G. Nardulli [*] and C. Marangi [+]

paper presented at the USPID - VII International Castiglioncello Conference on Nuclear and Conventional Disarmament: Progress or Stalemate?

Table of Content

1. Historical evolution
2. Trends in landmine warfare
3. Trends in landmine detection: new sensors and the problem of data fusion
   
• Dogs for landmine detection
• The problem of data fusion: the ILDC project
4. Footnote

1. Historical evolution

The historical evolution of the mine warfare can be useful to elucidate future trends and developments of these weapons. The definition of mine in the Britannica is as follows: stationary explosive device that is designed to destroy personnel, ships, or vehicles when the latter come in contact with it [1]. While rather comprehensive, this definition does not describe in detail the continuous evolution of these weapons in the last century. This evolution continues today and will constitute the theme of the first two Sections of this paper; in the remaining part we shall examine problems related to the production and the removal of antipersonnel landmines from the infested areas.

The first war where mines played a relevant role was the Russo-Japanese war of 1904-05: this conflict demonstrated to many interested spectators (governments, strategic thinkers) the power of the new defensive technologies developed in the last decades of the 19th century [2] . The evidence was clear. Even though the Japanese army succeeded in winning the war, their losses where very heavy; the Russian army defended its positions at Port Arthur and Mukden with trenches protected by barbed wires, machine guns, rifled and repeating small arms; in particular the trenches were defended by minefields with electric ignition. All these defenses resulted in 50,000 Japanese casualties at Port Arthur and 70,000 during the 10 battle days at Mukden [3] .

In spite of this evidence the general lesson learnt from this conflict was not one of caution, but, on the contrary, the idea of the superiority of the offensive over defense, a general attitude that according to several authors [4]   was in large part responsible for the conduct of the operations in the first months of the First World War: to give an example, in 6 weeks (August- September 1914) the attacks conducted by the French Army produced 385,000 casualties (100,000 deads)[5]. Subsequently, as is well known, the attitude changed and the 1914-18 conflict became an exhausting war of attrition with supremacy of the defense, guaranteed by the above-mentioned technologies.

Besides the continuous use of landmines to protect trenches, the First World War witnessed for the first time a large scale use of submarine mines. According to B. Liddell Hart [6], the mines at sea reproduced in naval warfare the same predominance of defensive over offensive power which was the key factor on land. A clear example of their relevance for the sea battle is offered by the battle for the Dardanelles. The relevance of Turkish Straits during the conflict was due to the fact that their control would have allowed the Allies to open communication with Russia. During the attack of a French-British fleet at Gallipoli, on March 18th 1915, the allied ships, passing in the Eren Keui bay, struck a line of mines. Out of 18 Allied ships, three were sunk and three were damaged. The consequences of this battle were memorable because, being unaware of the lack of turkish reserves of mines and ammunition after the battle, the Allied Commander de Robeck decided that the Straits could be taken only with a huge intervention by land. For 5 weeks the German and Turkish commands had time to reinforce their postion in the Gallipoli peninsula. When landing at Gallipoli was finally performed, surprise was lost. The British troops remained blocked in a costly war of attrition for several months until their evacuation occurred between December 18th, 1915 and January 8th, 1916.

Mines were also essential part of the German naval strategy and their threat was the main responsible of the lack of any decisive action from the superior British fleet against the German navy [7] . They were also extremely effective as antisubmarine weapons: the German war loss totalled 199 submarines, of which 175 fell victims to the British navy. And of the various weapons, the mine claimed forty-two and the depth-charge thirty-one submarines[8].

Sea-based and land-based mines played an important role also during World War II. Already in the first months of war (September-October 1939) losses by magnetic sea-based mines were severe and amounted to 56,000 tons, mostly merchant ships approaching the British harbours (subsequently the effectiveness of magnetic mines decreased when a system of demagnetising ships ( degaussing) was adopted [9]) ; a significant proportion of the war effort was devoted to combating naval mines; the peak figure, reached in June 1944 was of nearly 60,000 employed in mine-sweeping [9].

