![Hounslow Branch](https://upload.wikimedia.org/wikipedia/commons/6/69/Hounslow_Branch.svg)
Navigation
is a field of study that focuses on the process of monitoring and controlling the
movement of a craft or
vehicle
A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), ...
from one place to another.
[Bowditch, 2003:799.] The field of navigation includes four general categories: land navigation, marine navigation, aeronautic navigation, and space navigation.
It is also the term of art used for the specialized knowledge used by
navigator
A navigator is the person on board a ship or aircraft responsible for its navigation.Grierson, MikeAviation History—Demise of the Flight Navigator FrancoFlyers.org website, October 14, 2008. Retrieved August 31, 2014. The navigator's primar ...
s to perform navigation tasks. All navigational techniques involve locating the navigator's
position
Position often refers to:
* Position (geometry), the spatial location (rather than orientation) of an entity
* Position, a job or occupation
Position may also refer to:
Games and recreation
* Position (poker), location relative to the dealer
* ...
compared to known locations or patterns.
Navigation, in a broader sense, can refer to any skill or study that involves the determination of position and
direction.
In this sense, navigation includes
orienteering and
pedestrian navigation.
History
In the European medieval period, navigation was considered part of the set of ''
seven mechanical arts'', none of which were used for long voyages across open ocean.
Polynesian navigation
Polynesian navigation or Polynesian wayfinding was used for thousands of years to enable long voyages across thousands of kilometers of the open Pacific Ocean. Polynesians made contact with nearly every island within the vast Polynesian Triangl ...
is probably the earliest form of open-ocean navigation; it was based on memory and observation recorded on scientific instruments like the
Marshall Islands Stick Charts of Ocean Swells. Early Pacific Polynesians used the motion of stars, weather, the position of certain wildlife species, or the size of waves to find the path from one island to another.
Maritime navigation using scientific instruments such as the
mariner's astrolabe
The mariner's astrolabe, also called sea astrolabe, was an inclinometer used to determine the latitude of a ship at sea by measuring the sun's noon altitude (declination) or the meridian altitude of a star of known declination. Not an astrolabe ...
first occurred in the Mediterranean during the Middle Ages. Although
land astrolabes were invented in the
Hellenistic period
In Classical antiquity, the Hellenistic period covers the time in Mediterranean history after Classical Greece, between the death of Alexander the Great in 323 BC and the emergence of the Roman Empire, as signified by the Battle of Actium in ...
and existed in
classical antiquity
Classical antiquity (also the classical era, classical period or classical age) is the period of cultural history between the 8th century BC and the 5th century AD centred on the Mediterranean Sea, comprising the interlocking civilizations of ...
and the
Islamic Golden Age
The Islamic Golden Age was a period of cultural, economic, and scientific flourishing in the history of Islam, traditionally dated from the 8th century to the 14th century. This period is traditionally understood to have begun during the reign ...
, the oldest record of a sea astrolabe is that of
Majorcan
Mallorca, or Majorca, is the largest island in the Balearic Islands, which are part of Spain and located in the Mediterranean.
The capital of the island, Palma, is also the capital of the autonomous community of the Balearic Islands. The Balea ...
astronomer
Ramon Llull dating from 1295.
[''The Ty Pros Companion to Ships and the Sea'', Peter Kemp ed., 1976 ] The perfecting of this navigation instrument is attributed to
Portuguese
Portuguese may refer to:
* anything of, from, or related to the country and nation of Portugal
** Portuguese cuisine, traditional foods
** Portuguese language, a Romance language
*** Portuguese dialects, variants of the Portuguese language
** Portu ...
navigators during early
Portuguese discoveries in the
Age of Discovery
The Age of Discovery (or the Age of Exploration), also known as the early modern period, was a period largely overlapping with the Age of Sail, approximately from the 15th century to the 17th century in European history, during which seafarin ...
.
The earliest known description of how to make and use a sea astrolabe comes from Spanish cosmographer
Martín Cortés de Albacar's ''Arte de Navegar'' (''The Art of Navigation'') published in 1551,
[Swanick, Lois Ann. ''An Analysis Of Navigational Instruments In The Age Of Exploration: 15th Century To Mid-17th century'', MA Thesis, Texas A&M University, December 2005] based on the principle of the
archipendulum used in constructing the
Egyptian pyramids.
Open-seas navigation using the astrolabe and the
compass
A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself wit ...
started during the Age of Discovery in the 15th century. The Portuguese began systematically exploring the
Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
coast of
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
from 1418, under the sponsorship of
Prince Henry Prince Henry (or Prince Harry) may refer to:
People
*Henry the Young King (1155–1183), son of Henry II of England, who was crowned king but predeceased his father
*Prince Henry the Navigator of Portugal (1394–1460)
*Henry, Duke of Cornwall (Ja ...
