There are several traditions of navigation.
Polynesian navigation
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. Polynesia (from Greek, poly = many and nesi = island) is a large grouping of over 1,000 islands in the central and southern Pacific Ocean. ...
For the WWW browsers of the same name, see Netscape Navigator and Mozilla. ...
In Eastern Polynesia, navigators, in order to locate directions at various times of day and year, memorized extensive facts concerning:
- the motion of specific stars, and where they would rise and set on the horizon of the ocean
- weather
- times of travel
- wildlife species (which congregate at particular positions)
- directions of swells on the ocean, and how the crew would feel their motion
- colors of the sea and sky, especially how clouds would cluster at the locations of some islands
- angles for approaching harbors
These, and outrigger canoe construction methods, were kept as guild secrets. Generally each island maintained a guild of navigators who had very high status, since in times of famine or difficulty, only they could trade for aid or evacuate people. The guild secrets might have been lost, had not one of the last living navigators trained a professional small boat captain so that he could write a book. The Pleiades star cluster A star is any massive gaseous body in outer space, just like the Sun. ...
Horizon The horizon is the line that separates earth from sky. ...
Ocean (from Okeanos, a Greek god of sea and water; Greek ωκεανός) covers almost three quarters (71%) of the surface of the Earth. ...
Composite satellite image showing the progress of a hurricane weather system approaching the east coast of America Weather comprises all the various phenomena that occur in the atmosphere of a planet. ...
In a canoe or bangca, an outrigger is a thin, long, solid, hull used to stabilise an inherently unstable main hull. ...
Canoe at El Nido, Philippines A canoe is a relatively small human-powered boat. ...
The first settlers of the Hawaiian Islands were said to have used these navigation methods to sail to the Hawaiian Islands from the Marquesas Islands. In 1973, the Polynesian Voyaging Society was established in Hawaii to research Polynesian navigation methods. They built a replica of an ancient double-hulled canoe called the Hokule'a, whose crew, in 1976, successfully navigated the Pacific Ocean from Hawaii to Tahiti using no instruments. Map of the Hawaiian Islands, a chain of islands that stretches 2,400 km in a northwesterly direction from the southern tip of the Island of Hawai‘i. ...
National motto: Mau‘u‘u ha‘e iti Official languages French, Tahitian Political status Dependent territory, administrative division of French Polynesia Capital Tai o Hae Largest City Tai o Hae Area 1,274 km² ( 492 sq. ...
1973 was a common year starting on Monday. ...
The Hawaiian voyaging canoe, Hokulea, arrives off Kailua Beach on May 1, 2005 The Polynesian Voyaging Society (PVS) is a non-profit research and educational corporation based in Honolulu, Hawaii that was established to research and perpetuate traditional Polynesian voyaging methods. ...
State nickname: The Aloha State Other U.S. States Capital Honolulu Largest city Honolulu Governor Linda Lingle Official languages Hawaiian and English Area 28,337 km² (43rd) - Land 16,649 km² - Water 11,672 km² (41. ...
Hokule‘a is a full-scale replica of a wooden sailing vessel used in ancient Hawaii. ...
1976 is a leap year starting on Thursday (link will take you to calendar). ...
Tahiti is the largest island in French Polynesia, located in the archipelago of Society Islands in the southern Pacific Ocean, at 17°40′ S 149°30′ W. The island had a population of 169,674 inhabitants at the 2002 census. ...
Western navigation
Modern methods There are several different branches of navigation, including but not limited to: Knowing the ship's current position is the main problem for all navigators. Early navigators used pilotage, relying on local knowledge of land marks and coastal features, forcing all ships to stay close to shore. The magnetic compass allowing a course to be maintained and estimates of the ship's location to be calculated. Nautical charts were developed to record new navigational and pilotage information for use by other navigators. The development of accurate systems for taking lines of position based on the measurement of stars and planets with the sextant allowed ships to navigate the open ocean without needing to see land marks. Celestial navigation is a position fixing technique that was the first system devised to help sailors locate themselves on a featureless ocean. ...
Pilotage is the use of fixed visual references on the ground or sea to guide oneself to a destination. ...
Red buoy in San Diego Harbor. ...
This page discusses Beacons, fires designed to attract attention. ...
Dead reckoning is the process of estimating a global position of a vehicle by advancing a known position using course, speed, time and distance to be traveled. ...
This article is about the navigational instrument. ...
A log is: a cut portion of a tree bole or large branch (see logging) a time-sequential data record (see data logging) logarithm a device to measure the speed of a ship This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the...
