Array processing for direction of arrival of infrasound,
- R. D. Costley, W. G. Frazier, Dillion, K.D
- J. Acoust. Soc. Am.,
Microbarometers have conventionally been used to detect infrasound. Pipe arrays, used in conjunction with microbarometers, provide noise reduction by averaging wind noise over a large aperture. In recent years, distributed arrays have been used for the same effect. In addition to reducing wind noise via spatial averaging, these arrays have the ability to process the individual signals from each sensor to estimate the Direction of Travel (DOT) of acoustic signals. This is especially true for infrasound and low-frequency acoustic sources of tactical interest in the 1 to 100 Hz range. The work described herein discusses the application of a frequency-wave number (F-K) signal processing technique to signals from rectangular infrasound arrays for detection and estimation of DOT of infrasound. Arrays of 100 sensors were arranged in square configurations with the sensor spacing of 2 m. Wind noise data were collected at one site. Synthetic infrasound signals were superposed on top of the wind noise to determine the accuracy and sensitivity of the technique with respect to signal-to-noise ratio. The technique was then applied to an impulsive event recorded at a different site. Preliminary results demonstrated the feasibility of this approach. Permission to publish was granted by Director, Geotechnical and Structures Laboratory.