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. The field of navigation includes four general categories: land navigation, marine navigation , aeronautic navigation, and space navigation.
168-575: Circumnavigation is the complete navigation around an entire island , continent , or astronomical body (e.g. a planet or moon ). This article focuses on the circumnavigation of Earth . The first circumnavigation of the Earth was the Magellan Expedition , which sailed from Sanlucar de Barrameda, Spain in 1519 and returned in 1522, after crossing the Atlantic , Pacific , and Indian oceans. Since
336-444: A Daily News -sponsored round-the-world flight. The first aerial circumnavigation of the planet was flown in 1924 by aviators of the U.S. Army Air Service in a quartet of Douglas World Cruiser biplanes. The first non-stop aerial circumnavigation of the planet was flown in 1949 by Lucky Lady II , a United States Air Force Boeing B-50 Superfortress . Since the development of commercial aviation, there are regular routes that circle
504-501: A Portuguese ambassador was sent to Paris to report the French intrusion, João III appointed Mem de Sá as new Brazilian governor general, and Sá left for Brazil in 1557. Sá and his forces had by 1560 expelled the combined Huguenot , Scottish Calvinist , and slave forces from France Antarctique, but left survivors after burning their fortifications and villages. These survivors would settle Gloria Bay , Flamengo Beach , and Parapapuã with
672-741: A cautious trade began. In 1557 the Chinese authorities allowed the Portuguese to settle in Macau, creating a warehouse in the trade of goods between China, Japan, Goa and Europe. Portuguese operations in Asia did not go unnoticed, and in 1521 Magellan arrived in the region and claimed the Philippines for Spain. In 1525, Spain under Charles V sent an expedition to colonise the Moluccas islands , claiming they were in his zone of
840-469: 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. 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 or LOP. A line of position can refer to two different things, either
1008-543: A degree or so. Similar to latitude, the longitude of a place on Earth is the angular distance east or west of the prime meridian 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 has a longitude of 74° west . For most of history, mariners struggled to determine longitude. Longitude can be calculated if
1176-537: A disappointment for the Portuguese, the decision was taken to hold it while exploring along the Atlantic African coast. A key supporter of this policy was Infante Dom Henry the Navigator , who had been involved in the capture of Ceuta , and who took the lead role in promoting and financing Portuguese maritime exploration until his death in 1460. At the time, Europeans did not know what lay beyond Cape Bojador on
1344-478: 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 position to establish an estimated position. Lines (or circles) of position can be derived from
1512-587: A few meters 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. As of October 2011, only the United States NAVSTAR Global Positioning System (GPS) and the Russian GLONASS are fully globally operational GNSSs. The European Union 's Galileo positioning system
1680-509: A few years after Cabral arrived from Brazil, competition came along from France. In 1503, an expedition under the command of Gonçalo Coelho reported French raids on the Brazilian coasts, and explorer Binot Paulmier de Gonneville traded for brazilwood after making contact in southern Brazil a year later. Expeditions sponsored by Francis I along the North American coast directly violated of
1848-564: A fifth of Portugal's per-capita income. When King Philip II of Spain (Philip I of Portugal) seized the Portuguese crown in 1580, there began a 60-year union between Spain and Portugal known to subsequent historiography as the Iberian Union , although the realms continued to have separate administrations. As the King of Spain was also King of Portugal, Portuguese colonies became the subject of attacks by three rival European powers hostile to Spain:
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#17330852523632016-455: A force led by António Correia captured Bahrain , defeating the Jabrid King, Muqrin ibn Zamil . In a shifting series of alliances, the Portuguese dominated much of the southern Persian Gulf for the next hundred years. With the regular maritime route linking Lisbon to Goa since 1497, the island of Mozambique became a strategic port, and there was built Fort São Sebastião and a hospital. In
2184-529: A global scale, controlling vast portions of the Americas , Africa and various islands in Asia and Oceania . It was one of the most powerful empires of the early modern period , while at its greatest extent in 1820, covering over 5.5 million square km (5 million square miles), making it among of the largest empires in history. Composed of the overseas colonies , factories , and later overseas territories , governed by
2352-407: 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. 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
2520-440: A large Castilian fleet attempted to wrest control of this lucrative trade, but were decisively defeated in the 1478 Battle of Guinea , which firmly established an exclusive Portuguese control. In 1481, the recently crowned João II decided to build São Jorge da Mina in order to ensure the protection of this trade, which was held again as a royal monopoly. The equator was crossed by navigators sponsored by Fernão Gomes in 1473 and
2688-402: A line on a chart or a line between the observer and an object in real life. 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 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,
2856-533: A non-stop race where use of the Panama and Suez Canals would be impossible. Yacht racing therefore defines a world circumnavigation to be a passage of at least 21,600 nautical miles (40,000 km) in length which crosses the equator , crosses every meridian and finishes in the same port as it starts. The second map on the right shows the route of the Vendée Globe round-the-world race in red; overlaid in yellow are
3024-450: 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. 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
3192-399: 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 World War II aircraft, as loops under
3360-418: A radio time signal. Times and frequencies of radio time signals are listed in publications such as Radio Navigational Aids . 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
3528-643: A role in their alliance. The Adal Sultanate defeated the Ethiopians in the battle of Shimbra Kure in 1529, and Islam spread further in the region . Portugal responded by aiding king Gelawdewos with Portuguese soldiers and muskets. Though the Ottomans responded with support of soldiers and muskets to the Adal Sultanate, after the death of the Adali sultan Ahmad ibn Ibrahim al-Ghazi in the battle of Wayna Daga in 1543,
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#17330852523633696-610: A sea route to Asia was finally achieved in a ground-breaking voyage commanded by Vasco da Gama . The squadron of Vasco da Gama left Portugal in 1497, rounded the Cape and continued along the coast of East Africa, where a local pilot was brought on board who guided them across the Indian Ocean, reaching Calicut , the capital of the kingdom ruled by Zamorins , also known as Kozhikode ) in south-western India in May 1498. The second voyage to India
3864-400: A single object," "two or more bearings," "tangent bearings," and "two or more ranges." Radar can also be used with ECDIS as a means of position fixing with the radar image or distance/bearing overlaid onto an Electronic nautical chart . Parallel indexing is a technique defined by William Burger in the 1957 book The Radar Observer's Handbook . This technique involves creating a line on
