On the furtivity of signals used in oceanic acoustic tomography experiments

In this paper, the furtivity of acoustic signals commonly used in oceanic acoustic tomography experiments is addressed. Three kinds of detectors are presented that can be used by an outsider to detect either unknown signals or signals showing the main characteristics of common tomographic signals. In the first case, the detector decision statistic is based on the signals energy, whereas in the second case it exploits either cyclostationarity properties of the signals or their time-frequency characteristics. Performance of these detectors on signals transmitted through a multipath underwater channel is studied.