Mini-automatic Radar Plotting Aid
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Mini-automatic Radar Plotting Aid
Mini-automatic radar plotting aid (or MARPA) is a maritime radar feature for target tracking and collision avoidance. Targets must be manually selected, but are then tracked automatically, including range, bearing, target speed, target direction (course), CPA (closest point of approach), and TCPA (time of closest point of approach), safe or dangerous indication, and proximity alarm. MARPA is a more basic form of ARPA ( automatic radar plotting aid). User selected Targets are initially highlighted with a small box whilst MARPA resolves the relative motion by comparing the relative motion of the target on the screen with the true, actual motion (speed) of the tracking vessel. Once resolved the acquiring box will become either a Circle for safe targets or a triangle for dangerous targets. MARPA can indicate further information with 2 very different but similar looking vectors: True Vectors and Relative Vectors. True heading and speed of a target can be ascertained with a True Vect ...
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Marine Radar
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. They are electronic navigation instruments that use a rotating antenna to sweep a narrow beam of microwaves around the water surface surrounding the ship to the horizon, detecting targets by microwaves reflected from them, generating a picture of the ship's surroundings on a display. The X-Band and S-Band radar has different characteristics and detection capabilities compared with each other. Most merchant ships carry at least one of each type to ensure adequate target detection and response. For example, the S-band operates better in sea clutter and rain than the X-band, however, the X-band has greater definition and accuracy in clear weather. Radar is a vital navigation component for safety at sea and near the shore. It allows a 'lookout' to be maintained, being one of the approved available means ...
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Collision Avoidance In Transportation
In transportation, collision avoidance is the maintenance of systems and practices designed to prevent vehicles (such as aircraft, motor vehicles, ships, cranes and trains) from colliding with each other. They perceive the environment with sensors and prevent collisions using the data collected from the sensors. Collision avoidance is used in autonomous vehicles, aviation, trains and water transport. Examples of collision avoidance include: * Airborne collision avoidance systems for aircraft * Automatic Identification System for collision avoidance in water transport * Collision avoidance (spacecraft) * Collision avoidance system in automobiles * Positive train control * Tower Crane Anti-Collision Systems Collison avoidance requires the position of objects in its surroundings and the location of the vehicle relative to their positions. Technology Many collision avoidance systems need two things: * The position of all other vehicles * The position of the vehicle relative to ot ...
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Bearing (navigation)
In navigation, bearing or azimuth is the horizontal angle between the direction of an object and north or another object. The angle value can be specified in various angular units, such as degrees, mils, or grad. More specifically: * Absolute bearing refers to the clockwise angle between the magnetic north (''magnetic bearing'') or true north (''true bearing'') and an object. For example, an object to due east would have an absolute bearing of 90 degrees. Thus, it is the same as azimuth.U.S. Army, ''Advanced Map and Aerial Photograph Reading'', Headquarters, War Department, Washington, D.C. (17 September 1941), pp. 24-2/ref> * #Relative, Relative bearing refers to the angle between the craft's forward direction ( heading) and the location of another object. For example, an object relative bearing of 0 degrees would be immediately in front; an object relative bearing 180 degrees would be behind. Bearings can be measured in mils, points, or degrees. Thus, it is the same as ...
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Course (navigation)
In navigation, the course of a watercraft or aircraft is the cardinal direction in which the craft is to be Steering, steered. The course is to be distinguished from the ''Heading (navigation), heading'', which is the direction where the watercraft's Bow (watercraft), bow or the aircraft's Nose cone, nose is pointed. The path that a vessel follows is called a track or, in the case of aircraft, ground track (also known as ''course made good'' or ''course over the ground''). The intended track is a route. Discussion For ships and aircraft, routes are typically Great-circle distance, straight-line segments between Waypoint, waypoints. A navigator determines the ''bearing'' (the compass direction from the craft's current position) of the next waypoint. Because water currents or wind can cause a craft to drift off course, a navigator sets a ''course to steer'' that compensates for drift. The helmsman or pilot points the craft on a ''heading'' that corresponds to the course to s ...
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Raymarine
Raymarine is a manufacturer and major supplier of electronic equipment for marine use. The company targets both recreational and light commercial markets with their products, which include: *GPS Chartplotters *Marine VHF radio, VHF Radios *Digital Fishfinders / Sonar *Radar *Self-steering gear, Self-steering gear (Autohelm / Autopilot) *Satellite television *Software The Raymarine brand has been on the market for over 80 years. Within this time, their product range has included visual navigation information equipment. Their products work with performance sensors that operate along with intelligence operating systems. Raymarine has a global service network that operates in over 80 countries all over the world. Until 2005, the company manufactured the majority of its products, but then started outsourcing the production process. A year later the company declared to have completed this reorganization. The company focuses on development, marketing, sales and service. Raymarine has b ...
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Radar
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 used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain. The term ''RADAR'' was coined in 1940 by the United States Navy as an acronym for "radio detection and ranging". The term ''radar'' has since entered English and other languages as an anacronym, a common noun, losing all capitalization. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwave domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving ...
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