GB2330801A

GB2330801A - Detecting and eliminating land mines

Info

Publication number: GB2330801A
Application number: GB9814630A
Authority: GB
Inventors: Heinz Hoch; Hartmut Krahwinkel
Original assignee: Ac & S Dr Ing J V D Decken & P; Bodenseewerk Geratetechnik GmbH
Current assignee: Ac & S Dr Ing J V D Decken & P; Bodenseewerk Geratetechnik GmbH
Priority date: 1997-07-10
Filing date: 1998-07-06
Publication date: 1999-05-05
Anticipated expiration: 2018-07-06
Also published as: DE19729483A1; FR2765960B1; GB2330801B; FR2765960A1; GB9814630D0

Abstract

For detecting and eliminating land mines, a site (40) is observed from an aircraft (10) by means of an image resolving sensor (26) on which an image of the site surface is generated. The sensor (26) responds to differences in the radiation and/or reflection of the land mine or the ground surface over the land mine with respect to the surroundings. The position of the land mine is determined from image data of the sensor (26). An aiming device (20), for example, a gun is aimed at the position of the land mine thus detected. Thereby, the land mine is caused to detonate. Alternatively, the aiming device (20) may be a marking device for marking the position of the land mine for a subsequent clearing of the mine on the ground.

Description

1 Method and Device for Detecting and Eliminating Land Mines 2330801 The

invention relates to a method for detecting and eliminating land mines, in which land mines are recognised and localised from an aircraft.

The invention flirther relates to a device for detecting and eliminating land mines, in which land mines are recognised and localised from an aircraft.

is Land mines are buried in the ground during war conflicts. They explode, if a person steps on them or if a vehicle drives over them. Such land mines remain in the ground after the conflict is over. They represent a considerable potential danger and can render a mined region unusable for a long time.

Elimination of land mines is conventionally carried out from the ground. This occurs with the aid of mine detection devices and mine sweeping vehicles. This form of mine elimination is time consuming, difficult and dangerous.

Trials are in progress to search for mines from the air by helicopters or drones. With the prior art method, the position of the mine is determined. The mines are then eliminated by conventional means from the ground. Determination of the position of the mines as well as the retrieval of the absolute position of the mines must be very accurate. That requires great expense for the devices for the position determination.

It is an object of the invention to detect and eliminate mines quickly, simply and in a non-dangerous manner.

According to the invention this object is achieved by a method for detecting and eliminating land mines, in which land mines are recoan 1 ised and localised from an aircraft having the method steps:

2 (a) observing the site from the aircraft by means of an image resolving sensor, on which an image of the' site surface is generated and which responds to differences in the radiation andlor reflection of the land mine or the ground surface above the land mine with respect to the surroundings, (b) detecting the position of the land mine in the field of view of the sensor from image data of the sensor and (c) directing an aiming device on the position of the land mine thus detected.

The aiming device can be a gun or a high energy laser by means of which the mine is detonated. There are also other possibilities to render a land mine harmless. For example, a hole can be burned in the land mine housing with a high energy laser such that it bums out without being detonated. The aiming device may, however, also be just a marking device by which a marking means can be brought to the site of the land mine. The marking device can be provided with a gun with which the marking means can be fired. The marking means can be, for example, a colour shot, by which the site of the land mine is marked, radar reflectors which permits the retrieval of the site of the land mine by means of a radar device or a transponder. The land mine is then easily found on the ground and eliminated in conventional manner.

The method according to the invention is not dangerous for the mine sweeping personnel. A large area can be freed ftorn land mines in a short time. The technical expense is reasonable, as the position of the land mine needs not to be defined in absolute coordinates and, therefore, the system does not require a high precision of the position determination.

According to the invention the device for detecting and eliminating land mines characterised by is (a) an image resolving sensor on which an image of the site surface is generated and which responds to differences in the radiation andlor reflection of the land mine or the ground surface over the land mine with respect to the surroundings, 3 (b) a means to detect the position of the land mine using image data of the sensor, (c) a aiming device and (d) a directing means for directing the aiming device on the position of the land mine thus detected.

Modifications of the invention are the subject matter of the dependent claims.

Some embodiments of the invention are described in detail hereinafter with reference to the accompanying drawings.

Fig. 1 shows a helicopter with a device for detecting and eliminating land mines.

Fig.2 shows a first embodiment of the device for detecting and eliminating land mines.

Fig.3 shows a second embodiment of the device for detecting and eliminating land mines Fig.4 shows an alternative to the device in Fig. 3.

Referring to Fig. 1, numeral 10 designates a helicopter. The helicopter 10 is provided with a device for detecting and eliminating land mines. In the embodiment of Fig. 1, this device is provided with two units 12 and 14.

The unit 12 comprises an illumination laser 16 with an axis 18 and a aiming device 20 in the form of gun with an axis 22. The illumination laser 16 and aiming device 20 are arranged closely next to each other. The axes 18 and 20 are mutually parallel. The illumination laser 16 and the aiming device 20 are arranged on a common platform 24.

4 The platform 24 can be rotated to permit both the laser 16 and the aiming device 20 to point to a selected location on the ground.

The unit 14 comprises an image resolving multi-spectral sensor 26 which, on the one hand, responds to infrared illumination and to visible light, on the other hand, as indicated by the two objectives 28 and 30. The infrared radiation is detected by an infrared sensitive matrix detector (not illustrated). Instead of a matrix detector, a single or a series detector can, of course, be provided, which scans the field of view point by point or line by line. The visible light is detected by a video detector (also not illustrated), which detects light in three separate visible wavelength ranges. The unit 14 comprises a farther means 32 for the data processing and an inertial reference unit 34. Instead of the inertial reference unit 34, simply an interface to the flight control system can be provided. The inertial reference unit of the helicopter 10 is then used to allow for the angular movement of the helicopter 10 in space.

A first embodiment of a device for detecting and eliminating mines is illustrated in Fig. 2 as a block diagram which substantially corresponds to the embodiment of Fig. 1. Corresponding parts in Fig. 2 are given the same reference numerals as in Fig. 1.

The search sensor 26 with an objective 36 is aimed downwards from the helicopter 10 and receives an image of a site section 38. During the flight of the helicopter 10, the search sensor 26 observes a site strip 40. The search sensor 26 is in the position to recognise land mines by the evaluation of sensor data and data fusion. Land mines can be recognised by the earch sensor from the wavelength range of the observed radiation due 25 to temperature differences and differences in the reflectance of the ground surface or the vegetation.

The means 32 for the data processing carries out an image processing and supply, therefrom, the position of the land mine in the field of view of the search sensor 26. The position of the land mine in the field of view of the search sensor is, however, constantly changing due to the angular movement of the helicopter 10. Hence, the means 32 for the data processing receives position information about the position of the helicopter in space from the inertial reference unit 34. The means 32 supply the data of a space-fixed line of sight from the helicopter to the position of the land mine detected by the unit 14, for the data processing, independent of the movements of the helicopter, The platform 24 is equipped such that, the axis 18 of the illumination laser 16 and, therefore also, the axis 22 of the aiming device 20 is directed such as to be aligned with the space-fixed line of sight (taking parallax into account if necessary). Then, the aiming device 20 is released. In Fig. 2, the aiming device 20 is a high energy laser. The land mine is rendered harmless by the aiming device 20, for example, by ignition and detonation as illustrated in Fig. 1. That can be caused by a projectile from a gun as illustrated in Fig. 1 or a high energy light impulse from a high energy laser as illustrated in Fig. 2.

In the embodiment according to Fig. 2, the fine adjustment of the platform 24 is effected by a feedback from the illumination laser 16. The illumination laser 16 operates in the infrared spectral range and generates an infrared light spot on the site. The infrared component of the search sensor detects this light spot. With means 44, the data processing ascertains the position deviation between the position of the light spot as determined by the infrared component of the search sensor 26 and, likewise, the position of the land mine as determined by the search sensor. Depending on this position deviation, a precision alignment of the platform 24 occurs such that this position deviation becomes zero. Then, the aiming device 22 is directed on the land mine.

