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Encyclopedia > Navigation
Table of geography, hydrography, and navigation, from the 1728 Cyclopaedia.
Table of geography, hydrography, and navigation, from the 1728 Cyclopaedia.

Navigation is the process of planning, recording, and controlling the movement of a craft or vehicle from one place to another.[1] The word navigate is derived from the Latin roots navis meaning "ship" and agere meaning "to move" or "to direct."[1] Different navigational techniques have evolved over the ages in different cultures, but all involve locating one's position compared to known locations or patterns. It is also used in computer science as a term related to the Internet. In its most general meaning, the term navigation refers to planning of motion. ... Image File history File linksMetadata Download high resolution version (1809x2725, 2269 KB) This article incorporates content from the 1728 Cyclopaedia, a publication in the public domain. ... Image File history File linksMetadata Download high resolution version (1809x2725, 2269 KB) This article incorporates content from the 1728 Cyclopaedia, a publication in the public domain. ... 1913 advertisement for Encyclopædia Britannica. ...

Contents

Basic concepts

Map of Earth
Longitude (λ)
Lines of longitude appear curved and vertical in this projection, but are actually halves of great circles.
Latitude (φ)
Lines of latitude appear straight and horizontal in this projection, but are actually circular with different radii. All locations with a given latitude are collectively referred to as a circle of latitude.
The equator divides the planet into a Northern Hemisphere and a Southern Hemisphere, and has a latitude of 0°.
This box: view  talk  edit

Based on a screenshot of a CIA World Factbook PDF. I cropped it, added text labels, and changed file format. ... For other uses, see Map (disambiguation). ... This article is about Earth as a planet. ... Longitude is the east-west geographic coordinate measurement most commonly utilized in cartography and global navigation. ... This article is about the geographical term. ... In astronomy, geography, geometry and related sciences and contexts, a plane is said to be horizontal at a given point if it is locally perpendicular to the gradient of the gravity field, i. ... On the Earth, a circle of latitude is an imaginary east-west circle that connects all locations with a given latitude. ... World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ... Northern hemisphere highlighted in yellow. ... southern hemisphere highlighted in yellow (Antarctica not depicted). ... Image File history File links Download high-resolution version (3630x1870, 1364 KB) Summary The original is a GIMP native XCF format (16 MB) which contains the base map with lines contained on separate layers. ...

Latitude

Further information: Latitude

The latitude of a place on the earth's surface is the angular distance north or south of the [equator].[2] Latitude is usually expressed in [degree (angle)|degrees]] (marked with °) ranging from 0° at the Equator to 90° at the North and South poles.[2] The latitude of the North Pole is 90° N, and the latitude of the South Pole is 90° S.[2] This article is about the geographical term. ... World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ... For other uses, see North Pole (disambiguation). ... For other uses, see South Pole (disambiguation). ...


Longitude

Further information: Longitude

Similar to latitude, the longitude of a place on the earth's surface is the angular distance east or west of the prime meridian or Greenwich meridian.[2] Longitude is usually expressed in degrees (marked with °) ranging from 0° at the Greenwich meridian to 180° east and west. Sydney, Australia, for example, has a longitude of about 151° east. New York City has a longitude of about 74° west. Longitude is the east-west geographic coordinate measurement most commonly utilized in cartography and global navigation. ... Location of the Prime Meridian Image:Prime Meridian. ... The Prime Meridian, Greenwich The Prime Meridian is the meridian (line of longitude) passing through the Royal Greenwich Observatory, Greenwich, England; it is the meridian at which longitude is 0 degrees. ... This article describes the unit of angle. ... This is about the city of Sydney in Australia. ... New York, New York and NYC redirect here. ...


Modern technique

Most modern navigation relies primarily on positions determined electronically by receivers collecting information from satellites. Most other modern techniques rely on crossing lines of position or LOP.[3] A line of position can refer to two different things: a line on a chart and a line between the observer and an object in real life.[4] A bearing is a measure of the direction to an object.[4] If the navigator measures the direction in real life, he can then draw the angle on a nautical chart and presume he lies on that line on the chart.[4] A position line is a line that can be identified both on a nautical chart or aeronautical chart and by observation out on the surface of the earth. ... A 1976 United States NOAA chart of part of Puerto Rico A nautical chart is a graphic representation of a maritime area and adjacent coastal regions. ...


In addition to bearings, navigators also often measure distances to objects.[3] On the chart, a distance produces a circle or arc of position.[3] Circles, arcs, and hyperbolae of positions are often referred to as lines of position.


If the navigator draws two lines of position, and they intersect he must be at that position.[3] A fix is the intersection of two or more LOPs.[3] The word fix has several possible meanings: a fix is the result of position fixing in navigation a fix is a dose of a drug taken by an addict to fix is to prepare or to repair something to fix is to fasten one object to another using adhesive or...


If only one line of position is available, this may be evaluated against the dead reckoning position to establish an estimated position.[5]


Lines (or circles) of position can be derived from a variety of sources:

  • celestial observation (actually, a short segment of the circle of equal altitude, but generally represented as a line),
  • terrestrial range (natural or man made) when two charted points are observed to be in line with each other,[6]
  • compass bearing to a charted object,
  • radar range to a charted object,
  • on certain coastlines, a depth sounding from echo sounder or hand lead line.

