User Manual: Generic Section
Section: Introduction 0-4
Revision: 00
Page
9 of 21
User Operator Terms
Term
Definition
Digital Signal Processing (DSP)
The representation of signals by a sequence of numbers or
symbols and the processing of these signals. DSP includes
subfields like: audio and speech signal processing, sonar and
radar signal processing, sensor array processing.
Dynamic Positioning System (DPS)
Automatically maintains a vessel with a constant heading, and
in a fixed position without an anchor and provides more
flexibility in operation
Dynamic Positioning reference (DP
Reference)
Several position inputs e.g. GPS receivers, taut wire sensors,
LBL, SBL or USBL acoustic positioning sensors, wind speed
indicators etc
Dynamic Positioning telegram (DP
Telegram)
The report an acoustic positioning system sends to a DP
system over a serial interface
Geodetic Co-ordinates
The position of any point on or near the earth surface is defined
by an angle of latitude and an angle of longitude.
For a point on earth P:
Latitude is defined as the angle between the normal plane at P
and the plane of the earth’s equator.
Longitude is defined as the angles between the meridians
plane through P and the defined zero meridian plane or
"Greenwich" plane.
(Ref. Geodesy, fourth edition, Bomford, Oxford, sections 2.03
and 4.10(d)).
Gyro Compass
A gyro compass is similar to a gyroscope. It is a compass that
finds true north by using an (electrically powered) fast-spinning
wheel and friction forces in order to exploit the rotation of the
Earth. Gyro compasses are widely used on ships. They have
two main advantages over magnetic compasses:
They find true north, i.e., the direction of Earth's rotational axis,
as opposed to magnetic north.
They are far less susceptible to external magnetic fields, e.g.
those created by ferrous metal in a ship's hull.
Inclinometer
An analogue device, which measures the angle of the
transponder.
Individual Interrogation Signal (IIS)
Signal used to uniquely address a transponder, based on the
transponders acoustic address.
Individual Reply Signal (IRS)
Signal used to uniquely identify a reply from a transponder.
Mobile
An object that can move freely between the seabed and the
sea surface.
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