Specifications for the Subbottom profiler
portion of the SIS-1000:
(for more information, see Benthos,
Inc.)
Transducer: Transmit projector array; line array receiving
hydrophone; 30º conical radiation pattern
Frequency: 2kHz to 7kHz swept FM (4 KW output), synchronous with
sidescan
Resolution: 10 cm
Processing: Calibrated transmit waveform stored in ROM, matched
filter FFT digital signal processing
Scale Selection: 25 meters to 750 meters full scale
Tow Vehicle Specifications:
Depth Rating: 1000 meters
Vehicle Dimensions: 18 inches OD x 64 inches long
Weight: in air: 300lbs; in water: 170 lbs
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 Windows 95 based
Pentium machine
Saves sidescan-sonar
data via network interface or on an Exabyte 8200 tape subsystem
Will accept up
to 5 channels of data
Serial I/O ports
(i.e., for navigation)
Parallel (Centronics)
ports for printing the sidescan-sonar data
Array processor
handling the digitized sidescan-sonar signal
12 bit analog
to digital converter OR: DSP card for digital signals
The topside data acquisition computer the USGS uses to collect and store
the digital signal is the ISISTM system,
which runs under the Windows 95 operating system and is built by Triton
Elics International, Inc., Watsonville, CA using a 12-bit (72 db effective
dynamic range) A/D converter in conjunction with an array processor. ISISTM
is capable of digitizing up to four channels of information at aggregate
rates of up to 750 kHz, thus preserving the content and the dynamic range
of the sidescan-sonar signal. An installed Digital Signal Processing (DSP)
board is an alternative to handling signals digitized at the towfish (SIS-1000).
Port and starboard sidescan-sonar data are displayed in real-time on a
high-resolution color display (1280 x 1024 pixels). Telemetry from navigation
systems and the towfish, including full towfish attitude information,
is displayed in separate windows. The backup data storage media used is
8 mm Exabyte tape.
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