4032-466: A squadron of junks against Portuguese caravels that succeeded in driving the Portuguese away and reclaiming Tamao. As a result, the Chinese posted an edict banning men with Caucasian features from entering Canton, killing multiple Portuguese there, and driving the Portuguese back to sea. After the Sultan of Bintan detained several Portuguese under Tomás Pires, the Chinese then executed 23 Portuguese and threw
4200-404: A sufficient depth of water below the hull as well as a consideration for squat . It may also involve navigating a ship within a river, canal or channel in close proximity to land. 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
4368-414: A trading hub at Tangasseri , Quilon ( Coulão , Kollam ) city in (1503) in 1502, which became the centre of trade in pepper, and after founding manufactories at Cochin ( Cochim , Kochi) and Cannanore ( Canonor , Kannur), built a factory at Quilon in 1503. In 1505 King Manuel I of Portugal appointed Francisco de Almeida first Viceroy of Portuguese India, establishing the Portuguese government in
4536-413: A variety of sources: 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. 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
4704-449: 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 and ESA . 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
4872-520: 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 into a global system. Portuguese East Indies The Portuguese Empire was a colonial empire that existed between 1415 and 1999. In conjunction with the Spanish Empire , it ushered in the European Age of Discovery . It achieved
5040-436: 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 one 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
5208-425: 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
Circumnavigation - Misplaced Pages Continue
5376-434: Is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks. All navigational techniques involve locating the navigator's position 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. In
5544-549: Is approximately the length of the Tropic of Cancer ). The course must include set control points at latitudes outside the Arctic and Antarctic circles. In ballooning, which is at the mercy of the winds, the requirements are even more relaxed. The course must cross all meridians, and must include a set of checkpoints which are all outside of two circles, chosen by the pilot, having radii of 3,335.85 kilometres (2,072.80 mi) and enclosing
5712-1027: 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. 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 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 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. Not to be confused with satellite navigation, which depends upon satellites to function, space navigation refers to
5880-407: Is currently held by a wind-powered vessel, the trimaran IDEC 3 . The record was established by six sailors: Francis Joyon , Alex Pella , Clément Surtel, Gwénolé Gahinet, Sébastien Audigane and Bernard Stamm. On 26 January, 2017, this crew finished circumnavigating the globe in 40 days, 23 hours, 30 minutes and 30 seconds. The absolute speed sailing record around the world followed
6048-441: 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. A chronometer differs from a spring-driven watch principally in that it contains a variable lever device to maintain even pressure on
6216-478: 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
6384-512: Is not generally considered a "circumnavigation". The path of a true (global) circumnavigation forms a continuous loop on the surface of Earth separating two regions of comparable area. A basic definition of a global circumnavigation would be a route which covers roughly a great circle , and in particular one which passes through at least one pair of points antipodal to each other. In practice, people use different definitions of world circumnavigation to accommodate practical constraints, depending on
6552-449: Is particularly useful due to their high power and location near major cities. 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
6720-455: 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 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,
6888-817: Is the cultural successor of the Empire, analogous to the Commonwealth of Nations for countries formerly part of the British Empire . The origin of the Kingdom of Portugal lay in the reconquista , the gradual reconquest of the Iberian Peninsula from the Moors . After establishing itself as a separate kingdom in 1139, Portugal completed its reconquest of Moorish territory by reaching Algarve in 1249, but its independence continued to be threatened by neighbouring Castile until
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7056-954: The Battle of Tunmen in Tamão or Tuen Mun . In 1521, the Portuguese lost two ships at the Battle of Sincouwaan in Lantau Island . The Portuguese also lost two ships at Shuangyu in 1548 where several Portuguese were captured and near the Dongshan Peninsula . In 1549 two Portuguese junks and Galeote Pereira were captured. During these battles the Ming Chinese captured weapons from the defeated Portuguese which they then reverse engineered and mass-produced in China such as matchlock musket arquebuses which they named bird guns and breech-loading swivel guns which they named as Folangji ( Frankish ) cannon because
7224-529: The Bering Strait on the ice, and around 3,000 kilometres (1,900 mi) of roadless swamped or freezing cold areas in Alaska and eastern Russia. No one has so far travelled all of this route by foot. David Kunst was the first person that Guinness verified to have walked around the world between 20 June 1970 and 5 October 1974, by "[walking] 23,250 km (14,450 miles) through four continents". Navigation It
7392-568: The Bijapur sultanate in 1510 was soon countered by the Bijapuris, but with the help of Hindu privateer Timoji , on 25 November of the same year it was recaptured. In Goa, Albuquerque began the first Portuguese mint in India in 1510. He encouraged Portuguese settlers to marry local women, built a church in honor of St. Catherine (as it was recaptured on her feast day), and attempted to build rapport with
7560-808: The Bruneian Empire from 1530 and described the capital of Brunei as surrounded by a stone wall. The Portuguese empire expanded into the Persian Gulf, contesting control of the spice trade with the Ajuran Empire and the Ottoman Empire . Albuquerque conquered the Huwala state of Hormuz at the head of the Persian Gulf in 1515, establishing it as a vassal state. Aden , however, resisted Albuquerque's expedition in that same year and another attempt by Albuquerque's successor Lopo Soares de Albergaria in 1516. In 1521
7728-482: The Congo River by Diogo Cão in 1482. It was during this expedition that the Portuguese first encountered the Kingdom of Kongo , with which it soon developed a rapport. During his 1485–86 expedition, Cão continued to Cape Cross , in present-day Namibia , near the Tropic of Capricorn . In 1488, Bartolomeu Dias rounded the southern tip of Africa and reached Great Fish River on the coast of Africa, proving false
7896-736: The Dahomey annexed the Fort of São João Baptista de Ajudá , and in December that year India annexed Goa, Daman, and Diu . The Portuguese Colonial War in Africa lasted from 1961 until the final overthrow of the Estado Novo regime in 1974. The Carnation Revolution of April 1974 in Lisbon led to the hasty decolonization of Portuguese Africa and to the 1975 annexation of Portuguese Timor by Indonesia. Decolonization prompted
