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Pseudolite
Pseudolite is a contraction of the term "pseudo-satellite," used to refer to something that is not a satellite which performs a function commonly in the domain of satellites. Pseudolites are most often small transceivers that are used to create a local, ground-based Global Positioning System (GPS) alternative. The range of each transceiver's signal is dependent on the power available to the unit. Being able to deploy one's own positioning system, independent of the GPS, can be useful in situations where the normal GPS signals are either blocked/jammed (military conflicts), or simply not available (exploration of other planets). Pseudolites are normally used to augment the GPS by improving dilution of precision (DOP). Or pseudolites are also used to implement GPS-like indoor location systems, where pseudolites are acting as GPS satellites. Pseudolites use cheap voltage controlled oscillator, so pseudolite based location system shall provide a methodology to compensate clock diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Positioning System
A positioning system is a system for determining the position of an object in space. Positioning system technologies exist ranging from interplanetary coverage with meter accuracy to workspace and laboratory coverage with sub-millimeter accuracy. A major subclass is made of '' geopositioning systems'', used for determining an object's position with respect to Earth, i.e., its geographical position; one of the most well-known and commonly used geopositioning systems is the Global Positioning System (GPS) and similar global navigation satellite systems (GNSS). Coverage Interplanetary systems Interplanetary-radio communication systems not only communicate with spacecraft, but they are also used to determine their position. Radar can track targets near the Earth, but spacecraft in deep space must have a working transponder on board to echo a radio signal back. Orientation information can be obtained using star trackers. Global systems Global navigation satellite systems (GNSS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Locata Corporation
Locata Corporation is a privately held technology company headquartered in Canberra, Australia, with a fully owned subsidiary in Las Vegas, Nevada. Locata has invented a local positioning system that can either replace or augment Global Positioning System (GPS) signals when they are blocked, jammed or unreliable. Government, commercial and other organizations use Locata to determine accurate positioning as a local backup to GPS. History David Small and Nunzio Gambale started work on the initial Locata concepts in 1994 and founded Locata as a company in 1997. As of December 2013, the company has been granted 122 patents around their positioning technology. Products LocataNet A LocataNet is a ground-based local positioning system that provides positioning information which is indistinguishable from GPS to an appropriately configured receiver. The LocataNet achieves this without the satellites, atomic clocks or ground support structure required by traditional GPS satellite-based s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite
A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which are small CubeSats. Similar satellites can work together as groups, forming constellatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transceiver
In radio communication, a transceiver is an electronic device which is a combination of a radio ''trans''mitter and a re''ceiver'', hence the name. It can both transmit and receive radio waves using an antenna, for communication purposes. These two related functions are often combined in a single device to reduce manufacturing costs. The term is also used for other devices which can both transmit and receive through a communications channel, such as ''optical transceivers'' which transmit and receive light in optical fiber systems, and ''bus transceivers'' which transmit and receive digital data in computer data buses. Radio transceivers are widely used in wireless devices. One large use is in two-way radios, which are audio transceivers used for bidirectional person-to-person voice communication. Examples are cell phones, which transmit and receive the two sides of a phone conversation using radio waves to a cell tower, cordless phones in which both the phone hands ... [...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] |
Dilution Of Precision (navigation)
Dilution of precision (DOP), or geometric dilution of precision (GDOP), is a term used in satellite navigation and geomatics engineering to specify the error propagation as a mathematical effect of navigation satellite geometry on positional measurement precision. Introduction The concept of dilution of precision (DOP) originated with users of the Loran-C navigation system. The idea of geometric DOP is to state how errors in the measurement will affect the final state estimation. This can be defined as: :\operatorname = \frac Conceptually you can geometrically imagine errors on a measurement resulting in the \Delta ( \text ) term changing. Ideally small changes in the measured data will not result in large changes in output location. The opposite of this ideal is the situation where the solution is very sensitive to measurement errors. The interpretation of this formula is shown in the figure to the right, showing two possible scenarios with acceptable and poor GDOP. With ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States's civil list of government space agencies, space program, aeronautics research and outer space, space research. National Aeronautics and Space Act, Established in 1958, it succeeded the National Advisory Committee for Aeronautics (NACA) to give the American space development effort a distinct civilian orientation, emphasizing peaceful applications in space science. It has since led most of America's space exploration programs, including Project Mercury, Project Gemini, the 1968–1972 Apollo program missions, the Skylab space station, and the Space Shuttle. Currently, NASA supports the International Space Station (ISS) along with the Commercial Crew Program and oversees the development of the Orion (spacecraft), Orion spacecraft and the Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ames Research Center
The Ames Research Center (ARC), also known as NASA Ames, is a major NASA research center at Moffett Federal Airfield in California's Silicon Valley. It was founded in 1939 as the second National Advisory Committee for Aeronautics (NACA) laboratory. That agency was dissolved and its assets and personnel transferred to the newly created NASA, National Aeronautics and Space Administration (NASA) on October 1, 1958. NASA Ames is named in honor of Joseph Sweetman Ames, a physicist and one of the founding members of NACA. At last estimate NASA Ames had over US$3 billion in capital equipment, 2,300 research personnel and a US$750 million annual budget. Ames was founded to conduct wind-tunnel research on the aerodynamics of propeller-driven aircraft; however, its role has expanded to encompass spaceflight and information technology. Ames plays a role in many NASA missions. It provides leadership in astrobiology; small satellites; robotic lunar exploration; the search for habitable plane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stanford University
Leland Stanford Junior University, commonly referred to as Stanford University, is a Private university, private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth List of governors of California, governor of and then-incumbent List of United States senators from California, United States senator representing California) and his wife, Jane Stanford, Jane, in memory of their only child, Leland Stanford Jr., Leland Jr. The university admitted its first students in 1891, opening as a Mixed-sex education, coeducational and non-denominational institution. It struggled financially after Leland died in 1893 and again after much of the campus was damaged by the 1906 San Francisco earthquake. Following World War II, university Provost (education), provost Frederick Terman inspired an entrepreneurship, entrepreneurial culture to build a self-sufficient local industry (later Silicon Valley). In 1951, Stanfor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellites By Type
A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which are small CubeSats. Similar satellites can work together as groups, forming constellations. Becaus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geopositioning
Geopositioning is the process of determining or estimating the geographic position of an object or a person. Geopositioning yields a set of geographic coordinates (such as latitude and longitude) in a given map datum. Geographic positions may also be expressed indirectly, as a distance in linear referencing or as a bearing and range from a known landmark. In turn, positions can determine a meaningful location, such as a street address. Geoposition is sometimes referred to as ''geolocation'', and the process of geopositioning may also be described as ''geo-localization''. Specific instances include: * animal geotracking, the process of inferring the location of animals over time; * positioning system, the mechanisms for the determination of geographic positions in general; * internet geolocation, geolocating a device connected to the internet; * and mobile phone tracking. Geofencing ''Geofencing'' involves creating a virtual geographic boundary (a geofence), enabling software ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