During the Second World War two important developments took place in landmine warfare; the first one was the development of the anti-tank mine and the second was the introduction of antipersonnel mines (APMs), usually employed agains infantry and to protect antitank mines from mine detection and removal. Some of the present antitank are derived from antitank mines of the Second World War; for example, the TMM1, produced by Yugoslavia, and the PT Mi-Ba, produced by Czech Republic and Slovakia derive from the German antitank Tellermine 43 and 42. As to the APMs, some of the models introduced during the Second World War, with some modifications, are still in service, e.g. the Russian Anti-Personnel mine POMZ (and the later model POMZ-2M) which is a stake mine consisting of a wooden stake with a cast-iron fragmentation body [10]. Another Russian APM is the wooden PDM-6 (and its successor PDM-7, PDM-7ts, PDM-57) used during the Russo-Finnish war of 1939-40 or the the bounding mine OZM (fragmentation obstacle APM), consisting of an artillery shell or a mortar bomb buried in the ground, nose down [10].

After the Second World War, as documented elsewhere in this Conference, the main evolutionary trend has been one of miniaturization and of substitution of metallic parts with plastic. For example the Russian APM PFM-1 and PFM-1S, first used during the Israeli-Syrian conflict of October 1973 and massively by Soviet troops in Afghanistan (where is named 'Green Parrot') is a small air-delivered plastic weapon with a low metallic signature, whose weight is around 70 g. Other very common APMs with low metallic content are the Type-72 series (China), encountered throughout South-east Asia and the PMN (Russia) present in Asia (Afghanistan, China, Irak, Vietnam) and in southern Africa, where is known as the "Black Widow".

2. Trends in landmine warfare

The future factors that will shape the landmine warfare are related to the developments in warfare that are already visible. The following developments in landmine technology can be foreseen [10]:

1) Incorporation of self-destruct devices to meet possible future international legal obligations.
2) Integration with intelligent battlefield.
3) Decreasing role of the tank in comparison to the helicopter.
4) Decreasing manpower in the armies, which will increase the role of minefields for local protection.

Let us comment on these trends and their significance for future technological developments.

1) A built in self destruct device will be probably necessary in the future to meet the requirements of the Geneva Convention. Technology of self destructing devices is in fact not difficult to achieve, since a battery can be a simple way to control the mine life. The problem of costs is however open and might be a relevant obstacle to the spreading of this new standard.

There are however other options to control the time of service of the laid landmines. One of the alternative solutions is the so-called "programmable laid life" mines. This means that they should have some sophisticated electronics by which the life of the laid mine can be predetermined. In principle these mines might be recovered after the expiry of the programmed life and used again, but this option might be extremely costly. Some programmable laid life mines are presently produced, for example a nonmetallic model from the Italian company Valsella is already available.

Another electronic facility that might be introduced in mines is the so-called "switch on switch off" options. This means that these particular mines might be switched off, if necessary, to allow the passage of friendly troops. There are however serious difficulties to the realization and adoption of this innovation: high costs of production; risk of damage to the same mines when the minefield is turned off and used by friendly troops; the existence of electronic key for remote control which can become accessible by enemy. All that makes the "switch on switch off" facility not much useful from a military point of view.

2) Future minefields have to be designed as intelligent entities and landmines endowed with sensors might be used to extend the territorial control.

An example of intelligent mine is represented by the Intelligent Horizontal Mine by Naschem, a division of the Denel Group of Companies (Pty) Ltd, from South Africa. It is an anti-armour off-route fragmentation mine provided with acoustic sensors than can discriminate between wheeled and tracked vehicles, small or large. The acoustic sensors activate an infrared detection system that will indicate the approaching direction of the vehicle in a range of up to 100 m. Warheads can then be fight with the maximum effect.

A significant effort is put in developing families of scatterable mines wich can be handled by a remote delivering systems and quickly emplaced to fit changing battle situations. A monitoring of battlefields is then required and landmines can play an important role in that sense.

3) The decrease of relevance of tanks in the future battlefields will reduce relatively the role of antitank mines; conversely the role of anti-helicopter mines. The military rationale for these mines is in the fact that their presence would force helicopters to fly at higher altitudes, thus becoming subject to other air defenses. The scatterable anti-helicopter mine by Textron Defence System from USA is an example of this weapon. It is able to detect low-flying helicopter and also to distinguish friendly helicopters from enemy's ones . A model of this mine is compatible with remote control for arming and disarming the multiple explosively formed projectile (EFP) warhead.