Fig. 3 shows another embodiment of the device for detecting and eliminating land mines. Corresponding parts in Fig. 3 are given the same reference numerals as in Fig. 1. and Fig.2.

In the embodiment in Fig. 3, a second universally movable platform 48 is provided. The platform 48 carries an image resolving infrared sensor 50. The infrared sensor 50 1P responds to the radiation of the illumination laser 16. The infrared sensor 50 detects the light spot which is generated on the site by the illumination laser 16. The search sensor 26 supplies the position of the land mine detected. The means 32 for the data processing supplies, therefrom, the orientation of the line of sight to this position of the land mine.

6 The platform 48 is now aligned such that the optical axis 52 of the infrared sensor 50 points in the direction of this line of sight. The image resolving infrared sensor 50 also detects the land mine. The position of the land mine in the field of view of the infrared sensor 50 is given by the image signals of the infrared sensor 50. In addition, the image resolving infrared sensor 50 also responds to the radiation reflected from the light spot generated by the illumination laser 16. The means 54 for the data processing ascertains the position of the light spot in the field of view of the infrared sensor 50 and determines the position deviation data of the light spot relative to the determined position of the land mine.

From this position deviation data, the alignment of the first platform 24 is effected such that the position deviation becomes zero. Then, the position of the light spot is located on the position of the land mine. Now, a high energy laser is released again from the aiming device 20 in Fig. 3. The land mine is ignited or, for example, as explained above, rendered harmless by burning, as illustrated in Fig. 1.

In this arrangement the function of the detection of a land mine for the determination of the line of sight to this land mine and the function of directing the aiming device on the land mine by comparing the position of the line of sight to the land mine and the laser light spot are separate from each other. The former function is fulfilled by the search sensor, the latter function is fulfilled by the infrared sensor on the platform 48. This separation of the functions offers the advantage that the search sensor is ready again for the detection of the next land mine while the inftared sensor, which has a smaller field of view than the search sensor, remains aimed at the region of the land mine and acts as the guidance of the platform 24 with the aiming device by means of the laser light spot.

The embodiment of Fig. 4 is similar to Fig. 3. Corresponding parts in Fig. 4 are given the same reference numerals as in Fig. 3.

In the embodiment of Fig. 4, a single multi-spectral sensor 56 is provided instead of the search sensor 26 and the infrared sensor 50. The multlspectral sensor 56 detects the land mines to be eliminated and simultaneously detects the light spot on the site generated by the illumination laser 16. The spectral ranges are chosen such that, predominantly the 7 light spot is detected in one spectral range which corresponds to the light of the illumination laser 16 and predominantly the land mine is detected in the other spectral ranges. The image data of the multi-spectral sensor 56, thereby, supplies wavelength dependent information about the position of the land mine as well as information about the position of the light spot in the field of view of the multi-spectral sensor 56.

The means 58 for the data processing comprises two parts or programs 60 and 62: Part 60 processes the information about the land mine and supplies data about the position of the is land mine. This data is applied to the platform 48. The platform carries the multi-spectral sensor 56. The platform 48 is adjusted such that the optical axis 64 of the multi-spectral sensor 56 is directed on the position of the land mine. The position of the light spot in the field of view of the multi-spectral sensor 56 relative to its optical axis corresponds to the position deviation of the light spot from the land mine. Part 62 of the means 58 for the data processing effects an image processing of the image of the light spot and supplies position deviation data. This position deviation data orientates the first platform 24.

Thereby, the illumination laser 16 and, therefore, the aiming device 20 are directed on the land mine, similar to Fig. 3. If the light spot is coincident with the site of the land mine, the aiming device 20 is released. In Fig. 4, the aiming device 20 is a gun.