Radio navigation is the application of radio frequencies to determining a position on the earth. ...
Satellite navigation systems use radio time signals transmitted by satellites to enable mobile receivers on the ground to determine their exact location. ...
A waypoint is a fixed location with a specified longitude and latitude and UTM coordinates, which is maintained by a global positioning system (GPS). ...
Position fixing is the branch of navigation concerned with the use of a variety of visual and electronic methods to determine the position of a ship, aircraft or person on the surface of the Earth. ...
This long range radar antenna (approximately 40m (130ft) in diameter) rotates on a track to observe activities near the horizon. ...
For the WWW browsers of the same name, see Netscape Navigator and Mozilla. ...
Pilotage is the use of fixed visual references on the ground or sea to guide oneself to a destination. ...
This article is about the navigational tool. ...
A nautical chart is a graphic representation of a maritime area and adjacent coastal regions. ...
A sextant is a measuring instrument used to measure the angle of elevation of a celestial object above the horizon. ...
Later developments included the placing of lighthouses and buoys close to shore to act a marine signposts identifying ambiguous features, highlighting hazards and pointing to safe channels for ships approaching some part of a coast after a long sea voyage. The invention of the radio lead to radio beacons and radio direction finders providing accurate land-based fixes even hundreds of miles from shore. These were made obsolete by satellite navigation systems. The Peggys Point lighthouse in Nova Scotia, Canada An aid for navigation and pilotage at sea, a lighthouse is a tower building or framework sending out light from a system of lamps and lenses or, in older times, from a fire. ...
A seal on a buoy in San Diego Harbor A buoy is a floating device that can have various purposes, which determine whether the buoy is tethered (stationary) or allowed to drift: The word is derived from the Dutch boei. sea mark - aids pilotage by marking a maritime channel, hazard...
A radio direction finder, or RDF, is a device for finding the direction to a radio source. ...
Traditional maritime navigation with a compass uses multiple redundant sources of position information to locate the ship's position. A navigator uses the ship's last known position and dead reckoning, based on the ship's logged compass course and speed, to calculate the current position. If the set and drift, due to tide and wind, can be determined, an estimated position can also be calculated. Dead reckoning is the process of estimating a global position of a vehicle by advancing a known position using course, speed, time and distance to be traveled. ...
In navigation set and drift are external forces acting upon a ship that make it deviate from its intended course. ...
The tide is the regular rising and falling of the oceans surface caused by changes in gravitational forces external to the Earth. ...
Wind is the quasi-horizontal movement of air (as opposed to an air current) caused by a horizontal pressure gradient force. ...
Periodically, the navigator needs confirm the accuracy of the dead reckoning or estimated position calculations using position fixing techniques. This is done by correctly identifying reference points and measuring their bearings from the ship. These lines of position can be plotted on a nautical chart, with the intersection being the ship's current location. Addition lines of position can be measured in order to validate the results taken against other reference points. This is known as a fix. Position fixing is the branch of navigation concerned with the use of a variety of visual and electronic methods to determine the position of a ship, aircraft or person on the surface of the Earth. ...
In navigation, a bearing is the angle between the direction to an object and a reference direction. ...
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 nautical chart is a graphic representation of a maritime area and adjacent coastal regions. ...
A position fix or simply a fix is a term used in position fixing in navigation to describe a position derived from measuring external reference points. ...
Celestial navigation systems are based on observation of the positions of the Sun, Moon and stars relative to the observer and a known location. Anciently the home port was used as the known location, currently the Greenwich Meridian or Prime Meridian is used as the known location for celestial charts. A sun is the star at the center of a planetary system. ...
Crust composition Oxygen 43% Silicon 21% Aluminium 10% Calcium 9% Iron 9% Magnesium 5% Titanium 2% Nickel 0. ...
The Pleiades star cluster A star is any massive gaseous body in outer space, just like the Sun. ...
Navigators could determine their latitude by measuring the angular altitude of Polaris any time that it was visible. Determining latitude by the sun was a little more difficult since the sun's altitude at noon during the year changes for a given location.
Calculating the anticipated altitude of the sun for a given day and known position is done easily using Calculus. But prior to its invention by Newton around 1700, tables of the sun's altitude during the year for a known port were used. The sun's angle over the horizon at noon was measured, and compared to the known angle at the same date as the known port. Local noon is easily determined by recording periodic readings of the altitude of the sun. Since periodic readings of the altitude will plot a sine wave, the maximum reading is the one used for local noon. Horizon The horizon is the line that separates earth from sky. ...