. In 1488
Bartolomeu Dias reached the
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...
by this route. In 1492 the
Spanish monarchs funded
Christopher Columbus
Christopher Columbus
* lij, Cristoffa C(or)ombo
* es, link=no, Cristóbal Colón
* pt, Cristóvão Colombo
* ca, Cristòfor (or )
* la, Christophorus Columbus. (; born between 25 August and 31 October 1451, died 20 May 1506) was a ...
's expedition to sail west to reach the
Indies
The East Indies (or simply the Indies), is a term used in historical narratives of the Age of Discovery. The Indies refers to various lands in the East or the Eastern hemisphere, particularly the islands and mainlands found in and around ...
by crossing the Atlantic, which resulted in the
Discovery of the Americas
The prehistory of the Americas (North America, North, South America, South, and Central America, and the Caribbean) begins with people migrating to these areas from Asia during the height of an ice age. These groups are generally believed to have ...
. In 1498, a Portuguese expedition commanded by
Vasco da Gama reached
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
by sailing around Africa, opening up direct trade with
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
. Soon, the Portuguese sailed further eastward, to the
Spice Islands
A spice is a seed, fruit, root, bark, or other plant substance primarily used for flavoring or coloring food. Spices are distinguished from herbs, which are the leaves, flowers, or stems of plants used for flavoring or as a garnish. Spices are ...
in 1512, landing in
China one year later.
The first circumnavigation of the earth was completed in 1522 with the
Magellan-Elcano expedition
The Magellan expedition, also known as the Magellan–Elcano expedition, was the first voyage around the world in recorded history. It was a 16th century Spanish expedition initially led by Portuguese explorer Ferdinand Magellan to the Maluku I ...
, a Spanish voyage of discovery led by Portuguese explorer
Ferdinand Magellan
Ferdinand Magellan ( or ; pt, Fernão de Magalhães, ; es, link=no, Fernando de Magallanes, ; 4 February 1480 – 27 April 1521) was a Portuguese explorer. He is best known for having planned and led the 1519 Spanish expedition to the Eas ...
and completed by Spanish navigator
Juan Sebastián Elcano
Juan Sebastián Elcano (Elkano in modern Basque; sometimes given as ''del Cano''; 1486/1487Some sources state that he was born in 1476. Most of this sources try to make a point about him participating on a military campaign at the Mediterranean ...
after the former's death in the
Philippines
The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no),
* bik, Republika kan Filipinas
* ceb, Republika sa Pilipinas
* cbk, República de Filipinas
* hil, Republ ...
in 1521. The fleet of seven ships sailed from
Sanlúcar de Barrameda
Sanlúcar de Barrameda (), or simply Sanlúcar, is a city in the northwest of Cádiz province, part of the autonomous community of Andalucía in southern Spain. Sanlúcar is located on the left bank at the mouth of the Guadalquivir River opposit ...
in Southern
Spain
, image_flag = Bandera de España.svg
, image_coat = Escudo de España (mazonado).svg
, national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond")
, national_anthem = (English: "Royal March")
, i ...
in 1519, crossed the Atlantic Ocean and after several stopovers rounded the southern tip of
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
. Some ships were lost, but the remaining fleet continued across the
Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...
making a number of discoveries including
Guam
Guam (; ch, Guåhan ) is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. It is the westernmost point and territory of the United States (reckoned from the geographic cent ...
and the Philippines. By then, only two galleons were left from the original seven. The ''Victoria'' led by Elcano sailed across the Indian Ocean and north along the coast of Africa, to finally arrive in Spain in 1522, three years after its departure. The ''Trinidad'' sailed east from the Philippines, trying to find a maritime path back to the
Americas
The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World.
Along with th ...
, but was unsuccessful. The eastward route across the Pacific, also known as the ''tornaviaje'' (return trip) was only discovered forty years later, when Spanish cosmographer
Andrés de Urdaneta
Andrés de Urdaneta (1508 – June 3, 1568) was a maritime explorer for the Spanish Empire of Basque heritage, who became an Augustinian friar. At the age of seventeen, he accompanied the Loaísa expedition to the Spice Islands where he sp ...
sailed from the Philippines, north to parallel 39°, and hit the eastward
Kuroshio Current
The , also known as the Black or or the is a north-flowing, warm ocean current on the west side of the North Pacific Ocean basin. It was named for the deep blue appearance of its waters. Similar to the Gulf Stream in the North Atlantic, the Ku ...
which took its galleon across the Pacific. He arrived in
Acapulco on October 8, 1565.