4) A consequence of the end of the Cold War is the decrease of manpower in the armies of the largest countries. This will put a new emphasis on antipersonnel mines to protect undefended areas. Therefore, in spite of their rising unpopularity, these mines are far from obsolete, as also the recent conclusion of the Oslo Conference shows. It is likely that their importance and effectiveness will extend also to future battlefields, for example to protect vulnerable points as well as high value defence systems, e.g. anti-tank and anti-helicopter mines. It is possible that some innovation in electronics will be included to overcome legal limitations, as seen before, but this is not very likely. As a matter of fact their main advantage is represented by the low production costs that would get lost in the perspective of more sophisticated devices.

3.Trends in landmine detection: new sensors and the problem of data fusion

Several new methods to detect landmines are under study. Some of them are traditional, specialized in metallic mines (Electromagnetic Sensors) and are reviewed in a number of reports [11], [12]. Some other are new and rather sophisticated (Thermal Neutron Analysis, Ground Probing Radar, Infrared Sensors); they are reviewed elsewhere in this Conference. Here we wish to mention an old biochemical sensor (the dog) that might evolve in a very sophisticated sensor in the future.

Dogs for landmine detection

Dogs are considered so far the best detector of explosives. Their sensitivity to that kind of substances is estimated to be a factor of 10,000 higher than for a man made detector. On this consideration Mechem Consultants based their Mechem Explosives and Drugs Detection System (MEDDS). The system they developed overcomes the main problem in the use of dogs, namely the relative small period of effective work they can provide (about an hour a day). The way dogs are normally used is in the search mode, i.e. they are brought near the place where mine presence is suspected and they start searching for the source of the particular scent they have to identify. The idea underlying MEDDS method is to save dog's energies by bringing to it the source of the scent instead of using the dog in search mode. The method has been proved succesful for demining of roads . A mine resistent vehicle runs on the road with a vapour collection box endowed of chemical filters fitted on its front. Road is run along in stages of about 1 km; at each stop vapour collected from the scanned area have to be associated to that area by a physical marker or a GPS location, and a new filter is put in the collection box . Vapour collected in filters are then brought in an uncontaminated area where trained dogs start identification of explosives in the different samples. That allows to discriminate relevant sections of the roads where dogs can be used, now in search mode, for a more precise localisation of the landmine. At this stage, if the mine contains a metal part, a metal detector can be used to get the exact position. Then the mine can be digged up without exploding it to minimize damage to the road. Otherwise a fuel air charge can be used to detone it in place.

An advantage of the MEDDS method, with respect to man made detector used in roads demining, is that due to blow of wind, vapours are collected from a larger area than just the road line, and it allows detection of mines buried nearby the road. Moreover, vapours collected in chemical filters can remain on the absorbent material for up to four months. An other important and appealing feature of biochemical detection is that it detects explosives directly; for that reason it has been proved to be the more effective method for explosive charges buried without a case.

The problem of data fusion: the ILDC project

Let us finally describe in some detail, just to give an example of integration among different sensors and data fusion, the canadian project (ILDC) for landmine detector.

The main requirement for a landmine detector is a high probability of detection (PD) together with a low false alarm rate (FAR). These results should be possibly obtained in any weather and soil condition, regardless of size and type of buried mines. A further constraint is the high speed of detection. This is mandatory for military operations in intensive battlefield environment, but can be relaxed in peacekeeping operations, which allows a better performance in terms of PD and FAR. We stress here that up to date no detection tecnique has been proved to be able to operate in any environmental condition while maintaining a satisfying level of both parameters.