In the embodiment according to Fig. 4, the functions of the search sensor and infrared sensor are both fulfilled by the multi-spectral sensor 56. A line of sight is not calculated from the signals of a search sensor and an inertial sensor unit. On the contrary, the multispectral sensor in its function as search sensor by the means 60 for the data processing and the platform 48 is kept directed on the land mine. In addition, as the multispectral 25 sensor 56 recognises the laser light spot of the illumination laser 16, it serves simultaneously to keep the illumination laser 16 and the gun 20 aligned with the land mine by means of the platform 24.

The aun can fire a projectile which causes the land mine to detonate. The gun can also ZP fire a marking means which simply marks the site of the land mine. The land mine is then eliminated by conventional means. That can be necessary, for example, when the detonation of the mine can cause damage to streets or building works.

8 The marking means can be formed by a colour shoot. The marking means can also be formed by an infrared, ultraviolet or radar reflector, which marks the site of the land mine. The marking means can also be a transponder. Prior to the firing, data can be inputted in this transponder relating to, for example, time, date, flight number etc.. The inputted data can be read out months after the marking. Furthermore, the transponder can be combined with a sensor, for example an odour sensor. In the case of a marking with sensor transponders, i.e. a combination of a transponder with a sensor, data obtained from the sensor on the land mine can be accessed from a safe distance.

The multi-spectral sensor 56 can, apart from sensors which respond to infrared radiation in the middle band (3 to 5 gm wavelength) and visible light, also comprise sensors which respond to a longer wave spectral range from, for example, 8 to 12 gm wavelength. The multi-spectral sensor can also comprise a radar sensor. Information about the position of land mines and light spots is obtained from data from the individual sensors by data fusion.

9

Claims

Claims

1. A method for detecting and eliminating land mines, in which land mines are recognised and localised from an aircraft, having the method steps:

(a) observing the site from the aircraft by means of an image resolving sensor, on which an image of the site surface is generated and which responds to differences in the radiation and/or reflection of the land mine or the ground surface above the land mine with respect to the surroundings, (b) detecting the position of the land mine from image data of the sensor and (c) directing an aiming device at the position of the land mine thus detected.

2. A method according to claim 1 for directing the aiming device at the land mine, characterised in that, (a) a light beam is directed onto the site which generates a light spot on the site, (b) the position of the light spot relative to the detected position of the land mine is detected and (c) the light spot is caused to cover the position of the land mine by tracking, (d) the aiming device being directed in the direction of the light beam.

3. A method according to claim 1 or 2, characterised in that, the land mine is caused to be detonated by the aiming device A method according to claim 1 or 2, characterised in that, the position of the land mine is marked by the aiming device and the land mine is subsequently eliminated on the ground.

5.

A method according to claim 1 or 2, characterised in that, a hole is burned into the land mine housing by the aiming device having the form of a high energy laser, whereby the land mine is rendered harmless, because the explosives are burned out without being detonated due to the pressure compensation thus enabled.

6. A device for detecting and eliminating land mines, in which land mines are recognised and localised from an aircraft, characterised by 4 is (a) an image resolving sensor on which an image of the site surface is generated and which responds to differences in the radiation and/or reflection of the land mine or the ground surface over the land mine with respect to the surroundings, (b) a means for detecting the position of the land mine using image data from the sensor 3 (c) a aiming device and (d) an directing means position of the land mine thus detected.

for directing the aiming device on the 7. A device according to claims 6, characterised in that, the means for detecting, of the position of the land mine using image data from the sensor comprises 11 (a) an imaging processing means to which the image data of the sensor is applied for the generation of data which give the position of the land mine in the system of the sensor as well as (b) an inertial reference unit which detects the angular movement of the aircraft in space and (c) a computing means for the co-ordinate transformation to which data, the inertial reference unit and the data of the image resolving sensor is applied and which supply the position of a space-fixed line of sight to the position of the land mine.

