Counteraction to explosive devices with radio fuses.
According to statistics, in the vast majority of cases, explosive devices (ED) with radio fuses (RF) were used to destroy slow-moving or stationary objects. For this purpose, moments were chosen when the target of the attack was entering or leaving the house (Likhodey, Shantsev), leaving the office or residence (Shevardnadze, Berezovsky), or the terrorist act was carried out in places of mass gathering of people (Kotlyakovskoye Cemetery, the railway station in Pyatigorsk). Cases of using such ED to destroy objects in a fast-moving car are isolated and did not lead to the desired result for the terrorists (the assassination attempts on the President of Chechnya Maskhadov and the Prime Minister of Ukraine Lazarenko).
By assessing the possible ways of constructing and using RV, the ranges of frequencies used and the transmission range of the radio control signal, it is possible to assess the possibilities of counteracting the operation of such fuses.
Counteraction to explosive devices with RV can be theoretically based on the following schemes:
• localization of the possible consequences of the explosion of a detected and identified explosive device with RV;
• complete shielding in the radio air of the receiving and executive and/or command and transmitting devices of the RV;
• disabling the receiving and executive and/or command and transmitting devices of the RV with high-power microwave radiation;
• provoking premature operation of the RV by sending a corresponding radio control signal to its receiving and executing device;
• complete radio-electronic suppression (blocking) of the receiving and executing device of the RV by exposing it to special radio signals.
Let's consider the advantages and disadvantages of each of the schemes.
The explosive device can be detected both visually and with the help of a dog or various technical means: non-linear radar or metal detector. If the range of visual identification of an uncamouflaged explosive device with a radar is limited by terrain conditions and the operator's qualifications, then the range of detection of a camouflaged (for example, placed in an opaque plastic bag) explosive device using a non-linear radar does not exceed 5 m, using a metal detector — no more than 1 m. In the case of using the specified technical means, the operator conducting the search is faced with two serious dangers:
• the terrorist’s desire to prevent the deactivation of the explosive device he has installed by sending a radio control signal to detonate it with an attempt to simultaneously destroy the operator (such cases have occurred repeatedly):
• the possibility of provoking the activation of the radioactive device by the operator when exposed to radiation from a technical device (especially a non-linear radar, the operation of which is based on the use of pulsed radiation in the microwave range).
If the explosive device has a main charge weight of more than 1 kg or a powerful fragmentation body, the operator has practically no chance of survival, even if dressed in a sapper's protective suit. In this regard, ensuring the safety of personnel when searching for explosive devices with RV and installing various types of protective structures near it to localize the possible consequences of an explosion is problematic.
There is an opinion that it is possible to block the operation of the RV receiving and executive devices by covering them with metal or metallized screens that prevent the passage of radio control signals. It should be noted that the installation of such a screen does not guarantee reliable shielding of the passage of the radio control signal due to the possibility of diffraction of radio waves, their propagation in underground utilities or nearby metal structures. Reliable shielding can only be ensured if the RV receiving and executive device is completely placed in a shielded grounded chamber, which is associated with a huge risk for the operator. The possibility of shielding the radiation of the command and transmitting device is generally problematic, since this requires finding a terrorist with this device and secretly creating a shielded chamber around him.
It is known that the action of microwave radiation with a high power flux density (about tens of milliwatts per square centimeter) can lead to irreversible disruption of the operability of electronic components (transistors, integrated circuits, etc.) due to electrical breakdown of p-n junctions. At lower microwave radiation intensity, temporary failure of these components is possible for up to tens of minutes with subsequent full or partial restoration of operability. In case of breakdown of the p-n junction in the transistor (thyristor), on the basis of which the electronic key of the actuator unit of the detonator is made, providing the transfer of an electric pulse from the current source to the electric detonator, the key opens with the corresponding initiation of the explosion of the electric detonator and the entire explosive device. If the detonators have conductive housings made of metal or metallized plastic, the possibility of microwave radiation affecting the electronic circuit is significantly reduced or completely eliminated.
It should be noted that the non-selective nature of microwave radiation can lead to damage to household and industrial electronic equipment in urban and industrial environments that fall within the radiation pattern of the emitter. In addition, to create a powerful microwave generator, it is necessary to use a narrow radiation pattern, which will require precise knowledge of the location of the microwave units.