There are some older methods seldom used today such as "dipping a light" to calculate the geographic range from observer to lighthouse Cabin display of a commercial or oceanographic fathometer sonar A fishfinder is a type of Fathometer, both being specialized types of echo sounding systems, a type of Active SONAR. (Sounding is the measurement of water depth, a historical nautical term of very long usage. ... A sounding line or lead line is a length of thin rope with a weight, generally of lead at its end. ...


Methods of navigation have changed through history.[7] Each new method has enhanced the mariner’s ability to complete his voyage safely and expeditiously.[7] One of the most important judgments the navigator must make involves choosing the best method to use.[7] Some commonly recognized types of navigation are depicted in the table.

Modern navigation methods
Illustration Description Application
Dead reckoning or DR, in which one advances a prior position using the ship's course and speed. The new position is called a DR position. It is generally accepted that only course and speed determine the DR position. Correcting the DR position for leeway, current effects, and steering error result in an estimated position or EP. An inertial navigator develops an extremely accurate EP.[7] Used at all times.
Pilotage involves navigating in restricted waters with frequent determination of position relative to geographic and hydrographic features.[7] When within sight of land.
Celestial navigation involves reducing celestial measurements to lines of position using tables, spherical trigonometry, and almanacs. Used primarily as a backup to satellite and other electronic systems in the open ocean.[7]
Electronic navigation covers any method of position fixing using electronic means, including:
Radio navigation uses radio waves to determine position by either radio direction finding systems or hyperbolic systems, such as Decca, Omega and LORAN-C. Losing ground to GPS.
Radar navigation uses radar to determine the distance from or bearing of objects whose position is known. This process is separate from radar’s use as a collision avoidance system.[7] Primarily when within radar range of land.
Satellite navigation uses artificial earth satellite systems, such as GPS, to determine position.[7] Used in all situations.

The practice of navigation usually involves a combination of these different methodologies.[7] Dead reckoning (DR) is the process of estimating ones current position based upon a previously determined position, or fix, and advancing that position based upon measured velocity, time, heading, as well as the effect of currents or wind. ... Leeway is the lateral movement of a ship to the leeward of her course; drift. ... An inertial guidance system consists of an Inertial Measurement Unit (IMU) combined with a set of guidance algorithms and control mechanisms, allowing the path of a vehicle to be controlled according to the position determined by the inertial navigation system. ... Image File history File links SplitPointLighthouse. ... Pilotage is the use of fixed visual references on the ground or sea to guide oneself to a destination. ... Image File history File links Download high-resolution version (1024x1024, 281 KB) moon This is a stack of 10 frames taken through a 150mm Maksutov-Cassegrain telescope. ... For the episode of The West Wing, see Celestial Navigation (The West Wing). ... Spherical triangle Spherical trigonometry is a part of spherical geometry that deals with polygons (especially triangles) on the sphere and explains how to find relations between the involved angles. ... A nautical almanac is a publication describing the positions and movements of celestial bodies, including the sun, moon, planets, and 57 stars chosen for their ease of identification and wide spacing. ... Satellite navigation systems use radio time signals transmitted by satellites to enable mobile receivers on the ground to determine their exact location. ... Electronic navigation normally refers to one of two systems of navigation: Satellite Navigation: Navigation using signals from orbital satellites (such as GPS) as a reference. ... Electronic navigation normally refers to one of two systems of navigation: Satellite Navigation: Navigation using signals from orbital satellites (such as GPS) as a reference. ... Image File history File links Size of this preview: 666 × 599 pixelsFull resolution (999 × 899 pixel, file size: 186 KB, MIME type: image/jpeg) Decca Navigator Mk 12 eigenes Bild File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Radio navigation is the application of radio frequencies to determining a position on the earth. ... A radio direction finder, or RDF, is a device for finding the direction to a radio source. ... Decca Navigator Mk 12 The Decca Navigator System was a hyperbolic low frequency radio navigation system (also known as multilateration) that was first deployed during World War II when the Allied forces needed a system which could be used to achieve accurate landings. ... Omega is the name for the first truly global radionavigation system for aircraft operated by the United States of America in cooperation with six partner nations. ... LORAN (LOng RAnge Navigation) is a terrestrial navigation system using low frequency radio transmitters. ... Image File history File linksMetadata Download high-resolution version (2048x1536, 1408 KB) Description écran radar marine Licensing Source Clipper File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Radar Metadata This file contains additional information, probably added from the... Image File history File links Download high resolution version (1006x806, 110 KB) Summary Artist Interpretation of GPS satellite, image courtesy of NASA [[1]] Licensing File links The following pages link to this file: Global Positioning System ... Satellite navigation systems use radio time signals transmitted by satellites to enable mobile receivers on the ground to determine their exact location. ...


Dead reckoning

Further information: Dead reckoning
The navigator plots his 9am position, indicated b the triangle, and, using his course and speed, estimates his position at 9:30am and 10am.
The navigator plots his 9am position, indicated b the triangle, and, using his course and speed, estimates his position at 9:30am and 10am.

Dead reckoning is the process of estimating one’s present position by projecting course and speed from a known past position.[8] It is also used to predict a future position by projecting course and speed from a known present position.[8] The DR position is only an approximate position because it does not allow for the effect of leeway, current, helmsman error, compass error, or any other external influences.[8] Dead reckoning (DR) is the process of estimating ones current position based upon a previously determined position, or fix, and advancing that position based upon measured velocity, time, heading, as well as the effect of currents or wind. ...


