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Laser Airborne Depth Sounder Flight RAN
The Laser Airborne Depth Sounder (LADS) Flight was a unit of the Royal Australian Navy. Unlike the rest of the flying units of the RAN, it was not controlled by the Fleet Air Arm from , but instead fell under the operational control of the Australian Hydrographic Service at , providing a platform for the operation of the laser airborne depth sounder system. LADS Flight conducted its last sortie on 7 November 2019. History In the 1970s, the Royal Australian Navy's Hydrographic Service was still limited in its ability to survey the vastness of Australia's coastal waters, and was still producing charts on areas where surveying was incomplete or had not even taken place. As a consequence, the RAN began to search for a way of effectively surveying the Australian coastline from the air, which led to the development of the Laser Airborne Depth Sounder system by the Defence Science and Technology Organisation, a part of the Australian Department of Defence, with trials beginning in 1977.S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship's Badge
Naval heraldry is a form of identification used by naval vessels from the end of the 19th century onwards, after distinguishing features such as Figurehead (object), figureheads and gilding were discouraged or banned by several navies. Naval heraldry commonly takes the form of a badge, seal, crest, or coat of arms designed specifically for a ship (or a series of ships bearing the same name), which in Commonwealth of Nations, Commonwealth navies takes the form of a large plaque, referred to as the ship's badge, mounted on the superstructure of the ship, and in the United States Navy is known as the ship's seal or ship's crest, and is primarily found on crew uniform patches. An item of naval heraldry is seen as the identifying logo of the vessel, and is commonly reproduced on hats, stationery, trophies, souvenirs, and gifts related to the ship. In many navies, the ship's badge is also displayed on the tampions – the covers for the gun Muzzle (firearms), muzzles. The naval heraldri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautical Miles
A nautical mile is a unit of length used in air, marine, and space navigation, and for the definition of territorial waters. Historically, it was defined as the meridian arc length corresponding to one minute ( of a degree) of latitude at the equator, so that Earth's polar circumference is very near to 21,600 nautical miles (that is 60 minutes × 360 degrees). Today the international nautical mile is defined as exactly . The derived unit of speed is the knot, one nautical mile per hour. Unit symbol There is no single internationally agreed symbol, with several symbols in use. * NM is used by the International Civil Aviation Organization. * nmi is used by the Institute of Electrical and Electronics Engineers and the United States Government Publishing Office. * M is used as the abbreviation for the nautical mile by the International Hydrographic Organization. * nm is a non-standard abbreviation used in many maritime applications and texts, including U.S. Government Coast Pilot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Positioning System
The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephone or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls, and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. Overview The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft was launched in 1978 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Scanning
Laser scanning is the controlled Deflection (physics), deflection of laser beams, visible or invisible. Scanned laser beams are used in some 3-D printers, in rapid prototyping, in machines for material processing, in laser engraving machines, in ophthalmological laser systems for the treatment of presbyopia, in confocal microscopy, in laser printers, in laser shows, in Laser TV, and in barcode scanners. Applications specific to mapping and 3D object reconstruction are known as ''3D laser scanner''. Technology Scanning mirrors Most laser scanners use moveable mirrors to steer the laser beam. The steering of the beam can be ''one-dimensional'', as inside a laser printer, or ''two-dimensional'', as in a laser show system. Additionally, the mirrors can lead to a ''periodic'' motion - like the rotating ''polygon mirror'' in a barcode scanner or so-called ''resonant galvanometer'' scanners - or to a ''freely addressable'' motion, as in servo-controlled galvanometer scanners. One al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Coupler
An opto-isolator (also called an optocoupler, photocoupler, or optical isolator) is an electronic component that transfers electrical signals between two isolated circuits by using light. Opto-isolators prevent high voltages from affecting the system receiving the signal.Lee et al., p. 2. Commercially available opto-isolators withstand input-to-output voltages up to 10 kVHasse, p. 145. and voltage transients with speeds up to 25 kV/μs.Joffe and Kai-Sang Lock, p. 279. A common type of opto-isolator consists of an LED and a phototransistor in the same opaque package. Other types of source-sensor combinations include LED-photodiode, LED- LASCR, and lamp-photoresistor pairs. Usually opto-isolators transfer digital (on-off) signals and can act as an electronic switch, but some techniques allow them to be used with analog signals. History The value of optically coupling a solid state light emitter to a semiconductor detector for the purpose of electrical isolation was rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second-harmonic Generation
