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An acoustic doppler current profiler (ADCP) is a hydroacoustic current meter similar to a sonar, used to measure water current velocities over a depth range using the Doppler effect of sound waves scattered back from particles within the water column. The term ADCP is a generic term for all acoustic current profilers, although the abbreviation ...
The automatic identification system (AIS) is an automatic tracking system that uses transceivers on ships and is used by vessel traffic services (VTS). When satellites are used to receive AIS signatures, the term Satellite-AIS (S-AIS) is used. AIS information supplements marine radar, which continues to be the primary method of collision ...
A chip log consists of a wooden board attached to a line (the log-line). The log-line has a number of knots at uniform intervals. The log-line is wound on a reel so the user can easily pay it out. Over time, log construction standardized. The shape is a quarter circle, or quadrant with a radius of 5 inches (130 mm) or 6 inches (150 mm), [1] and ...
Any ships or obstructions reflect microwaves back to the antenna, displaying on the radar screen. Marine radars are X band or S band radars on ships, used to detect other ships and land hazards, to provide bearing and distance for collision avoidance and navigation at sea. [1] They are electronic navigation instruments that use a rotating ...
The AN/SPS-49 is a United States Navy two-dimensional, long range air search radar built by Raytheon that can provide contact bearing and range. It is a primary air-search radar for numerous ships in the U.S. fleet and in Spain, Poland, Taiwan aboard Oliver Hazard Perry-class frigates, Canada on its Halifax-class frigate (prior to FELEX mid-life upgrade) and New Zealand on its Anzac-class ...
Doppler Velocity Log (DVL): Some ships are equipped with sonar instruments that can measure the Doppler shift in a sound pulse generated by the ship's motion as it reflects off the ocean bottom or off particles in the water. The speed measurements from a Doppler instrument can therefore be relative to the ground, or to the water.
Doppler effect. The emitted signal toward the car is reflected back with a variation of frequency that depends on the speed away/toward the radar (160 km/h). This is only a component of the real speed (170 km/h). The Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842, is the difference ...
Radar is a system that uses radio waves to determine the distance (ranging), direction (azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method [1] used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain.