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ISome of the many tasks
that Prospector can be used for include; underwater inspection,
debris searches, mapping, inshore construction work, ordnance
clearance, marine salvage assessment, marine biology surveys
and marine archaeology.
This simplified acoustic
system is extremely easy to use and yet brings the inshore
diver and ROV operator the same advanced Sonardyne technology
used to save time and money in most of the world's offshore
oilfield developments.Four acoustic transponders are deployed
on the seabed with surface or sub-surface floats to form
an underwater navigation network with each transponder being
deployed at one corner of a square. The positions of these
four transponders are then calibrated by sailing the vessel
briefly around the square (typically in under 20 minutes).
A Typical Prospector
System
The components of a Prospector
system are an acoustic transceiver, Surface Interface Unit
(or SCU), four transponders and Windows-based software.
A computer and Global Positioning System (GPS) receiver
are also required. All the equipment is supplied in a rugged
case for ease of transport and storage.
Transceiver
The transceiver is the
electronics module that is fitted to the diver or ROV. A
connector on one end of the unit provides power and communication
to the SIU while the other connector is used to attach the
acoustic transducer. The transducer is the part that actually
transmits and receives the acoustic signals.
The transceiver’s
transducer sends an acoustic interrogation signal to a transponder
through the water and receives an acoustic reply signal
back from the transponder. By measuring the time between
sending the interrogation and receiving the reply the transponder’s
distance can be determined
Surface Interface
Unit (SIU)
The SIU provides power
and a communications link between the transceiver and the
computer running the Prospector software. The SIU connects
to the transceiver over a long cable fitted with a waterproof
connector and to the computer using a USB link. Four additional
serial ports are included that can be used to connect to
external instruments.
Transponders
Prospector is compatible
with either Coastal or LRT transponders . These can be deployed
in a maximum water depth of 500 metres and either mounted
in fixed seabed stands or supplied with release hooks for
easy recovery on the surface.
Computer and Software
The computer running the
Prospector software connects to the SIU using a serial communications
cable. The software on the computer talks to the transceiver
via the SIU sending it commands to make it measure acoustic
ranges to transponders. The software also takes the range
measurements made by the transceiver and calculates the
position of the transceiver from them. The boat, the transponders
and a chart of the working area can be displayed on the
computer’s monitor.
Global Positioning
System (GPS) Receiver
Positions from a Global
Positioning System (GPS) receiver are used when determining
or ‘calibrating’ the positions of the transponders
just after they have been deployed. The GPS receiver is
fitted to the boat and provides position measurements in
real-world co-ordinates. The GPS receiver connects to the
SIU via a serial port.
Features
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