Navigation Electronics and Equipment
Expert-defined terms from the Postgraduate Certificate in Marine Navigation and Nautical Technology course at LearnUNI. Free to read, free to share, paired with a professional course.
A AIS (Automatic Identification System) – a VHF‑based transponder that au… #
Related terms: VDM, S‑AIS. Example: A cargo ship broadcasting its MMSI and ETA to improve situational awareness. Challenges: Signal interference in congested ports and the need for regular firmware updates to maintain compliance with evolving standards.
AB ABR (Acoustic Beacon Receiver) – a hydroacoustic device that detects u… #
Related terms: Racon, SART. Example: A research vessel using ABR to locate a deployed acoustic tag on a marine animal. Challenges: Ambient noise and variable sound‑speed profiles affecting detection range.
AD ADCP (Acoustic Doppler Current Profiler) – an instrument that measures… #
Related terms: DVL, current meter. Example: An offshore platform monitoring tidal currents for turbine alignment. Challenges: Beam alignment errors and interference from surface waves.
AR ARPA (Automatic Radar Plotting Aids) – a computer‑based radar function… #
Related terms: Radar, CPA, R/V. Example: A ferry using ARPA to monitor crossing traffic in a narrow channel. Challenges: Target clutter, false tracks, and reliance on accurate radar calibration.
BF BF (Beamforming) – a signal‑processing technique used in sonar and rad… #
Related terms: Phased array, sonar. Example: A modern hull‑mounted sonar employing beamforming to locate underwater obstacles. Challenges: Computational load and side‑lobe interference.
BR BRG (Bearing) – the angular direction from the observer to a target, m… #
Related terms: Azimuth, heading. Example: A handheld compass giving a bearing of 045° to a lighthouse. Challenges: Magnetic deviation and sensor drift in electronic compasses.
C CHARTPLOTTER – an electronic device that displays digital nautical char… #
Related terms: ECDIS, ENC, DGNSS. Example: A coastal patrol boat using a chartplotter to navigate narrow inlets. Challenges: Chart update latency and the need for rigorous validation against paper charts.
CR CR (Compass Rose) – a graphical representation on charts or displays i… #
Related terms: Chart symbols, north arrow. Example: An ECDIS screen showing a compass rose that rotates with the vessel’s heading. Challenges: Misinterpretation when the rose is locked to true north versus magnetic north.
D DOP (Dilution of Precision) – a numeric factor that describes the geome… #
Related terms: PDOP, HDOP, GDOP. Example: A survey vessel noting a PDOP of 0.8 before commencing a high‑resolution seabed survey. Challenges: Satellite geometry changes with time, leading to fluctuating position quality.
DVL DVL (Doppler Velocity Log) – a sonar‑based instrument that measures t… #
Related terms: ADCP, speed log. Example: An offshore support ship using a DVL for precise dynamic positioning. Challenges: Bottom loss in deep water and beam‑angle errors.
E ECDIS (Electronic Chart Display and Information System) – a mandatory b… #
Related terms: ENC, S‑57, IHO. Example: A container vessel complying with IMO regulations by operating an ECDIS in the open ocean. Challenges: Data integrity, cybersecurity threats and the need for regular chart updates.
EPIRB EPIRB (Emergency Position Indicating Radio Beacon) – a satellite‑li… #
Related terms: PLB, COSPAS‑SARSAT. Example: A fishing boat automatically activating its EPIRB after a hull breach. Challenges: Battery life management and ensuring the beacon is registered with correct vessel details.
F FOG (Fiber‑Optic Gyro) – a solid‑state gyroscope that measures rotation… #
Related terms: MEMS gyro, inertial navigation. Example: A modern icebreaker employing a FOG for precise heading control in polar regions. Challenges: Sensitivity to temperature fluctuations and the need for periodic calibration.
GYO GYO (Gyrocompass) – a non‑magnetic compass that finds true north by e… #
Related terms: FOG, magnetic compass. Example: A naval frigate relying on a gyrocompass for precise heading during missile engagements. Challenges: Power consumption and the need for warm‑up time after power loss.
H HOD (Heading) – the direction in which the vessel’s bow is pointing, ex… #
Related terms: Course, track. Example: A pilot entering a heading of 270° to steer westward across a channel. Challenges: Drift caused by currents and wind, requiring frequent correction.
IBS IBS (Integrated Bridge System) – a suite of interoperable electronic… #
) that provide a unified interface for navigation and vessel control. Related terms: Bridge management system, IACS. Example: A cruise liner using an IBS to coordinate navigation, engine order and alarm management from a single console. Challenges: System interoperability, user training and redundancy planning.
IEC IEC (International Electrotechnical Commission) – the global organiza… #
Related terms: IEC 61162‑1 (NMEA 0183), IEC 61162‑2 (NMEA 2000). Example: A shipyard ensuring that a new radar complies with IEC 60945 for marine equipment. Challenges: Keeping pace with evolving technology while maintaining compliance.
