Discrete time series analysis of en route air traffic control radar and unknown anomalous sound

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Date

2004-08-16

Authors

Kruger, Marcus Scott

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Abstract

Traditionally, en route air traffic control radar systems have provided spatial and temporal information of a particular aircraft during flight. With spectral analysis tools, a low frequency longitudinal stability and control mode, known as the phugoid, can be detected in flight path data; this establishes an additional utility of en route air traffic control radar. The method was first tested on well-documented flight test data from a Beech Aircraft Study of the V-tail Bonanza, and it showed a well defined frequency near the estimated phugoid frequency and half phugoid frequency. Similar results were found for the last flights of a Mooney Rocket 305 and a Cessna 208B Caravan. Based on the results of this study, an unstable phugoid mode may have caused these airplanes to crash. In particular, this study showed the strength of the phugoid mode increased throughout the flight of the Cessna 208B Caravan. In addition, higher order statistics were used to show the nonlinear coupling inherent in the phugoid oscillation. A surveillance camera captured a strange event outside a house in October 2003. The audio from the surveillance camera was extracted and analyzed for the spectral content. Several audible events transpired in the recording that were characterized as unknown anomalous sounds. Known natural sounds were compared to some of the unknown anomalous sounds by means of time series analysis. No definite conclusion was reached, as far as the source of the unknown sounds, but the results do suggest that the anomalous sounds do not match any of the known natural sounds

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