The navigator uses dead reckoning in many ways, such as:[8]

  • to determine sunrise and sunset,
  • to predict landfall, sighting lights and arrival times,
  • to evaluate the accuracy of electronic positioning information,
  • to predict which celestial bodies will be available for future observation.

The most important use of dead reckoning is to project the position of the ship into the immediate future and avoid hazards to navigation.[8]


A prudent navigator carefully tends the DR plot, updating it when required, and uses it to evaluate external forces acting on the ship. The navigator also consults the DR plot to avoid potential navigation hazards.[8] A fix taken at each DR position will reveal the effects of current, wind, and steering error, and allow the navigator to stay on track by correcting for them.[8]


The use of DR when an Electronic Charts Display and Information System (ECDIS) is the primary plotting method will vary with the type of system. An ECDIS allows the display of the ship’s heading projected out to some future position as a function of time, the display of waypoint information, and progress toward each waypoint in turn.[8] ECDIS (Electronic Chart Display and information system) INTRODUCTION Electronic Chart (including charting systems for land or recreation use) is very broad term to describe the data, the software and the electronic system, capable of displaying chart information, which may or may not be equivalent to the paper chart required by...


Until ECDIS is proven to provide the level of safety and accuracy required, the use of a traditional DR plot on paper charts is a prudent backup, especially in restricted waters.[8]


Before the development of the lunar distance method or the marine chronometer, dead reckoning was the primary method of determining longitude available to mariners such as Christopher Columbus and John Cabot on their trans-Atlantic voyages. A marine chronometer is a timekeeper precise enough to be used as a portable time standard, used to determine longitude by means of celestial navigation. ... Longitude is the east-west geographic coordinate measurement most commonly utilized in cartography and global navigation. ... Christopher Columbus (1451 – May 20, 1506) was a navigator, colonizer, and explorer and one of the first Europeans to explore the Americas after the Vikings. ... John Cabot. ...


Piloting

Further information: Pilotage

Piloting (also called pilotage) involves navigating a vessel in restricted waters and fixing its position as precisely as possible at frequent intervals.[9] More so than in other phases of navigation, proper preparation and attention to detail are important.[9] Procedures vary from vessel to vessel, and between military, commercial, and private vessels.[9] It is the responsibility of the navigator to choose the procedures applicable to his own situation, to train the piloting team in their execution, and to ensure that duties are carried out properly.[9] Pilotage is the use of fixed visual references on the ground or sea to guide oneself to a destination. ... A navigator is the person onboard a ship responsible for the navigation of the vessel. ...


A military navigation team will nearly always consist of several people.[9] A military navigator might have bearing takers stationed at the gyro repeaters on the bridge wings for taking simultaneous bearings, while the civilian navigator must often take and plot them himself.[9] While the military navigator will have a bearing book and someone to record entries for each fix, the civilian navigator will simply plot the bearings on the chart as they are taken and not record them at all.[9]


If the ship is equipped with an ECDIS, it is reasonable for the navigator to simply monitor the progress of the ship along the chosen track, visually ensuring that the ship is proceeding as desired, checking the compass, sounder and other indicators only occasionally.[9] If a pilot is aboard, as is often the case in the most restricted of waters, his judgement can generally be relied upon explicitly, further easing the workload.[9] But should the ECDIS fail, the navigator will have to rely on his skill in the manual and time-tested procedures discussed in this chapter.[9] left|Signal flag H(Hotel) - Pilot on Board Boarding is tricky, as both vessels are moving and cannot afford to slow down. ...


Celestial navigation

Main article: Celestial navigation
A celestial fix will be at the intersection of two or more circles.
A celestial fix will be at the intersection of two or more circles.

Celestial navigation systems are based on observation of the positions of the Sun, Moon and stars. By knowing which point on the rotating earth a celestial object is currently above and measuring its height above the observer's horizon, the navigator can determine his distance from that subpoint. A Nautical almanac and a chronometer are used to compute the subpoint on earth a celestial body is over, and a sextant is used to measure the body's angular height above the horizon. That height can then be used to compute ones distance from the subpoint to create a circular line of position. A navigator shoots a number of stars in succession to give a series of overlapping lines of position. Where they intersect is his celestial fix. The moon and sun may also be used. The sun can also be used by itself to shoot a succession of lines of position (best done around local noon) to determine a position as well. [10] For the episode of The West Wing, see Celestial Navigation (The West Wing). ... Sol redirects here. ... This article is about Earths moon. ... This article is about the astronomical object. ... A nautical almanac is a publication describing the positions and movements of celestial bodies, including the sun, moon, planets, and 57 stars chosen for their ease of identification and wide spacing. ... A chronometer is a timekeeper precise enough to be used as a portable time standard, usually in order to determine longitude by means of celestial navigation. ... A sextant is a measuring instrument generally used to measure the angle of elevation of a celestial object above the horizon. ...

Marine chronometer

Further information: Marine chronometer
A traditional marine chronometer.
A traditional marine chronometer.

In order to accurately measure longitude, one must record the precise time of a sextant sighting (down to the second, if possible). Various types of chronometers are widely used. A marine chronometer is a timekeeper precise enough to be used as a portable time standard, used to determine longitude by means of celestial navigation. ... A marine chronometer is a timekeeper precise enough to be used as a portable time standard, used to determine longitude by means of celestial navigation. ...


