Spatially Modulated Auditory Alerts for Aviation

The technique of spatially modulating an existing or newly created auditory alert along a virtual trajectory to improve its detection in a noisy environment is described. Threshold data from 14 participants were gathered as a function of the spatial modulation rate (0, 1.6, and 3.3 Hz) of an avionics "wind sheer" alert (two successive 300-ms square waves) against a steady-state background noise (Boeing 737-300 flight deck ambient sound). The 70.7% detection threshold for the spatially modulated alert was on average 7.8 dB lower than that for an alert without spatial modulation, with noise and signal both presented over headphones using virtual simulation techniques. The threshold for a headphone-delivered spatially modulated alert was 13.4 dB lower than that for a nonmodulated alert delivered over a single loudspeaker.