A digital programmable high resolution 200 kHz water column profiler

Acoustical instrumentation for imaging the water column has traditionally been ship mounted and configured to work in a downward looking orientation. Until recently, data acquisition for these acoustic instruments has used an analog strip chart recorder tended by an operator on board a surface vessel. With the advent of digital electronics, digital echo sounders have begun to appear. However, these instruments have followed the traditional configuration and, for the most part, have remained shipboard mounted. The past five years has seen unprecedented growth in the development of low power digital microprocessor, storage and data acquisition technologies. An acoustical 200 kHz high resolution, digital, programmable Water Column Profiler (WCP) has been developed incorporating these new technologies. The WCP offers unprecedented flexibility for the user and, except for the analog front end, is completely digital, fully programmable and is housed in a pressure case capable of bottom (upward looking), mooring or shipboard (downward looking) mounting configurations. The aluminum pressure case is capable of deployments to 200 m with connectors for telemetry and power if real time data are required. The WCP can ping at up to 2 Hz with an acoustic range resolution of 3 cm and is capable of digitizing four samples per acoustic range bin. The maximum probing depth, depending on the water column properties, is 200 m and the WCP is capable of storing data internally for up to 3 weeks at maximum ping and sampling rates. Data can be transferred realtime via a 10 Mbit/s 10Base2 Ethernet link to a surface system or local area network for viewing and/or data storage. The system can also be controlled remotely over the local area network. For self-contained autonomous in situ deployments, internally recorded data can be recovered from the WCP at very high rates to a storage system over a high speed Ethernet connection.