The spring-driven marine chronometer is a precision timepiece used aboard ship to provide accurate time for celestial observations.[10] A chronometer differs from a spring-driven watch principally in that it contains a variable lever device to maintain even pressure on the mainspring, and a special balance designed to compensate for temperature variations.[10]


A spring-driven chronometer is set approximately to Greenwich mean time (GMT) and is not reset until the instrument is overhauled and cleaned, usually at three-year intervals.[10] The difference between GMT and chronometer time is carefully determined and applied as a correction to all chronometer readings.[10] Spring-driven chronometers must be wound at about the same time each day.[10] At maximum intervals of about three years, a spring-driven chronometer should be sent to a chronometer repair shop for cleaning and overhaul.[10]


Quartz crystal marine chronometers have replaced spring-driven chronometers aboard many ships because of their greater accuracy.[10] They are maintained on GMT directly from radio time signals.[10] This eliminates chronometer error and watch error corrections.[10] Should the second hand be in error by a readable amount, it can be reset electrically.[10]


The basic element for time generation is a quartz crystal oscillator.[10] The quartz crystal is temperature compensated and is hermetically sealed in an evacuated envelope.[10] A calibrated adjustment capability is provided to adjust for the aging of the crystal.[10]


The chronometer is designed to operate for a minimum of 1 year on a single set of batteries.[10] A good marine chronometer has a built-in push button battery test meter.[10] The meter face is marked to indicate when the battery should be replaced.[10] The chronometer continues to operate and keep the correct time for at least 5 minutes while the batteries are changed.[10] The chronometer is designed to accommodate the gradual voltage drop during the life of the batteries while maintaining accuracy requirements.[10]


A chronometer should not be removed from its case to time sights.[10] Observations may be timed and ship’s clocks set with a comparing watch, which is set to chronometer time and taken to the bridge wing for recording sight times.[10] In practice, a wrist watch coordinated to the nearest second with the chronometer will be adequate.[10]


A stop watch, either spring wound or digital, may also be used for celestial observations.[10] In this case, the watch is started at a known GMT by chronometer, and the elapsed time of each sight added to this to obtain GMT of the sight.[10]


All chronometers and watches should be checked regularly with a radio time signal.[10] Times and frequencies of radio time signals are listed in publications such as Radio Navigational Aids.[10]


The marine sextant

The modern marine sextant is used to measure the elevation of celestial bodies above the horizon.
The modern marine sextant is used to measure the elevation of celestial bodies above the horizon.
For more details on this topic, see Sextant.

The second critical component of modern celestial navigation is to measure the angle formed at the observer's eye between the celestial body and the sensible horizon. The sextant, a clever optical instrument, is used to perform this function. The sextant consists of two primary assemblies. The frame is a rigid triangular structure with a pivot at the top and a graduated segment of a circle, referred to as the "arc", at the bottom. The second component is the index arm, which is attached to the pivot at the top of the frame. At the bottom is an endless vernier which clamps into teeth on the bottom of the "arc". The optical system consists of two mirrors and, generally, a low power telescope. One mirror, referred to as the "index mirror" is fixed to the top of the index arm, over the pivot. As the index arm is moved, this mirror rotates, and the graduated scale on the arc indicates the measured angle ("altitude"). The second mirror, referred to as the "horizon glass", is fixed to the front of the frame. One half of the horizon glass is silvered and the other half is clear. Light from the celestial body strikes the index mirror and is reflected to the silvered portion of the horizon glass, then back to the observer's eye through the telescope. The observer manipulates the index arm so the reflected image of the body in the horizon glass is just resting on the visual horizon, seen through the clear side of the horizon glass. A sextant is a measuring instrument generally used to measure the angle of elevation of a celestial object above the horizon. ... A sextant is a measuring instrument generally used to measure the angle of elevation of a celestial object above the horizon. ...


Adjustment of the sextant consists of checking and aligning all the optical elements to eliminate "index correction". Index correction should be checked, using the horizon or more preferably a star, each time the sextant is used. The practice of taking celestial observations from the deck of a rolling ship, often through cloud cover and with a hazy horizon, is by far the most challenging part of celestial navigation. The mechanics of celestial navigation can be mastered in the classroom, but proficiency with a sextant at sea is a matter for expert instruction and extensive practice.


Inertial navigation

Further information: Inertial navigation

Inertial navigation is a dead reckoning type of navigation system that computes its position based on motion sensors. Once the initial latitude and longitude is established, the system receives impulses from motion detectors that measure the acceleration along three or more axes enabling it continually and accurately to calculate the current latitude and longitude. Its advantages over other navigation systems are that, once the starting position is set, it does not require outside information, it is not affected by adverse weather conditions and it cannot be detected or jammed by the enemy. The US Navy developed a Ships Inertial Navigation System (SINS) during the Polaris missile program to insure a safe, reliable and accurate navigation system for its missile submarines. Inertial navigation systems were in wide use until satellite navigation systems (GPS) became available. An inertial navigation system measures the position and altitude of a vehicle by measuring the accelerations and rotations applied to the systems inertial frame. ... An inertial navigation system measures the position and altitude of a vehicle by measuring the accelerations and rotations applied to the systems inertial frame. ... Dead reckoning (DR) is the process of estimating ones current position based upon a previously determined position, or fix, and advancing that position based upon measured velocity, time, heading, as well as the effect of currents or wind. ... The Polaris Missile was a submarine-launched ballistic missile (SLBM) carrying a nuclear warhead developed during the Cold War for the United States Navy. ... Satellite navigation systems use radio time signals transmitted by satellites to enable mobile receivers on the ground to determine their exact location. ...