Etymology
The term stems from the 1530s, from
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''navigationem'' (nom. ''navigatio''), from ''navigatus'', pp. of ''navigare'' "to sail, sail over, go by sea, steer a ship," from ''navis'' "ship" and the root of ''agere'' "to drive".
Basic concepts
Latitude
Roughly, the latitude of a place on Earth is its angular distance north or south of the
equator.
[Bowditch, 2003:4.] Latitude is usually expressed in
degrees (marked with °) ranging from 0° at the
Equator to 90° at the North and South poles.
The latitude of the
North Pole
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's rotation, Earth's axis of rotation meets its surface. It is called the True North Pole to distingu ...
is 90° N, and the latitude of the
South Pole
The South Pole, also known as the Geographic South Pole, Terrestrial South Pole or 90th Parallel South, is one of the two points where Earth's axis of rotation intersects its surface. It is the southernmost point on Earth and lies antipod ...
is 90° S.
Mariners calculated latitude in the Northern Hemisphere by sighting the
pole star
A pole star or polar star is a star, preferably bright, nearly aligned with the axis of a rotating astronomical body.
Currently, Earth's pole stars are Polaris (Alpha Ursae Minoris), a bright magnitude-2 star aligned approximately with its ...
(
Polaris) with a
sextant and using sight reduction tables to correct for height of eye and atmospheric refraction. The height of Polaris in degrees above the horizon is the latitude of the observer, within a degree or so.
Longitude
Similar to latitude, the longitude of a place on Earth is the angular distance east or west of the
prime meridian
A prime meridian is an arbitrary meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great ...
or
Greenwich meridian.
Longitude is usually expressed in
degrees (marked with °) ranging from
0° at the Greenwich meridian to
180° east and west.
Sydney, for example, has a longitude of about
151° east.
New York City
New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the Un ...
has a longitude of
74° west. For most of history, mariners struggled to determine longitude. Longitude can be calculated if the precise time of a sighting is known. Lacking that, one can use a
sextant to take a
lunar distance (also called ''the lunar observation'', or "lunar" for short) that, with a
nautical almanac
A nautical almanac is a publication describing the positions of a selection of celestial bodies for the purpose of enabling navigators to use celestial navigation to determine the position of their ship while at sea. The Almanac specifies for eac ...
, can be used to calculate the time at zero longitude (see
Greenwich Mean Time
Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich, London, counted from midnight. At different times in the past, it has been calculated in different ways, including being calculated from noon; as a con ...
).
[
] Reliable
marine chronometer
A marine chronometer is a precision timepiece that is carried on a ship and employed in the determination of the ship's position by celestial navigation. It is used to determine longitude by comparing Greenwich Mean Time (GMT), or in the modern ...
s were unavailable until the late 18th century and not affordable until the 19th century.
[
][
][
] For about a hundred years, from about 1767 until about 1850, mariners lacking a chronometer used the method of lunar distances to determine Greenwich time to find their longitude. A mariner with a chronometer could check its reading using a lunar determination of Greenwich time.
Loxodrome
In navigation, a rhumb line (or loxodrome) is a line crossing all meridians of longitude at the same angle, i.e. a path derived from a defined initial bearing. That is, upon taking an initial bearing, one proceeds along the same bearing, without changing the direction as measured relative to true or magnetic north.
Methods of navigation
Most modern navigation relies primarily on positions determined electronically by receivers collecting information from satellites. Most other modern techniques rely on finding intersecting
lines of position
A position line or line of position (LOP) is a line (or, on the surface of the earth, a curve) that can be both identified on a chart (nautical chart or aeronautical chart) and translated to the surface of the earth. The intersection of a minimum o ...
or LOP.
[Maloney, 2003:615.]
A line of position can refer to two different things, either a line on a chart or a line between the observer and an object in real life.
[Maloney, 2003:614] A bearing is a measure of the direction to an object.
If the navigator measures the direction in real life, the angle can then be drawn on a
nautical chart
A nautical chart is a graphic representation of a sea area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land ( topographic map), natural features of the seabed, details of the co ...
and the navigator will be somewhere on that bearing line on the chart.
In addition to bearings, navigators also often measure distances to objects.
On the chart, a distance produces a circle or arc of position.
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.
A
fix is the intersection of two or more LOPs.
If only one line of position is available, this may be evaluated against the
dead reckoning
In navigation, dead reckoning is the process of calculating current position of some moving object by using a previously determined position, or fix, and then incorporating estimates of speed, heading direction, and course over elapsed time. ...
position to establish an estimated position.
[Maloney, 2003:618.]
Lines (or circles) of position can be derived from a variety of sources:
* celestial observation (a short segment of the
circle of equal altitude
The circle of equal altitude, also called circle of position (CoP), is defined as the locus (geometry), locus of points on Earth on which an observer sees a celestial object such as the sun or a star, at a given time, with the same observed altitud ...
