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Quantum Compass
The terminology quantum compass often relates to an instrument which measures relative position using the technique of atom interferometry. It includes an ensemble of accelerometers and gyroscope based on quantum technology to form an Inertial Navigation Unit. Description The work about quantum technology based inertial measurement units (IMUs), the instruments containing the gyroscopes and accelerometers follows from the early demonstrations of matter-wave based accelerometers and gyrometers. The first demonstration of onboard acceleration measurement was made on an Airbus A300 in 2011. A quantum compass contains clouds of atoms frozen using lasers. By measuring the movement of these frozen particles over precise periods of time the motion of the device can be calculated. The device would then provide a tamper proof accurate position in circumstances where satellites are not available for satellite navigation, e.g. a fully submerged submarine. Various defence agencies worldwide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Position (vector)
In geometry, a position or position vector, also known as location vector or radius vector, is a Euclidean vector that represents the position of a point ''P'' in space in relation to an arbitrary reference origin ''O''. Usually denoted x, r, or s, it corresponds to the straight line segment from ''O'' to ''P''. In other words, it is the displacement or translation that maps the origin to ''P'': :\mathbf=\overrightarrow The term "position vector" is used mostly in the fields of differential geometry, mechanics and occasionally vector calculus. Frequently this is used in two-dimensional or three-dimensional space, but can be easily generalized to Euclidean spaces and affine spaces of any dimension.Keller, F. J, Gettys, W. E. et al. (1993), p 28–29 Relative position The relative position of a point ''Q'' with respect to point ''P'' is the Euclidean vector resulting from the subtraction of the two absolute position vectors (each with respect to the origin): :\Delta \mathbf=\ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atom Interferometry
An atom interferometer is an interferometer which uses the wave character of atoms. Similar to optical interferometers, atom interferometers measure the difference in phase between atomic matter waves along different paths. Atom interferometers have many uses in fundamental physics including measurements of the gravitational constant, the fine-structure constant, the universality of free fall, and have been proposed as a method to detect gravitational waves. They also have applied uses as accelerometers, rotation sensors, and gravity gradiometers. Overview Interferometry inherently depends on the wave nature of the object. As pointed out by de Broglie in his PhD thesis, particles, including atoms, can behave like waves (the so-called wave–particle duality, according to the general framework of quantum mechanics). More and more high precision experiments now employ atom interferometers due to their short de Broglie wavelength. Some experiments are now even using molecules to o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accelerometers
An accelerometer is a tool that measures proper acceleration. Proper acceleration is the acceleration (the rate of change of velocity) of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is acceleration in a fixed coordinate system. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earth's gravity, straight upwards (by definition) of g ≈ 9.81 m/s2. By contrast, accelerometers in free fall (falling toward the center of the Earth at a rate of about 9.81 m/s2) will measure zero. Accelerometers have many uses in industry and science. Highly sensitive accelerometers are used in inertial navigation systems for aircraft and missiles. Vibration in rotating machines is monitored by accelerometers. They are used in tablet computers and digital cameras so that images on screens are always displayed upright. In unmanned aerial vehicles, accelerometers help to stabilise flight. W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gyroscope
A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining orientation and angular velocity. It is a spinning wheel or disc in which the axis of rotation (spin axis) is free to assume any orientation by itself. When rotating, the orientation of this axis is unaffected by tilting or rotation of the mounting, according to the conservation of angular momentum. Gyroscopes based on other operating principles also exist, such as the microchip-packaged MEMS gyroscopes found in electronic devices (sometimes called gyrometers), solid-state ring lasers, fibre optic gyroscopes, and the extremely sensitive quantum gyroscope. Applications of gyroscopes include inertial navigation systems, such as in the Hubble Space Telescope, or inside the steel hull of a submerged submarine. Due to their precision, gyroscopes are also used in gyrotheodolites to maintain direction in tunnel mining. Gyroscopes ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inertial Navigation
An inertial navigation system (INS) is a navigation device that uses motion sensors (accelerometers), rotation sensors ( gyroscopes) and a computer to continuously calculate by dead reckoning the position, the orientation, and the velocity (direction and speed of movement) of a moving object without the need for external references. Often the inertial sensors are supplemented by a barometric altimeter and sometimes by magnetic sensors ( magnetometers) and/or speed measuring devices. INSs are used on mobile robots and on vehicles such as ships, aircraft, submarines, guided missiles, and spacecraft. Other terms used to refer to inertial navigation systems or closely related devices include inertial guidance system, inertial instrument, inertial measurement unit (IMU) and many other variations. Older INS systems generally used an inertial platform as their mounting point to the vehicle and the terms are sometimes considered synonymous. Overview Inertial navigation is a self-c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airbus A300