8064-584: The Dutch Republic , England , and France . With its smaller population, Portugal found itself unable to effectively defend its overstretched network of trading posts, and the empire began a long and gradual decline. Eventually, Brazil became the most valuable colony of the second era of empire (1663–1825), until, as part of the wave of independence movements that swept the Americas during the early 19th century, it broke away in 1822. The third era of empire covers
8232-650: The Kingdom of Portugal , and later the Republic of Portugal , it was one of the longest-lived colonial empires in European history, lasting 584 years from the conquest of Ceuta in North Africa in 1415 to the transfer of sovereignty over Macau to China in 1999. The power and influence of the Kingdom of Portugal would eventually expand across the globe. In the wake of the Reconquista , Portuguese sailors began exploring
8400-645: The Philippines . The voyage was initially led by the Portuguese Ferdinand Magellan but he was killed on Mactan in the Philippines in 1521. The remaining sailors decided to circumnavigate the world instead of making the return voyage—no passage east across the Pacific would be successful for four decades —and continued the voyage across the Indian Ocean, round the southern cape of Africa , north along Africa's Atlantic coasts, and back to Spain in 1522. Of
8568-550: The Red Sea and passing through Bassein to pay duties and allow the horse trade. After Mughal ruler Humayun had success against Bahadur, the latter signed another treaty with the Portuguese to confirm the provisions and allowed the fort to be built in Diu. Shortly afterward, Humayun turned his attention elsewhere, and the Gujarats allied with the Ottomans to regain control of Diu and lay siege to
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#17330852523638736-764: The Spanish monarchs funded Christopher Columbus 's expedition to sail west to reach the Indies by crossing the Atlantic, which resulted in the Discovery of the Americas . In 1498, a Portuguese expedition commanded by Vasco da Gama reached India by sailing around Africa, opening up direct trade with Asia . Soon, the Portuguese sailed further eastward, to the Spice Islands in 1512, landing in China one year later. The first circumnavigation of
8904-669: The Sultanate of Gujarat due to his suspicions of traders from the region possessing more power. The Mamlûk Sultanate sultan Al-Ashraf Qansuh al-Ghawri along with the Gujarati sultanate attacked Portuguese forces in the harbor of Chaul , resulting in the death of Almeida's son . In retaliation, the Portuguese fought and destroyed the Mamluks and Gujarati fleets in the sea Battle of Diu in 1509. Along with Almeida's initial attempts, Manuel I and his council in Lisbon had tried to distribute power in
9072-477: The Treaty of Tordesilhas . By 1531, the French had stationed a trading post off of an island on the Brazilian coast. The increase in brazilwood smuggling from the French led João III to press an effort to establish effective occupation of the territory. In 1531, a royal expedition led by Martim Afonso de Sousa and his brother Pero Lopes went to patrol the whole Brazilian coast, banish the French, and create some of
9240-502: The Treaty of Tordesillas , since there was no set limit to the east. The expedition of García Jofre de Loaísa reached the Moluccas, docking at Tidore . With the Portuguese already established in nearby Ternate, conflict was inevitable, leading to nearly a decade of skirmishes. A resolution was reached with the Treaty of Zaragoza in 1529, attributing the Moluccas to Portugal and the Philippines to Spain. The Portuguese traded regularly with
9408-537: The United States 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
9576-479: The Vostok 2 was the first human to fully circumnavigate Earth in spaceflight and made 17.5 orbits on August 6, 1961. According to adjudicating bodies Guinness World Records and Explorersweb, Jason Lewis completed the first human-powered circumnavigation of the globe on 6 October 2007. This was part of a thirteen-year journey entitled Expedition 360 . In 2012, Turkish-born American adventurer Erden Eruç completed
9744-450: The cartaz licensing system, granting merchant ships protection against pirates and rival states. Profiting from the rivalry between the ruler of Kochi and the Zamorin of Calicut , the Portuguese were well-received and seen as allies, as they obtained a permit to build the fort Immanuel ( Fort Kochi ) and a trading post that was the first European settlement in India. They established
9912-466: The jet streams , which circulate in the northern and southern hemispheres without crossing the equator. There is therefore no requirement to cross the equator, or to pass through two antipodal points, in the course of setting a round-the-world aviation record. For powered aviation, the course of a round-the-world record must start and finish at the same point and cross all meridians; the course must be at least 36,770 kilometres (19,850 nmi) long (which
10080-558: The "Island of the Papua". In 1517, João da Silveira commanded a fleet to Chittagong , and by 1528, the Portuguese had established a settlement in Chittagong . The Portuguese eventually based their centre of operations along the Hugli River , where they encountered Muslims, Hindus, and Portuguese deserters known as Chatins . Jorge Álvares was the first European to reach China by sea, while
10248-400: 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
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#173308525236310416-442: The "sweet salt" that was rare in Europe. Already cultivated in Algarve , the accessibility of Madeira attracted Genoese and Flemish traders keen to bypass Venetian monopolies. Slaves were used, and the proportion of imported slaves in Madeira reached 10% of the total population by the 16th century. By 1480 Antwerp had some seventy ships engaged in the Madeira sugar trade, with the refining and distribution concentrated in Antwerp. By
10584-435: The 1490s Madeira had overtaken Cyprus as a producer of sugar. The success of sugar merchants such as Bartolomeo Marchionni would propel the investment in future travels. In 1469, after prince Henry's death and as a result of meagre returns of the African explorations, King Afonso V granted the monopoly of trade in part of the Gulf of Guinea to merchant Fernão Gomes . Gomes, who had to explore 100 miles (160 km) of
10752-402: The 1530s, from Latin 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". Roughly, the latitude of a place on Earth is its angular distance north or south of the equator . Latitude is usually expressed in degrees (marked with °) ranging from 0° at the Equator to 90° at
10920-464: The 270 crew members who set out from Seville, only 18 were still with the expedition at the end including its surviving captain, the Spaniard Juan Sebastián Elcano . The next to circumnavigate the globe were the survivors of the Castilian/Spanish expedition of García Jofre de Loaísa between 1525 and 1536. None of the seven original ships of the Loaísa expedition nor its first four leaders—Loaísa, Elcano , Salazar , and Íñiguez —survived to complete
11088-537: The African coast. Henry wished to know how far the Muslim territories in Africa extended, and whether it was possible to reach Asia by sea, both to reach the source of the lucrative spice trade and perhaps to join forces with the fabled Christian kingdom of Prester John that was rumoured to exist somewhere in the "Indies". Under his sponsorship, soon the Atlantic islands of Madeira (1419) and Azores (1427) were reached and started to be settled, producing wheat for export to Portugal. Soon its ships were bringing into
