Tritech International Ltd Intelligent Gyro Compass
5. Introduction
5.1 Intelligent Gyro Compass (iGC):
The Tritech intelligent gyrocompass is the core component within an integrated and flexible family of
products that provide the user with heading direction, attitude and motion data. This device finds
numerous applications as a component in underwater navigation and positioning systems, ranging
from ROV heading sensors, tooling skid positioning, heave compensation systems, construction
projects, vessel navigation etc.
As standard the iGC is supplied in a 1-atmosphere pressure housing suitable for use down to 4000
metres depth, but is available in a 6000 metre version or in a ‘surface’ housing (i.e. suitable for use
inside an existing pressure vessel or at the surface) as an option.
The iGC is based around a sophisticated set of sensors measuring acceleration, magnetic field and
rate of turn on three orthogonal axes. Data from these sensors is processed internally using state of
the art digital signal processing and advanced adaptive filtering techniques to give outputs of heading,
pitch, roll and heave acceleration. Optionally, the unit can also provide surge and sway accelerations.
In order to find applications in a wide range of areas, the output data from the iGC is selectable by the
user to match numerous industry standard formats. This allows the iGC to ‘emulate’ more expensive
or existing heading sensors and therefore provide an easy upgrade or replacement path for customers
looking for a more reliable or compact solution.
As standard, the iGC is supplied with a PC software application that gives a clear animated display of
heading, pitch, roll, turns counter, heave acceleration and iGC status. This PC programme is normally
used when the user does not have an effective heading display, for diagnostics / additional data control
or in applications where an additional display is useful to complement the existing heading display
system.
The iGC communicates with the ‘host’ system via a digital communication link, either using RS232,
RS485 or ‘Arcnet’ protocols. The data rate and output telegram format are user selectable depending
on the application. When in Arcnet mode, the iGC can co-exist with other Tritech sensors on an Arcnet
network (e.g. sonars, profilers etc.).
Power to the iGC is nominally 24V dc at 250mA, but supply voltages in the range 12V to 26V are
acceptable.
Since the iGC is based around magnetic North detecting sensors, it is sensitive to external magnetic
fields that are not produced by the earth’s magnetic field. Such fields may vary in intensity and
direction, and will affect the performance and accuracy of the iGC outputs to a greater or lesser extent,
depending on their severity.
By careful positioning of the iGC on the host system, local ‘soft iron’ magnetic errors can normally be
avoided, but external effects may produce undesirable results under certain circumstances.
There are several other members of the iGC product family that increase the functionality and
application areas of the iGC.
These are described in more detail later in this manual and comprehensively in their own Operators
Manuals, but comprise
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