GB2345471A

GB2345471A - Clearing land mines

Info

Publication number: GB2345471A
Application number: GB9930667A
Authority: GB
Inventors: David Reeves-Payne
Original assignee: REEVES PAYNE DAVID
Current assignee: REEVES PAYNE DAVID
Priority date: 1999-01-06
Filing date: 1999-12-24
Publication date: 2000-07-12
Also published as: GB9900216D0; GB9930667D0

Abstract

Land mines 10 are detected and/or detonated by a system 20 which feeds acoustic and/or mechanical vibrations into the ground. Vibrating mines may be detected by the microwaves of an accompanying ground penetrating radar system (not shown). The vibrations may be supplied at different intensity levels, and may cause certain types of mine to rise to the surface of the ground.

Description

Clearing Land Mines The present invention relates to a system and method for clearing land mines. In particular, it also relates to detecting land mines and simultaneously or subsequently rendering them harmless, e. g. by detonation.

Hitherto, land mines have been detected by metal detection methods. Such methods have not proved very successful in detecting mines made of plastics material. Detection methods involving the use of helicopters, hovercraft, modified tractors or similar large earth moving machines have also been employed, but these are relatively complicated, unreliable and costly.

The present invention seeks to overcome or reduce one or more of the above problems.

According to a first aspect of the present invention there is provided a system for clearing land mines comprising a source of vibrations which can feed the vibrations into the ground.

The vibrations are preferably acoustic vibrations, which may be supplemented by mechanical vibrations.

According to a second aspect of the present invention there is provided a method of clearing land mines comprising feeding vibrations in to the ground to be cleared.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawing which shows a minefield to be cleared.

The Figure shows a minefield having buried mines 10. A system 20 according to the present invention for clearing the land mines is placed on the ground adjacent the minefield. The system comprises amplification apparatus 21 connected to a suitable power supply and driving loudspeakers 22-25 in enclosures 27 and 28. Apparatus 21 causes the loudspeakers to emit acoustic waves over a wide range of volumes and a wide range of frequencies.

The invention is based on two realisations: firstly, that some types of landmine, having a so called cocked striker mechanism such as the Soviet PMN or Hungarian Gyata 64, are directly detonated by suitable acoustic waves; and secondly, that for landmines in a second class which are not directly detonated, it is still possible to explode them by acoustically exciting the detonator and the core explosive material itself. Sound with a suitable intensity and at a particular resonant frequency for each type of explosive can vibrate the molecules themselves to detonation by sympathetic oscillation. Mines falling within this second class include so-called diaphragm operated mines, such as the Chinese Type 72 or the USA M14 which require a direct pressure to invert the diaphragm, and various Italian mines which require pressure to be exerted on to the pressure plate to compress the strike spring, which then moves a safety detent and then fires the striker into the detonator via the newly compressed strike spring.

In use of the system, mines 10 are simultaneously detected and eliminated by directing at the minefield acoustic vibrations of a predetermined intensity and with a predetermined frequency or range of frequencies. In addition to the two ways of detonating mines outlines above, this procedure produces a third way of detecting mines, especially some diaphragm mines which may not be detonated by acoustic vibration alone. For certain types of ground, if the vibrations are sufficiently large they break up the ground so that the mines can rise up to the surface as the smaller ground particles are shaken downwards. This enables the mines to be located and then disposed of.

Various modifications may be made to the above-described system and method. For example, the loudspeaker enclosures may be located in a trench in the ground and/or suitable acoustic guides may be provided for improving the introduction of sound into the ground. In addition, sound focusing means such as acoustic mirrors may be provided. The method may be performed in two stages: a first step with sound at a relatively low intensity to detect the mines by echo location and a second step, at higher intensity and/or using acoustic focusing means or other acoustic intensifiers, to detonate the mines or to bring them to the surface. An advantage of his modification is that the first step is environmentally less intrusive.

For the second class of mines mentioned previously, an alternative method of detonation is to direct into the minefield mechanical vibrations in addition to acoustic vibrations.

The mechanical vibrations may be introduced by a spring mechanism, e. g. like a ground compacting device, or a plunger operating under gravity, e. g. like a pile-driver.

The system may be arranged to be carried by an individual operator, in which case it may be battery-powered. Alternatively, it may be carried by a vehicle.

The system 20 may incorporate any desired number of loudspeakers 22-25. They may be arranged to be operated in common or individually; this latter arrangement permits different loudspeakers to be operated at different volumes and/or different frequencies, so that different types of mines 10 may be simultaneously detected and/or eliminated by the system.

The system 20 may be supplemented by the use of a GPR (Ground Penetrating Radar) system.

The system operates using active and/or passive microwaves and millimeterwave sensors.

Millimeterwave radiometers are very sensitive receivers working according to the heterodyne principle. A pencil beam antenna collects the electromagnetic radiation, caused by the natural thermal motion of the molecules in the matter and by the reflected radiation of the surrounding objects. The information content of this radiation is dependent on frequency, polarisation, and object characteristics like chemical composition (dielectric material properties), surface roughness etc. The imaging principle is based on the fact that land mines show different radiation behaviour from their environment.

As there are many different types of Ground Penetrating Radar, the GPR radiation may be applied to the ground in a variety of ways, either mounted in, on or under, land vehicles, helicopters, aeroplanes, both full scale or remote control ; boats or in small hand-held-portable systems designed to be carried by a personal operative.

Thus if system 20 is used to make the landmines or their internal components vibrate, it makes them much clearer and easier to detect by any GPR system.

Claims

CLAIMS 1. A system for clearing land mines comprising a source of vibrations which can feed the vibrations into the ground.
2. A system according to claim 1, in which the vibrations can be supplied at different intensity levels.
3. A system according to claim 1 or 2, wherein the vibrations include acoustic vibrations.
4. A system according to any preceding claim, wherein the vibrations include mechanical vibrations.
5. A system according to claim 3 or 4, combined with a radar system for detecting the vibrating land mines or parts thereof.
6. A system substantially as herein described with reference to the accompanying drawing.
7. A method of clearing land mines comprising feeding vibrations into the ground to be cleared.
8. A method according to claim 7. wherein the vibrations include acoustic vibrations.
9. A method according to claim 7 or 8, wherein the vibrations include mechanical vibrations.
10. A method according to any of claims 7 to 9, wherein the vibrations are used to detect the land mines.
11. A method according to any of claims 7 to 10, wherein the vibrations are used to vibrate the land mines or parts thereof, and the vibrations of the land mines are detected by a radar system.
12. A method according to claim 11, wherein the radar system is a ground penetrating system employing microwaves.
13. A method according to any of claims 7 to 12, wherein the vibrations are used to detonate the land mines.
14. A method according to any of claims 7 to 12, wherein the vibrations are used to cause the land mines to rise within the ground.
15. A method according to any of claims 7 to 14, wherein the vibrations are fed into the ground at different intensity levels.
16. A method of clearing land mines substantially as herein described with reference to the accompanying drawing.