11256-436: The Azores, the Islands Armada protected the ships en route to Lisbon. In 1534, Gujarat faced attack from the Mughals and the Rajput states of Chitor and Mandu . The Sultan Bahadur Shah of Gujarat was forced to sign the Treaty of Bassein with the Portuguese, establishing an alliance to regain the country, giving in exchange Daman , Diu , Mumbai and Bassein . It also regulated the trade of Gujarati ships departing to
11424-439: The Christian crusade against Islam; to the military class, it promised glory on the battlefield and the spoils of war; and finally, it was also a chance to expand Portuguese trade and to address Portugal's economic decline. In 1415 an attack was made on Ceuta , a strategically located North African Muslim enclave along the Mediterranean Sea, and one of the terminal ports of the trans-Saharan gold and slave trades. The conquest
11592-410: The European market highly valued gold, ivory, pepper, cotton, sugar, and slaves. The slave trade, for example, was conducted by a few dozen merchants in Lisbon. In the process of expanding the trade routes, Portuguese navigators mapped unknown parts of Africa, and began exploring the Indian Ocean. In 1487, an overland expedition by Pêro da Covilhã made its way to India, exploring trade opportunities with
11760-404: 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 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
11928-488: The Hindus by protecting their temples and reducing their tax requirements. The Portuguese maintained friendly relations with the south Indian Emperors of the Vijayanagara Empire . In April 1511, Albuquerque sailed to Malacca on the Malay Peninsula , the largest spice market of the period. Though the trade was largely dominated by the Gujarati, other groups such as the Turks, Persians, Armenians, Tamils and Abyssinians traded there. Albuquerque targeted Malacca to impede
12096-478: The Indian Ocean, creating three areas of jurisdiction: Albuquerque was sent to the Red Sea, Diogo Lopes de Sequeira to South-east Asia, seeking an agreement with the Sultan of Malacca, and Jorge de Aguiar followed by Duarte de Lemos were sent to the area between the Cape of Good Hope and Gujarat. However, such posts were centralised by Afonso de Albuquerque after his succession and remained so in subsequent ruling. By
12264-567: The Indians and Arabs, and winding up finally in Ethiopia. His detailed report was eagerly read in Lisbon, which became the best-informed centre for global geography and trade routes. Fears of what lay beyond Cape Bojador , and whether it was possible to return once it was passed, were assuaged in 1434 when it was rounded by one of Infante Henry's captains, Gil Eanes . Once this psychological barrier had been crossed, it became easier to probe further along
12432-504: The Muslim and Venetian influence in the spice trade and increase that of Lisbon. By July 1511, Albuquerque had captured Malacca and sent Antonio de Abreu and Francisco Serrão (along with Ferdinand Magellan) to explore the Indonesian archipelago. The Malacca peninsula became the strategic base for Portuguese trade expansion with China and Southeast Asia. A strong gate, called the A Famosa ,
12600-532: The North Atlantic Ocean, Equator, South Atlantic Ocean, Southern Ocean, South Atlantic Ocean, Equator, North Atlantic Ocean route in an easterly direction. The map on the right shows, in red, a typical, non-competitive, route for a sailing circumnavigation of the world by the trade winds and the Suez and Panama canals; overlaid in yellow are the points antipodal to all points on the route. It can be seen that
12768-536: The North Pole to Russia. Later, it was found useful for submarines. 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 terminated on September 30, 1997, and all stations ceased operation. LORAN is a terrestrial navigation system using low frequency radio transmitters that use
12936-626: The North and South poles. The latitude of the North Pole is 90° N, and the latitude of the South Pole is 90° S. Mariners calculated latitude in the Northern Hemisphere by sighting the pole star ( 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
13104-599: The Pacific coast of the Americas. Drake set out from Plymouth, England in November 1577, aboard Pelican , which he renamed Golden Hind mid-voyage. In September 1578, the ship passed south of Tierra del Fuego, the southern tip of South America, through the area now known as the Drake Passage . In June 1579, Drake landed somewhere north of Spain's northernmost claim in Alta California , presumably Drakes Bay . Drake completed
13272-515: The Philippines, trying to find a maritime path back to the Americas , 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 sailed from the Philippines, north to parallel 39°, and hit the eastward Kuroshio Current which took its galleon across the Pacific. He arrived in Acapulco on October 8, 1565. The term stems from
13440-455: The Portuguese were known to the Chinese under the name of Franks at this time. The Portuguese later returned to China peacefully and presented themselves under the name Portuguese instead of Franks in the Luso-Chinese agreement (1554) and rented Macau as a trading post from China by paying annual lease of hundreds of silver taels to Ming China. Despite initial harmony and excitement between
13608-607: The Portuguese, and even had Portuguese ambassadors from São Tomé support Ndongo against the Kingdom of Kongo. However, when the Jaga attacked and conquered regions of Kongo in 1568, Portuguese assisted Kongo in their defeat. In response, the Kongo allowed the colonization of Luanda Island; Luanda was established by Paulo Dias de Novais in 1576 and soon became a slave port. De Novais' subsequent alliance with Ndongo angered Luso-Africans who resented
13776-504: The Romans were the first overland via Asia Minor. He was also the first European to discover Hong Kong. In 1514, Afonso de Albuquerque, the viceroy of the Estado da India, dispatched Rafael Perestrello to sail to China in order to pioneer European trade relations with the nation. In their first attempts at obtaining trading posts by force, the Portuguese were defeated by the Ming Chinese at
13944-516: The Spanish and the Portuguese. These were eventually settled by the Treaty of Tordesillas in 1494, which divided the world outside of Europe in an exclusive duopoly between the Portuguese and the Spanish along a north–south meridian 370 leagues , or 970 miles (1,560 km), west of the Cape Verde islands. However, as it was not possible at the time to correctly measure longitude , the exact boundary
14112-455: The Tamoios and as spies for their resources. From 1565 through 1567 Mem de Sá and his forces eventually destroyed France Antarctique at Guanabara Bay. He and his nephew, Estácio de Sá , then established the city of Rio de Janeiro in 1567, after Mem de Sá proclaimed the area "São Sebastião do Rio de Janeiro" in 1565. By 1575, the Tamoios had been subdued and essentially were extinct, and by 1580
14280-645: The advent of world cruises in 1922, by Cunard's Laconia , thousands of people have completed circumnavigations of the globe at a more leisurely pace. Typically, these voyages begin in New York City or Southampton , and proceed westward. Routes vary, either travelling through the Caribbean and then into the Pacific Ocean via the Panama Canal , or around Cape Horn . From there ships usually make their way to Hawaii,
14448-593: The assistance of the Tamoio natives. The Tamoio had been allied with the French since the settlement of France Antarctique, and despite the French loss in 1560, the Tamoio were still a threat. They launched two attacks in 1561 and 1564 (the latter event was assisting the French), and were nearly successful with each. By this time period, Manuel de Nóbrega, along with fellow Jesuit José de Anchieta , took part as members of attacks on
14616-492: 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
