Striation Processing of Continuously Active Sonar Data
The Journal of the Acoustical Society of America
Previous work by the authors has shown that striations associated with the waveguide invariant can provide a new physics-based tracking constraint that improves tracking performance in pulsed active sonar data. A necessary pre-processing step is to isolate the target return from the direct arrival and other target echoes. Striation-based beamforming can be used as an optional pre-processing step to preserve the multipath structure in the beamformer output of a horizontal line array. Recent interest in continuously active sonar (CAS) processing has motivated research to determine how striations might be similarly exploited for tracking when the sonar is operated with a high duty cycle. In CAS signals, the direct arrival is almost always overlapping in time with the target echo return and the standard time-gating technique cannot isolate the echo return. In this paper, a time-dependent filter is introduced to isolate and extract the CAS echo spectrum. The conditions in which striation-based beamforming should be applied to preserve the striation structure in the beam output are also explored. The physics-based signal processing algorithms discussed here are expected to provide valuable information about the target’s multipath structure, which can be exploited in an extended Kalman filter for enhanced tracker performance.
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Scott Schecklman and Lisa M. Zurk (2015). Striation Processing of Continuously Active Sonar Data. The Journal of the Acoustical Society of America, 137:4, 2438-2438.