, 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,
[Maloney, 2003:622.]
* compass bearing to a charted object,
* radar range to a charted object,
* on certain coastlines, a depth sounding from
echo sounder
Echo sounding or depth sounding is the use of sonar for ranging, normally to determine the depth of water (bathymetry). It involves transmitting acoustic waves into water and recording the time interval between emission and return of a pulse; ...
or hand
lead line.
There are some methods seldom used today such as "dipping a light" to calculate the geographic range from observer to lighthouse.
Methods of navigation have changed through history.
[Bowditch, 2002:1.] Each new method has enhanced the mariner's ability to complete his voyage.
One of the most important judgments the navigator must make is the best method to use.
Some types of navigation are depicted in the table.
The practice of navigation usually involves a combination of these different methods.
Mental navigation checks
By mental navigation checks, a pilot or a navigator estimates tracks, distances, and altitudes which will then help the pilot avoid gross navigation errors.
Piloting
![Navigatie](https://upload.wikimedia.org/wikipedia/commons/6/65/Navigatie.jpg)
Piloting (also called pilotage) involves navigating an aircraft by visual reference to landmarks,
[Federal Aviation Regulations Part 1 §1.1] or a water vessel in restricted waters and fixing its position as precisely as possible at frequent intervals.
[Bowditch, 2002:105.] More so than in other phases of navigation, proper preparation and attention to detail are important.
Procedures vary from vessel to vessel, and between military, commercial, and private vessels.
A military navigation team will nearly always consist of several people.
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.
While the military navigator will have a bearing book and someone to record entries for each fix, the civilian navigator will simply pilot the bearings on the chart as they are taken and not record them at all.
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.
If a
pilot
An aircraft pilot or aviator is a person who controls the flight of an aircraft by operating its directional flight controls. Some other aircrew members, such as navigators or flight engineers, are also considered aviators, because they a ...
is aboard, as is often the case in the most restricted of waters, his judgement can generally be relied upon, further easing the workload.
But should the ECDIS fail, the navigator will have to rely on his skill in the manual and time-tested procedures.
Celestial navigation
![Sun-Moon path](https://upload.wikimedia.org/wikipedia/commons/1/18/Sun-Moon_path.PNG)
Celestial navigation systems are based on observation of the positions of the
Sun
The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
,
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
,
Planet
A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...
s and
navigational stars
Fifty-seven navigational stars and additionally the star Polaris are given a special status in the field of celestial navigation. Of the approximately 6,000 stars visible to the naked eye under optimal conditions, these selected stars are ...
. Such systems are in use as well for terrestrial navigating as for interstellar navigating. By knowing which point on the rotating earth a celestial object is above and measuring its height above the observer's horizon, the navigator can determine his distance from that subpoint. A
nautical almanac
A nautical almanac is a publication describing the positions of a selection of celestial bodies for the purpose of enabling navigators to use celestial navigation to determine the position of their ship while at sea. The Almanac specifies for eac ...
and a
marine chronometer
A marine chronometer is a precision timepiece that is carried on a ship and employed in the determination of the ship's position by celestial navigation. It is used to determine longitude by comparing Greenwich Mean Time (GMT), or in the modern ...
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 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 the 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.
Marine chronometer
In order to accurately measure longitude, the precise time of a sextant sighting (down to the second, if possible) must be recorded. Each second of error is equivalent to 15 seconds of longitude error, which at the equator is a position error of .25 of a nautical mile, about the accuracy limit of manual celestial navigation.
The spring-driven marine chronometer is a precision timepiece used aboard ship to provide accurate time for celestial observations.
[Bowditch, 2002:269.] 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.
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.
The difference between GMT and chronometer time is carefully determined and applied as a correction to all chronometer readings.
Spring-driven chronometers must be wound at about the same time each day.
Quartz crystal marine chronometers have replaced spring-driven chronometers aboard many ships because of their greater accuracy.
They are maintained on GMT directly from radio time signals.
This eliminates chronometer error and watch error corrections.
Should the second hand be in error by a readable amount, it can be reset electrically.
The basic element for time generation is a quartz crystal oscillator.
The quartz crystal is temperature compensated and is hermetically sealed in an evacuated envelope.
A calibrated adjustment capability is provided to adjust for the aging of the crystal.
The chronometer is designed to operate for a minimum of 1 year on a single set of batteries.
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.
In practice, a wrist watch coordinated to the nearest second with the chronometer will be adequate.
A stop watch, either spring wound or digital, may also be used for celestial observations.
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.
All chronometers and watches should be checked regularly with a radio time signal.