Electronic navigation

Image File history File links Size of this preview: 602 × 600 pixelsFull resolution (800 × 797 pixel, file size: 67 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Size of this preview: 602 × 600 pixelsFull resolution (800 × 797 pixel, file size: 67 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ...

Radio navigation

For more details on this topic, see Radio navigation.

A radio direction finder or RDF is a device for finding the direction to a radio source. Due to radio's ability to travel very long distances "over the horizon", it makes a particularly good navigation system for ships and aircraft that might be flying at a distance from land. Radio navigation is the application of radio frequencies to determining a position on the earth. ... A radio direction finder, or RDF, is a device for finding the direction to a radio source. ...


RDF's work by pointing a directional antenna in "various directions" and then listening for the direction in which the signal from a known station comes through most strongly. This sort of system was widely used in the 1930s and 1940s. RDF antennas are particularly very easy to spot on German World War II aircraft, as loops under the rear section of the fuselage, whereas most US aircraft enclosed the antenna in a small teardrop-shaped fairing. A yagi antenna Most simply, an antenna is an electronic component designed to send or receive radio waves. ... The 1930s (years from 1930–1939) were described as an abrupt shift to more radical and conservative lifestyles, as countries were struggling to find a solution to the Great Depression, also known as the World Depression. ... The 1940s decade ran from 1940 to 1949. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... For other uses of terms redirecting here, see US (disambiguation), USA (disambiguation), and United States (disambiguation) Motto In God We Trust(since 1956) (From Many, One; Latin, traditional) Anthem The Star-Spangled Banner Capital Washington, D.C. Largest city New York City National language English (de facto)1 Demonym American...


In navigational applications, RDF signals are provided in the form of radio beacons, the radio version of a lighthouse. The signal is typically a simple AM broadcast of a morse code series of letters, which the RDF can tune in to see if the beacon is "on the air". Most modern detectors can also tune in any commercial radio stations, which is particularly useful due to their high power and location near major cities. Eddystone Lighthouse, one of the first wavewashed lighthouses For other uses, see Lighthouse (disambiguation). ... Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. ... 1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting telegraphic information, using standardized sequences of short and long elements to represent the letters, numerals, punctuation and special characters of a message. ...


Decca, OMEGA, and LORAN-C are three similar hyperbolic navigation systems. Decca was a hyperbolic low frequency radio navigation system (also known as multilateration) that was first deployed during World War II when the Allied forces needed a system which could be used to achieve accurate landings. As was the case with Loran C, its primary use was for ship navigation in coastal waters. Fishing vessels were major post-war users, but it was also used on aircraft, including a very early (1949) application of moving-map displays. The system was deployed extensively in the North Sea and was used by helicopters operating to oil platforms. After being shut down in the spring of 2000, it has been superseded by systems such as the American GPS and the planned European Galileo positioning system. Decca Navigator Mk 12 The Decca Navigator System was a hyperbolic low frequency radio navigation system (also known as multilateration) that was first deployed during World War II when the Allied forces needed a system which could be used to achieve accurate landings. ... Omega is the name for the first truly global radionavigation system for aircraft operated by the United States of America in cooperation with six partner nations. ... LORAN (LOng RAnge Navigation) is a terrestrial navigation system using low frequency radio transmitters. ... In mathematics, a hyperbola (Greek literally overshooting or excess) is a type of conic section defined as the intersection between a right circular conical surface and a plane which cuts through both halves of the cone. ... Low Frequency or LF refers to Radio Frequencies (RF) in the range of 30–300 kHz. ... Radio navigation is the application of radio frequencies to determining a position on the earth. ... Multilateration, also known as hyperbolic positioning, is the process of locating an object by accurately computing the time difference of arrival (TDOA) of a signal emitted from the object to three or more receivers. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... LORAN (LOng RAnge Navigation) is a terrestrial navigation system using low frequency radio transmitters. ... The Hibernia platform is the worlds largest oil platform. ... GPS redirects here. ... The Galileo positioning system is a planned Global Navigation Satellite System, to be built by the European Union (EU) and European Space Agency (ESA). ...


The OMEGA Navigation System was the first truly global radio navigation system for aircraft, operated by the United States in cooperation with six partner nations. OMEGA was originally developed by the United States Navy for military aviation users. It was approved for development in 1968 and promised a true worldwide oceanic coverage capability with only eight transmitters and the ability to achieve a four mile accuracy when fixing a position. Initially, the system was to be used for navigating nuclear bombers across the North Pole to Russia. Later, it was found useful for submarines.[1] Due to the success of the Global Positioning System the use of Omega declined during the 1990s, to a point where the cost of operating Omega could no longer be justified. Omega was permanently terminated on September 30, 1997 and all stations ceased operation. Radio navigation is the application of radio frequencies to determining a position on the earth. ... Year 1968 (MCMLXVIII) was a leap year starting on Monday (link will display full calendar) of the Gregorian calendar. ... GPS redirects here. ... is the 273rd day of the year (274th in leap years) in the Gregorian calendar. ... For the band, see 1997 (band). ...