Providing an authorized detonation of a VU with a RV is possible by sending a corresponding radio control signal to its receiving and executive device. But, considering the virtually unlimited number of possible combinations, for example, in the digital code of such a command and the corresponding time for selecting this code, such an option for countering RV as a realistic option can be excluded. A peculiar exception was made by isolated cases of RV capture at opposition bases in Afghanistan, when the grid of operating frequencies and possible code combinations of radio control signals were determined. Taking into account the information received, samples of so-called radio minesweepers were created, which made it possible to select the code of the radio control signal at specific operating frequencies and trigger the receiving and executive devices of RV with powerful high-explosive charges of explosives installed in the roadbed on the routes of military convoys. The authorized detonation of charges in this case, which were also difficult to technically detect, was justified and allowed to avoid unnecessary casualties.
Unfortunately, this method of combating RV is practically inapplicable in conditions of using RV with a large variety of operating frequencies and types of coding of radio control signals.
It is obvious that all the above options for counteracting RV are either ineffective or dangerous for the personnel searching for and neutralizing explosive devices with such a fuse. Nevertheless, work in these areas is periodically carried out in different countries of the world, so far without achieving any significant results.
The most realistic way to combat radio waves is to use special radio signals to affect its receiving and executing device, preventing the reception and processing of the radio control signal. It should be noted that this method is the main one in all countries of the world and is implemented using various types of interference generators, radio wave blockers or so-called jammers.
The essence of electronic suppression (blocking) of receiving and executive devices of the RV is to create radio interference at its operating frequency. The level of this interference at the input of the receiving and executive devices should be such that the signal/interference ratio at the moment of transmitting the radio control signal is no more than 3/1. In the ideal case, when the operating frequency of the RV is precisely known, it is possible to use a noise generator that creates targeted interference, the bandwidth of which exceeds the bandwidth of the receiving and executive device of the RV by only 1.5 — 2.0 times. Unfortunately, in practice, this parameter of the RV is unknown in the vast majority of cases and can be determined using a scanning receiver only at the moment of transmitting the radio control signal, when it is too late to implement any countermeasures.
In the simplest case, the interference generator provides for the formation of a broadband barrage interference in the range from 10 to 500 MHz (in some models — up to 1000 MHz) with a total signal power supplied to one or several antennas of 10 to 500 (1000) W. As can be seen from the values of the given parameters, the spectral density of the interference is a very small value. Considering that the passband of most receivers, including the receiving and executive devices of the RV, is, as a rule, 10 kHz, it can be assumed that the radius of reliable suppression (blocking) of the receiving and executive devices of the RV will be several meters depending on the power of the interference generator, which is confirmed by the results of full-scale tests. In this case, the interference-protected RV can be blocked, and the non-interference-protected — is brought to action. When blocking a nearby (at a distance of up to 10 m) interference-protected radioactive weapon, there is a danger of provoking and detonating it due to the complex effect of two factors:
• interference by a powerful electromagnetic field in the wires of the electric detonator of an electric potential (EMF) sufficient to trigger the electric detonator, regardless of the presence or absence of electrical contact with the power source of the detonator;
• breakdown of the p-n junction in the transistor (thyristor) of the electronic key of the detonator and closing of the electrical contact of the electric detonator to the power source (when exposed to interference in the microwave range — above 800 MHz).
Considering the above-mentioned distance between the jammer and the explosive device, it can be assumed that in the event of an explosion, the consequences for the generator itself and its operator will be quite serious.
Quite often, developers of such jammers, using interference in the range above 800 MHz, demonstrate the capabilities of their products in conditions of limited space on computers, TVs, voice recorders and microphones. Outwardly, this looks very impressive, since the normal operation of such equipment is disrupted, although it has nothing to do with counteracting the operation of real RV. Considering the operating ranges of real RV, their design schemes and the transmission range of radio control signals, it can be argued that the use of interference in the range above 800 MHz in jammers to block RV is not only ineffective, but also dangerous.
To increase the range of suppression of the receiving and executive devices of the RV, the principle of forming such a broadband barrage interference can be used, when the density of interference is not uniform across the entire range, but has increased values in individual sub-ranges, for example, in those in which the operation of the RV is most likely. But even in this case, the spectral density of interference increases insignificantly and, accordingly, the radius of suppression of the receiving and executive devices of the RV increases insignificantly.
