MOBILE DETECTION SYSTEMS

MOBILE DETECTION SYSTEMS WITH NON-LINEAR RADAR-DETECTORS 

Vladimir Tkach¹, 

Igor Parfentsev, PhD in Engineering Science, Assistant Professor¹, 

Stanislav Zvezhinsky, Doctor of Science, Professor²

The development of new mobile systems for automatic detection of explosive objects and radioelectronic devices is ongoing. These systems are designed for the installation on different mobile platforms (vehicles, quad-bikes, drones) and operate using non-linear radio detection principle. 

Keywords: non-linear radar-detector, microwave signal, radiated power, detection range, monitoring rate.

Non-linear radio detection method is widely used in special systems for the detection of explosive items and their electronic accessories, which may be housed in metal enclosures and in non-conducting or semi-conducting concealment environment (soil, underlying terrain etc.). Relevant items are detected by scanning the environment with microwave magnetic field at f₀  frequency (ranging from hundreds of MHz to several GHz) and the recording of secondary re-radiated signals in harmonic frequencies 2f₀, 3f₀ etc arising from the non-linearity of current-voltage curves of radio elements and metal oxides that present in target objects [1, 2]. Microwave signal of non-linear radio detectors is limited for safety reasons [3] and the direction pattern and signal frequency are optimized for the actual operating environment. Generally, non-linear detectors are operated by trained specialists, who can use characteristic properties of visualized or sound signal to determine the assumed location of the remote-controlled explosive item.

As it has already been mentioned [2, 4], a  «weak» (in both direct and indirect sense) link in the detection process is the operator himself, who sometimes needs additional heavy personal protection due to the risk of (initiated or accidental) explosion of the explosive object, which results in lower efficiency of such detection. Moreover, such protection cannot guarantee that a person does not get injuries or even lethal injuries (just remember the case, when a combat engineer died while trying to de-activate an explosive item in Moscow in July 2003). Therefore the operator has to work at relatively big (safe) distance from the assumed target object location. This results in the reduction of detection efficiency as the useful signal of non-linear radar detectors is in inverse ratio to 6…8 degree of the distance to the exposed item. Moreover as the distance grows, the direction pattern of the detector may cover "background' items, which results in background noise.

Thus there appeared a vital scientific and technical task to create a safe approach mode (for the operator) of the non-linear radar detector to the assumed explosive item location, which may be solved with the use of mobile remotely controlled device, i.e. vehicles, mini-vehicles and drones. The main challenge here is to ensure, that the relatively sensitive non-linear detector is compatible with adjacent metal elements of mobile platform, which may generate significant background noise.

ZAO “Gruppa Zashchity JUTTA” (Moscow) has launched an R&D initiative to create mobile automatic systems for remote detection of explosive items with non-linear radars manufactured by the  company, which are well recognized in Russia [4]. Fully functional pilot systems (prototypes) of three types have been created so far for the following mobile platforms:

• off-road  vehicle, Teamster type (Fig. 1);
• robotic electric quad bike, Murawey type  (Fig. 2);
• helicopter drone, Strekoza type  (Fig. 3).

Figure 1 – Teamster vehicle mounted remote control detection system

The main purpose of Teamster detection system is the screening of motor roads for possible explosive items (electronic control devices) during the escorting (security escorting) of different convoys. Features:

• high monitoring (detection) rate;
• Jamming possibility for a control signal of detected explosive items (to avoid explosion initiation), i.e. synchronous operation of the non-linear detector and radio suppressor;
• visual examination (camera) and laser tagging of the assumed explosive item location.

Main specifications of Teamster system:

• explosive item detection range - up to 30 m;
• pulse power of non-linear radar detector – 200 W;
• vehicle-carrier admissible speed without detectability deterioration, not more – 20 km/h (6 m/s).

Specifications of Teamster radio signal suppressor: operating ranges – 0.02…2.7 GHz, 5.6…5.9 GHz; noise type – barrage jamming; integral output– 90 W.

Figure 2 – Murawey robotic remote control detection system

Murawey detection system is mounted on a small robotic quad bike (Fig. 2). It is used mainly for the screening of narrow, rough and hard-to-reach routes (trailways, mountain roads), that are used by vehicle columns and people, for remote detection of explosive items. Features:

• advanced screening rate;
• co-ordinate and visual reference of assumed explosive items locations;
• provisions for the identification and diagnostics of electronic devices;
• real time transmission of screening results from the system to a remote control panel.

Main specifications of Murawey system:

• explosive item detection range - up to 10 m;
• pulse power of microwave signal of the non-linear radar detector – 2 W;
• attached equipment weight (with built-in battery) – up to 7 kg;
• admissible speed without detectability deterioration, not more –10 km/h (3 m/s).

Strekoza system is mounted on a helicopter drone (Fig. 3) and is used mainly for the preliminary terrain reconnaissance for the detection of explosive items (electronic control devices) during special activities. The system is provided with a  non-linear radar, video camera, GPS unit, radio-channel for communication. The features are as follows:

• high combat engineer reconnaissance rate;
• high positioning accuracy of assumed explosive items;
• detailed screening of terrain at very low altitude (static hovering);
• identification and diagnostics of electronic devices;
• real time transmission of screening results from the drone to a remote control panel.

Figure 3 – Strekoza drone mounted remote control detection system

Main specifications of Strekoza system:

• explosive item detection altitude (range) - up to 30 m;
• average microwave signal power of the non-linear radar detector – 0.4 W (powered by two 2 Soshine 18950 rechargeable batteries);
• attached equipment weight of accessories (with built-in battery) – up to 2 kg.

Fully functional prototypes of these systems were demonstrated  in August, 2015 at the International Mine Action Centre of the Russian Armed Forces in Nakhabino during the First International Conference on the Improvement of Approaches to Mine Actions and Protection Against Improvised Explosive Devices (Fig. 4).

Figure 4 – New detection systems demonstration at the exhibition in August, 2015

Possible directions of further development of these remote control explosive items detection systems can be as follows:

• combining different channels of explosive items detection;
• antenna systems performance improvement;
• improvement of reliability and the quality of visualization of communication channels;
• efficient application of systems for solving typical tasks faced by combat engineering units of the Russian Armed Forces and other power structures.

Conclusion

ZAO “Gruppa Zashchity JUTTA” has developed and tested prototypes of mobile remote control systems for the detection of explosive items and electronic control devices, that apply non-linear detection method and use different mobile platforms. The company would appreciate any requests of potential customers, which may assist in the improvement of products` performance and interface. Preparation for further research and development and compilation of detailed engineering documentation and pilot products manufacturing is ongoing.