Auditory signals for enhanced operator performance with hand-held mine detectors

Abstract

Selection of temporal and spectral properties of the auditory signal directly affects the listener ability to detect and recognize the signal. A properly designed auditory signal for mine detection operations should be resistant to predominantly low frequency environmental masking noises and easily heard by most users, many of whom suffer from high-frequency noise-induced hearing loss. In fact, high frequency hearing loss caused by noise exposure is the most common occupational illness in DOD as well as the USA.Regrettably, many current hand-held mine detection systems use a high-frequency pure tone or a highlyunbalanced high-pitch complex tone to alert the user to the presence of an object buried in the ground. Inability to hear the auditory signal or even small variations of the auditory signal can result in an operator failing to detect a mine, a potentially fatal operator error. Unfortunately, proper engineering of the auditory signal is not as simple as selecting another lower frequency pure tone and the use of complex stimuli may be needed. The purpose of this study was to investigate changes in detectability of a specific auditory stimulus (f=5OO Hz) as a function of the number of components (n116) added to the basic signal. Obtained data provide support to the doctrine that mine detector warning signals should be complex signals expanding over several octaves.