Bistatic continuous active sonar processing using arrays towed from unmanned underwater vehicles

Continuous active sonar (CAS) offers the possibility to continuously illuminate targets in underwater detection scenarios. The Cooperative Antisubmarine Programme at the Centre for Maritime Research and Experimentation has developed a real-time continuous active sonar signal processing algorithm and tested it at sea during two recent sea trials. These sea trials, undertaken with partners of the Littoral Continuous Active Sonar multinational project, were conducted in littoral environments for the purpose of evaluating the effectiveness of CAS against a traditional pulse active sonar benchmark. Data collected during these sea trials have been collected on both ship-towed triplet arrays and smaller arrays deployed from AUVs. Some details of the algorithm are given and results at the beamforming, detection and tracking level are presented for both CAS and PAS for an echo repeater target. [This work was made possible by the LCAS Multi-National Joint Research Project (MN-JRP), including as Participants CMRE (NATO), DSTG (AUS), DRDC (CAN), Dstl (GBR), CSSN (ITA), FFI (NOR), DTA (NZL), and ONR (USA). Funding for CMRE was provided by the NATO Allied Command Transformation.]