8. A device according to claims 7, characterised in that (a) the aiming device is arranged on a universally movable platform which is decoupled from the angular movements of the aircraft and (b) the platform with the aiming device directing means the position of the land mine.

is movable by means of the in accordance with the space-fixed line of sight to 9. A device according to claims 6, characterised in that, the directing means for directing the aiming device on the land mine is provided with (a) a means for the generation of a light beam directed on the site, the light beam generating a light spot on the site as well as (b) a means for the detection of the position of the light spot relative to the detected position of the land mine, 12 (c) a tracking means to cause the light spot to coincide with the position of the land mine, (d) the aiming device being directed in the direction of the light beam.

10. A device according to claims 9, characterised in that, (a) the aiming device together with the light spot generating means are arranged on a first universally movable platform (b) the means for the detection of the position of the light spot relative to the detected position of the land mine is provided with a second universally movable platform as well as a sensor responding to the light spot and also responding to the land mine which is arranged on the second platform 3 a means for directing the second platform the position of the land mine and with the sensor on an image processing means to which the image data of the sensor are applied for the generation of position deviation data which give the position of the light spot in the system of the sensor as the position of the light spot relative to the detected position of the land mine, (c) the tracking means for causing the light spot to be coincident with the position of the land mine is formed of a means for the tracking of the first platform to which tracking means the position deviation data from the data processing means is applied.

13 11. A device according to claims 10, characterised in that, the sensor the light spot is a sensor responding to infrared radiation.

12. A device according to claims 11, characterised in that, -esponding to (a) an image resolving multi-spectral sensor is arranged on the second platform for the detection of the position of the land mine (b) this image resolving multi-spectral sensor predominantly responds to the light spot in a spectral range such that, from the data of the multispectral sensor, simultaneously, tracking signals for directing the second platform with the multi-spectral sensor on the position of the land mine and simultaneously, position deviation data for the tracking of the first platform are derived.

13. A device according to one of the claims 6 to 12, characterised in that, the aiming device is a gun which is triggered on the coincidence of the light spot and the position of the land mine in order to cause the land mine to detonate.

14. A device according to one of the claims 6 to 12, characterised in that, the aiming device is a high energy laser which is tfiggered on the coincidence of the light spot and the position of the land mine.

15. A device according to one of the claims 6 to 12, characterised in that, the aiming device is a marking device for marking the position of the land mine for a subsequent clearing of the mine on the ground.

3"0 16. A device according to claim 15, characterised in that, the marking device is a gun for firing a marking means.

17. A device according to claim 16, characterised in that, the marking means are formed by a colour shot.

14 18. A device according to claim 16, characterised in that, the marking means are formed by an infrared, ultraviolet or radar reflector.

19. A device according to claim 16, characterised in that, the marking means are formed by a transponder.

20. A device according to claim 19, characterised in that, additional data such as time and date of the firing or the flight number is inputted into the transponder.

21. A device according to claim 19 or 20, characterised in that, the marking means are formed by a combination of sensor and transponder (sensor-transponder), which collects the sensor data on the site of the land mine until the elimination of the land mine.

22. A device according to claim 21, characterised in that, the data from the sensortransponder are accessible from a safe distance.

23. A device according to one of the claims 6 to 22, characterised in that, the means for the generation of a light beam aimed at the site are formed by a laser.

24. A device according to claim 23, characterised in that, the laser is an infrared laser.

25. A device according to one of the claims 6 to 24, characterised in that, the sensor comprises an image resolving detector responding to infrared radiation as well as a video detector aligned parallel thereto, sensitive to three ranges of the visible light.

26. A device according to claim 25, characterised in that, the sensor is provided with an additional image resolving detector sensitive to another inftared range.

27. A device according to claim 25 or 26, characterised in that, the sensor comprises a radar sensor.

28. A device for detecting and eliminating land mines substantially as hereinbefore described with reference to and as shown in Figures 1 and 2, Figures 1 and 3 or Figures 1 and 4.

29. A method for detecting and eliminating land mines substantially as hereinbefore described with reference to and as shown in Figures 1 and 2, Figures 1 and 3 or Figures 1 and 4.