Accession Number : ADA479744


Title :   Detection of Nuclear Explosions Using Infrasound Techniques


Descriptive Note : Final rept. 14 Sep 2004-14 Sep 2007


Corporate Author : AUSTRALIAN NATIONAL UNIV CANBERRA RESEARCH SCHOOL OF EARTH SCIENCES


Personal Author(s) : Christie, D R ; Kennett, B L


Full Text : http://www.dtic.mil/dtic/tr/fulltext/u2/a479744.pdf


Report Date : 01 Dec 2007


Pagination or Media Count : 78


Abstract : The performance of typical IMS infrasound monitoring stations has been examined in detail in order to evaluate the detection capability of the global network for regional and distant nuclear explosions. Three significant problems have been identified: a) problems with the loss of higher frequency signal components in the primary monitoring passband, b) detection problems associated with a low degree of signal coherence between array elements and c) problems with high levels of wind-generated background noise. Loss of higher frequency signal components normally occurs when signal propagation is restricted to a thermospheric waveguide. This problem can often be resolved by ensuring that routine processing algorithms include a long-period passband. Coherence studies show that detection capability for regional and distant explosions may be limited by the small degree of signal correlation between array elements. This problem can be resolved by modifications to the array configuration. Wind-generated background noise is a potentially serious problem at most infrasound monitoring stations. We have developed a new wind-noise-reducing system that effectively eliminates wind-generated noise in the monitoring passband. This system is based on the use of a closed screened enclosure that mechanically degrades turbulent eddies in the atmospheric boundary layer. This system can be used as an effective, stand-alone wind-noise-reducing system that does not require the use of a pipe array.


Descriptors :   *NUCLEAR EXPLOSIONS , MONITORING , WIND , ARRAYS , FREQUENCY BANDS , CORRELATION , NOISE REDUCTION , BACKGROUND NOISE , EXPLOSIVES DETECTION , INFRASONIC RADIATION


Subject Categories : Ammunition and Explosives


Distribution Statement : APPROVED FOR PUBLIC RELEASE