A significative improvement can be represented by integrated multisensor detector, where different detection tecniques are implemented and combined to get better results, partially by compensation of single detector faults. In the integrated system each detector performs a measure of a different property of mines or soil around buried mines and the detection is a result of fusion of data collected by all sensors. On this idea is based the Canadian project of integrated multisensor landmine detector which started in 1994 and is now at its conclusive stage. The aim of the Improved Landmine Detector Concept (ILDC) project, carried on by the Defence Research Establishment Suffield (DRES) laboratory, with the assistance DRE Ottawa (DREO) and DRE Valcatier (DREV), is to develop a multisensor detector for low metal content and nonmetallic mines. The system is designed to be mounted on a teleoperated vehicle and used for peacekeeping operations on roads. It consists of four different type of detectors: a forward looking infrared imager (IR), an 3m wide down-looking highly sensitive electromagnetic induction (EMI) detector, a 3m wide down-looking ground probing radar (GPR) and a thermal neutron activation (TNA) detector. Among them only the TNA detector is able to perfom direct detection of the explosive contained in mines; for this reason it is used in a last stage for eventual confirmation. The whole system is designed for detection of non metallic buried mines of medium size: protection from small anti-personnel mines is assured by a vehicle which precedes the detecting system. A consideration has to be made about nonmetallic mines and the EMI detector. Most (about 80 % ) of the nonmetallic mines, have some small metallic parts in the fuze and then can be revealed by a metal detector. The high sensitivity required to detect the small amount of metal in the fuze leads of course to a high FAR, strongly dependent on the scenario and on the terrain composition.

While the EMI detector is used to detect a property of the landmine, namely the metal component, the IR imager reveals the presence of a buried mine by measuring properties of soil around it. At the point where a mine is buried the intensity of the spectrum of infrared radiation emitted by the soil changes due to the alteration of the heat flow at the mine location and of the surface emissivity of disturbed soil. Measurements of spectrum changes (which corresponds to surface temperature changes) are taken in the 3-5 or 9-14 micrometers wavebands or both and then compared to the same measurements from undisturbed soil . Data are displayed as images and processed by a recognition algorithm for target identification to discriminate mines among the numerous phenomena that can be related to similar measured temperature differences.

The third step consists on detection by a Ground Probing Radar and is eventually followed by TNA detection for confirmation. Definitive results can be obtained by co-registration and fusion of data collected by each detector and projected in a common coordinate system. Combination of sensor information and well coordinated communication between the sensors and navigation system play a determinant role for the success of the system. The common coordinate system includes the fields of view of each detector and the position of a detection is tracked through them starting from the initial detector. Depending on the data fusion scheme, tracks corresponding to new detection from subsequent detector's field of view can be added or combined following the particular scheme. Of course there is not a unique way to combine data and a consistent part of the project was devoted to the search for an optimal data fusion method. The data fusion scheme can be a simple parallel (logical OR) or series (logical AND) combination, both with advantages and disadvantages. More complicate schemes can make use of the confidence interval of each detector. The scheduled completion date of the whole project is late Autumn 1997. Results obtained so far indicates that the design goal of 95% of PD and a FAR of 2 per km is achievable.

Footnote

[*] Physics Department and Center for Peace Research, University of Bari,
Istituto Nazionale di Fisica Nucleare, Sez. di Bari, Via Amendola 176, 70126 Bari, Italy.
E-mail: nardulli@ba.infn.it

[+] Istituto Internazionale per gli Alti Studi Scientifici, Via G. Pellegrino 19, 84019 Vietri sul Mare, Salerno, Italy.
E-mail: marangi@ba.infn.it

[1] The Encyclopaedia Britannica, 1991.

[2] Similar lessons could also be drawn from the Anglo-Boer war.

[3] M. Howard, in Makers of Modern Strategy, Princeton Univ. Press, 1986.

[4] See e.g. M. Howard, Men against fire: expectations of war in 1914, in International Security Vol. 9, n.1 (1984), p. 41; S. Van Evera, The cult of the offensive and the origins of the First World war, ibid. p. 58; J. Snyder, Civil-military relations and the cult of the offensive, 1914 and 1984, ibid. p.108.

[5] Quoted in M. Howard, Men Against Fire, cit.

[6] B. H. Liddell Hart, History of the First World War, London 1972.

[7] The only naval battle of the First World War was the Battle of Jutland (May 31st, 1916), whose value was in every sense negligible, B. H. Liddell Hart, cit. p. 291.

[8] B. H. Liddell Hart, cit. p. 310.

[9] W.S. Churchill, The Second World War, Penguin Books, 1989, pp. 174-6.

[10] C. Heyman, Trends in Land Mine Warfare, A Jane's Special Report, August 1995,

[11] Localization and Identification of AntiPersonnel Landmines, Joint Research Centre Report EUR 16329 EN (1995).

[12] N. Cufaro Petroni, G. Nardulli, Sapere, 63, no.1 (1997) p.32.