Possibilities of new magnetometric detection devices for the protection of civil and military facilities.

Capabilities of new magnetometric detection devices for the protection of civilian and military facilities..

Zvezhinsky S.S., Candidate of Technical Sciences

CAPABILITIES OF NEW MAGNETOMETRIC DETECTION MEANS FOR PROTECTING CIVIL AND MILITARY FACILITIES  

Our time dictates new tasks for detecting intruders of objects, they are caused by the changes taking place in the country, in the models of intruders, as well as in the conditions of protection, for example, the emergence of new borders with neighboring countries. The recent exhibition «Interpolitex-2005» showed that the range of TSO equipment offered for solving dual-use problems (civil and military) is expanding. In this regard, it is of interest to consider the technical capabilities of new domestic products, and in particular, stationary magnetometric detection means (MSO), designed for signal blocking of «open» extended boundaries of objects, the state border [1]. They are distinguished by a passive mode of action, camouflage (radio and visual), high noise immunity due to the direction of «action» on ferromagnetic objects, which allows, for example, the most reliable way to discriminate people and animals — the main source of interference in other means.

The main performance characteristics of the MSO are the probability of detecting an intruder P0 and the average time to false alarm Tl, which determine its signaling reliability. In accordance with international standards, the MSO must provide P0 ≥ 0.95 and Tl ≥ 720 hours; in the Russian Federation, no single standard has been developed, and manufacturers tend to overstate the main performance characteristics, especially Tl, for opportunistic reasons [2].

The functioning of the MSO is ensured in almost any soil without engineering preparation of the area, under any natural and climatic conditions (deep snow, vegetation, water flows), they are characterized by relatively low energy consumption (~ 0.5 W/km) and cost, high operational reliability, maintainability and a large length (up to 700 m) of the detection zone (DZ). They do not require technical maintenance during the service life (at least 8 years). On the other hand, passive MSO have limitations on the scope of application: 1) prepared «magnetically clean» (i.e. having removed all ferromagnets from their clothing and equipment) intruders are not detected; 2) low electromagnetic compatibility (EMC) in close proximity to industrial sources of strong current electromagnetic fields. The problem of a trained intruder is to one degree or another inherent to all security systems without exception (for example, for radio beam systems — this is an intruder crawling in the grass) and is solved by combining various detection principles and organizing several lines of security.

Despite the existing shortcomings, the need for modern MSO for signal blocking of individual state border lines and extended objects is increasing, which is due to several circumstances:

• the development of new extended borders of the Russian Federation should be carried out primarily by means of camouflaged SO in accordance with friendly relations with neighboring CIS countries, it should be accompanied by minimal engineering and landscape work, SO should be, if possible, unattended, all-weather;
• the requirement for minimum power consumption is due to the possible use of the CO in autonomous mode (with a radio channel) and the difficulties with distributing power over long borders;
• the model of a modern border violator is increasingly criminalized and is acquiring an armed, magnetized appearance;
• the use of barrier CO is often impractical for many reasons — economic (expensive), environmental (natural migrations of animals).

Ordinary unarmed intruders are detected by the MSO by ferromagnetic objects in their clothes (buttons, zippers, keys, etc.), shoes (nails, instep supports) and ammunition (glasses, cigarette case, knife, lighter, etc.). However, due to the unstable distribution of useful ferromagnetic properties — the dipole magnetic moment (on average ~ 0.03 … 0.05 Am2), their detection (P0 і 0.8) occurs at the extreme high sensitivity, therefore they are subject to the action of numerous industrial electromagnetic interference. Armed intruders, possessing a much higher magnetic moment (M ~ 0.06 … 0.6 Am2), are detected reliably (P0 і 0.95), but also with high sensitivity.

According to the magnetometric detection model [2], a vehicle with a magnetic dipole moment 20…60 dB greater than that of an armed person causes the same increase in “useful signals. By limiting the class of detection objects to only vehicles (reducing sensitivity), it is possible to provide a very high P0, realizing greater noise immunity and a wider range of application (proximity to industrial sources of interference).

