An Investigation of the Sources and Characteristics of the Noise Component in SeaMarc II Echo Signals.

• Main Author: Zisk, Stanley
• Other Authors: HAWAII UNIV HONOLULU SCHOOL OF OCEAN AND EARTH SCIENCE AND TECHNOLOGY
• Format: Text
• Language: English
• Published: 1996
• Subjects: Physical and Dynamic Oceanography; Recording and Playback Devices; Acoustics; *ECHOES; *REVERBERATION; *ACOUSTIC RECORDING SYSTEMS; SIGNAL PROCESSING; SIGNAL TO NOISE RATIO; SHALLOW WATER; BATHYMETRY; REPLACEMENT; MAPPING; NOISE; DEEP WATER; OCEAN BOTTOM; ACOUSTIC IMPEDANCE; DIGITAL RECORDING SYSTEMS; DEEP SCATTERING LAYERS; SEAMARC II; HAWAII MR1 MAPPING; ECHO SIGNALS; Southern Ocean
• Online Access: http://www.dtic.mil/docs/citations/ADA327339; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA327339

As is well known, the SeaMarc II towfish system was lost at sea during a scientific survey cruise in the Southern Ocean near the beginning of this project. Work was immediately begun on the design and construction of a replacement mapping system to be called HAWAII MR1. The signal processing for this system was designed based on the crude and incomplete information obtained earlier from one short series of noise measurements that had been made on SeaMarc II with experimental modifications. In the new MR1 system, the recorded signal consisted of digital, complex samples of the acoustic echo (i.e. in-phase and quadrature components, referenced to transmitter sinusoidal waveform). The entire duration of the echo signal was recorded, including the entire water column reverberation and the subsequent seafloor echoes, usually out to 70 - 80 degrees incidence angle.