LORAN is a terrestrial navigation system using low frequency radio transmitters that use the time interval between radio signals received from three or more stations to determine the position of a ship or aircraft. The current version of LORAN in common use is LORAN-C, which operates in the low frequency portion of the EM spectrum from 90 to 110 kHz. Many nations are users of the system, including the United States, Japan, and several European countries. Russia uses a nearly exact system in the same frequency range, called CHAYKA. LORAN use is in steep decline, with GPS being the primary replacement. However, there are current attempts to enhance and re-popularize LORAN. Radio navigation or radionavigation is the application of radio frequencies to determining a position on the Earth. ... Low Frequency or LF refers to Radio Frequencies (RF) in the range of 30–300 kHz. ... Low Frequency or LF refers to Radio Frequencies (RF) in the range of 30–300 kHz. ... This article is about the SI unit of frequency. ... Chayka (Russian: ~ English: ) is a Russian terrestrial radio navigation system, similar to LORAN-C. It is also run on 100 kHz and is described like LORAN-C by its GRI. // There are 5 Chayka-chains in use: GRI 8000 - Western (European) Russia Chayka Chain (1969) GRI 7950 - Eastern Russia Chayka... GPS redirects here. ...


Radar navigation

Further information: Radar navigation
Radar ranges and bearings can be very useful navigation.
Radar ranges and bearings can be very useful navigation.

Marine radar systems can provide very useful navigation information in a variety of situations. When the vessel is within radar range of land or special radar aids to navigation, the navigator can take distances and angular bearings to charted objects and use these to establish arcs of position and lines of position on a chart.[11] A fix consisting of only radar information is called a radar fix.[12] Image File history File linksMetadata Download high-resolution version (2048x1536, 1408 KB) Description écran radar marine Licensing Source Clipper File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Radar Metadata This file contains additional information, probably added from the... Image File history File linksMetadata Download high-resolution version (2048x1536, 1408 KB) Description écran radar marine Licensing Source Clipper File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Radar Metadata This file contains additional information, probably added from the...


Some types of radar fixes include the relatively self-explanatory methods of "range and bearing to a single object,"[13] "two or more bearings,"[13] "tangent bearings,"[13] and "two or more ranges."[13]


Parallel indexing is a technique defined by William Burger in the 1957 book The Radar Observer's Handbook.[14] This technique involves creating a line on the screen that is parallel to the ship's course, but offset to the left or right by some distance.[14] This parallel line allows the navigator to maintain a given distance away from hazards.[14]


Some techniques have been developed for special situations. One, known as the "contour method," involves marking a transparent plastic template on the radar screen and moving it to the chart to fix a position.[15]


Another special technique, known as the Franklin Continuous Radar Plot Technique, involves drawing the path a radar object should follow on the radar display if the ship stays on its planned course.[16] During the transit, the navigator can check that the ship is on track by checking that the pip lies on the drawn line.[16]


Satellite navigation

Further information: Satellite navigation

Global Navigation Satellite System or GNSS is the standard generic term for satellite navigation systems that provide autonomous geo-spatial positioning with global coverage. A GNSS allow small electronic receivers to determine their location (longitude, latitude, and altitude) to within a few metres using time signals transmitted along a line of sight by radio from satellites. Receivers on the ground with a fixed position can also be used to calculate the precise time as a reference for scientific experiments. Satellite navigation systems use radio time signals transmitted by satellites to enable mobile receivers on the ground to determine their exact location. ... This article is about the engineering discipline. ... Longitude is the east-west geographic coordinate measurement most commonly utilized in cartography and global navigation. ... This article is about the geographical term. ... Altitude is the elevation of an object from a known level or datum. ... This article is about the unit of length. ... A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day. ... When viewing a scene, as in optics, photography, or even hunting, the line of sight is the straight line between the observer and the target. ... For other uses, see Satellite (disambiguation). ...


As of 2007, the United States NAVSTAR Global Positioning System (GPS) is the only fully operational GNSS. The Russian GLONASS is a GNSS in the process of being restored to full operation. The European Union's Galileo positioning system is a next generation GNSS in the initial deployment phase, scheduled to be operational in 2010. China has indicated it may expand its regional Beidou navigation system into a global system. 2007 is a common year starting on Monday of the Gregorian calendar. ... GPS redirects here. ... GLONASS GLONASS (Russian ГЛОНАСС; ГЛОбальная НАвигационная Спутниковая Система; Globalnaya Navigatsionnaya Sputnikovaya Sistema. ... The Galileo positioning system is a planned Global Navigation Satellite System, to be built by the European Union (EU) and European Space Agency (ESA). ... The Beidou navigation system is a project by the Peoples Republic of China to develop an independent satellite navigation system. ...


More than two dozen GPS satellites are in medium Earth orbit, transmitting signals allowing GPS receivers to determine the receiver's location, speed and direction. Intermediate circular orbit (ICO), also called medium earth orbit (MEO), is used by satellites between the altitudes of low earth orbit (up to 1400 km) and geostationary orbit (ca. ... The geographic location of anything is measured by the latitude and longitude of it, as on a map or globe. ...


Since the first experimental satellite was launched in 1978, GPS has become an indispensable aid to navigation around the world, and an important tool for map-making and land surveying. GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks. Cartography or mapmaking (in Greek chartis = map and graphein = write) is the study and practice of making maps or globes. ... Surveyor at work with a leveling instrument. ... Time transfer describes methods for transferring reference clock synchronization from one point to another, often over long distances. ... This article is about the natural seismic phenomenon. ... Synchronization (or Sync) is a problem in timekeeping which requires the coordination of events to operate a system in unison. ...