At present, a new MSO Dukat has appeared on the domestic market of TSO; its preliminary and state tests have been successfully completed, and a pilot batch is planned for release in early 2006. The MSO is designed for covert detection of transport (including horse-drawn vehicles and cyclists) at approaches to important facilities, as well as for signal blocking of extended sections of the state border. Due to the rejection of universality and the use of imported components, it was possible to achieve uniquely small dimensions, ease of installation, and a low linear cost of ~ $ 7/m. The labor intensity of deploying the product for 500 m using manual labor is on average no more than 50 man-hours, and with the use of mechanization it can be reduced by an order of magnitude. The main performance characteristics of the MSO Dukat are presented in Table 1.

Table 1 — Main tactical and technical characteristics of the MSO «Dukat»

The Ducat MSO consists of 3 main parts:

• single-turn distributed sensing element (SE) based on P-274M wire, which is supplied in factory packaging, is deployed, switched and sealed at the place of use;
• electronic unit (EU), located in a sealed container, is installed in the ground at a distance of no more than 5 m from the SE;
• set of mounting parts (KMCh), which ensures reliable connection and sealing of the SE, UE, etc. at the place of use.

During the performance check, the control and indication unit is docked and then undocked to the BE. The product is docked with the data collection and processing system (DCS) using a coupling unit sealed on site. The DCS is stably operational under the following conditions:

• rain, snowfall and hail with an intensity of up to 30 mm/h;
• wind with a speed of up to 30 m/s;
• melt water, snow cover, the presence of grass cover of arbitrary height, small bushes;
• seasonal and natural migrations of any animals across the security line.

The scope of application of the MSO, including within the city limits, is limited by permissible distances to interference sources: electrified railway — 300 m; energy nodes of nuclear power plants, hydroelectric power plants, state district power plants, thermal power plants — 200 m; 110 kV power transmission lines, urban electric transport, non-electrified railway — 50 m; travel along the border and/or operation of vehicles — 10 m; 220/380 V power transmission lines — 5 m, allowing intersection of the CE line.

Reduced power consumption and output parameters determine its possible operation in autonomous mode with a radio channel SSOS. A distinctive feature of the MSO «Dukat» is the absence of adjustments (tuning), thereby overcoming the known compromise between sensitivity and noise immunity. Another advantage is high maintainability in the field, provided by the new imported technology of switching communication lines of the skoch-lok type («3M», «Rayhem»).

Compared to known products, the MSO provides increased noise immunity, high operational reliability, ease of installation, which can be mechanized, very low linear cost (~ 10 times less, for example, compared to the MSO Multiguard-2000” by Galdor/Secotec) and weight and dimensions. However, the sensitivity implemented in the MSO Dukat” does not allow detecting people, even heavily armed ones.

A new idea implemented in the device is the ability to build a distributed SE structure so that it incorporates the advantages of both three-line and two-line SE [2], ensuring determination of the direction of object movement. The BE is implemented on the basis of a widely used imported AT90Mega8535 microcontroller; it is made on the structural basis of a polyethylene sealed coupling “3M”, the internal volume of which is used to accommodate electronic units and elements. The location of the BE in the ground ensures a “military” range of operating temperatures despite the use of conventional electronic components. Sealing is carried out with special seals such as raw rubber and polyurethane sealant, which make it possible to achieve both simplicity and high reliability of the product. The standard unit provides grounding (R Ј 100 Ohm), necessary for diverting currents during lightning discharges.

Figure 1 shows the Ducat MSO diagram at the site of application, where:
1 — end coupling (from the KMC composition) — end of ZO
2 — dead-end connecting coupling (from the KMC composition) — middle of ZO;
3 — P-274M wire — CE;
4 — Electronic unit (EU);
5 — Connecting cables (part of EU);
6 — Grounding source (part of EU);
7 — Interface unit (part of EU);
8 — Detachable control and indication unit;
I, II, III — parallel trenches along the security line

The “Dukat” product has the potential to transmit information about the speed of detected objects (with an accuracy of ~ 10%) and to classify them correctly with a probability of at least 0.9 according to the principle of “small” — “medium” — “large transport”. “Small” may mean a bicycle and horse-drawn transport, “medium” — a motorcycle and a passenger car, “large” — a Gazel, a truck, military equipment. The problem is that the known perimeter SSSI do not allow transmitting this tactically important information, which is necessary to increase the effectiveness of the security forces.