14784-444: The calculated track. The equator must be crossed. The solo wind powered circumnavigation record of 42 days, 16 hours, 40 minutes and 35 seconds was established by François Gabart on the maxi-multihull sailing yacht MACIF and completed on 7 December 2017. The voyage followed the North Atlantic Ocean, Equator, South Atlantic Ocean, Southern Ocean, South Atlantic Ocean, Equator, North Atlantic Ocean route in an easterly direction. Since
14952-421: The civilian navigator on a merchant ship or leisure craft must often take and plot their position themselves, typically with the aid of electronic position fixing. 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
15120-555: The coast each year for five years, discovered the islands of the Gulf of Guinea, including São Tomé and Príncipe , and found a thriving alluvial gold trade among the natives and visiting Arab and Berber traders at the port then named Mina (the mine), where he established a trading post. Trade between Elmina and Portugal grew throughout a decade. During the War of the Castilian Succession ,
15288-532: The coast of Africa and the Atlantic archipelagos in 1418–1419, using recent developments in navigation, cartography, and maritime technology such as the caravel , with the aim of finding a sea route to the source of the lucrative spice trade . In 1488, Bartolomeu Dias rounded the Cape of Good Hope , and in 1498 Vasco da Gama reached India. In 1500, either by an accidental landfall or by the crown's secret design, Pedro Álvares Cabral reached what would be Brazil . Over
15456-521: The coast to the Tordesillas limit, were decreed by João III on 28 September 1532. The plot of the lands formed as a hereditary captaincies (Capitanias Hereditárias) to grantees rich enough to support settlement, as had been done successfully in Madeira and Cape Verde islands. Each captain-major was to build settlements, grant allotments and administer justice, being responsible for developing and taking
15624-414: The coast. In 1443, Infante Dom Pedro , Henry's brother and by then regent of the Kingdom, granted him the monopoly of navigation, war and trade in the lands south of Cape Bojador. Later this monopoly would be enforced by the papal bulls Dum Diversas (1452) and Romanus Pontifex (1455), granting Portugal the trade monopoly for the newly discovered lands. A major advance that accelerated this project
15792-486: The contraction of Portuguese ambitions in Africa . Under António Salazar (in office 1932–1968), the Estado Novo dictatorship made some ill-fated attempts to cling on to its last remaining colonies. Under the ideology of pluricontinentalism , the regime renamed its colonies " overseas provinces " while retaining the system of forced labour , from which only a small indigenous élite was normally exempt. In August 1961,
15960-401: The costs of colonization, although not being the owner: he could transmit it to offspring, but not sell it. Twelve recipients came from Portuguese gentry who become prominent in Africa and India and senior officials of the court, such as João de Barros . Of the fifteen original captaincies, only two, Pernambuco and São Vicente, prospered. Both were dedicated to the crop of sugar cane , and
16128-586: The earth was completed in 1522 with the Magellan-Elcano expedition , a Spanish voyage of discovery led by Portuguese explorer Ferdinand Magellan and completed by Spanish navigator Juan Sebastián Elcano after the former's death in the Philippines in 1521. The fleet of seven ships sailed from Sanlúcar de Barrameda in Southern Spain in 1519, crossed the Atlantic Ocean and after several stopovers rounded
16296-604: The east. That year the Portuguese also conquered Kannur , where they founded St. Angelo Fort , and Lourenço de Almeida arrived in Ceylon (modern Sri Lanka), where he discovered the source of cinnamon . Although Cankili I of Jaffna initially resisted contact with them, the Jaffna kingdom came to the attention of Portuguese officials soon after for their resistance to missionary activities as well as logistical reasons due to its proximity with Trincomalee harbour among other reasons. In
16464-580: The end of 1509, Albuquerque became viceroy of the East Indies with the capital at Velha Goa , after the Cape route was discovered by Vasco da Gama. In contrast to Almeida, Albuquerque was more concerned with strengthening the navy, as well as being more compliant with the interests of the kingdom. His first objective was to conquer Goa, due to its strategic location as a defensive fort positioned between Kerala and Gujarat, as well as its prominence for Arabian horse imports. The initial capture of Goa from
16632-856: The entrance of the Red Sea in 1506 and Muscat in 1507. Having failed to conquer Ormuz , they instead followed a strategy intended to close off commerce to and from the Indian Ocean. Madagascar was partly explored by Cunha, and Mauritius was discovered by Cunha whilst possibly being accompanied by Albuquerque. After the capture of Socotra, Cunha and Albuquerque operated separately. While Cunha travelled India and Portugal for trading purposes, Albuquerque went to India to take over as governor after Almeida's three-year term ended. Almeida refused to turn over power and soon placed Albuquerque under house arrest, where he remained until 1509. Although requested by Manuel I to further explore interests in Malacca and Sri Lanka, Almeida instead focused on western India, in particular
16800-477: The equator or hit the minimum of two antipodal points as stipulated by the rules of Guinness World Records and AdventureStats by Explorersweb. People have both bicycled and run around the world, but the oceans have had to be covered by air or sea travel, making the distance shorter than the Guinness guidelines. To go from North America to Asia on foot is theoretically possible but very difficult. It involves crossing
16968-567: The exodus of nearly all the Portuguese colonial settlers and of many mixed-race people from the colonies. Portugal returned Macau to China in 1999. The only overseas possessions to remain under Portuguese rule, the Azores and Madeira , both had overwhelmingly Portuguese populations, and Lisbon subsequently changed their constitutional status from " overseas provinces " to " autonomous regions ". The Community of Portuguese Speaking Countries (CPLP)
17136-506: The final stage of Portuguese colonialism after the independence of Brazil in the 1820s. By then, the colonial possessions had been reduced to forts and plantations along the African coastline (expanded inland during the Scramble for Africa in the late 19th century), Portuguese Timor , and enclaves in India ( Portuguese India ) and China ( Portuguese Macau ). The 1890 British Ultimatum led to
17304-486: The first colonial towns – among them São Vicente , in 1532. Sousa returned to Lisbon a year later to become governor of India and never returned to Brazil. The French attacks did cease to an extent after retaliation led to the Portuguese paying the French to stop attacking Portuguese ships throughout the Atlantic, but the attacks would continue to be a problem well into the 1560s. Upon de Sousa's arrival and success, fifteen latitudinal tracts, theoretically to span from
17472-509: The first entirely solo human-powered circumnavigation, travelling by rowboat, sea kayak , foot and bicycle from 10 July 2007 to 21 July 2012, crossing the equator twice, passing over 12 antipodal points, and logging 66,299 kilometres (41,196 mi) in 1,026 days of travel time, excluding breaks. National Geographic lists Colin Angus as being the first to complete a human-powered global circumnavigation in 2006. However, his journey did not cross