Longitude is calculated as a time difference between the same celestial event at different locations. Noon was an easy event to observe. Local noon is determined while shooting the azimuth as described above. The time of the maximum altitude is easily determined by interpolating between periodic readings. The time of noon at the known location is carried by the navigator on an accurate clock. Then the local time of local noon is observed by the navigator. The difference of longitude is determined knowing that the sun moves to the west at 15 degrees per hour.
The need for accurate navigation led to the development of progressively more accurate clocks. Once accurate clocks were available, detailed tables for celestial bodies were created so that navigational activities could take place anytime during the day or night, rather than at noon.
In modern celestial navigation, a nautical almanac and trigonometric sight-reduction tables permit navigators to measure the Sun, Moon, visible planets or any of 57 navigational stars at any time of day or night. From a single sight, a time within a second and an estimated position, a position can be determined within a third of a mile (500 m). 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 planet (from the Greek πλανήτης, planētēs which means wanderer or more forcefully vagrant, tramp) is an object in orbit around a star that is not a star in its own right. ...
Conceptually, the angle to the celestial object establishes a ring of possible positions on the surface of the Earth. A second sighting on a different object establishes an intersecting ring. Usually the navigator knows his position well enough to pick which of the two intersections is the current position. The math required for sight reduction is simple addition and subtraction, if sight-reduction tables are available. The numerous celestial objects permit navigators to shoot through holes in clouds. Most navigation is performed with the sun and moon.
Accurately knowing the time of an observation is important. Time is measured with a chronometer, a quartz watch or a short wave radio broadcast from an atomic clock. A chronometer is a clock designed to have sufficient long-term accuracy that it can be used as a portable time standard on a vehicle, usually in order to determine longitude by means of celestial navigation. ...
A quartz clock is a timepiece that uses an electronic oscillator and a quartz crystal to keep precise time. ...
Atomic clock Chip-Scale Atomic Clock Unveiled by NIST An atomic clock is a type of clock that uses an atomic resonance frequency standard as its counter. ...
A quartz wristwatch normally keeps time within a half-second per day. If it is worn constantly, keeping it near body heat, its rate of drift can be measured with the radio, and by compensating for this drift, a navigator can keep time to better than a second per month.
Traditionally, three chronometers are kept in gimbals in a dry room near the center of the ship, and used to set a watch for the actual sight, so that no chronometers are ever risked to the elements. Winding the chronometers was a crucial duty of the navigator. A gimbal is a device using Euler angles to measure the rotation of an object in three dimensions and to control that rotation. ...
The angle is measured with a special optical instrument called a "sextant." Sextants use two mirrors to cancel the relative motion of the sextant. During a sight, the user's view of the star and horizon remains steady as the boat rocks. An arm moves a split image of the star relative to the split image of the horizon. When the image of the star touches the horizon, the angle can be read from the sextant's scale. Some sextants create an artificial horizon by reflecting a bubble. Inexpensive plastic sextants are available, though they have less accuracy than the more expensive metal models. A sextant is a measuring instrument used to measure the angle of elevation of a celestial object above the horizon. ...
Horizon The horizon is the line that separates earth from sky. ...
The LORAN system is based on measuring the phase shift of radio waves sent simultaneously from a master and slave station. Signals from these two point establish a hyperbolic curve for possible positions. A third source along with dead-reckoning will generally resolve to a single position.
GPS uses 3D trilateration based on measuring the time-of-flight of radio waves using the well-known speed of light to measure distance from at least three satelites. This can be accomplished using low cost quarts clocks because the satellites send time correction signals to the GPS receivers.
History In the West, navigation was at first performed exclusively by dead-reckoning, the process of estimating one's present position based on the navigators' experience with wind, tide and currents.
Most sailors have always been able find absolute north from the stars, which currently rotate around Polaris, or by using a dual sundial called a diptych. Polaris or Cynosura (α UMi / α Ursae Minoris / Alpha Ursae Minoris) is the brightest star in the constellation Ursa Minor. ...
Wall sundial Wall sundial in Warsaws Old Town A sundial measures time by the position of the sun. ...
A diptych is any object with two flat plates attached at a hinge. ...
When combined with a plumb bob, some diptychs could also determine latitude. Basically, when the diptych's two sundials indicated the same time, the diptych was aligned to the current latitude and true north.