Second-harmonic generation (SHG), also known as frequency doubling, is the lowest-order wave-wave nonlinear interaction that occurs in various systems, including optical, radio, atmospheric, and magnetohydrodynamic systems. As a prototype behavior of waves, SHG is widely used, for example, in doubling laser frequencies. SHG was initially discovered as a nonlinear optical process in which two photons with the same frequency interact with a nonlinear material, are "combined", and generate a new photon with twice the energy of the initial photons (equivalently, twice the frequency and half the wavelength), that conserves the coherence of the excitation. It is a special case of sum-frequency generation (2 photons), and more generally of harmonic generation. The second-order nonlinear susceptibility of a medium characterizes its tendency to cause SHG. Second-harmonic generation, like other even-order nonlinear optical phenomena, is not allowed in media with inversion symmet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base units is 1/s or s−1, meaning that one hertz is one per second or the Inverse second, reciprocal of one second. It is used only in the case of periodic events. It is named after Heinrich Hertz, Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. For high frequencies, the unit is commonly expressed in metric prefix, multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YAG Laser
YAG, YaG, Yağ, or yag can refer to: * Yttrium aluminium garnet, a synthetic crystal used in solid-state laser systems * Fort Frances Municipal Airport, Ontario, Canada, IATA code * YMCA Youth and Government, a model government program for youth * Yahgan language, spoken in Chile and Argentina, ISO 639 code * Cansu Yağ (born 1990), a female Turkish footballer * YAG training vessels, wooden Canadian Navy boats 1954–1955 * List of yard and district craft of the United States Navy#District auxiliary, miscellaneous (YAG), District auxiliary, miscellaneous (YAG), US Navy hull classification symbol {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautical Chart
A nautical chart or hydrographic chart is a graphic representation of a sea region or water body and adjacent coasts or river bank, banks. Depending on the scale (map), scale of the chart, it may show depths of water (bathymetry) and heights of land (topography), natural features of the seabed, details of the coastline, navigational hazards, locations of natural and human-made aids to navigation, information on tides and Ocean current, currents, local details of the Earth's magnetic field, and human-made structures such as harbor, harbours, buildings, and bridges. Nautical charts are essential tools for marine navigation; many countries require vessels, especially commercial ships, to carry them. Nautical charting may take the form of charts printed on paper (raster navigational charts) or computerized electronic navigational charts. Recent technologies have made available paper charts which are printed "on demand" with cartographic data that has been downloaded to the commercial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Age Of Sail
The Age of Sail is a period in European history that lasted at the latest from the mid-16th (or mid-15th) to the mid-19th centuries, in which the dominance of sailing ships in global trade and warfare culminated, particularly marked by the introduction of naval artillery, and ultimately reached its highest extent at the advent of steam power. Enabled by the advances of the related age of navigation, it is identified as a distinctive element of the early modern period and the Age of Discovery. Periodization Like most periodic eras, defining the age is inexact and serves only as a general description. The term is used differently for warships and merchant vessels. By the 14th century naval artillery was employed in Europe, documented at the Battle of Arnemuiden (1338). The 15th century saw the Iberian naval ventures all the way along the African Atlantic coast and across the Atlantic Ocean, starting the Age of Discovery. For warships, the age of sail runs roughly from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrographic Surveying
Hydrographic survey is the science of measurement and description of features which affect maritime navigation, marine construction, dredging, offshore wind farms, offshore oil exploration and drilling and related activities. Surveys may also be conducted to determine the route of subsea cables such as telecommunications cables, cables associated with wind farms, and HVDC power cables. Strong emphasis is placed on soundings, shorelines, tides, currents, seabed and submerged obstructions that relate to the previously mentioned activities. The term ''hydrography'' is used synonymously to describe ''maritime cartography'', which in the final stages of the hydrographic process uses the raw data collected through hydrographic survey into information usable by the end user. Hydrography is collected under rules which vary depending on the acceptance authority. Traditionally conducted by ships with a sounding line or echo sounding, surveys are increasingly conducted with the aid o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airborne Lidar Bathymetry
Lidar (, also LIDAR, an acronym of "light detection and ranging" or "laser imaging, detection, and ranging") is a method for determining ranges by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. Lidar may operate in a fixed direction (e.g., vertical) or it may scan multiple directions, in a special combination of 3-D scanning and laser scanning. Lidar has terrestrial, airborne, and mobile applications. It is commonly used to make high-resolution maps, with applications in surveying, geodesy, geomatics, archaeology, geography, geology, geomorphology, seismology, forestry, atmospheric physics, laser guidance, airborne laser swathe mapping (ALSM), and laser altimetry. It is used to make digital 3-D representations of areas on the Earth's surface and ocean bottom of the intertidal and near coastal zone by varying the wavelength of light. It has also been increasingly used in control and navigation for auto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
