We have been tracking for a while a small software which seems to be very promising now. Only available for IPhone and IPad, it is anyway the best one to be associated with an adhesive diffraction cap. 
We are undertaking some tests with it. Read first outcomes Here. Software: Theodolite Adhesive cap : Order here Some other applications can be found under Android for example.
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You can find online a series of videos captured during two acquisition campaigns, in April and August 2009.
UFO-Science explains the interest of the acoustic detection for the study of the UFO phenomenon, through an experience on the sounds perceived by an observer equipped with a microphone, located near an aircraft in landing phase.
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