17640-516: The first woman to have completed a voyage of circumnavigation of the globe, which she did via maritime transport . A key part of her journey was as a member of Louis Antoine de Bougainville 's expedition on the ships La Boudeuse and Étoile in 1766–1769. Captain James Cook became the first navigator to record three circumnavigations through the Pacific aboard the Endeavour from 1769 to 1779. He
17808-481: The following decades, Portuguese sailors continued to explore the coasts and islands of East Asia, establishing forts and factories as they went. By 1571, a string of naval outposts connected Lisbon to Nagasaki along the coasts of Africa, the Middle East, and South Asia. This commercial network and the colonial trade had a substantial positive impact on Portuguese economic growth (1500–1800) when it accounted for about
17976-511: The fort. The two failed sieges of 1538 and 1546 put an end to Ottoman ambitions, confirming the Portuguese hegemony in the region, as well as gaining superiority over the Mughals. However, the Ottomans fought off attacks from the Portuguese in the Red Sea and in the Sinai Peninsula in 1541, and in the northern region of the Persian Gulf in 1546 and 1552. Each entity ultimately had to respect
18144-527: The globe in 60 days, 21 hours for Operation Sandblast . The current circumnavigation record in a powered boat of 60 days 23 hours and 49 minutes was established by a voyage of the wave-piercing trimaran Earthrace which was completed on 27 June 2008. The voyage followed the North Atlantic Ocean, Panama Canal, Pacific Ocean, Indian Ocean, Suez Canal, Mediterranean Sea route in a westerly direction. In 1922 Norman Macmillan (RAF officer) , Major W T Blake and Geoffrey Malins made an unsuccessful attempt to fly
18312-417: The globe, such as Pan American Flight One (and later United Airlines Flight One). Today planning such a trip through commercial flight connections is simple. The first lighter-than-air aircraft of any type to circumnavigate under its own power was the rigid airship LZ 127 Graf Zeppelin , which did so in 1929. Aviation records take account of the wind circulation patterns of the world; in particular
18480-698: The government of the colony in order to "give help and assistance" to grantees. In 1548 he created the first General Government, sending in Tomé de Sousa as first governor and selecting a capital at the Bay of All Saints , making it at the Captaincy of Bahia . Tomé de Sousa built the capital of Brazil, Salvador , at the Bay of All Saints in 1549. Among de Sousa's 1000 man expedition were soldiers, workers, and six Jesuits led by Manuel da Nóbrega . The Jesuits would have an essential role in
18648-426: 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 system (INS) is a dead reckoning type of navigation system that computes its position based on motion sensors. Before actually navigating,
18816-480: 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
18984-590: The influence from the Crown. In 1579, Ndongo ruler Ngola Kiluanje kia Ndamdi massacred Portuguese and Kongolese residents in the Ndongo capital Kabasa under the influence of Portuguese renegades. Both the Portuguese and Kongo fought against Ndongo, and off-and-on warfare between the Ndongo and Portugal would persist for decades. In east-Africa, the main agents acting on behalf of the Portuguese Crown, exploring and settling
19152-614: 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
19320-639: The islands of the South Pacific, Australia, New Zealand, then northward to Hong Kong, South East Asia, and India. At that point, again, routes may vary: one way is through the Suez Canal and into the Mediterranean; the other is around Cape of Good Hope and then up the west coast of Africa. These cruises end in the port where they began. In 1960, the American nuclear-powered submarine USS Triton circumnavigated
19488-537: The joint Adal-Ottoman force retreated. The Portuguese also made direct contact with the Kongolose vassal state Ndongo and its ruler Ngola Kiljuane in 1520, after the latter requested missionaries. Kongolese king Afonso I interfered with the process with denunciations, and later sent a Kongo mission to Ndongo after the latter had arrested the Portuguese mission that came. The growing official and unofficial slave trading with Ndongo strained relations between Kongo and
19656-522: The land be settled, and two follow up voyages were sent in 1501 and 1503. The land was found to be abundant in pau-brasil , or brazilwood, from which it later inherited its name, but the failure to find gold or silver meant that for the time being Portuguese efforts were concentrated on India. In 1502, to enforce its trade monopoly over a wide area of the Indian Ocean , the Portuguese Empire created
19824-504: The locals were impressed by firearms , that would be immediately made by the Japanese on a large scale. By 1570 the Portuguese bought part of a Japanese port where they founded a small part of the city of Nagasaki , and it became the major trading port in Japan in the triangular trade with China and Europe. Guarding its trade from both European and Asian competitors, Portugal dominated not only
19992-448: 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
20160-456: The method of travel. Since the planet is quasispheroidal , a trip from one Pole to the other, and back again on the other side, would technically be a circumnavigation. There are practical difficulties (namely, the Arctic ice pack and the Antarctic ice sheet ) in such a voyage, although it was successfully undertaken in the early 1980s by Ranulph Fiennes . The first circumnavigation was that of
20328-584: 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 first occurred in the Mediterranean during the Middle Ages. Although land astrolabes were invented in the Hellenistic period and existed in classical antiquity and the Islamic Golden Age ,
20496-540: 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
20664-459: The navigator will have to rely on his skill in the manual and time-tested procedures. Celestial navigation systems are based on observation of the positions of the Sun , Moon , planets and navigational stars . 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
20832-557: The north Atlantic coast of Canada, which accounts for the appearance of "Labrador" on topographical maps of the period. Subsequently, in 1500–1501 and 1502, the brothers Gaspar and Miguel Corte-Real explored what is today the Canadian province of Newfoundland and Labrador , and Greenland, claiming these lands for Portugal. In 1506, King Manuel I created taxes for the cod fisheries in Newfoundland waters. Around 1521, João Álvares Fagundes
21000-405: The observer's horizon, the navigator can determine his distance from that subpoint. A nautical almanac and a marine 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 distance from the subpoint to create a circular line of position. A navigator shoots
21168-503: The oldest record of a sea astrolabe is that of Spanish astronomer Ramon Llull dating from 1295. The perfecting of this navigation instrument is attributed to Portuguese navigators during early Portuguese discoveries in the Age of Discovery . 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, based on
21336-476: The path a radar object should follow on the radar display if the ship stays on its planned course. During the transit, the navigator can check that the ship is on track by checking that the pip lies on the drawn line. Global Navigation Satellite System or GNSS is the term for satellite navigation systems that provide positioning with global coverage. A GNSS allow small electronic receivers to determine their location ( longitude , latitude , and altitude ) within
21504-399: The points antipodal to all points on the route. It can be seen that the route does not pass through any pairs of antipodal points. Since the winds in the higher southern latitudes predominantly blow west-to-east it can be seen that there are an easier route (west-to-east) and a harder route (east-to-west) when circumnavigating by sail; this difficulty is magnified for square-rig vessels due to
