e/Active acoustics

Information
has gloss	eng: Active Acoustics is a means of measuring the range to an object and its relative size by producing a pulse of sound and measuring the time it takes for an echo to return from the object and the amplitude of the returned echo. The range is calculated as a function of the speed of sound and the time it takes for the echo to return.
lexicalization	eng: Active acoustics
instance of	c/Sound measurements