Times and frequencies of radio time signals are listed in publications such as
Radio Navigational Aids
The ''Radio Navigational Aids'' (Publication 117) publication contains a detailed list of selected worldwide radio stations that provide services to the mariner.National Geospatial Intelligence Agency, 2008. The publication is divided into chapte ...
.
The marine sextant
![Marine sextant](https://upload.wikimedia.org/wikipedia/commons/4/4a/Marine_sextant.svg)
The second critical component of celestial navigation is to measure the angle formed at the observer's eye between the celestial body and the sensible horizon. The sextant, an 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.
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.
Inertial navigation
Inertial navigation system
An inertial navigation system (INS) is a navigation device that uses motion sensors (accelerometers), rotation sensors ( gyroscopes) and a computer to continuously calculate by dead reckoning the position, the orientation, and the velocity (dir ...
(INS) is a
dead reckoning
In navigation, dead reckoning is the process of calculating current position of some moving object by using a previously determined position, or fix, and then incorporating estimates of speed, heading direction, and course over elapsed time. ...
type of navigation system that computes its position based on motion sensors. Before actually navigating, the initial latitude and longitude and the INS's physical orientation relative to the earth (e.g., north and level) are established. After alignment, an INS receives impulses from motion detectors that measure (a) the acceleration along three axes (accelerometers), and (b) rate of rotation about three orthogonal axes (gyroscopes). These enable an INS to continually and accurately calculate its current latitude and longitude (and often velocity).
Advantages over other navigation systems are that, once aligned, an INS does not require outside information. An INS is not affected by adverse weather conditions and it cannot be detected or jammed. Its disadvantage is that since the current position is calculated solely from previous positions and motion sensors, its errors are cumulative, increasing at a rate roughly proportional to the time since the initial position was input. Inertial navigation systems must therefore be frequently corrected with a location 'fix' from some other type of navigation system.
The first inertial system is considered to be the V-2 guidance system deployed by the Germans in 1942. However, inertial sensors are traced to the early 19th century.
["An historical perspective on inertial navigation systems", Daniel Tazartes, ''2014 International Symposium on Inertial Sensors and Systems (ISISS)'', Laguna Beach, CA, USA] The advantages INSs led their use in aircraft, missiles, surface ships and submarines. For example, the U.S. Navy developed the Ships Inertial Navigation System (SINS) during the
Polaris missile
The UGM-27 Polaris missile was a two-stage solid-fueled nuclear-armed submarine-launched ballistic missile (SLBM). As the United States Navy's first SLBM, it served from 1961 to 1980.
In the mid-1950s the Navy was involved in the Jupiter missi ...
program to ensure a reliable and accurate navigation system to initial its missile guidance systems. Inertial navigation systems were in wide use until
satellite navigation
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high pr ...
systems (GPS) became available. INSs are still in common use on submarines (since GPS reception or other fix sources are not possible while submerged) and long-range missiles.
Space navigation
Not to be confused with satellite navigation, which depends upon satellites to function, space navigation refers to the navigation of spacecraft themselves. This has historically been achieved (during the
Apollo program) via a
navigational computer, an Inertial navigation system, and via celestial inputs entered by astronauts which were recorded by sextant and telescope. Space rated navigational computers, like those found on Apollo and later missions, are designed to be hardened against possible data corruption from radiation.
Another possibility that has been explored for deep space navigation is
Pulsar navigation, which compares the X-ray bursts from a collection of known pulsars in order to determine the position of a spacecraft. This method has been tested by multiple space agencies, such as
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...
and
ESA
, owners =
, headquarters = Paris, Île-de-France, France
, coordinates =
, spaceport = Guiana Space Centre
, seal = File:ESA emblem seal.png
, seal_size = 130px
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.
Electronic navigation
Radio navigation
A radio direction finder or RDF is a device for finding the direction to a
radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmi ...
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.
RDFs works by rotating a directional
antenna and 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 easy to spot on
German
German(s) may refer to:
* Germany (of or related to)
** Germania (historical use)
* Germans, citizens of Germany, people of German ancestry, or native speakers of the German language
** For citizens of Germany, see also German nationality law
**Ge ...
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
aircraft, as loops under the rear section of the fuselage, whereas most
US aircraft enclosed the antenna in a small teardrop-shaped fairing.
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.
Decca Decca may refer to:
Music
* Decca Records or Decca Music Group, a record label
* Decca Gold, a classical music record label owned by Universal Music Group
* Decca Broadway, a musical theater record label
* Decca Studios, a recording facility in W ...
,
OMEGA
Omega (; capital: Ω, lowercase: ω; Ancient Greek ὦ, later ὦ μέγα, Modern Greek ωμέγα) is the twenty-fourth and final letter in the Greek alphabet. In the Greek numeric system/ isopsephy ( gematria), it has a value of 800. The ...
