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Altimetry
An altimeter or an altitude meter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth under water. Types Pressure altimeter Sonic altimeter In 1931, the US Army Air corps and General Electric together tested a sonic altimeter for aircraft, which was considered more reliable and accurate than one that relied on air pressure when heavy fog or rain was present. The new altimeter used a series of high-pitched sounds like those made by a bat to measure the distance from the aircraft to the surface, which on return to the aircraft was converted to feet shown on a gauge inside the aircraft cockpit. Radar altimeter A radar altimeter measures altitude more directly, using the time taken for a radio signal to reflect from the surface back to the aircraft. Alternatively, Frequency Modulated Continuous-wave radar can be used. The greater t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jason-1
Jason-1 was a satellite altimeter oceanography mission. It sought to monitor global ocean circulation, study the ties between the ocean and the atmosphere, improve global climate forecasts and predictions, and monitor events such as El Niño and ocean eddies. Jason-1 was launched in 2001 and it was followed by OSTM/Jason-2 in 2008, and Jason-3 in 2016the Jason satellite series. Jason-1 was launched alongside the TIMED spacecraft. Naming The lineage of the name begins with the JASO1 meeting (JASO=Journées Altimétriques Satellitaires pour l'Océanographie) in Toulouse, France to study the problems of assimilating altimeter data in models. Jason as an acronym also stands for "Joint Altimetry Satellite Oceanography Network". Additionally, it is used to reference the mythical quest for knowledge of Jason and the Argonautsbr> [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Altimetry
Satellite geodesy is geodesy by means of artificial satellites—the measurement of the form and dimensions of Earth, the location of objects on its surface and the figure of the Earth's gravity field by means of artificial satellite techniques. It belongs to the broader field of space geodesy. Traditional geodetic astronomy, astronomical geodesy is ''not'' commonly considered a part of satellite geodesy, although there is considerable overlap between the techniques. The main goals of satellite geodesy are: # Determination of the figure of the Earth, positioning, and navigation (geometric satellite geodesy) # Determination of geoid, gravity of Earth, Earth's gravity field and its temporal variations (dynamical satellite geodesy or satellite physical geodesy) # Measurement of geodynamics, geodynamical phenomena, such as Crust (geology), crustal dynamics and polar motion Satellite geodetic data and methods can be applied to diverse fields such as navigation, hydrography, oceanogr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocean Surface Topography Mission
OSTM/Jason-2, or Ocean Surface Topography Mission/Jason-2 satellite, was an international Earth observation satellite altimeter joint mission for sea surface height measurements between NASA and CNES. It was the third satellite in a series started in 1992 by the NASA/CNES TOPEX/Poseidon mission and continued by the NASA/CNES Jason-1 mission launched in 2001. History Like its two predecessors, OSTM/Jason-2 used high-precision ocean altimetry to measure the distance between the satellite and the ocean surface to within a few centimeters. These very accurate observations of variations in sea surface height — also known as ocean topography — provide information about global sea level, the speed and direction of ocean currents, and heat stored in the ocean. Jason-2 was built by Thales Alenia Space using a Proteus platform, under a contract from CNES, as well as the main Jason-2 instrument, the Poseidon-3 altimeter (successor to the Poseidon and Poseidon 2 altimeter on-boar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Civil Aviation Organization
The International Civil Aviation Organization (ICAO ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international scheduled air transport, air transport to ensure safe and orderly growth. The ICAO headquarters are located in the Quartier international de Montréal of Montreal, Quebec, Canada. The ICAO Council adopts standards and recommended practices concerning air navigation, its infrastructure, flight inspection, prevention of unlawful interference, and facilitation of border-crossing procedures for international civil aviation. ICAO defines the protocols for Aviation accidents and incidents, air accident investigation that are followed by :Organizations investigating aviation accidents and incidents, transport safety authorities in countries signatory to the Convention on International Civil Aviation. The Air Navigation Commission (ANC) is the techn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Airlines Flight 389
United Air Lines Flight 389 was a scheduled flight from LaGuardia Airport, New York City, New York, to O'Hare International Airport, Chicago, Illinois. On August 16, 1965, at approximately 21:21 EST, the Boeing 727 crashed into Lake Michigan east of Fort Sheridan, near Lake Forest, while descending from mean sea level (MSL). There was no indication of any unusual problem prior to impact. All 30 persons aboard, including six crew members and 24 passengers, were killed. A definitive cause was not determined by National Transportation Safety Board (NTSB) investigators. However, it was believed that the crash was most likely the result of the pilots misreading their three-pointer (3p) altimeters by 10,000 feet. At the time of the accident, United Air Lines had 39 other 727s in its fleet (of the 247 Boeing 727s ordered), all of which were 727-100 (727-22). The accident was both the first hull-loss and first fatal accident of a Boeing 727. Aircraft The aircraft involved was a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turkish Airlines Flight 1951