Figure 1 — Scheme of MSO “Dukat”

Another promising direction of development of new MSO, which may have a practical solution in the near future, is connected with detection of underwater swimmers and saboteurs in the bottom layer of water at depth, in the surf zone or along shallow water obstacles (streams, rivers, spillways), where known sonar detection systems are inoperative. The solution of such problems, connected, for example, with protection of floating important civil and military objects, is becoming more relevant.

Hydroacoustic detection systems are used to protect coastal facilities from the water side at a depth of at least 3-4 m (at lesser depths, due to signal reflection from the bottom, they are practically inoperative). From the land side, at a distance of more than 10-15 m from the water's edge, outside the direct action of surf waves, it is possible to use SO (camouflaged or barrier), installed respectively in the ground or on a perimeter alarm fence. To create a continuous (solid) facility security line, it is necessary to “close” two extended lines (on land and water). That is, it is necessary to ensure blocking of a local line starting at a depth of 3 m in water (in shallow water) and ending on land at a distance of 10 m from the water's edge. Depending on the relief of the bottom and the coast, the length of such a local boundary may vary, but it is unlikely that it will exceed 150…200 m.

At the same time, the choice of suitable SS is significantly limited by the fact that they must function inside and at the interface of different environments (water/soil/air) with different physical properties, under the dynamic impact of the surf, possible tides and ebbs. Therefore, such detection principles as radio engineering and infrared will, in all likelihood, be inoperative, and vibration and seismic SS will experience interference effects significantly exceeding the useful signals from intruders, which will inevitably lead to a high frequency of false alarms.

The task of signal blocking of shallow water areas and coasts from penetration of underwater saboteurs, people on small watercraft to important objects is not new in TSO. However, in the technical literature no known products with direct purpose were found, although, apparently, a similar task had to be solved in the USA, which has a large number of naval bases. Indirectly, two known foreign technical solutions can be adapted to solve this problem:

1) A fiber-optic network in water up to 10 m high, mounted on pontoons and loads along the coast, is used to protect against penetration of PD in the water column — product «F-8000» by TSS (Israel) [3]. Damage or severe deformation of a durable multimode fiber-optic SE leads to the issuance of an alarm signal. However, such a solution is expensive (~ 1000 USD/m), in addition, it provides the ability to climb over the top of the pontoon, which also needs to be blocked. In the surf zone or the water's edge, the fiber-optic network is inoperative.

2) Point-type MSO (MINIMAGID, GSQ-180) were used by the US Army in the late 1960s — early 1970s to detect armed swimmers, including those swimming in narrow canals or even ditches (up to 3…4 m wide) used to irrigate the lands of South Vietnam [4]. Detection of PD was carried out based on the presence of automatic weapons (machine gun, machine gun) and other ferromagnetic objects on the saboteurs.

The fundamental differences of the new task are as follows:

• the size of the ZO (shallow water can extend up to 100 m or more);
• the presence of a non-standard “magnetic mass” on the intruder (scuba gear, mine);
• the presence of an interference source — aquatic disturbances that can reach 3 points (it is considered that with greater disturbances it is difficult to move), producing strong seismic, optical and other interference that limits or excludes the use of most types of CO;
• the presence of “close” sources of industrial electromagnetic interference (for example, the protected object may be a floating nuclear power plant).

The magnetometric method, as a promising method for solving problems of detecting objects in water, is mentioned quite often in technical literature [5]. In this regard, the use of a stationary MSO with a distributed induction SE for solving the above-mentioned problem is of interest. General physical conclusions, as well as experience in the development and testing of various MSO, allow us to positively evaluate such a prospect:

1) There are no physical limitations on the performance of the MSO (unlike, for example, seismology), based on recording changes in the Earth's magnetic field caused by ferromagnetics in moving intruders. The detection principle does not undergo any change in the three environments of formation and propagation of useful signals (soil, air, water) due to their diamagnetic nature.

2) Interference from the surf is mainly indirect, mechanical in nature, microscopically changing the configuration of the SE in the EMF, which reduces the influence of this main interference factor. The influence of the magnetic field of surf wave turbulence at achievable levels of signal recording can be neglected in the first approximation.

3) The impact of vibrations of the SE from the surf can be reduced by known design methods.