, and
LORAN-C
Loran-C is a hyperbolic radio navigation system that allows a receiver to determine its position by listening to low frequency radio signals that are transmitted by fixed land-based radio beacons. Loran-C combined two different techniques to ...
are three similar hyperbolic navigation systems. Decca was a
hyperbolic
Hyperbolic is an adjective describing something that resembles or pertains to a hyperbola (a curve), to hyperbole (an overstatement or exaggeration), or to hyperbolic geometry.
The following phenomena are described as ''hyperbolic'' because they ...
low frequency radio navigation
Radio navigation or radionavigation is the application of radio frequencies to determine a position of an object on the Earth, either the vessel or an obstruction. Like radiolocation, it is a type of radiodetermination.
The basic principles a ...
system (also known as
multilateration Trilateration is the use of distances (or "ranges") for determining the unknown position coordinates of a point of interest, often around Earth (geopositioning).
When more than three distances are involved, it may be called multilateration, for e ...
) that was first deployed during
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
when the Allied forces needed a system which could be used to achieve accurate landings. As was the case with
Loran C
Loran-C is a hyperbolic radio navigation system that allows a receiver to determine its position by listening to low frequency radio signals that are transmitted by fixed land-based radio beacons. Loran-C combined two different techniques to p ...
, 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 in the North Sea and was used by helicopters operating to
oil platforms.
The OMEGA Navigation System was the first truly global
radio navigation
Radio navigation or radionavigation is the application of radio frequencies to determine a position of an object on the Earth, either the vessel or an obstruction. Like radiolocation, it is a type of radiodetermination.
The basic principles a ...
system for aircraft, operated by the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
in cooperation with six partner nations. OMEGA was 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 (6 km) 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 submarine
OmegaDue to the success of the
Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
the use of Omega declined during the 1990s, to a point where the cost of operating Omega could no longer be justified. Omega was terminated on September 30, 1997, and all stations ceased operation.
LORAN is a terrestrial
navigation
Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land 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
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
,
Japan, and several European countries. Russia uses a nearly exact system in the same frequency range, called
CHAYKA
Chayka (russian: Чайка, lit. "seagull") also known as Radioteknicheskaya Systema Dalyoloiy Navigatsii abbreviated as RSDN (lit. Russian Hyperbolic Radio Navigation System) is a Russian terrestrial radio navigation system, similar to Loran ...
. LORAN use is in steep decline, with
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
being the primary replacement. However, there are attempts to enhance and re-popularize LORAN. LORAN signals are less susceptible to interference and can penetrate better into foliage and buildings than GPS signals.
Radar navigation
![Navigation_system_on_a_merchant_ship_2](https://upload.wikimedia.org/wikipedia/commons/c/cf/Navigation_system_on_a_merchant_ship_2.jpg)
When a 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.
[Maloney, 2003:744.] A fix consisting of only radar information is called a radar fix.
[Bowditch, 2002:816.]
Types of radar fixes include "range and bearing to a single object,"
[National Imagery and Mapping Agency, 2001:163.] "two or more bearings,"
"tangent bearings,"
and "two or more ranges."
Parallel indexing is a technique defined by William Burger in the 1957 book ''The Radar Observer's Handbook''.
[National Imagery and Mapping Agency, 2001:169.] 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.
This parallel line allows the navigator to maintain a given distance away from hazards.
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.
[National Imagery and Mapping Agency, 2001:164.]
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.
[National Imagery and Mapping Agency, 2001:182.] During the transit, the navigator can check that the ship is on track by checking that the pip lies on the drawn line.
Satellite navigation
Global Navigation Satellite System or GNSS is the term for satellite navigation systems that provide positioning with global coverage. A GNSS allow small
electronic
Electronic may refer to:
*Electronics, the science of how to control electric energy in semiconductor
* ''Electronics'' (magazine), a defunct American trade journal
*Electronic storage, the storage of data using an electronic device
*Electronic co ...
receivers to determine their location (
longitude
Longitude (, ) is a geographic coordinate that specifies the east– west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek lette ...
,
latitude
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...
, and
altitude
Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context ...
) within a few meters using
time signal
A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day.
Church bells or voices announcing hours of prayer gave way to automatically operated chimes on public clocks; however, a ...
s transmitted along a
line of sight
The line of sight, also known as visual axis or sightline (also sight line), is an imaginary line between a viewer/observer/ spectator's eye(s) and a subject of interest, or their relative direction. The subject may be any definable object taken ...
by
radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmi ...
from
satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioi ...
s. Receivers on the ground with a fixed position can also be used to calculate the precise time as a reference for scientific experiments.
