000			01385nam a22001577a 4500
003			OSt
005			20160715152031.0
008			160715b xxu||||| |||| 00| 0 eng d
040			_cNational Acoustic Laboratories
100			_aFranklin, Stephen
245			_aTime delay estimation of acoustic tones under low SNR conditions
520	3		_aThis paper describes a novel approach for autonomously detecting and tracking aircraft in the vicinity of an unmanned aerial vehicle (UAV). The time difference of arrival (TDOA) of acoustic tones originating from distant aircraft are correlated between spatially distributed microphone pairs located onboard the UAV. The geometry of multiple microphone pairs then allows the elevation and azimuth of the approaching aircraft to be estimated, despite the high levels of narrow- and broadband noise emanating from the engine firing sequence, propeller, airflow over the microphones and mechanical vibration. The technique enables estimation of the signal at levels 20 dB below the broadband noise floor. Potential detection ranges in excess of 1 km are demonstrated when the signal processing is combined with careful suppression of the many noise sources onboard the UAV.
773	3		_tAcoustics 2015 Hunter Valley
856			_uhttp://dspace.nal.gov.au/xmlui/bitstream/handle/123456789/413/p77.pdf?sequence=1&isAllowed=y
942			_2udc _cJOURNALS
999			_c2601 _d2601