Development of Models for Bat Echolocation

Theorizing about how bats sensed their environments predated the actual experimental discovery of echolocation, which in turn inspired the development of models and theories exploring the intersection of acoustics (the bat’s biosonar sounds), auditory research (reception of echoes), and signal processing. Some early models and theories of echolocation drew upon concepts from contemporaneous radar and radio communication technology. They emphasized the connection between the use of frequency-modulated sounds by bats and the development of “chirp” radar, which employed a receiver matched to the broadcast. The idea of a matched-filter receiver, which displays the cross-correlation of echoes to broadcasts, is still prominent in some modern models of echolocation. Other early models drew upon comparisons between echo processing and human perception of pitch. Modern models of echolocation strive to identify common parameters that govern the operation of radar systems, human psychoacoustics, and the behavioral performance of echolocating bats.