Interception of bio-mimicked underwater acoustic communications

We present an interceptor for the detection of bio-mimicking Underwater Acoustic Communication (UAC). In recent years, bio-mimicking UAC is becoming a popular low probability of detection (LPD) communication method. The idea is to hide the communication by misleading the eavesdropper to classify the detected signal as a biological source and thus ignore it. Different than other LPD approaches, this allows transmission at high power since the signal can be detected by the eavesdropper. Our interceptor is based on tracking the dynamics of the source's Channel Impulse Response (CIR). In particular, assuming a real biological source moves faster and less smooth than a bio-mimicking source, we expect consecutive CIR instances of the former to be less related than that of the later. As a result, we use the cross correlation between consecutive CIRs as a detection mechanism for bio-mimicking. We test our interceptor over several motion dynamics typical for biological and man-made sources. The results show a favorable trade-off between the probability of detection and the probability of false alarm.