TY  - BOOK
AU  - Franklin, Stephen
TI  - Time delay estimation of acoustic tones under low SNR conditions
N2  - This 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
UR  - http://dspace.nal.gov.au/xmlui/bitstream/handle/123456789/413/p77.pdf?sequence=1&isAllowed=y
ER  -