A Decision Support System to Ease Operator Overload in Multibeam Passive Sonar

Abstract

Abstract-Creating human-informative signal processing systems for the underwater acoustic environment that do not generate operator cognitive saturation and overload is a major challenge. To alleviate cognitive operator overload, we present a visual analytics methodology in which multiple beam-formed sonar returns are mapped to an optimized 2-D visual representation, which preserves the relevant data structure. This representation alerts the operator as to which beams are likely to contain anomalous information by modeling a latent distribution of information for each beam. Sonar operators therefore focus their attention only on the surprising events. In addition to the principled visualization of high-dimensional uncertain data, the system quantifies anomalous information using a Fisher Information measure. Central to this process is the novel use of both signal and noise observation modeling to characterize the sensor information. A demonstration of detecting exceptionally low signal-to-noise ratio targets embedded in real-world 33-beam passive sonar data is presented.

A Broadband Beamformer Suitable for UUV to Detect the Tones Radiated from Marine Vessels

“…The lofargram is calculated at each beam output. Then, a multi-dimensional output with time, frequency, and direction, namely “multi-beam lofargram”, is obtained [ 12 , 13 , 14 ]. For example, a target tone of 475 Hz appears constantly in the direction of 70° for 20 s. Figure 3 a shows the multi-beam lofargram in which the lofargrams of the beam output signals are arranged according to the beam angles.…”

“…At present, a convenient and effective method is to pre-form the multiple beams covering the entire viewing area, which is widely applied in a manned sonar system. The sonar operator provides an auxiliary decision to extract the target tones from the multiple beams output [ 12 , 13 , 14 ]. However, the complexity of the multi-dimensional information fusion in time-frequency-direction makes it difficult to apply the multi-beam processing in the unmanned sonar system.…”