21672-506: The poles (though not necessarily centred on them). For example, Steve Fossett 's global circumnavigation by balloon was entirely contained within the southern hemisphere. The first person to fly in space, Yuri Gagarin , also became the first person to complete an orbital spaceflight in the Vostok 1 spaceship within 2 hours on April 12 1961. The flight started at 63° E, 45 N and ended at 45° E 51° N; thus Gagarin did not circumnavigate Earth completely. Gherman Titov in
21840-499: The politics of the Kingdom of Mutapa , to the point of installing client kings upon its throne. In 1542, Jesuit missionary Francis Xavier arrived in Goa at the service of João III of Portugal, in charge of an Apostolic Nunciature . At the same time Francisco Zeimoto, António Mota , and other traders arrived in Japan for the first time. According to Fernão Mendes Pinto , who claimed to be in this journey, they arrived at Tanegashima , where
22008-412: 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 , can be used to calculate the time at zero longitude (see Greenwich Mean Time ). Reliable marine chronometers were unavailable until the late 18th century and not affordable until the 19th century. For about
22176-503: The principle of the archipendulum used in constructing the Egyptian pyramids . Open-seas navigation using the astrolabe and the compass started during the Age of Discovery in the 15th century. The Portuguese began systematically exploring the Atlantic coast of Africa from 1418, under the sponsorship of Prince Henry . In 1488 Bartolomeu Dias reached the Indian Ocean by this route. In 1492
22344-429: The radar scanner. When a vessel (ship or boat) is within radar range of land or fixed objects (such as special radar aids to navigation and navigation marks) 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. A fix consisting of only radar information is called a radar fix. Types of radar fixes include "range and bearing to
22512-514: 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
22680-410: The rest into prison where they resided in squalid, sometimes fatal conditions. The Chinese then massacred Portuguese who resided at Ningbo and Fujian trading posts in 1545 and 1549, due to extensive and damaging raids by the Portuguese along the coast, which irritated the Chinese. Portuguese pirating was second to Japanese pirating by this period. However, they soon began to shield Chinese junks and
22848-604: The rise of commercial aviation in the late 20th century, circumnavigating Earth is straightforward, usually taking days instead of years. Today, the challenge of circumnavigating Earth has shifted towards human and technological endurance, speed, and less conventional methods . The word circumnavigation is a noun formed from the verb circumnavigate , from the past participle of the Latin verb circumnavigare , from circum "around" + navigare "to sail". A person walking completely around either pole will cross all meridians , but this
23016-431: The route roughly approximates a great circle , and passes through two pairs of antipodal points. This is a route followed by many cruising sailors, going in the western direction; the use of the trade winds makes it a relatively easy sail, although it passes through a number of zones of calms or light winds. In yacht racing , a round-the-world route approximating a great circle would be quite impractical, particularly in
23184-409: The same frequency range, called CHAYKA . LORAN use is in steep decline, with GPS 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 is an effective aid to navigation because it provides ranges and bearings to objects within range of
23352-412: 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
23520-560: The same year, Manuel I ordered Almeida to fortify the Portuguese fortresses in Kerala and within eastern Africa, as well as probe into the prospects of building forts in Sri Lanka and Malacca in response to growing hostilities with Muslims within those regions and threats from the Mamluk sultan. A Portuguese fleet under the command of Tristão da Cunha and Afonso de Albuquerque conquered Socotra at
23688-400: 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 . The line on the radar screen is set to a specific distance and angle, then the ship's position relative to the parallel line is observed. This can provide an immediate reference to the navigator as to whether
23856-402: The second complete circumnavigation of the world in a single vessel on September 1580, becoming the first commander to survive the entire circumnavigation. Thomas Cavendish completed his circumnavigation between 1586 and 1588 in record time—in two years and 49 days, nine months faster than Drake. It was also the first deliberately planned voyage of the globe. Jeanne Baret is recognized as
24024-412: The second group of circumnavigators when they were transported under guard to Lisbon in 1536. A third group came from the 117 survivors of the similarly failed Villalobos Expedition in the next decade; similarly ruined and starved, they were imprisoned by the Portuguese and transported back to Lisbon in 1546. In 1577, Elizabeth I sent Francis Drake to start an expedition against the Spanish along
24192-553: The settlement of Brazil, including the cities of São Vicente, and São Paulo , the latter co-founded by Nóbrega. Along with the Jesuit missions later came disease among the natives, among them plague and smallpox . [REDACTED] Are we sure it was the Jesuits in particular who brought smallpox with them Subsequently, the French would resettle in Portuguese territory at Guanabara Bay , which would be called France Antarctique . While
24360-462: The settlers managed to maintain alliances with Native Americans . The rise of the sugar industry came about because the Crown took the easiest sources of profit (brazilwood, spices, etc.), leaving settlers to come up with new revenue sources. The establishment of the sugar cane industry demanded intensive labour that would be met with Native American and, later, African slaves. Deeming the capitanias system ineffective, João III decided to centralize
24528-603: The ship Victoria between 1519 and 1522, now known as the Magellan–Elcano expedition . It was a Castilian ( Spanish ) voyage of discovery. The voyage started in Seville , crossed the Atlantic Ocean, and—after several stops—rounded the southern tip of South America , where the expedition named the Strait of Magellan . It then continued across the Pacific, discovering a number of islands on its way (including Guam ), before arriving in
24696-495: The ship is on or off its intended course for navigation. Other techniques that are less used in general navigation 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. Another special technique, known as the Franklin Continuous Radar Plot Technique, involves drawing
24864-466: The signing of the Treaty of Ayllón in 1411. Free from threats to its existence and unchallenged by the wars fought by other European states, Portuguese attention turned overseas and towards a military expedition to the Muslim lands of North Africa. There were several probable motives for their first attack, on the Marinid Sultanate (in present-day Morocco). It offered the opportunity to continue
25032-421: The slave and gold trades. Portugal enjoyed a virtual monopoly on the African seaborne slave trade for over a century, importing around 800 slaves annually. Most were brought to the Portuguese capital Lisbon, where it is estimated black Africans came to constitute 10 percent of the population. Christopher Columbus 's 1492 discovery for Spain of the New World , which he believed to be Asia, led to disputes between