Developed by the United States Department of Defense, GPS is officially named NAVSTAR GPS (NAVigation Satellite Timing And Ranging Global Positioning System). The satellite constellation is managed by the United States Air Force 50th Space Wing. The cost of maintaining the system is approximately US$750 million per year,[17] including the replacement of aging satellites, and research and development. Despite this fact, GPS is free for civilian use as a public good. Department of Defense redirects here. ... A group of electronic satellites working in concert is known as a satellite constellation. ... “The U.S. Air Force” redirects here. ... The 50th Space Wing (50 SW) is a wing of the United States Air Force under the major command of Air Force Space Command (AFSPC). ... USD redirects here. ... In economics, a public good is a good that is non-rival and non-excludable. ...


Navigation processes

Day's Work in Navigation

The Day's Work in Navigation is an attempt to summarize a minimal set of tasks consistent with prudent navigation. The definition will vary on military and civilian vessels, and from ship to ship, but takes a form resembling[18]:

  1. Maintain continuous dead reckoning plot.
  2. Take two or more star observations at morning twilight for a celestial fix. (prudent to observe 6 stars)
  3. Morning sun observation. Can be taken on or near prime vertical for longitude, or at any time for a line of position.
  4. Determine compass error by azimuth observation of the sun.
  5. Computation of the interval to noon, watch time of local apparent noon, and constants for meridian or ex-meridian sights.
  6. Noontime meridian or ex-meridian observation of the sun for noon latitude line. Running fix or cross with Venus line for noon fix.
  7. Noontime determination the day's run and day's set and drift.
  8. At least one afternoon sun line, in case the stars are not visible at twilight.
  9. Determine compass error by azimuth observation of the sun.
  10. Take two or more star observations at evening twilight for a celestial fix. (prudent to observe 6 stars)

Passage planning

Main article: Passage planning
Poor passage planning and deviation from the plan can lead to groundings and oil spills.
Poor passage planning and deviation from the plan can lead to groundings and oil spills.

Passage planning or voyage planning is a procedure to develop a complete description of vessel's voyage from start to finish. The plan includes leaving the dock and harbor area, the enroute portion of a voyage, approaching the destination, and mooring. According to international law, a vessel's captain is legally responsible for passage planning,[19] however on larger vessels, the task will be delegated to the ship's navigator.[20] Poor passage planning and deviation from the plan can lead to groundings and oil spills. ... FUCK FUCK FUCK File links The following pages link to this file: Exxon Valdez ... FUCK FUCK FUCK File links The following pages link to this file: Exxon Valdez ... A dockworker places a mooring line on a bollard. ... Captain Sir Arthur Henry Rostron receiving a loving cup from Margaret Brown for his rescue of RMS Titanic survivors Main article: Seafarers professions and ranks Captain is the traditional customary title given to the person in charge of a ship at sea. ... A navigator is the person onboard a ship responsible for the navigation of the vessel. ...


Studies show that human error is a factor in 80 percent of navigational accidents and that in many cases the human making the error had access to information that could have prevented the accident.[20] The practice of voyage planning has evolved from penciling lines on nautical charts to a process of risk management.[20] A 1976 United States NOAA chart of part of Puerto Rico A nautical chart is a graphic representation of a maritime area and adjacent coastal regions. ... For non-business risks, see risk or the disambiguation page risk analysis. ...


Passage planning consists of four stages: appraisal, planning, execution, and monitoring,[20] which are specified in International Maritime Organization Resolution A.893(21), Guidelines For Voyage Planning,[21] and these guidelines are reflected in the local laws of IMO signatory countries (for example, Title 33 of the U.S. Code of Federal Regulations), and a number of professional books and publications. There are some fifty elements of a comprehensive passage plan depending on the size and type of vessel, each applicable according to the individual situation. Headquarters of the International Maritime Organisation in Lambeth, adjacent to the east end of Lambeth Bridge Headquarters building taken from the west side of the Thames Headquartered in London, U.K., the International Maritime Organization (IMO) promotes cooperation among governments and the shipping industry to improve maritime safety and to... The Code of Federal Regulations (CFR) is the codification of the general and permanent rules and regulations (sometimes called administrative law) published in the Federal Register by the executive departments and agencies of the Federal Government of the United States. ...


The appraisal stage deals with the collection of information relevant to the proposed voyage as well as ascertaining risks and assessing the key features of the voyage. In the next stage, the written plan is created. The third stage is the execution of the finalised voyage plan, taking into account any special circumstances which may arise such as changes in the weather, which may require the plan to be reviewed or altered. The final stage of passage planning consists of monitoring the vessel's progress in relation to the plan and responding to deviations and unforeseen circumstances.


Integrated bridge systems

Electronic integrated bridge concepts are driving future navigation system planning.[7] Integrated systems take inputs from various ship sensors, electronically display positioning information, and provide control signals required to maintain a vessel on a preset course.[7] The navigator becomes a system manager, choosing system presets, interpreting system output, and monitoring vessel response.[7]