Some models of foreign-made jammers have the ability to significantly increase the spectral density of interference by significantly narrowing the radiation range to 3.5% of the central value of the selected operating frequency fpaб (setting targeted interference). At fpa6 = 27 MHz, interference will be created in the range from 26.52 to 27.47 MHz, at fc = 160 MHz — in the range from 157.2 to 162.8 MHz. Due to such a narrowing of the radiation range and the corresponding increase in the spectral density of interference, the suppression radius of the receiving and executive devices of the RV increases significantly. However, to implement such a mode of RV suppression, precise knowledge of the operating frequency of the control radio signal is required. While this is not a problem for some countries (for example, in the vast majority of cases, a remote on/off channel for acoustic monitoring of premises with an operating frequency of 160 MHz is used as a jammer), Russia is characterized by the use of a wide variety of devices as a jammer with different operating frequencies for transmitting radio control signals. In addition, given this feature of the operation of some types of jammers, jammers with several parallel control channels with different operating frequencies have already been manufactured abroad by terrorist organizations and seized by the police. Radio control signals could be transmitted simultaneously via all channels or using a panoramic scanning receiver, which allows determining the boundaries of a narrowed jamming range, via one of the channels, guaranteed to be free of interference.
A separate issue is the harmful impact on biological objects, and above all — on humans, of electromagnetic radiation from broadband interference generators with a high level of signal power supplied to the antenna. In Russia as a whole and in the city of Moscow in particular, the State Sanitary and Epidemiological Surveillance of the Russian Federation has established very strict maximum standards for the intensity of the electromagnetic field created by electrical devices, regardless of their purpose. And this must be taken into account both when creating interference generators and when operating them.
Based on the analysis of possible schemes for constructing and using interference generators, their operating frequencies, taking into account the restrictions associated with operational safety, a family of interference blockers of the Perseus series has been developed and is being mass-produced in Russia. The operation of these devices is based on the following principles (in order of their importance):
• elimination of cases of provoking the detonation of electronic fuses, including RV, when placing the RV blocker in close proximity to the explosive device;
• the level of electromagnetic impact on biological objects should not exceed the relevant standards established by the State Sanitary and Epidemiological Surveillance of the Russian Federation for electrical equipment;
• ensuring the maximum possible radius of RV blocking, including with a high level of noise immunity;
• no damage to nearby electrical equipment for various purposes.
To implement these principles in the Perseus series of RV blockers, first of all, the ranges of interference emission are significantly narrowed and tied to the probable ranges of RV operation. In each of the Perseus series of RV blockers, the emission is created by two or more independent interference generators — channels, located in one housing, with their own antenna-feeder devices.
Each channel provides the formation of scanning (sweeping) interference within its own frequency range with values of signal amplitude, shape, pulse duration and sweep speed changing according to certain laws. Theoretical and experimental studies of the complex of these parameters, taking into account the operating features of the receiving and executive devices of the RV, made it possible to find an optimal solution that ensured the minimization of the signal power level supplied to the antenna, while significantly increasing the blocking range of the receiving and executive devices of the RV.
In addition, a positive effect was achieved by placing antennas in a certain pattern relative to each other in areas of strong mutual electromagnetic influence. Simultaneous operation of several interference generators with closely spaced antennas, due to various nonlinear effects caused by electromagnetic connections between nonlinear elements of the generator output stages, ensures the formation of intermodulation radiation and the impact of intermodulation interference on the receiving and executive device of the RV. In this case, components of various harmonics of the radiation of the interacting generators are formed, the main frequency ranges of the radiation are expanded without reducing the signal power in them. In addition, intermodulation interference, due to the nonlinearity of the amplifying devices of the first amplification stage of the receiving and executive device of the RV, ensures the formation of components of various harmonics in the reception band, which allows expanding the radius of the RV blocking zone, including interference-proof ones, by 15 — 20%, all other things being equal (experimental data).
As is known, to ensure maximum efficiency of the antenna complex, the values of the upper and lower limits of the radiation range for each channel should differ by no more than 2 — 2.5 times. An attempt to provide radiation from several jammers using one antenna-feeder device or to reduce the number of generators while simultaneously expanding the radiation range of the remaining generators leads to a sharp decrease in the efficiency of the complex. Additional connectors for the possibility of dismantling antennas do not contribute to increasing the efficiency of the jammer complex, since in this case the SWR (standing wave ratio) of the antenna-feeder device, which is a kind of efficiency factor of this part of the complex, significantly worsens.
As the experience of creating the Perseus series of RV jammers has shown, the optimal solution is to use unified channels — jammer modules with the following emission ranges guaranteed to cover the operating ranges of the RV:
• 20 — 40 MHz;
• 40 — 80 MHz;
• 110 — 260 MHz;
• 260 — 700 MHz.