25200-442: The southern tip of South America . Some ships were lost, but the remaining fleet continued across the Pacific making a number of discoveries including Guam 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
25368-421: The sphere of influence of the other, albeit unofficially. After a series of prolonged contacts with Ethiopia, the Portuguese embassy made contact with the Ethiopian (Abyssinian) Kingdom led by Rodrigo de Lima in 1520. This coincided with the Portuguese search for Prester John, as they soon associated the kingdom as his land. The fear of Turkish advances within the Portuguese and Ethiopian sectors also played
25536-403: The square rig's dramatic lack of upwind ability when compared to a more modern Bermuda rig . For around the world sailing records , there is a rule saying that the length must be at least 21,600 nautical miles calculated along the shortest possible track from the starting port and back that does not cross land and does not go below 63°S. It is allowed to have one single waypoint to lengthen
25704-809: The table. The practice of navigation usually involves a combination of these different methods. 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 (also called pilotage) involves navigating an aircraft by visual reference to landmarks, or a water vessel in restricted waters and fixing its position as precisely as possible at frequent intervals. 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. As pilotage takes place in shallow waters , it typically involves following courses to ensure sufficient under keel clearance , ensuring
25872-428: The territory of what would become Mozambique were the prazeiros , to whom vast estates around the Zambezi River were leased by the King as a reward for their services. Commanding vast armies of chikunda warrior-slaves, these men acted as feudal-like lords, either levying tax from local chieftains, defending them and their estates from marauding tribes, participating in the ivory or slave trade, and becoming involved in
26040-414: 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
26208-550: The trade between Asia and Europe, but also much of the trade between different regions of Asia and Africa, such as India, Indonesia, China, and Japan. Jesuit missionaries, followed the Portuguese to spread Catholicism to Asia and Africa with mixed success. Based on the Treaty of Tordesillas , the Portuguese Crown, under the kings Manuel I, João III and Sebastão, also claimed territorial rights in North America (reached by John Cabot in 1497 and 1498). To that end, in 1499 and 1500, João Fernandes Lavrador explored Greenland and
26376-473: The two cultures, difficulties began to arise shortly afterwards, including misunderstanding, bigotry, and even hostility. The Portuguese explorer Simão de Andrade incited poor relations with China due to his pirate activities, raiding Chinese shipping, attacking a Chinese official, and kidnappings of Chinese. He based himself at Tamao island in a fort. The Chinese claimed that Simão kidnapped Chinese boys and girls to be molested and cannibalised. The Chinese sent
26544-494: The view that had existed since Ptolemy that the Indian Ocean was land-locked . Simultaneously Pêro da Covilhã , travelling secretly overland, had reached Ethiopia , suggesting that a sea route to the Indies would soon be forthcoming. As the Portuguese explored the coastlines of Africa, they left behind a series of padrões , stone crosses engraved with the Portuguese coat of arms marking their claims, and built forts and trading posts. From these bases, they engaged profitably in
26712-409: The voyage. The last of the original ships, the Santa María de la Victoria , was sunk in 1526 in the East Indies (now Indonesia ) by the Portuguese. Unable to press forward or retreat, Hernando de la Torre erected a fort on Tidore , received reinforcements under Alvaro de Saavedra that were similarly defeated, and finally surrendered to the Portuguese. In this way, a handful of survivors became
26880-427: Was a military success, and marked one of the first steps in Portuguese expansion beyond the Iberian Peninsula, but it proved costly to defend against the Muslim forces that soon besieged it. The Portuguese were unable to use it as a base for further expansion into the hinterland, and the trans-Saharan caravans merely shifted their routes to bypass Ceuta and/or used alternative Muslim ports. Although Ceuta proved to be
27048-502: Was among the first to complete west–east circumnavigation in high latitudes. For the wealthy, long voyages around the world, such as was done by Ulysses S. Grant , became possible in the 19th century, and the two World Wars moved vast numbers of troops around the planet. However, it was the rise of commercial aviation in the late 20th century that made circumnavigation, when compared to the Magellan–Elcano expedition, quicker and safer. The nautical global and fastest circumnavigation record
27216-407: Was dispatched in 1500 under Pedro Álvares Cabral . While following the same south-westerly route as Gama across the Atlantic Ocean, Cabral made landfall on the Brazilian coast. This was probably an accidental discovery, but it has been speculated that the Portuguese secretly knew of Brazil's existence and that it lay on their side of the Tordesillas line. Cabral recommended to the Portuguese King that
27384-436: Was disputed by the two countries until 1777. The completion of these negotiations with Spain is one of several reasons proposed by historians for why it took nine years for the Portuguese to follow up on Dias's voyage to the Cape of Good Hope, though it has also been speculated that other voyages were in fact taking place in secret during this time. Whether or not this was the case, the long-standing Portuguese goal of finding
27552-462: Was erected to defend the city and remains. Learning of Siamese ambitions over Malacca, Albuquerque immediately sent Duarte Fernandes on a diplomatic mission to the Kingdom of Siam (modern Thailand), where he was the first European to arrive, establishing amicable relations and trade between both kingdoms. The Portuguese empire pushed further south and proceeded to discover Timor in 1512. Jorge de Meneses discovered New Guinea in 1526, naming it
27720-506: Was established in 1445 on the island of Arguin , off the coast of Mauritania, to attract Muslim traders and monopolise the business in the routes travelled in North Africa. In 1446, Álvaro Fernandes pushed on almost as far as present-day Sierra Leone , and the Gulf of Guinea was reached in the 1460s. The Cape Verde Islands were discovered in 1456 and settled in 1462. Expansion of sugarcane in Madeira started in 1455, using advisers from Sicily and (largely) Genoese capital to produce
27888-408: Was granted donatary rights to the inner islands of the Gulf of St. Lawrence and also created a settlement on Cape Breton Island to serve as a base for cod fishing. Pressure from natives and competing European fisheries prevented a permanent establishment and it was abandoned five years later. Several attempts to establish settlements in Newfoundland over the next half-century also failed. Within
28056-438: 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 in the North Sea and was used by helicopters operating to oil platforms . The OMEGA Navigation System was the first truly global radio navigation system for aircraft, operated by
28224-415: Was the introduction of the caravel in the mid-15th century, a ship that could be sailed closer to the wind than any other in operation in Europe at the time. Using this new maritime technology, Portuguese navigators reached ever more southerly latitudes , advancing at an average rate of one degree a year. Senegal and Cape Verde Peninsula were reached in 1445. The first feitoria trade post overseas
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