8 |
Introduction
Definition
Description
Autopilot
A Heading Control System.
COG (Course Over
Ground)
COG is the actual direction of progress of a vessel, between two
points, with respect to the surface of the eart
h. The vessel’s heading
may differ from the COG because of wind, tide and currents.
Course
A vessel's course is the cardinal direction along which the vessel is to
be steered. It is to be distinguished from the vessel's heading, which is
the compass direction in which the craft's bow is pointed.
Cross track distance
Perpendicular distance of the vessel from the track including direction
(negative if the vessel is left of the intended track)
Cross track error
S
ee ‘Cross track distance’
Cross-track limit
Maximum cross track distance before an alert is activated.
Curved track
Non-straight track between two straight legs.
ECDIS (Electronic Chart
Display and Information
System)
A geographic information system used for nautical navigation that
complies with IMO regulations as an alternative to paper nautical
charts.
An ECDIS displays the information from ENC or DNC and integrates
position information from position, heading and speed through water
reference systems and optionally other navigational sensors. Other
sensors which could interface with an ECDIS are radar, Navtex,
Automatic Identification Systems (AIS), and depth sounders.
Electronic Navigational
Charts
An official database created by a national hydrographic office for use
with an ECDIS.
Heading
The horizontal direction in which a vessel points or heads at any
instant, expressed in angular units from a reference direction, usually
from 000° at the reference direction clockwise through 360°.
Heading control
Control of the vessel's heading.
HCS (Heading Control
System)
A system which enables a vessel to keep a pre-set heading with
minimum operation of the vessel's steering gear, within limits related
to the vessel's manoeuvrability in conjunction with their sources of
heading information. The HCS may work together with a TCS.
A turn rate control or a turning-radius control for performing turns
may be provided.
The term HCS differentiates the automatic pilot (autopilot) from a
system designed to keep a vessel on a pre-determined track
throughout its passage, which is called TCS.
Heading Monitor System
This system monitors the actual heading sensor by an independent
second source.
Helm
A wheel or tiller by which a vessel is steered.
IEC
A non-profit, non-governmental international standards organization
that prepares and publishes International Standards for all electrical,
electronic and related technologies.
Indication
Visual display of any message to the user which may be accompanied
by a low intensity acoustic signal to gain attention.
Latitude and Longitude
The units that represent the coordinates at geographic coordinate
system.
LOG
Speed data from Water Speed Log
