AIS
Automatic Identification System (AIS) is a ship borne system capable of regularly broadcasting own ship’s unique information and continually receiving and displaying information broadcast from other vessels. All vessels and VTS operators within VHF range and equipped with an AIS transponder can continually receive and display information from other vessels. The AIS can
Anchor alarm
An alarm indicating that the vessel has deviated more than the set distance from a position.
AOR-E
Atlantic Ocean Region-West (used for Inmarsat)
AOR-W
Atlantic Ocean Region-East (used for Inmarsat)
ARPA
A maritime radar with Automatic Radar Plotting Aid (ARPA) integrated is capable to track radar targets. The system can calculate the tracked object’s course, speed, closest point of approach and time to closest point of approach, thereby knowing if there is a danger of collision with such targets.
Arrival alarm
An alarm indicating that the vessel has come within the set distance of a waypoint.
ASCII
American Standard Code for Information Interchange. A standard alphanumeric character set based on 7-bit codes.
ATIS
Automatic Transmitter Identification System is used for notification on the radio station ID to receivers when using European inland waterway (IWW) channels.
Automatic Sequencing Mode
This will automatically move one waypoint to the next when the arrivals’ perpendicular point has been detected.
Bow
The front of a vessel.
Cavitation
Air bubbles in the water which affects the echo level measured by a transducer. This is normally caused by mounting the transducer at an incorrect angle or location, or due to an obstruction on the hull in front of the transducer.
CCRP
As set by IMO regulations, a Consistent Common Reference Point (CCRP) is a location on own ship, to which all horizontal measurements, such as target range, bearing, relative course/speed, closest point of approach, or time to closest point of approach are referenced. Where multiple antennas are installed, different position offsets for each antenna in the radar system should be applied with respect to the CCRP. If you switch between scanners, the information displayed is generated allows for consistency and uniform output
CDI
Course Deviation Indicator. Information that indicates the extend you have strayed from the route intended and the direction to steer.
COG
Course Of Ground.
Constaview™
Exclusively by JRC developed and patented Constaview™ digital signal processing will gather all information by the radar and is fully processed within a few milliseconds before being displayed. This generates a smooth image rotation when sailing in Head-Up mode. After changing from Head-Up to North-Up, the new image is display without any delay caused by the scanner rotation.
CTS
Course To Steer (heading command).
Current
Sea and ocean currents – expressed in speed and direction.
Default value
Factory set default.
DGPS
This is the process of correcting inaccuracies of GPS position data from GPS satellites with accuracy enhanced by the use of transmission of differential corrections from suitably located shore-based radio beacons.
DSC
Digital Selective Calling. This is used in routine calls, safety and urgency calls, and distress calls.
Duplex
The ability of a communications channel to transmit data simultaneously in both directions.
ECDIS
Electronic Chart Display and Information System (ECDIS) is a specific form of computer-based navigation information system that complies with International Maritime Organisation (IMO) regulations. The ECDIS system displays information from electronic navigation charts (ENC) and integrates position information from the Global Positioning System (GPS) and other navigational sensors, such as radar and AIS, providing continuous position and navigational safety information.
EGC
Enhance Group Calling. EGC enables authorized information providers to broadcast international safety and commercial service messages to selected groups of ships. Two EGC services are available: SafetyNET and FleetNET.
EPIRB
Emergency Position-Indicating Radio Beacons, a portable device which can send maritime distress alerts.
FleetNET
An international commercial service, it is a subscription service, and allows shipping companies or governments to broadcast messages to selected groups of vessels.
Geodetic
Conditions for expressing position via latitude and longitude.
GMDSS
Global Maritime Distress and Safety System is an internationally agreed-upon set of safety procedures, types of equipment, and communication protocols used to increase safety and make it easier to rescue distressed ships.
GMT
Greenwich Mean Time.
GPS
Global Positioning System. Several satellites launched by the US department of defense to establish a military navigational aid system, normally available to the public.
HDG
Heading, indicating the heading of the ship’s bow.
Hull
The exterior surface of a ship
IMO
International Maritime Organization
Initialization
It can take up to 20 minutes for GPS position fixing when it is used for the first time or after a master reset has been performed. The time can be reduced by entering initialization values, such as estimated position, time and antenna height.
IOR
Indian Ocean Region (used for Inmarsat)
IPX
A standard of waterproofing. There are nine grades. (IPX4 is splash-proof and IPX6 is waterproof)
ISDN
Integrated Service Digital Network, a high capacity digital line which lets users send voice and data at 64kbit/s over one telephone line from a common network interface.
JRC
Japan Radio Company
Keel
The center of the hull, running from the bow to the stern.
LMT
Local Mean Time.
Loran C
A position-fixing system, based on chains of shore-based, low-frequency radio transmissions.
Manual sequencing mode
After the arrival alarm sounds, the operator can manually select the next waypoint.
MED
Marine Equipment Directive. This directive covers certain equipment carried and used on ships registered under the flags of European Union member states.
