Аcoustic monitoring of sources of emergency situations related to the device of firearms

The method of identifying the facts of the use of various types of firearms has been improved based on the use of the average characteristic of the acoustic spectrum of a shot, by determining the characteristic frequencies with maximum amplitude values, which consists in determining the characteristic frequencies under conditions of exceeding the threshold level of amplitudes of the harmonics of the received signal, determining the energy of such a spectrum, and subtracting the energy of the reference spectrum from the energies of the experimentally obtained spectra of shots. The use of the improved method for studying the characteristics of the acoustic spectra of shots from a Makarov pistol of 9 mm caliber, a traumatic pistol "Fort-14R" and an AK-74 assault rifle of 5.45 mm caliber made it possible to identify the type of firearms by the received acoustic signal with a probability of 0.95. Based on the research results, a functional diagram of the hardware implementation of the improved method for identifying the facts of using various types of firearms by the spectral properties of the received acoustic signal has been developed. The circuit implements a median filter, bandpass filters, a block of characteristic frequencies of shots, an encoding block, a decoder block and a block of logical elements "Conjunction". The identification process consists of analyzing an 18-bit code in 6 groups of 3 digits, at the output of the processing results there is a corresponding combination of signals that determines the belonging to a certain type of weapon and / or its presence in the database of known samples. Based on the hardware implementation circuit of the improved method for identifying the facts of the use of various types of firearms by the spectral properties of the received acoustic signal, the features of the development and operation of a geographic information system for acoustic monitoring of terrorist emergencies and automated identification of facts of use in an urban area are established.