Abstract:
High resolution measurements of acoustic spatial variability in shallow water (SW) and very shallow water (VSW) over a wide range of environmental conditions, were obtained using the towed vehicle described in the following abstract, 3aAO8. To obtain real-time vehicle attitude and current measurements a Doppler velocity log from EDO Corporation, Motion PAK accelerometer from Systron Donner were integrated with pitch, roll, and heading sensors to provide a real-time three-axis navigation system. Real-time data acquisition software was developed by the Naval Research Laboratory utilizing National Instruments LABView object oriented programming language to record vehicle attitude and optionally provide real-time pitch and roll corrections based upon changes in vehicle velocity. The system is designed to measure, record, and monitor up to 16 bins of current velocity between vehicle and bottom surface. Technical detail of data acquisition design, operation, and some results from a high-frequency experiment conducted during 1996 are presented.