The Airbus A300 is a wide-body airliner developed and manufactured by Airbus. In September 1967, aircraft manufacturers in the United Kingdom, France, and West Germany signed a memorandum of understanding to develop a large airliner. West Germany and France reached an agreement on 29 May 1969 after the British withdrew from the project on 10 April 1969. European collaborative aerospace manufacturer Airbus Industrie was formally created on 18 December 1970 to develop and produce it. The prototype first flew on 28 October 1972. The first twin-engine widebody airliner, the A300 typically seats 247 passengers in two classes over a range of 5,375 to 7,500 km (2,900 to 4,050 nmi). Initial variants are powered by General Electric CF6-50 or Pratt & Whitney JT9D turbofans and have a three-crew flight deck. The improved A300-600 has a two-crew cockpit and updated CF6-80C2 or PW4000 engines; it made its first flight on 8 July 1983 and entered service later that year. The A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Cooling
Laser cooling includes a number of techniques in which atoms, molecules, and small mechanical systems are cooled, often approaching temperatures near absolute zero. Laser cooling techniques rely on the fact that when an object (usually an atom) absorbs and re-emits a photon (a particle of light) its momentum changes. For an ensemble of particles, their thermodynamic temperature is proportional to the variance in their velocity. That is, more homogeneous velocities among particles corresponds to a lower temperature. Laser cooling techniques combine atomic spectroscopy with the aforementioned mechanical effect of light to compress the velocity distribution of an ensemble of particles, thereby cooling the particles. The 1997 Nobel Prize in Physics was awarded to Claude Cohen-Tannoudji, Steven Chu, and William Daniel Phillips "for development of methods to cool and trap atoms with laser light". Methods The first example of laser cooling, and also still the most common method (so mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Navigation
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high precision (within a few centimetres to metres) using time signals transmitted along a line of sight by radio from satellites. The system can be used for providing position, navigation or for tracking the position of something fitted with a receiver (satellite tracking). The signals also allow the electronic receiver to calculate the current local time to a high precision, which allows time synchronisation. These uses are collectively known as Positioning, Navigation and Timing (PNT). One set of critical vulnerabilities in satellite communications are the signals that govern positioning, navigation and timing (PNT). Failure to properly secure these transmissions could not only disrupt satellite networks but wreak havoc on a host of dependent s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ministry Of Defence (United Kingdom)
The Ministry of Defence (MOD or MoD) is the department responsible for implementing the defence policy set by His Majesty's Government, and is the headquarters of the British Armed Forces. The MOD states that its principal objectives are to defend the United Kingdom of Great Britain and Northern Ireland and its interests and to strengthen international peace and stability. The MOD also manages day-to-day running of the armed forces, contingency planning and defence procurement. The expenditure, administration and policy of the MOD are scrutinised by the Defence Select Committee, except for Defence Intelligence which instead falls under the Intelligence and Security Committee of Parliament. History During the 1920s and 1930s, British civil servants and politicians, looking back at the performance of the state during the First World War, concluded that there was a need for greater co-ordination between the three services that made up the armed forces of the United Kingdom: t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Daily Telegraph
''The Daily Telegraph'', known online and elsewhere as ''The Telegraph'', is a national British daily broadsheet newspaper published in London by Telegraph Media Group and distributed across the United Kingdom and internationally. It was founded by Arthur B. Sleigh in 1855 as ''The Daily Telegraph & Courier''. Considered a newspaper of record over ''The Times'' in the UK in the years up to 1997, ''The Telegraph'' generally has a reputation for high-quality journalism, and has been described as being "one of the world's great titles". The paper's motto, "Was, is, and will be", appears in the editorial pages and has featured in every edition of the newspaper since 19 April 1858. The paper had a circulation of 363,183 in December 2018, descending further until it withdrew from newspaper circulation audits in 2019, having declined almost 80%, from 1.4 million in 1980.United Newspapers PLC and Fleet Holdings PLC', Monopolies and Mergers Commission (1985), pp. 5–16. Its si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Scientist
''New Scientist'' is a magazine covering all aspects of science and technology. Based in London, it publishes weekly English-language editions in the United Kingdom, the United States and Australia. An editorially separate organisation publishes a monthly Dutch-language edition. First published on 22 November 1956, ''New Scientist'' has been available in online form since 1996. Sold in retail outlets (paper edition) and on subscription (paper and/or online), the magazine covers news, features, reviews and commentary on science, technology and their implications. ''New Scientist'' also publishes speculative articles, ranging from the technical to the philosophical. ''New Scientist'' was acquired by Daily Mail and General Trust (DMGT) in March 2021. History Ownership The magazine was founded in 1956 by Tom Margerison, Max Raison and Nicholas Harrison as ''The New Scientist'', with Issue 1 on 22 November 1956, priced at one shilling (a twentieth of a pound in pre-decimal UK cu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Measuring Instruments
A measuring instrument is a device to measure a physical quantity. In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities of real-world objects and events. Established standard objects and events are used as units, and the process of measurement gives a number relating the item under study and the referenced unit of measurement. Measuring instruments, and formal test methods which define the instrument's use, are the means by which these relations of numbers are obtained. All measuring instruments are subject to varying degrees of instrument error and measurement uncertainty. These instruments may range from simple objects such as rulers and stopwatches to electron microscopes and particle accelerators. Virtual instrumentation is widely used in the development of modern measuring instruments. Time In the past, a common time measuring instrument was the sundial. Today, the usual measuring instru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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