J JRC (Joint Radio Communications) – a coordinated system that integrates… #
Related terms: VHF, MF, SATCOM. Example: A fleet commander using JRC to relay tactical orders to multiple vessels. Challenges: Frequency congestion and the need for robust encryption.
K KDM (Kalman Filter) – an algorithm that fuses multiple sensor inputs (G… #
Related terms: Sensor fusion, INS. Example: An autonomous surface vehicle employing a Kalman filter to smooth GNSS jitter. Challenges: Tuning filter parameters and handling sensor outages.
M MARPA (Mini‑Automatic Radar Plotting Aids) – a simplified ARPA function… #
Related terms: ARPA, radar. Example: A pleasure yacht using MARPA to monitor a nearby fishing boat. Challenges: Reduced target capacity and susceptibility to clutter.
N NMEA 0183 – a serial communication protocol for exchanging marine senso… #
g., GPS, depth, wind) using ASCII sentences; widely used for legacy equipment. Related terms: NMEA 2000, IEC 61162. Example: A chartplotter receiving $GPRMC sentences from an external GPS receiver. Challenges: Limited bandwidth and single‑talker restriction.
NB NB (Nautical Beacon) – a shore‑based radio transmitter that provides a… #
Related terms: NDB, lighthouse. Example: A vessel taking a bearing on a coastal NB to verify its position in fog. Challenges: Signal attenuation over water and interference from nearby transmitters.
O OBS (Obstruction) – a charted feature such as a wreck, rock, or submerg… #
Related terms: Wreck, hazard, depth contour. Example: An AIS‑enabled buoy marking a newly discovered shoal as an OBS. Challenges: Accurate survey and timely chart update.
Q QZSS (Quasi‑Zenith Satellite System) – a regional augmentation satellit… #
Related terms: SBAS, GPS. Example: A vessel navigating the East China Sea using QZSS to improve GNSS reliability. Challenges: Limited footprint outside the service area and the need for compatible receivers.
R RADAR (Radio Detection and Ranging) – an active sensor that emits micro… #
Related terms: ARPA, Racon, SAR. Example: A ferry using X‑band radar to detect small craft in heavy rain. Challenges: Clutter from sea returns, rain attenuation and the necessity of regular calibration.
RACON RACON (Radar Beacon) – a transponder that, upon receiving a radar p… #
Related terms: Radar, beacon. Example: A lighthouse equipped with a RACON that appears as a Morse‑code “A” on a vessel’s radar. Challenges: Power supply reliability and maintenance in remote locations.
S SART (Search and Rescue Transponder) – a radar‑active device that, when… #
Related terms: RADAR, EPIRB. Example: A lifeboat deploying a SART after a man‑overboard incident. Challenges: Limited range and the need for proper orientation toward the interrogating radar.
SBAS SBAS (Satellite‑Based Augmentation System) – a system that improves… #
g., WAAS, EGNOS). Related terms: DGPS, RTK. Example: A coastal survey vessel using WAAS to achieve <1 m horizontal accuracy. Challenges: Dependency on satellite health and regional coverage constraints.
SEC SEC (Shipboard Electronic Chart) – a digital chart file conforming to… #
Related terms: ENC, CDM. Example: An offshore supply vessel loading the latest SEC updates before a charter. Challenges: Ensuring timely distribution and managing chart version control.
T Tidal Prediction – the process of forecasting sea‑level changes caused… #
Related terms: Tidal datum, harmonic constituents. Example: A coastal tanker checking electronic tide predictions to select a safe loading window. Challenges: Local bathymetric variations and the need for frequent updates.
U UHF (Ultra‑High Frequency) – a radio frequency band (300 MHz–3 GHz) use… #
Related terms: VHF, L‑band. Example: A vessel employing a UHF satellite terminal for high‑speed data exchange. Challenges: Atmospheric attenuation and antenna pointing accuracy.
V VHF (Very High Frequency) – the primary maritime radio band (156–162 MH… #
Related terms: AIS, VHF‑RDS. Example: A pilot transmitting a VHF call to a harbor pilotage office. Challenges: Limited range in mountainous coasts and susceptibility to interference from nearby transmitters.
W WAV (Waveform) – the shape of a transmitted or received signal in radar… #
Related terms: Pulse compression, chirp. Example: A modern hull‑mounted sonar using a linear‑frequency‑modulated WAV to improve target discrimination. Challenges: Designing optimal waveforms that balance range and resolution.
X X‑Band – a radar frequency range (8–12 GHz) offering high resolution an… #
Related terms: Radar, Ka‑band. Example: A pilot boat employing X‑band radar to detect small fishing vessels in congested waters. Challenges: Rain attenuation and the need for frequent antenna alignment.
Y Yaw Rate Sensor – a gyroscopic device that measures the rate of rotatio… #
Related terms: Gyro, INS. Example: An autopilot using yaw rate data to maintain a steady course during heavy seas. Challenges: Sensor drift and temperature sensitivity.