See also

Nautical Portal

Image File history File links No higher resolution available. ... The American Practical Navigator , written by Nathaniel Bowditch, is an encyclopedia of navigation, a valuable handbook on oceanography and meteorology, and contains useful tables and a maritime glossary. ... The principles of air navigation are the same for all aircraft, big or small. ... The word astrogation, used by science fiction writers beginning in the first half of the 20th century, denotes navigation of spacecraft, either in interplanetary travel or in interstellar travel. ... A taxi in Kyoto, equipped with GPS navigation system An automotive navigation system is a satellite navigation system designed for use in automobiles. ... Franz Xaver, Baron Von Zach Baron Franz Xaver von Zach (Franz Xaver Freiherr von Zach) (June 4, 1754 - September 2, 1832) was a German/Hungarian astronomer born at Pest. ... The Galileo positioning system is a planned Global Navigation Satellite System, to be built by the European Union (EU) and European Space Agency (ESA). ... It has been suggested that this article or section be merged with Datum. ... The great-circle distance is the shortest distance between any two points on the surface of a sphere measured along a path on the surface of the sphere (as opposed to going through the spheres interior). ... South Pointing Chariot (replica) Ma Jun (馬鈞, Wade-Giles: Ma Chün; 200 - 265), styled Deheng (徳衡), was a Chinese mechanical engineer and government official during the Three Kingdoms era of China. ... Map database management stems from navigation units becoming more common in automotive vehicles (see Automotive navigation system). ... Marshall Islands stick charts were made and used by the Marshallese to navigate the Pacific Ocean by canoe off the coast of the Marshall Islands. ... Robotic mapping can be used for serving robot guide The problem of Robotic mapping is related to cartography. ... South Pointing Chariot (replica) The South Pointing Chariot (Zhi Nan Che 指南車) is widely regarded as the most complex geared mechanism of the ancient Chinese civilization, and was continually used throughout the medieval period as well. ... This is a Chinese name; the family name is Shen Shen Kuo or Shen Kua (Chinese: ; pinyin: ) (1031–1095) was a polymathic Chinese scientist and statesman of the Song Dynasty (960–1279). ... In Norse Mythology, Sigi is a one of the sons of Odin. ... Spherical triangle Spherical trigonometry is a part of spherical geometry that deals with polygons (especially triangles) on the sphere and explains how to find relations between the involved angles. ... The wind triangle graphically represents the relationships among velocity vectors used for air navigation. ...

Notes

  1. ^ a b Bowditch, 2003:799.
  2. ^ a b c d Bowditch, 2003:4.
  3. ^ a b c d e Maloney, 2003:615.
  4. ^ a b c Maloney, 2003:614
  5. ^ Maloney, 2003:618.
  6. ^ Maloney, 2003:622.
  7. ^ a b c d e f g h i j k l Bowditch, 2002:1.
  8. ^ a b c d e f g h i Bowditch, 2002:99.
  9. ^ a b c d e f g h i j Bowditch, 2002:105.
  10. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z Bowditch, 2002:269.
  11. ^ Maloney, 2003:744.
  12. ^ Bowditch, 2002:816.
  13. ^ a b c d National Imagery and Mapping Agency, 2001:163.
  14. ^ a b c National Imagery and Mapping Agency, 2001:169.
  15. ^ National Imagery and Mapping Agency, 2001:164.
  16. ^ a b National Imagery and Mapping Agency, 2001:182.
  17. ^ GPS Overview from the NAVSTAR Joint Program Office. Accessed December 15, 2006.
  18. ^ Turpin and McEwen, 1980:6-18.
  19. ^ Regulation 34 - Safe Navigation. IMO RESOLUTION A.893(21) adopted on 25 November 1999. Retrieved on March 26, 2007.
  20. ^ a b c d ANNEX 24 – MCA Guidance Notes for Voyage Planning. IMO RESOLUTION A.893(21) adopted on 25 November 1999. Retrieved on March 26, 2007.
  21. ^ Guidelines For Voyage Planning. IMO RESOLUTION A.893(21) adopted on 25 November 1999. Retrieved on March 26, 2007.

is the 349th day of the year (350th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... March 26 is the 85th day of the year (86th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... March 26 is the 85th day of the year (86th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... March 26 is the 85th day of the year (86th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ...

References

Nathaniel Bowditch (March 26, 1773 – March 16, 1838) was an early American mathematician remembered for his work on ocean navigation. ... The U.S. National Geospatial-Intelligence Agency (NGA), before 2004 known as the National Imagery and Mapping Agency (NIMA), was established October 1, 1996, by the National Imagery and Mapping Agency Act of 1996. ... “The U.S. Air Force” redirects here. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 107th day of the year (108th in leap years) in the Gregorian calendar. ... The Stationery Office is a private publishing company that was created in 1995 when the publishing arm of Her Majestys Stationery Office was privatised. ... The U.S. National Geospatial-Intelligence Agency (NGA), before 2004 known as the National Imagery and Mapping Agency (NIMA), was established October 1, 1996, by the National Imagery and Mapping Agency Act of 1996. ... The Encyclopædia Britannica is a general English-language encyclopaedia published by Encyclopædia Britannica, Inc. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 107th day of the year (108th in leap years) in the Gregorian calendar. ... The Encyclopædia Britannica is a general English-language encyclopaedia published by Encyclopædia Britannica, Inc. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 107th day of the year (108th in leap years) in the Gregorian calendar. ...

External links

Wikimedia Commons has media related to:
Navigation
Image File history File links Commons-logo. ... Nathaniel Bowditch (March 26, 1773 – March 16, 1838) was an early American mathematician remembered for his work on ocean navigation. ...

  Results from FactBites:
 
Navigation - Wikipedia, the free encyclopedia (2553 words)
The Polynesian navigators routinely crossed thousands of miles of open ocean, to tiny inhabited islands, using only their own senses and knowledge, passed by oral tradition, from navigator to apprentice.
Celestial navigation systems are based on observation of the positions of the Sun, Moon and stars relative to the observer and a known location.
Navigators could determine their latitude by measuring the angular altitude of Polaris any time that it was visible (excepting, of course, in those southern latitudes from where it cannot be observed).
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