The optimal value of the integral power of the signal supplied to the antenna in each channel, taking into account the requirements discussed above, should not exceed 2.9 — 3.0 W. Specific versions of the RV blockers are assembled from these modules:
with 2 modules —
“Perseus — 2M” (20 — 40 MHz and 110 — 260 MHz);
“Perseus — 2M+” (40 — 80 MHz and 260 — 700 MHz);
“Perseus -2C” (similar to the product “Perseus — 2M”); “Perseus — 2C+” (similar to the product “Perseus — 2M+”);
with 3 modules —
“Perseus -3C” (20… 40 MHz, 110 … 260 MHz and 260 … 700 MHz);
with 4 modules —
“Perseus — 4T” (20 … 40 MHz, 40 … 80 MHz, 110 … 260 MHz, 260 … 700 MHz).
Due to the formation of intermodulation interference, its range is significantly wider than the specified ranges and extends from 10 MHz to 2 GHz. In particular, the Perseus 2M RV jammer, due to the specified effect, has a significant level of interference in the range of 300 — 330 MHz. In the range above 800 MHz, the level of interference is minimally possible, which ensures a minimum probability of provoking the detonation of nearby electronic fuses and disabling electrical equipment. In addition, it provides the ability to create a communication window for using cellular communications of 850, 900 and 1800 MHz standards.
The Perseus 2M+ product is an addition to the Perseus-2M product and should be used only in conjunction with the base product if the operating frequency of the RV is unknown. A characteristic feature of the Perseus 2M and Perseus 2M+ products is the presence of two telescopic pin antennas, which, on the one hand, automatically generate a circular radiation pattern and, on the other hand, unmask the product as a RV jammer (Fig. 1).
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APPEARANCE OF THE PERSEY 2M AND PERSEY 2M+ PRODUCTS 2M+” |
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Fig. 1 |
A characteristic feature of the Perseus 2C, Perseus 2C+ and Perseus ZC products is the covert placement of ribbon-type antennas in a thickened Pilot-type attaché case from Samsonite (Fig. 2).
EXTERNAL APPEARANCE OF THE PERSEY 2C AND PERSEY ZC PRODUCTS ZS”
Fig. 2
The Perseus 2C and Perseus 2C+ products are analogs of the Perseus 2M and Perseus 2M+ products (in terms of emission ranges) with approximately equal RW blocking zones in a virtually circular zone. The Perseus 3C product is a unique combination of the Perseus -2C and Perseus 2C+ products (without the 40 — 80 MHz channel). Naturally, these products are more complex compared to RV blockers with pin antennas, which is reflected in their cost.
All the considered RV blocker options have a built-in power source in the form of a 12 V battery with a capacity of 7 A* h, which is charged using an automatic charger from a single-phase AC network of 220 V/50 Hz or from a car battery when the car is moving or parked.
The Perseus 4T RV blocker is a transport version of the Perseus series of blockers, designed for installation on cars or armored vehicles powered by the on-board network (Fig. 3). By installing four pin antennas on the roof of the vehicle, their efficiency is significantly increased, since the body of the device acts as a natural counterweight for the antennas. This, in turn, allows, with the same signal power level supplied to the antenna (no more than 2.95 W), to increase the RV blocking radius by 30 — 50% compared to portable versions. The low signal power also results in low power consumption, which explains the absence of additional generators in the power supply circuit, which are installed on the engine in foreign analogues.
APPEARANCE OF THE PRODUCT “PERSEUS — 4T”
Fig. 3
All models of the RV blockers of the “Perseus” series can be used as stationary ones when using a special network power source.
The design of the Perseus series of RV blockers also determines their preferred areas of use:
• the Perseus 2C, Perseus 2C+ and Perseus 3C products are used for escorting VIPs on foot in the event of a possible terrorist attack against them using a RV with explosive devices (the Perseus 2C+ product should only be used as an additional product to the Perseus 2C product);
• the Perseus 2M and Perseus 2M+ products are designed to ensure the safety of specialists from the sapper (explosive engineering) units of the Ministry of Internal Affairs and the Ministry of Defense when searching for and rendering harmless explosive devices in the event of their possible presence of explosives;
• the Perseus 4T product is designed to ensure the safety of a vehicle (car) in the event of possible use of explosive devices with explosives against it.
If we are talking about constant VIP support, then for the optimal solution to the problem of its protection it is necessary to consistently use the products “Perseus — ZS” (moments of entry and exit from the house or residence, participation in events such as conferences, congresses) and “Perseus — 4T” (movement by vehicle).
The conducted experimental studies and field tests have shown that the Perseus series of RV blockers do not provoke the detonation of electronic fuses when placed in close proximity to each other, with the exception of the simplest non-interference-protected RV, the activation of which from the created interference is possible at a distance of up to 150 — 200 m. In this regard, when using RV blockers, it is recommended to turn them on in an area protected from the impact of damaging factors of an explosion of a VU with non-interference-protected RV, taking into account the places of their possible installation.
