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IAcoustic transceivers attached
to each streamer, air gun and tailbuoy/navbuoy measure ranges
between each other and the survey vessel, enabling both
the shape of the towed array to be known and the position
of the hydrophones, relative to the vessel to be precisely
determined.
SIPS 2 is capable of handling
large, complicated arrays with a high immunity to noise
and bottom bounce. The Digital Signal Processing architecture
offers a greater range resolution and allows many more ranges
to be collected and processed in a single shot point.
An additional analogue ‘tone-burst’
modulation mode ensures reliable operation in the harshest
of acoustic environments, as created by ship’s wakes
and gun arrays. To improve the efficiency of streamer deployment
and recovery operations, SIPS 2 can be integrated with Sonardyne’s
radio frequency asset tracking system.
A Typical SIPS
2 System
A typical SIPS 2 system
comprises acoustic positioning transceivers attached to
the streamer, sources and tailbuoys, transceiver controller
rack and a computer running Windows-based software.
XSRS
XSRS’ are streamer-mounted
transceivers that measure acoustic ranges to adjacent XSRS’.
The units are battery powered and are typically spaced at
100 metre intervals within the front, middle and tail sections
of the array. A typical 6 x 8 kilometre long streamer spread,
for example, will require 42 XSRS units to derive a position
solution with range redundancy.
Each XSRS has 4 receive
channels and 1 transmit channel allowing simultaneous ranging
between transceivers and the capability to receive 4 of
60 unique digital signals. Range data is transmitted to
the vessel via the inductive coils contained within each
streamer.
Where a long battery life
is required, the Type 8005 XSRS provides users with the
option of using alkaline or lithium ‘D’ size
cells.
Sound Velocity Option
Also available within the
XSRS product range is the Acoustic Sound Velocity XSRS which
incorporates a direct reading sound speed sensor. This ‘time
of flight’ sensor provides superior accuracy and ease
of use compared to the more traditional CTD methods, particularly
in areas affected by fresh water and salt water mixing.
HGPS
The Head and Gun Positioning
System (HGPS) comprises of shock-mounted acoustic transceivers
designed to position the seismic sources and tailbuoys.
The units are able to withstand the hostile environment
around airgun and can be supplied with different transducer
arrangements to accommodate an operator’s preferred
deployment method.
RTS
Where it is not possible
to run a communications and power cable between an HGPS
or XSRS and its vessel-based controller, a Radio Telemetry
System (RTS) is available. This utilises a ruggedised marine
radio in a splashproof enclosure to telemeter range data
to the survey vessel.
Controller Rack
The Controller Rack is
a 19" rack mounted unit that provides the interface
between the in-wateracoustic devices and the user’s
PC. As the slots of the rack are not designated for a particular
board type, it can accommodate a total of 6 Controller Cards
of any
combination (XSRS or HGPS).
Each XSRS Controller Card
can support up to 4 streamers with a maximum of 30 XSRS
transceivers per streamer. Each HGPS/RTS Controller Card
can communicate and provide power to 8 transceivers
Features
:-
- Positioning capacity for up to 20 streamers
- Multiple signal modulation modes to
suit operating conditions
- High immunity to bottom and surface
bounce
- Long equipment battery life
- Proven performance and reliability
- Scalable for both small and large arrays
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