Acoustic Signature of an Unmanned Air Vehicle - Exploitation for Aircraft Localisation and Parameter Estimation

Higher harmonics in the acoustic spectrogram of an unmanned air vehicle in-flight, as obtained from a ground-based microphone measurement, is shown to be useful for estimating the vehicle's altitude, speed and true engine revolutions per minute. Specifically, the Doppler-shifted frequency time histories derived from spectrogram contours are used in this estilnation approach which is based on a least mean square error fit to an instantaneous frequency model proposed in the literature. Benefits of employing higher harmonics rather than the fundamental only in the computations are brought out. The results obta ined a re satisfactory. A possible system conf igurat ion for automat ic detect ion and localisation of similar aircraft is briefly discussed here.