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Navigational Algorithms
The navigational algorithms are the quintessence of the executable software on portable calculators or PDA as an aid to the art of navigation, this attempt article describe both algorithms and software for ''"PC-PDA"'' implementing different calculation procedures for navigation . The calculation power obtained by the languages: Basic, "C", Java, etc. .., from portable calculators or PDAs , has made it possible to develop programs that allow calculating the position without the need for tables, in fact they have some basic tables with the correction factors for each year and calculate the values "on the fly" at runtime . Comparison between manual calculation methods and the use of calculators * The traditional methods require bulky and expensive nautical tables (which must be updated), pencil and paper, and calculation time, following the working algorithms. * Calculators (and the like) do not need books (they have tables and ephemeris integrated) and, with their own algorithms, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sextant
A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle, the altitude, is known as ''sighting'' or ''shooting'' the object, or ''taking a sight''. The angle, and the time when it was measured, can be used to calculate a position line on a nautical or aeronautical chart—for example, sighting the Sun at noon or Polaris at night (in the Northern Hemisphere) to estimate latitude (with sight reduction). Sighting the height of a landmark can give a measure of ''distance off'' and, held horizontally, a sextant can measure angles between objects for a position on a chart. A sextant can also be used to measure the lunar distance between the moon and another celestial object (such as a star or planet) in order to determine Greenwich Mean Time and hence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shortest Path Problem
In graph theory, the shortest path problem is the problem of finding a path between two vertices (or nodes) in a graph such that the sum of the weights of its constituent edges is minimized. The problem of finding the shortest path between two intersections on a road map may be modeled as a special case of the shortest path problem in graphs, where the vertices correspond to intersections and the edges correspond to road segments, each weighted by the length of the segment. Definition The shortest path problem can be defined for graphs whether undirected, directed, or mixed. It is defined here for undirected graphs; for directed graphs the definition of path requires that consecutive vertices be connected by an appropriate directed edge. Two vertices are adjacent when they are both incident to a common edge. A path in an undirected graph is a sequence of vertices P = ( v_1, v_2, \ldots, v_n ) \in V \times V \times \cdots \times V such that v_i is adjacent to v_ for 1 \leq i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, marine navigation, aeronautic navigation, and space navigation. It 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. 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 is probably the earliest form of open-ocean navigation; it was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute Of Navigation
The Institute of Navigation (ION) is the world's premier non-profit professional society advancing the art and science of positioning, navigation and timing. It was founded in 1945 and serves communities interested in navigation and positioning on land, air, sea and space. It is a worldwide organization with members in more than 50 countries. As of 2022, the ION has approximately 2,500 members. The ION is headquartered in Manassas, Virginia. History During World War II, the field of navigation experienced "dramatic developments uringa period of fast-moving changes... People recognized the need for an organization to provide a forum for discussion f thevarious aspects of navigation." Dr. Samuel Herrick, assistant professor of astronomy at UCLA, proposed an institute for navigation. Dr. Herrick envisioned a research center and publication of a journal. On June 25, 1945, the Institute of Navigation was founded at an organizational meeting held at UCLA. The Institute's fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Navigation
The Royal Institute of Navigation (RIN) is a learned society and a professional body for navigation. The RIN was founded in 1947 as a forum for mariners, pilots, engineers and academics to compare their experiences and exchange information. Today it is a leading centre for promoting knowledge in navigation and its associated sciences, including positioning, timing, tracking and conduct of a journey, whether on, in, over or under land, sea, air or space. The Institute has members in over 50 countries worldwide. History The organisation was formed in 1947 as the Institute of Navigation and was patterned after the US Institute of Navigation. Both organisations had been influenced by the role navigation had helped in moving troops and supplies during Second World War. Emerging technology such as radar and LORAN increased in the years following the war. The Institute sought to provide a forum where academics, engineers, mariners, and pilots could learn, exchange information, and sha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Institute Of Navigation
The Royal Institute of Navigation (RIN) is a learned society and a professional body for navigation. The RIN was founded in 1947 as a forum for mariners, pilots, engineers and academics to compare their experiences and exchange information. Today it is a leading centre for promoting knowledge in navigation and its associated sciences, including positioning, timing, tracking and conduct of a journey, whether on, in, over or under land, sea, air or space. The Institute has members in over 50 countries worldwide. History The organisation was formed in 1947 as the Institute of Navigation and was patterned after the US Institute of Navigation. Both organisations had been influenced by the role navigation had helped in moving troops and supplies during Second World War. Emerging technology such as radar and LORAN increased in the years following the war. The Institute sought to provide a forum where academics, engineers, mariners, and pilots could learn, exchange information, and sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhumbline Network
A rhumbline network, more properly called, a windrose network, or sometimes also called harbour-finding chart, compass chart, or rhumb chart, is a navigational aid drawn on early portolan charts dating from the medieval to early modern period. This network is like a web (see picture) forming a grid on the map. Before accurate surveying there was no method for measuring longitude at sea so maps possessed many distortions especially in the east west direction. There was also distortion due to the curvature of the Earth's surface. The multitude of compass roses with straight lines extending outwards across the map derived from how the maps were then made by compiling empirical observations from navigators who attempted to follow a constant bearing at sea. To calculate a course to follow from a ship's position to a point of desired destination, one would identify the windrose thought to be closest to the ship's position. Then, using a parallel rule, the "line of course" taken f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Practical Navigator
''The American Practical Navigator'' (colloquially often referred to as ''Bowditch''), originally written by Nathaniel Bowditch, is an encyclopedia of navigation. It serves as a valuable handbook on oceanography and meteorology, and contains useful tables and a maritime glossary. In 1867 the copyright and plates were bought by the Hydrographic Office of the United States Navy. As of 2019 it is still published by the U.S. Government and is available free online from the National Geospatial-Intelligence Agency (NGA), the modern successor agency to the 19th Century Hydrographic Office. The publication is considered one of America's nautical institutions. History The most popular navigational text of the late 18th century was ''The Practical Navigator'' by John Hamilton Moore of the Royal Navy, first published in 1772. To have exact tables to work from, Bowditch recomputed all of Moore's tables, and rearranged and expanded the work. He contacted the US publisher of the work, Edmun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Distance (navigation)
In celestial navigation, lunar distance is the angular distance between the Moon and another celestial body. The lunar distances method uses this angle, also called a lunar, and a nautical almanac to calculate Greenwich time if so desired, or by extension any other time. That calculated time can be used in solving a spherical triangle. The theory was first published by Johannes Werner in 1524, before the necessary almanacs had been published. A fuller method was published in 1763 and used until about 1850 when it was superseded by the marine chronometer. A similar method uses the positions of the Galilean moons of Jupiter. Purpose In celestial navigation, knowledge of the time at Greenwich (or another known place) and the measured positions of one or more celestial objects allows the navigator to calculate latitude and longitude. Reliable marine chronometers were unavailable until the late 18th century and not affordable until the 19th century. After the method was firs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 each whole hour of the year the position on the Earth's surface (in declination and Greenwich hour angle) at which the Sun, Moon, planets, and First Point of Aries is directly overhead. The positions of 57 selected stars are specified relative to the First Point of Aries. In Great Britain, ''The Nautical Almanac'' has been published annually by HM Nautical Almanac Office, ever since the first edition was published in 1767. In the United States, a nautical almanac has been published annually by the US Naval Observatory since 1852. It was originally titled '' American Ephemeris and Nautical Almanac''. Since 1958, the USNO and HMNAO have jointly published a unified nautical almanac, ''The Astronomical Almanac'' for use by the navies of b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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