The level of impact of the electromagnetic field created by the Perseus series RV blockers on biological objects does not exceed the relevant standards established by the State Sanitary and Epidemiological Surveillance of the Russian Federation for electrical equipment and valid throughout the territory of the Russian Federation, which is confirmed by the hygienic certificate of the State Sanitary and Epidemiological Surveillance of the Russian Federation.
The impact of radiation from the Perseus series RV blockers does not cause damage to nearby electrical equipment for various purposes.
The effectiveness of RV blocking is confirmed by the results of full-scale tests using various types of RV, including the most noise-resistant of those known today. In accordance with
According to test protocols, the range of radio frequency interference blocking is no less than 27 m for the Perseus 3C product and no less than 37 m for the Perseus 4T product when working with the most noise-immune radio frequency interference, the transmission of radio control signals to the receiving and executive devices of which was carried out from a distance of 100 m (Table 1). With an increase in the transmission range of radio control signals, the range of radio frequency interference blocking also increases, and according to a non-linear dependence.
Summary table of test results of the Perseus series RV blockers on RV
Table 1
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RV type |
Operating frequency, MHz | Transmitter power, W | Modulation type |
Minimum range of RV suppression, m — (“RV jammer model”) |
| 1. Based on the “Sova” car alarm system (Russia). | 26.94 | 2 | ЧТ (Fl) |
27 — (“3С”) 56 — (“2М”) 56 — (“4Т”) |
| 2. Small-scale industrial production based on radio-controlled models (Japan). Widely used by the opposition in Afghanistan in 1983-1988. | 26.99 | 5 | AT (Al) |
42 — (“ЗС”) 42 — (“2М”) 45 — (“4Т”) |
| 3. Industrial production model RS-284 developed by the University of Cambridge (Great Britain) | 156.0 | 3 | ЧМ (F3) |
27 — (“3С”) 37 — (“2М”) 37 — (“4Т”) |
| 4. SILICON, SUN-1 car alarms (possible analogues of РВ) | 300… 306 | 0.1 | ЧТ (Fl) |
70 — (“3C”) 13 — (“2M”) 75 — (“2M+”) 80 — (“4T”) |
Note:
1. The RV was considered suppressed if it did not work when at least 22 radio control signals were sent.
2. The distance between the RV receiving and executing devices and the RV command and transmitting devices was 100 m.
3. The antennas of the RV receiving and executing devices and the RV command and transmitting devices were located in such a way as to ensure the most favorable conditions for the transmission and reception of radio control signals.
4. Type of modulation (transmission type) of the signal: FT (FI) — frequency telegraphy; AT (A1) — amplitude telegraphy; FM (F3) — frequency modulation.
The possibility of significantly increasing the reduced radii of blocking the radioactive substances, for example, by increasing the signal power supplied to the antenna, is problematic for a number of reasons. Due to the nonlinear nature of the change in the electromagnetic field intensity in space, with such an increase in signal power, the field intensity in the near zone increases first of all. On the one hand, this increases the risk of provoking the detonation of electronic fuses and the failure of electrical equipment, on the other hand, it leads to an increase in the negative impact of radiation on biological objects and, first of all, on the operator and the escorted VIP. At the same time, at the far boundary of the radioactive substance blocking zone, the expansion of which was the purpose of increasing the radiation power, the intensity of the created electromagnetic field increases to a much lesser extent with a corresponding insignificant increase in the blocking radius.
In particular, when the signal power supplied to the antenna increases by 2 times (up to 6 W), the radius of the RW blocking increases by no more than 5 — 7%; when the power increases by 4 times (up to 12 W), the radius increases by no more than 8 — 10%. At the same time, the danger of provoking the detonation of the RW, the appearance of consequences of irradiation of biological objects and the failure of electrical equipment increases by tens and even hundreds of times. Thus, the path to increasing the range of RW blocking by increasing the power of the emitted signal is a dead end.
For a significant expansion of the RW blocking zone, the simultaneous use of several RW blockers, spaced at a distance of 50 — 70 m from each other, is optimal. In this case, in addition to the multiple increase in the area of the RV blocking zone corresponding to the number of blockers, additional blocking zones are formed at the junctions of circular zones due to the superposition in space of electromagnetic fields created by single blockers with a low level of intensity.
Thus, the most effective way to combat RV is to block the operation of their receiving and executive devices by exposing them to special radio signals. Some of the most advanced devices implementing this method are the RV blockers of the «Perseus» series.