Turkish Airlines Flight 1951 (also known as the Poldercrash or the Schiphol Polderbaan incident) was a passenger flight that crashed during landing at Amsterdam Schiphol Airport, the Netherlands, on 25 February 2009, resulting in the deaths of nine passengers and crew, including all three pilots. The aircraft, a Turkish Airlines Boeing 737-800, crashed into a field about north of the Polderbaan runway (18R), prior to crossing the A9 motorway inbound, at 09:26 UTC (10:26 CET), having flown from Istanbul, Turkey. The aircraft broke into three pieces on impact. The wreckage did not catch fire. The crash was caused primarily by the aircraft's automated reaction, which was triggered by a faulty radio altimeter. This caused the autothrottle to decrease the engine power to idle during approach. The crew noticed this too late to take appropriate action to increase the thrust and recover the aircraft before it stalled and crashed. Boeing has since issued a bulletin to remind pi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Altimeter
A radar altimeter (RA), also called a radio altimeter (RALT), electronic altimeter, reflection altimeter, or low-range radio altimeter (LRRA), measures altitude above the terrain presently beneath an aircraft or spacecraft by timing how long it takes a beam of radio waves to travel to ground, reflect, and return to the craft. This type of altimeter provides the distance between the antenna and the ground directly below it, in contrast to a barometric altimeter which provides the distance above a defined vertical datum, usually mean sea level. Principle As the name implies, radar (radio detection and ranging) is the underpinning principle of the system. The system transmits radio waves down to the ground and measures the time it takes them to be reflected back up to the aircraft. The altitude above the ground is calculated from the radio waves' travel time and the speed of light. Radar altimeters required a simple system for measuring the time-of-flight that could be displayed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Flight Display
A primary flight display or PFD is a modern aircraft instrument dedicated to flight information. Much like multi-function displays, primary flight displays are built around a Liquid-crystal display or CRT display device. Representations of older six pack or "steam gauge" instruments are combined on one compact display, simplifying pilot workflow and streamlining cockpit layouts. Most airliners built since the 1980s—as well as many business jets and an increasing number of newer general aviation aircraft—have glass cockpits equipped with primary flight and multi-function displays (MFDs). Cirrus Aircraft was the first general aviation manufacturer to add a PFD to their already existing MFD, which they made standard on their SR-series aircraft in 2003. Mechanical gauges have not been eliminated from the cockpit with the onset of the PFD; they are retained for backup purposes in the event of total electrical failure. Components While the PFD does not directly use the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure Sensor
Pressure measurement is the measurement of an applied force by a fluid (liquid or gas) on a surface. Pressure is typically measured in units of force per unit of surface area. Many techniques have been developed for the measurement of pressure and vacuum. Instruments used to measure and display pressure mechanically are called pressure gauges, vacuum gauges or compound gauges (vacuum & pressure). The widely used Bourdon gauge is a mechanical device, which both measures and indicates and is probably the best known type of gauge. A vacuum gauge is used to measure pressures lower than the ambient atmospheric pressure, which is set as the zero point, in negative values (for instance, −1 bar or −760 mmHg equals total vacuum). Most gauges measure pressure relative to atmospheric pressure as the zero point, so this form of reading is simply referred to as "gauge pressure". However, anything greater than total vacuum is technically a form of pressure. For very low pressu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Level Sensor
Level sensors detect the level of liquids and other fluids and fluidized solids, including slurries, granular materials, and powders that exhibit an upper free surface. Substances that flow become essentially horizontal in their containers (or other physical boundaries) because of gravity whereas most bulk solids pile at an angle of repose to a peak. The substance to be measured can be inside a container or can be in its natural form (e.g., a river or a lake). The level measurement can be either continuous or point values. Continuous level sensors measure level within a specified range and determine the exact amount of substance in a certain place, while point-level sensors only indicate whether the substance is above or below the sensing point. Generally the latter detect levels that are excessively high or low. There are many physical and application variables that affect the selection of the optimal level monitoring method for industrial and commercial processes. The selecti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypsometer
A hypsometer is an instrument for measuring height or elevation. Two different principles may be used: trigonometry and atmospheric pressure. Etymology The English word ''hypsometer'' originates from the Ancient Greek words ὕψος (húpsos, "height") and μέτρον (métron, "measure"). Scale hypsometer A simple scale hypsometer allows the height of a building or tree to be measured by sighting across a ruler to the base and top of the object being measured, when the distance from the object to the observer is known. Modern hypsometers use a combination of laser rangefinder and clinometer to measure distances to the top and bottom of objects, and the angle between the lines from the observer to each to calculate height. An example of such a scale hypsometer is illustrated here, and can be seen to consist of a sighting tube, a fixed horizontal scale, and an adjustable vertical scale with attached plumb line. The principle of operation of such a scale hypsometer is ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