As of October 2011, only the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
NAVSTAR
Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
(GPS) and the
Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
n
GLONASS
GLONASS (russian: ГЛОНАСС, label=none, ; rus, links=no, Глобальная навигационная спутниковая система, r=Global'naya Navigatsionnaya Sputnikovaya Sistema, t=Global Navigation Satellite System) is ...
are fully globally operational GNSSs. The
European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been de ...
's
Galileo positioning system
Galileo is a global navigation satellite system (GNSS) that went live in 2016, created by the European Union through the European Space Agency (ESA), operated by the European Union Agency for the Space Programme (EUSPA), headquartered in Pra ...
is a next generation GNSS in the final deployment phase, and became operational in 2016.
China has indicated it may expand its regional
Beidou navigation system
The BeiDou Navigation Satellite System (BDS; ) is a Chinese satellite navigation system. It consists of two separate satellite constellations. The first BeiDou system, officially called the BeiDou Satellite Navigation Experimental System and ...
into a global system.
More than two dozen GPS satellites are in
medium Earth orbit
A medium Earth orbit (MEO) is an Earth-centered orbit with an altitude above a low Earth orbit (LEO) and below a high Earth orbit (HEO) – between above sea level. , transmitting signals allowing GPS receivers to determine the receiver's
location
In geography, location or place are used to denote a region (point, line, or area) on Earth's surface or elsewhere. The term ''location'' generally implies a higher degree of certainty than ''place'', the latter often indicating an entity with an ...
, speed and direction.
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
Cartography (; from grc, χάρτης , "papyrus, sheet of paper, map"; and , "write") is the study and practice of making and using maps. Combining science, aesthetics and technique, cartography builds on the premise that reality (or an im ...
and
land surveying. GPS also provides a precise
time reference used in many applications including scientific study of
earthquake
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...
s, and
synchronization of telecommunications networks.
Developed by the
United States Department of Defense
The United States Department of Defense (DoD, USDOD or DOD) is an executive branch department of the federal government charged with coordinating and supervising all agencies and functions of the government directly related to national sec ...
, GPS is officially named NAVSTAR GPS (NAVigation Satellite Timing And Ranging Global Positioning System). The
satellite constellation
A satellite constellation is a group of artificial satellites working together as a system. Unlike a single satellite, a constellation can provide permanent global or near-global coverage, such that at any time everywhere on Earth at least one s ...
is managed by the
United States Air Force
The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...
50th Space Wing. The cost of maintaining the system is approximately
US$
The United States dollar (symbol: $; code: USD; also abbreviated US$ or U.S. Dollar, to distinguish it from other dollar-denominated currencies; referred to as the dollar, U.S. dollar, American dollar, or colloquially buck) is the official ...
750 million per year,
[GPS Overview from the NAVSTAR Joint Program Office](_blank)
. Accessed December 15, 2006. including the replacement of aging satellites, and research and development. Despite this fact, GPS is free for civilian use as a
public good.
Modern
smartphones act as personal
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
navigators for civilians who own them. Overuse of these devices, whether in the vehicle or on foot, can lead to a relative inability to learn about navigated environments, resulting in sub-optimal navigation abilities when and if these devices become unavailable. Typically a
compass
A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself wit ...
is also provided to determine direction when not moving.
Acoustic navigation
Navigation processes
Ships and similar vessels
One day's work in navigation
The day's work in navigation is a minimal set of tasks consistent with prudent navigation. The definition will vary on military and civilian vessels, and from ship to ship, but the traditional method takes a form resembling:
[Turpin and McEwen, 1980:6–18.]
# Maintain a continuous dead reckoning plot.
# Take two or more star observations at morning twilight for a celestial fix (prudent to observe 6 stars).
# Morning sun observation. Can be taken on or near
prime vertical
In astronomy, astrology, and geodesy, the prime vertical or first vertical is the vertical circle passing east and west through the zenith of a specific location, and intersecting the horizon in its east and west points.
In other words, the prime v ...
for longitude, or at any time for a line of position.
# Determine compass error by azimuth observation of the sun.
# Computation of the interval to noon, watch time of local apparent noon, and constants for meridian or ex-meridian sights.
# Noontime meridian or ex-meridian observation of the sun for noon latitude line. Running fix or cross with Venus line for noon fix.
# Noontime determination the day's run and day's set and drift.
# At least one afternoon sun line, in case the stars are not visible at twilight.
# Determine compass error by azimuth observation of the sun.
# Take two or more star observations at evening twilight for a celestial fix (prudent to observe 6 stars).
Navigation on ships is usually always conducted on the
bridge
A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somethi ...
. It may also take place in adjacent space, where chart tables and publications are available.
