Infrasound direction of arrival determination using a balloon-borne aeroseismometer.

Area of Science:

• Atmospheric acoustics
• Geophysics
• Array signal processing

Background:

• Free-floating balloons offer a novel platform for infrasound data collection.
• Current balloon technology lacks the necessary array aperture for traditional multi-sensor direction finding.
• Infrasound waves, being longitudinal, induce motion in balloons.

Purpose of the Study:

• To introduce and demonstrate aeroseismometry, a technique using balloon motion for infrasound direction finding.
• To enable sparse balloon-borne networks for acoustic source geolocation.
• To validate the aeroseismometry technique with real-world acoustic events.

Main Methods:

• Utilizing the motion of a stratospheric balloon as an aeroseismometer to record infrasound.
• Measuring the direction of arrival of acoustic waves from controlled ground chemical explosions.
• Adapting a geolocation algorithm from hydroacoustics for atmospheric acoustic source localization.

Main Results:

• Successfully measured the direction of arrival for acoustic waves from ground chemical explosions.
• Demonstrated that balloon motion in response to acoustic loading can determine signal azimuth.
• Calculated the location of acoustic sources using the aeroseismometry data and adapted algorithm.

Conclusions:

• Aeroseismometry provides a viable method for infrasound source localization using sparse balloon networks.
• This technique overcomes the limitations of traditional array-based direction finding for balloon platforms.
• The study validates the potential of aeroseismometry for geolocating atmospheric acoustic events.