 Compass with rose in center Another early invention was the compass rose, a cross or painted panel of wood oriented with the pole star or diptych. This was placed in front of the helmsman. A mariners compass © Public Domain Davis, John. ...
A mariners compass © Public Domain Davis, John. ...
A compass rose is a figure displaying the orientation of the cardinal directions, north, south, east and west on a map. ...
Latitude was determined with a "cross staff" an instrument vaguely similar to a carpenter's angle with graduated marks on it. Most sailors could use this instrument to take sun sights, but master navigators knew that sightings of Polaris were far more accurate, because they were not subject to time-keeping errors involved in finding noon.
Time-keeping was by precision hourglasses, filled and tested to 1/4 of an hour, turned by the helmsman, or a young boy brought for that purpose.
The most important instrument was a navigators' diary, later called a rutter. These were often crucial trade secrets, because they enabled travel to lucrative ports.
The above instruments were a powerful technology, and appear to have been the technique used by ancient Cretan bronze-age trading empire. Using these techniques, masters successfully sailed from the eastern Mediterranean to the south coast of the British Isles. The Minoans were an ancient pre-Hellenic civilization on what is now Crete (in the Mediterranean), during the Bronze Age, prior to classical Greek culture. ...
The Bronze Age is a period in a civilizations development when the most advanced metalworking has developed the techniques of smelting copper from natural outcroppings and alloys it to cast bronze. ...
The Mediterranean Sea is an intercontinental sea positioned between Europe to the north, Africa to the south and Asia to the east, covering an approximate area of 2. ...
Some time later, around 300, the magnetic compass was invented in China. This let masters continue sailing a course when the weather limited visibility of the sky. For other uses, see number 300. ...
This article is about the navigational tool. ...
Around 400, metallurgy allowed construction of astrolabes graduated in degrees, which replaced the wooden latitude instruments for night use. Diptychs remained in use during the day, until shadowing astrolabes were constructed. 15th century astrolabe The two-dimensional work of art depicted in this image is in the public domain in the United States and in those countries with a copyright term of life of the author plus 100 years. ...
15th century astrolabe The two-dimensional work of art depicted in this image is in the public domain in the United States and in those countries with a copyright term of life of the author plus 100 years. ...
For alternate uses, see Number 400. ...
For the ship of Dumont dUrville, see Astrolabe A 16th century astrolabe. ...
After Isaac Newton published the Principia, navigation was transformed. Starting in 1670, the entire world was measured using essentially modern latitude instruments and the best available clocks. Sir Isaac Newton in Godfrey Knellers 1689 portrait Sir Isaac Newton (25 December 1642 – 20 March 1727 by the Julian calendar in use in England at the time; or 4 January 1643 – 31 March 1727 by the Gregorian calendar) was an English physicist, mathematician, astronomer, philosopher, and alchemist who...
Newtons own copy of his Principia, with hand written corrections for the second edition. ...
1670 was a common year beginning on a Saturday in countries using the Julian calendar and a Wednesday in countries using the Gregorian calendar. ...
In 1730 the sextant was invented and navigators rapidly replaced their astrolabes. A sextant uses mirrors to measure the altitude of celestial objects with regard to the horizon. Thus, its "pointer" is as long as the horizon is far away. This eliminates the "cosine" error of an astrolabe's short pointer. Modern sextants measure to 0.2 minutes of arc, an error that translates to a distance of about 0.2 nautical miles (400 m). Events Pope Clement XII elected September 17 - Change of emperor of the Ottoman Empire from Ahmed III (1703-1730) to Mahmud I (1730-1754) Anna Ivanova (Anna I of Russia) became czarina Births May 13 - Charles Watson-Wentworth, 2nd Marquess of Rockingham, Prime Minister of the United Kingdom (d. ...
A sextant is a measuring instrument used to measure the angle of elevation of a celestial object above the horizon. ...
For the ship of Dumont dUrville, see Astrolabe A 16th century astrolabe. ...
At first, the best available "clocks" were the moons of Jupiter, and the calculated transits of selected stars by the moon. These methods were too complex to be used by any but skilled astronomers, but they sufficed to map most of the world. A number of scientific journals during this period were started especially to chronicle geography. Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ...
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. ...
Later, mechanical chronometers enabled navigation at sea and in the air using relatively unskilled procedures. A chronometer is a clock designed to have sufficient long-term accuracy that it can be used as a portable time standard on a vehicle, usually in order to determine longitude by means of celestial navigation. ...