Passage planning
![Exval](https://upload.wikimedia.org/wikipedia/commons/6/66/Exval.jpeg)
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 en route portion of a voyage, approaching the destination, and
mooring
A mooring is any permanent structure to which a vessel may be secured. Examples include quays, wharfs, jetties, piers, anchor buoys, and mooring buoys. A ship is secured to a mooring to forestall free movement of the ship on the water. An ''an ...
. According to international law, a vessel's
captain is legally responsible for passage planning,
however on larger vessels, the task will be delegated to the ship's
navigator
A navigator is the person on board a ship or aircraft responsible for its navigation.Grierson, MikeAviation History—Demise of the Flight Navigator FrancoFlyers.org website, October 14, 2008. Retrieved August 31, 2014. The navigator's primar ...
.
Studies show that
human error
Human error refers to something having been done that was " not intended by the actor; not desired by a set of rules or an external observer; or that led the task or system outside its acceptable limits".Senders, J.W. and Moray, N.P. (1991) Human ...
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.
The practice of voyage planning has evolved from penciling lines on
nautical chart
A nautical chart is a graphic representation of a sea area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land ( topographic map), natural features of the seabed, details of the co ...
s to a process of
risk management.
Passage planning consists of four stages: appraisal, planning, execution, and monitoring,
which are specified in ''
International Maritime Organization Resolution A.893(21), Guidelines For Voyage Planning,''
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 or publications. There are some fifty elements of a comprehensive passage plan depending on the size and type of vessel.
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. This will involve considering the type of navigation required e.g.
Ice navigation
Ice navigation is a specialist area of navigation involving the use of maritime skills to determine and monitor the position of ships in cold waters, where ice is a hazard to the safety of navigation. The presence of sea ice requires a ship to ...
, the region the ship will be passing through and the
hydrographic information on the route. 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
![Integriertes Brückensystem](https://upload.wikimedia.org/wikipedia/commons/4/46/Integriertes_Br%C3%BCckensystem.jpg)
Electronic integrated bridge concepts are driving future navigation system planning.
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.
The navigator becomes a system manager, choosing system presets, interpreting system output, and monitoring vessel response.
Land navigation
Navigation for cars and other land-based travel typically uses
map
A map is a symbolic depiction emphasizing relationships between elements of some space, such as objects, regions, or themes.
Many maps are static, fixed to paper or some other durable medium, while others are dynamic or interactive. Although ...
s,
landmarks, and in recent times
computer navigation ("
satnav
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high pre ...
", short for satellite navigation), as well as any means available on water.
Computerized navigation commonly relies on
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
for current location information, a
navigational map database of roads and navigable routes, and uses
algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing ...
s related to the
shortest path problem to identify optimal routes.
Underwater navigation
Standards, training and organisations
Professional standards for navigation depend on the type of navigation and vary by country. For marine navigation,
Merchant Navy deck officers are trained and internationally certified according to the
STCW Convention.
Leisure and amateur mariners may undertake lessons in navigation at local/regional training schools.
Naval officers receive navigation training as part of their naval training.
In land navigation, courses and training is often provided to young persons as part of general or extra-curricular education. Land navigation is also an essential part of army training. Additionally, organisations such as the
Scouts
Scouting, also known as the Scout Movement, is a worldwide youth movement employing the Scout method, a program of informal education with an emphasis on practical outdoor activities, including camping, woodcraft, aquatics, hiking, backpack ...
and The Duke of Edinburgh's Award, DoE programme teach navigation to their students. Orienteering organisations are a type of sports that require navigational skills using a map and compass to navigate from point to point in diverse and usually unfamiliar terrain whilst moving at speed.
In aviation, pilots undertake air navigation training as part of learning to fly.
Professional organisations also assist to encourage improvements in navigation or bring together navigators in learned environments. The Royal Institute of Navigation (RIN) is a learned society with charitable status, aimed at furthering the development of navigation on land and sea, in the air and in space. It was founded in 1947 as a forum for mariners, pilots, engineers and academics to compare their experiences and exchange information.
In the US, the Institute of Navigation (ION) is a non-profit professional organisation advancing the art and science of positioning, navigation and timing.
Publications
Numerous nautical publications are available on navigation, which are published by professional sources all over the world. In the UK, the United Kingdom Hydrographic Office, the Witherby Publishing Group and the Nautical Institute provide numerous navigational publications, including the comprehensive Admiralty Manual of Navigation.
In the US, Bowditch's American Practical Navigator is a free available encyclopedia of navigation issued by the US Government.
See also
* Robot navigation
* TVMDC
* Collision avoidance in transportation
* Spatial cognition#Navigation
Notes
References
Nathaniel Bowditch, ''The American Practical Navigator,'' (2002) by the United States government*
*
*
*
*
*
*
*
*
*
External links
''Lectures in Navigation''by Ernest Gallaudet Draper
{{Authority control
Navigation,