A gas sensor based on zinc oxide obtained by magnetron spraying at direct current was investigated. There are methods of deposition of zinc oxide nanostructures such as thermal evaporation, chemical vapor deposition, organometallic chemical vapor deposition, magnetron sputtering, pulsed laser deposition, and hydrothermal process. The least investigated is magnetron sputtering. To obtain films, a vacuum unit VUP-5M with an original material-saving magnetron was used. Studies into the sensitivity and speed of the gas sensor based on ZnO with respect to the target gas – ethanol of different concentrations – were carried out. The resulting experimental dependences of the sensitivity of the gas sensor on the concentration of the target gas demonstrate that with increasing concentration of the target gas, the resistance decreased while the sensitivity of the sample increased. It was established that the change in the resistance of the test sample is proportional to the change in the concentration of the target gas. After the sensor surface becomes saturated with adsorbed molecules, the resistance no longer decreases, even if the gas concentration continues to increase. The reaction of the gas sensor to the target gas – ethanol – at concentrations above 150 ppm was almost absent. The time required to achieve the maximum response value should be lower at higher target gas concentrations. Sensitivity reaction repeatability studies were conducted to measure the resistance of a gas sensor based on ZnO in a target gas atmosphere with a concentration of 150 ppm. It was found that the gas sensor demonstrates excellent stability and consistent sensitivity reaction when re-exposed to the target gas – ethanol. It was established that the reaction time of a gas sensor based on ZnO to the target gas at each repeated exposure does not exceed 10 s. This repeatability index allows us to assert the stability of the ZnO-based gas sensor in an ethanol atmosphere under standard conditions

The work is devoted to the solution of an actual scientific task in the field of civil protection, namely, the development of a new model for the prevention of emergency situations of a terrorist nature at the objects of the critical infrastructure of Ukraine, which are protected, by means of timely detection and identification of small unmanned aerial vehicles by active optoelectronic means. Based on the analysis, it was established that one of the trends in the development of terrorist scenarios at protected critical infrastructure facilities is the use of various small manned and unmanned aerial vehicles to carry out terrorist acts. This work is a continuation of the cycle of previous works on the development of a structural and logical model for managing an emergency situation of a terrorist nature at an object of critical infrastructure of Ukraine, which is protected, caused by the appearance of small-sized aerial targets, intended for the development and constant implementation of procedures of an organizational and technical nature to ensure the safety of the object to the guarded object, when small air targets appear. A mathematical model for the detection of signals reflected from small aerial targets using active optical systems using the phenomena of light absorption and scattering in optically transparent media has been developed, which represents a system of four analytical dependencies. Further research will be directed to conducting field experiments, performed using a specially designed laboratory setup, and theoretical calculations of the value of expected target detection activities as part of numerous experiments that should prove the reliability of the results obtained in the work. Identified directions of further research regarding the presented mathematical model of detecting signals reflected from small unmanned aerial vehicles using active optical systems that use the phenomena of absorption and scattering of light in optically transparent media will be directed to conducting full-scale experiments performed using a specially developed laboratory installation and theoretical calculations of the value of expected target detection activities as part of numerous experiments, with the aim of proving the reliability of the results obtained in the work. Keywords: emergency situation, small unmanned aerial vehicle, violator, model, protected object.

The work is devoted to the solution of an actual scientific task in the field of civil protection, namely, the development of a new model for the prevention of emergency situations of a terrorist nature at the objects of the critical infrastructure of Ukraine, which are protected, by means of timely detection and identification of small unmanned aerial vehicles by active optoelectronic means. Based on the analysis, it was established that one of the trends in the development of terrorist scenarios at protected critical infrastructure facilities is the use of various small manned and unmanned aerial vehicles to carry out terrorist acts. This work is a continuation of the cycle of previous works on the development of a structural and logical model for managing an emergency situation of a terrorist nature at an object of critical infrastructure of Ukraine, which is protected, caused by the appearance of small-sized aerial targets, intended for the development and constant implementation of procedures of an organizational and technical nature to ensure the safety of the object to the guarded object, when small air targets appear. A mathematical model for the detection of signals reflected from small aerial targets using active optical systems using the phenomena of light absorption and scattering in optically transparent media has been developed, which represents a system of four analytical dependencies. Thus, the mathematical model of detecting signals reflected from small unmanned aerial vehicles using active optical systems using the phenomena of light absorption and scattering in optically transparent media is a system of four analytical dependencies. The first of them allows you to calculate the probability of detecting signals reflected from small air targets. The second determines the expected detection range. The third describes the geometric detection range. The fourth is the energy detection range of signals reflected from small unmanned aerial vehicles by optical systems. Further research will be directed to conducting field experiments, performed using a specially designed laboratory setup, and theoretical calculations of the value of expected target detection activities as part of numerous experiments that should prove the reliability of the results obtained in the work. Keywords: emergency situation, small unmanned aerial vehicle, violator, model, protected object.