A.V. Avraamov - Research Scientist, LTD «Special Technological Center» (St. Petersburg). E-mail: avraamov@stc-spb.ru V.Je. Asming - Ph.D. (Phys.-Math.), Leading Research Scientist, Kola Branch of Geophysical Service RAS (Apatity, Murmansk region). E-mail: asmingve@mail.ru Yu.A. Vinogradov - Ph.D. (Eng.), Deputy Director on Scientific Work, Kola Branch of Geophysical Service RAS (Apatity, Murmansk region). E-mail: uavin@mail.ru N.N. Voronin - Ph.D. (Eng.), Associate Professor, Research Scientist, LTD «Special Technological Center» (St. Petersburg). E-mail: voronin_nn@mail.ru Yu.L. Hohlenko - Ph.D. (Eng.), Associate Professor, Senior Research Scientist, LTD «Special Technological Center» (St. Petersburg). E-mail: xox1404@rambler.ru

Infrasound signals location methodic is discuss in this paper. There are different type of infrasound source - air and ground explosions, aircrafts, rockets and its falling fragments, bolides and other. Registration the signals are carried out by special infrasound stations. Each station concludes 3 spaced apart infrasound sensors. This station can determine 3 main options of infrasound signal - arrival time, back azimuth and vertical angle. The modeling results showed that we can reach back azimuth accuracy about 1,5-2,5° if the distance between infrasound sensors is 150-200 m, the sensors coordinate measurement accuracy are ±3 m and time accuracy not less 0,01 s. For the automatic detection of an infrasound signals special software is used. The algorithm STA/LTA is used for detection, where STA - it is average signal amplitude in a short time window, LTA - it is average signal amplitude in a long time window. The ratio STA/LTA is a signal-noise ratio (SNR). The records are filtered in various ranges and after that the SNR is calculated for each channel. If the SNR big-ger than specified a correlation between all 3 channels is carried out. The signal is determined as «detected» if the correlation is high. The 3 options - arrival time, back azimuth and vertical angle - are determined on each infrasound station as result. Comparison those options as minimum by 2 infrasound stations can determine the infrasound source location. This methodic have been tested at real rocket launches. The determining accuracy of the locations of falling rocket fragments was 190 m.

 

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