The essential concept of lidar was originated by EH Synge in 1930, who envisaged the use of powerful searchlights to probe the atmosphere. Īnimation of a satellite collecting digital elevation map data over the Ganges and Brahmaputra River basin using lidar A narrow laser beam can map physical features with very high resolutions for example, an aircraft can map terrain at 30-centimetre (12 in) resolution or better. It can target a wide range of materials, including non-metallic objects, rocks, rain, chemical compounds, aerosols, clouds and even single molecules. Lidar uses ultraviolet, visible, or near infrared light to image objects. The USGS uses both "LIDAR" and "lidar", sometimes in the same document the New York Times predominantly uses "lidar" for staff-written articles, although contributing news feeds such as Reuters may use Lidar. Various publications refer to lidar as "LIDAR", "LiDAR", "LIDaR", or "Lidar". The general public became aware of the accuracy and usefulness of lidar systems in 1971 during the Apollo 15 mission, when astronauts used a laser altimeter to map the surface of the moon.Īlthough the English language no longer treats "radar" as an acronym, (i.e., uncapitalized), the word "lidar" was capitalized as "LIDAR" or "LiDAR" in some publications beginning in the 1980s. Lidar's first applications were in meteorology, for which the National Center for Atmospheric Research used it to measure clouds and pollution. The name " photonic radar" is sometimes used to mean visible-spectrum range finding like lidar. Meanwhile, it is being used to study the moon by 'lidar' (light radar) ." The first mention of lidar as a stand-alone word in 1963 suggests it originated as a portmanteau of " light" and "radar": "Eventually the laser may provide an extremely sensitive detector of particular wavelengths from distant objects. The first practical terrestrial application of a colidar system was the "Colidar Mark II", a large rifle-like laser rangefinder produced in 1963 which had a range of 7 miles and an accuracy of 15 feet, to be used for military targeting. All laser rangefinders, laser altimeters and lidar units are derived from the early colidar systems. It was originally called "Colidar" an acronym for "coherent light detecting and ranging," derived from the term " radar", itself an acronym for "radio detection and ranging". Intended for satellite tracking, this system combined laser-focused imaging with the ability to calculate distances by measuring the time for a signal to return using appropriate sensors and data acquisition electronics. Under the direction of Malcolm Stitch, the Hughes Aircraft Company introduced the first lidar-like system in 1961, shortly after the invention of the laser. 6.17 Solar photovoltaic deployment optimization.6.3.1.1 Obstacle detection and road environment recognition using lidar.6.3.1 Object detection for transportation systems.2.3.3 Photodetector and receiver electronics.2.3.1.2 Microelectromechanical machines.It is also used in control and navigation for some autonomous cars and for the helicopter Ingenuity on its record-setting flights over the terrain of Mars. Lidar 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 swath mapping (ALSM), and laser altimetry. It is sometimes called 3-D laser scanning, a special combination of 3-D scanning and laser scanning. Lidar is an acronym of "light detection and ranging" or "laser imaging, detection, and ranging". It has terrestrial, airborne, and mobile applications. It can also be 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. Lidar ( / ˈ l aɪ d ɑːr/, also LIDAR, or LiDAR sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. Vegetation heights are depicted in shades of green, where dark greens are closest to the ground and light greens are the highest. For ground-level features, colors range from deep brown to tan. This visualization shows an airplane collecting a 50-kilometer swath of lidar data over the Brazilian rainforest.
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