Very-Long-Distance Remote Hearing and Vibrometry

Optical returns from weakly illuminated targets would be processed by advanced techniques.

A proposed development of laserbased instrumentation systems would extend the art of laser Doppler vibrometry beyond the prior limits of laserassisted remote hearing and industrial vibrometry for detecting defects in operating mechanisms. A system according to the proposal could covertly measure vibrations of objects at distances as large as thousands of kilometers and could process the measurement data to enable recognition of vibrations characteristic of specific objects of interest, thereby enabling recognition of the objects themselves. A typical system as envisioned would be placed in orbit around the Earth for use as a means of determining whether certain objects on or under the ground are of interest as potential military targets. Terrestrial versions of these instruments designed for airborne or land- or sea-based operation could be similarly useful for military or lawenforcement purposes.