MMSI
Maritime Mobile Service Identity. A 9 digit MMSI number is assigned to every ship and coast station.
Navtex
A low-frequency system developed by the IMO for the broadcast and automatic reception of coastal messages by means of direct-printing telegraphy.
NMEA0183
(or NMEA for short) is a combined electrical and data specification for communication between marine electronic devices, such as echosounder, sonars, GPS receivers and many other types of instruments. It has been defined by, and is controlled by, the US-based National Marine Electronics Association.
NSK
North Stabilization Kit, a true bearing unit. The output signal of a gyro (step or synchro) will be converted to NMEA standards.
Off course alarm
An alarm indicating that the vessel has deviated more than the a set distance from a predetermined course.
Omni-directional antenna
An antenna which is capable of line-of-sight communication without requiring any pointing.
Pitch
Medial rotation, expressed in deg/sec.
POR
Pacific Ocean Region (used for Inmarsat)
Port
Left.
Position fixing
The process of deriving the current location of a vessel using GPS, DGPS or other positioning device.
RAIM
Receiver Autonomous Integrity Monitoring, a system that assesses the integrity of GPS signals in the GPS receiver, assuring higher reliability in global positioning than conventional methods.
RMS
Remote Maintenance System, a system that cost-effectively maintains performance and functionality of your onboard equipment, reducing down time and service miscarriage by failure analysis as a JRC accredited technician can remotely link onboard the vessel to inspect, analyse, resolve and/or take follow-up action for next port attendance.
Roll
This is the port and starboard balance of a ship (leaning over to one side), expressed in deg/sec.
ROT
Rate of Turn. The rate at which the ship turns, expressed in “deg/min”
Route plan
A plan that registers plural waypoints in a navigational path.
RS232
Serial data transmission standard. It is unbalanced, hence can only be used for short distance transmission.
RS422
Balanced serial transmission standard.
SafetyNET
An international safety service, which broadcasts maritime safety information, such as meteorological and hydrographic messages to all ships in certain geographical areas.
SAR
Search and Rescue.
SART
Shipboard GMDSS installations include Search and Rescue Radar Transponder (SART) devices which are used to locate a survival craft or distressed vessel. A SART transmits a encoded signal over a 9GHz band, which creates a series of dots on a rescuing ship’s radar display, providing the exact location, which allows for an immediate response for search and rescue efforts.
SBAS
Satellite Based Augmentation System is a system that supports wide-area or regional augmentation through the use of additional satellite-broadcast messages. Such systems are commonly composed of multiple ground stations, located at accurately-surveyed points. The ground stations take measurements of one or more of the GPS satellites, the satellite signals, or other environmental factors which may impact the signal received by the users.
Simplex
The ability of a communication channel to carry communication traffic in one direction only at the same time.
SOG
Speed Over Ground. This is the ship’s speed relative to the ground.
SOLAS
Safety of Life at Sea.
Spot beam
A concentrated area offering coverage within the global footprint for particular regions in the world.
SQL
A function that suppresses the audio output of a receiver in the absence of a sufficient radio signal strength.
Starboard
Right.
Stern
The rear or aft of a vessel.
Store-and-forward messaging
The protocol used by the Inmarsat C system to transfer text or data messages in data packets to receiving equipment.
STW
Speed Through Water. This is the ship’s speed relative to the water.
SVDR
Simplified Voyage Data Recorder is a data recording system designed for all vessels in order to collect data from various sensors onboard the vessels. It stores all information in an externally mounted protective storage unit. The protective storage unit is a tamper-proof unit designed to withstand the extreme shock, impact, pressure and heat, which could be associated with a marine incident (fire, explosion, collision, sinking etc).
TEF™
Developed exclusively by JRC, TEF™, allows target enhancement relative to the target size. The smaller echoes are far more enlarged, giving better on-screen identification, against comparative larger echoes, such as land mass.
Transducer
A device mounted on the transom of a vessel or through the hull. It sends and receives ultrasonic signals which determine seabed conditions and the presence of marine life.
Transom
Is the surface that forms the stern of a vessel.
UTC
Universal Time Coordinated is a high-precision atomic time standard, as used by e.g. GPS satellites. UTC does not recognize “daylight saving”. For practical purpose, UTC has the same meaning as GMT.
VDR
Voyage Data Recorder is a data recording system designed for all vessels in order to collect data from various sensors onboard the vessels. It stores all information in an externally mounted protective storage unit. The protective storage unit is a tamper-proof unit designed to withstand the extreme shock, impact, pressure and heat, which could be associated with a marine incident (fire, explosion, collision, sinking etc).
VHF
Very High Frequency.
Waypoints
Waypoints are sets of coordinates that identify a point on the globe. For the purpose of navigation, these coordinates include longitude and latitude.
XTD
Cross Track Distance.
XTE
Cross Track Error.
XTL
Cross Track Limit.
