponds to the default settings.

TECHNICAL FIELD OF THE INVENTION 
The present invention relates in general to explosive materials and more 
particularly to a programmable munitions device. 
BACKGROUND OF THE INVENTION 
Certain munitions such as land mines can be programmed to detonate in 
response to a specific event. For example, land mines can be programmed to 
distinguish between a truck and a tank. Further, the land mine can be 
programmed to detonate after recognition of a first, second, third, or any 
number of specific vehicles. Remote communication may be performed with 
certain mines for activation and deactivation. To prepare the 
communication hardware for operation, the device needs to be programmed 
according to frequency, time, and channel. Mines have a sophisticated 
protection mechanism to allow troops to handle them and program them in a 
field environment. However once the mine has been positioned, the mine 
cannot be reprogrammed without physically recovering the mine. Land mines 
typically have to be programmed before they are deployed to their fixed 
positions. Further, the programming of munitions has to be performed 
before any energy, e.g., from an embedded battery, is available within the 
munition. Therefore, it is desirable to program land mines without using 
munitions provided power. 
SUMMARY OF THE INVENTION 
From the foregoing, it may be appreciated that a need has arisen for 
programming of munitions. A need has also arisen for a munitions device 
that can be programmed. 
In accordance with the present invention, a programmable munitions device 
is provided that substantially eliminates or reduces disadvantages and 
problems associated with conventional munitions devices. 
According to an embodiment of the present invention, there is provided a 
programmable munitions device that includes a transponder unit operable to 
receive a radio frequency programming signal wherein said radio frequency 
programming signal supplies power and information to the transponder unit 
without requiring munitions provided power. A digital interface unit is 
coupled to the transponder unit and is operable to retrieve the 
information stored in the transponder unit. A munitions unit reads the 
information retrieved by the digital interface unit and stores the 
information for use whenever the munition is activated. 
The present invention provides various technical advantages over 
conventional munitions devices. For example, one technical advantage is in 
programming a munitions device to detonate after the occurrence of a 
specific event. Another technical advantage is in programming a munitions 
device without the need of any energy from the munition, thereby 
maintaining the munition in a safe condition. Other technical advantages 
are readily apparent to one skilled in the art from the following figures, 
descriptions, and claims.

DETAILED DESCRIPTION OF THE. INVENTION 
The figure is a block diagram of a programmable munitions device 10. 
Programmable munitions device 10 includes a transponder unit 12 having a 
memory 14 and a timing unit 16. Transponder unit 12 is coupled to a 
digital interface 18 that allows access to transponder unit 12 by a 
munitions unit 20. Transponder unit 12 receives information from a remote 
interrogator unit 22. Further information on transponder unit 12 and 
interrogator unit 22 can be found in U.S. Pat. No. 5,053,774 issued Oct. 
1, 1991, entitled "Transponder Arrangement" and hereby incorporated by 
reference herein. 
In operation, programmable munitions device 10 can be remotely programmed 
from an interrogator unit 22 through the transfer of information by radio 
frequency signals. Transponder unit 12 receives a radio frequency signal 
from interrogation unit 22 and derives the necessary information from the 
radio frequency signal for storage into memory 14. Digital information is 
typically determined from the radio frequency signal through amplitude 
modulation in order to determine the binary zero and binary one values of 
data bits for the transmitted information. 
The information that transponder unit 12 receives from interrogation unit 
22 is the programming data used by programmable munitions device 10 in 
determining when detonation of the connected explosive material is to 
occur. The programming information received by transponder unit 12 is 
stored within memory 14. Memory 14 is preferably an electrically erasable 
programmable read only memory. 
A timing unit 16 is coupled to memory 14 and is used in determining the 
freshness of the data within memory 14. Timing unit 16 establishes a fixed 
time period from when memory 14 has been programmed. If the munitions 
device is activated within the fixed time established in unit 16, the 
munitions electronic will read via the digital interface 18 the programmed 
information and behave accordingly. If the time period established by 
timing unit 16 has elapsed, then programmable munitions device 10 will 
revert to default settings in order to determine whether detonation should 
occur. 
Digital interface 18 provides the communication of programmed information 
from transponder unit 12 to munitions unit 20. Upon activation, munitions 
unit 20 consults digital interface 18 in order to analyze the programmed 
information within memory 14 of transponder unit 12. Digital interface 18 
checks timing unit 16 to see if a timing flag has been set. A set timing 
flag indicates that programmed information within memory 14 has been 
received within the time period established by timing unit 16 for 
controlling operation of programmable munitions device 10. If the timing 
flag is cleared, the information within memory 14 is stale and 
programmable munitions device 10 is under the control of fixed default 
settings within digital interface 18. Once programmable munitions device 
10 has been placed in a field environment, programming may occur without 
disturbing the placement of programmable munitions device 10 by remote 
programming through interrogator unit 22. 
In summary, a programmable munitions device can be placed in a field 
environment and subsequently programmed without disturbing the location of 
the programmable munitions device and without activating the munitions 
power. The programmable munitions device includes a transponder unit that 
receives information from a remote interrogation unit and stores the 
programming information within a memory. A munitions unit reads the 
programming information within the memory through a digital interface to 
determine whether a recognized event has occurred for detonation of the 
programmable munitions device. The transponder unit also includes a timing 
unit that establishes the freshness of the programmable information within 
the memory. The programmable munitions device reverts to default settings 
when information within the memory has been in place beyond the time 
period established by the timing unit. 
Thus, it is apparent that there has been provided, in accordance with the 
present invention, a programmable munitions device that satisfies the 
advantages set forth above. Although the preferred embodiment has been 
described in detail, it should be understood that various changes, 
substitutions, and alterations can be made herein without departing from 
the spirit and scope of the present invention as defined by the following 
claims.