In the late 19th century Nikola Tesla invented radio and direction-finding was quickly adapted to navigation. Up until 1960 it was commonplace for ships and aircraft to use radio direction-finding on commercial stations in order to locate islands and cities within the last several miles of error. Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ...
Nikola Tesla (baptismal name: Ðиколай) was an inventor, physicist, mechanical engineer, and electrical engineer. ...
1960 was a leap year starting on Friday (link will take you to calendar). ...
Around 1960, LORAN was developed. This used time-of-flight of radio waves from antennas at known locations. It revolutionized navigation by permitting semiautomated equipment to locate geographic positions to less than a half mile (800 m). An analogous system for aircraft, VOR and DME, was developed around the same time. 1960 was a leap year starting on Friday (link will take you to calendar). ...
LORAN (LOng RAnge Navigation) is a terrestrial navigation system using low frequency radio transmitters that use the time interval between radio signals received from two or more stations to determine the position of a ship or aircraft. ...
In Norse Mythology Vor is a goddess of the Aesir. ...
Distance Measuring Equipment (DME) is a transponder-based radio navigation technology generally colocated at VORs. ...
At about the same, TRANSIT, the first satellite-based navigation system was developed. It was the first electronic navigation system to provide global coverage. The TRANSIT system, also known as NAVSAT (for Navy Navigation Satellite System), was the first satellite navigation system to be used operationally. ...
Other radionavigation systems include:
In 1974, the first GPS satellite was launched. The GPS system now permits accurate geographic location with an error of only a few metres, and precision timing to less than a microsecond. GLONASS is a positioning system launched by the Soviet Union. It relies on a slightly different geodesic model of the Earth. Galileo is a competing system, that will be placed into service by the European Union. The Decca Navigator System was a hyperbolic radio navigation system and first deployed during World War 2 when the Allied forces needed a system which could be used to achieve accurate landings. ...
Omega was the first truly global radionavigation system for aircraft operated by the United States of America. ...
Longwave radio frequencies are those below 500 kHz, which correspond to wavelengths longer than 600 meters. ...
The United States Navy (USN) is the branch of the United States armed forces responsible for naval operations. ...
Alpha by itself may refer to: The first letter of the Greek alphabet, Α α, which also has some cultural meanings; see alpha (letter). ...
Longwave radio frequencies are those below 500 kHz, which correspond to wavelengths longer than 600 meters. ...
1974 is a common year starting on Tuesday (click on link for calendar). ...
Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ...
GLONASS (Russian ГЛОНАСС; ГЛОбальная НАвигационная Спутниковая Система; Globalnaya Navigatsionnaya Sputnikovaya Sistema. ...
27 satellites in orbit. ...
"Point" measure of direction A "point" is defined as one eighth of a right angle, and therefore equals exactly 11.25 degrees. For example, a bearing of northwest by north differs by one point from a northwest bearing, and by a point from a north-northwest one. This article is about angles in geometry. ...
Degree (angle) - Wikipedia /**/ @import /skins-1. ...
See also The principles of air navigation are the same for all aircraft, big or small. ...
Great circle distance is the shortest distance between any two points on the surface of the Earth measured along a path on the surface of the Earth (as opposed to going through the Earths interior). ...
Localization can mean any of the following: Generally, localization is the determination of the locality (position) of an object. ...
Satellite navigation systems use radio time signals transmitted by satellites to enable mobile receivers on the ground to determine their exact location. ...
Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ...
GLONASS (Russian ГЛОНАСС; ГЛОбальная НАвигационная Спутниковая Система; Globalnaya Navigatsionnaya Sputnikovaya Sistema. ...
27 satellites in orbit. ...
The Decca Navigator System was an early precursor to positioning systems like the American GPS system and the planned European Galileo positioning system. ...
LORAN (LOng RAnge Navigation) is a terrestrial navigation system using low frequency radio transmitters that use the time interval between radio signals received from two or more stations to determine the position of a ship or aircraft. ...
A chronometer is a clock designed to have sufficient long-term accuracy that it can be used as a portable time standard on a vehicle, usually in order to determine longitude by means of celestial navigation. ...
A sextant is a measuring instrument used to measure the angle of elevation of a celestial object above the horizon. ...
A nautical chart is a graphic representation of a maritime area and adjacent coastal regions. ...
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. ...
Geodetic systems or map datums are used in geodesy, navigation, surveying and the Global Positioning System to indicate the datum or reference point to which a measured position is relative. ...
External links - Navigation - U.S Army Manual.
- Bowditch Online - complete online edition of Nathaniel Bowditch's American Practical Navigator
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