4) Previously conducted full-scale tests of the MSO on the sea coast showed its full functional operability and high noise immunity in storm conditions up to 4 points and wave run-up on the SE.

5) If we accept the natural model of the PD in the form of a scuba diver (armed or unarmed), swimming or walking in shallow water or along the edge of the shore, then the dipole magnetic moment, integrally characterizing his “useful” qualities, will be ~ 0.5-1.5 Am2 depending on the brand of the scuba gear and the presence of weapons. Such a relatively large value allows for reliable detection of an intruder at a distance of 2…3 m.

It is therefore not surprising that at the Interpolitex-2005 exhibition a new domestic MSO “Neptune” was announced, which carries out signal blocking of shallow and coastal areas of the coast. It is intended to create camouflaged boundaries for protecting shallow areas of the aquatic environment in order to detect violators, including underwater swimmers-saboteurs carrying ferromagnetic objects (scuba gear, machine guns, magnetic mines, etc.), as well as in the bottom layer of water at a depth of up to 100 m. Our own SSSI, designed to support several MSOs, allows us to speak not even about a means, but about the “Neptune” detection system. Its tests confirmed the performance characteristics presented in Table 1.

Table 1 — Tactical and technical characteristics of the Neptune system”

The MSO consists of a cable CE based on a sealed ship cable SMPEVG-60-27×0.5 with plastic insulation and BE. CE cables (3 pcs.) are laid on the bottom in parallel at a distance of 2 m from each other at any place of the water line. BE is installed in the ground or on the bottom. The connection of BE and SSOI (installed on the shore) is carried out via a cable line.

Fig. 2 shows a section of the security line. The Neptune MSO CHE up to 200 m long, starting from a place near the end element of the hydroacoustic “spit”, is laid on the shallow water bottom and fixed under its own weight, additionally using fastening blocks. Near the water’s edge (starting from a depth of ~ 1 m or less), in the zone of possible low tide, the CHE is buried and fixed with concrete blocks, passes along the bottom and in the ground to the point of docking with the stationary SO, blocking the land line of the object. Here it is connected to the BE, to which the communication line from the SSSOI approaches.

Fig. 2. Coastal protection line of the facility

An intruder with scuba gear or a weapon, attempting to cross the line in shallow water — by swimming or walking, on land — by crawling, walking or running (range of possible movement speeds 0.3-3 m/s), will cause a local low-frequency change in the magnetic field — a useful signal that will be registered and discriminated as an intrusion event, with the output of information to the SSIS.

Fig. 3 shows a variant of the design of the cable SE. Sealed end switching joints are connected to the mating cable using special connectors, forming a 13-turn differential distributed inductive sensor with a base of a = 2 m; at the place of use, the cables of the SE are switched with each other and with the BE.

Fig. 3. Variant of the design of the MSO «Neptune» SE

Work on the creation of the Harpun-M MSO, designed to protect the water boundaries of important facilities, has entered the final stage and should be completed in 2006. At present, there are prototypes that have successfully passed full-scale tests, including at sea.

A possible area of ​​application for the “Neptune” product is blocking relatively large water passages of important objects. With some modifications, the product can be used to block water obstacles (up to 3 m deep on the state border — rivers, streams, lakes, etc.

Literature

1. Zvezhinsky S.S., Larin A.I. Perimeter camouflaged magnetometric detection equipment //Moscow: Special Equipment, 2001. — No. 4. — Pp. 8-14.
2. Zvezhinsky S.S. The problem of choosing perimeter detection equipment //BDI, 2002. — No. 4 (44). — Pp. 36 — 41.
3. Zvezhinsky S.S. Technical features of vibration detection equipment //Security. Credibility. Information, 2004. — No. 4. — pp. 64-68; No. 5. — P. 62-68.
4. Johnson D.P. Remote sensors — not manpower //Naval Engineers Jour., 1974. — Vol.86. — 1. — P.51-60.
5. Czipott P.V., Podney W.N. Pulsed operation of a superconductive electromagnetic gradiometer //IEEE Trans. on Magnetics, 1991. — Vol.27. — No. 2 (part 4). — P. 2971-2974.
6. Information system «Equipment for special services» http://bnti.ru