Long-Range High Coverage Rate Synthetic Aperture Sonar for ASW and MCM Phase I: SAS Validation Experiments

摘要

In October 2003, Dynamics Technology, Inc. (DTI) and L-3 Communications Ocean Systems (L-3OS) took the L-3OS Seahawk 1.4 kHz variable depth sonar with twin-line receive array to sea and collected active sonar data against the Ex-USS Salmon (SS-573, diesel submarine) and M/S Bidevind (freighter sunk by torpedo) off the NJ/NY coast. DTI processed the data as synthetic aperture sonar (SAS) imagery. The limits of effective SAS processing were set by array motion and not by characteristics of the environment. Image resolutions for the Ex-USS Salmon of 6.5 m at 500 m range, 12 m at 4500 m range, and 13 m at 8000 m range were achieved. For the Bidevind our resolutions were 5 m at 500 m and 9 m at 4000 m. The system characteristics afforded us the opportunity to provide SAS imagery from multiple aspects. This imagery demonstrated potential classification clues for distinguishing targets from clutter. The data set collected against the Salmon is the most complete set to date against a submarine in terms of data at multiple aspects and multiple ranges in an uncluttered environment; it is an ideal data set for developing an automatic target recognition system (classifier). Additionally, the SAS images were processed to investigate frequency responses of the Ex-USS Salmon and Bidevind. Despite the small, 400 Hz bandwidth, there were indications that this could be a useful classification tool.