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Loran-C
Loran-C is a hyperbolic radio navigation system that allows a receiver to determine its position by listening to low frequency radio signals that are transmitted by fixed land-based radio beacons. Loran-C combined two different techniques to provide a signal that was both long-range and highly accurate, features that had been incompatible. Its disadvantage was the expense of the equipment needed to interpret the signals, which meant that Loran-C was used primarily by militaries after it was introduced in 1957. By the 1970s, the cost, weight and size of electronics needed to implement Loran-C had been dramatically reduced because of the introduction of solid-state electronics and, from the mid-1970s, early microcontrollers to process the signal. Low-cost and easy-to-use Loran-C units became common from the late 1970s, especially in the early 1980s, and the earlier LORAN system was discontinued in favor of installing more Loran-C stations around the world. Loran-C became one o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loran C Navigator
LORAN, short for long range navigation, was a Hyperbolic navigation, hyperbolic radio navigation system developed in the United States during World War II. It was similar to the UK's Gee (navigation), Gee system but operated at lower frequencies in order to provide an improved range up to with an accuracy of tens of miles. It was first used for ship convoys crossing the Atlantic Ocean, and then by long-range patrol aircraft, but found its main use on the ships and aircraft operating in the Pacific theater during World War II. LORAN, in its original form, was an expensive system to implement, requiring a cathode ray tube (CRT) display. This limited use to the military and large commercial users. Automated receivers became available in the 1950s, but the same improved electronics also opened the possibility of new systems with higher accuracy. The U.S. Navy began development of Loran-B, which offered accuracy on the order of a few tens of feet, but ran into significant technical p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LORAN
LORAN, short for long range navigation, was a hyperbolic radio navigation system developed in the United States during World War II. It was similar to the UK's Gee system but operated at lower frequencies in order to provide an improved range up to with an accuracy of tens of miles. It was first used for ship convoys crossing the Atlantic Ocean, and then by long-range patrol aircraft, but found its main use on the ships and aircraft operating in the Pacific theater during World War II. LORAN, in its original form, was an expensive system to implement, requiring a cathode ray tube (CRT) display. This limited use to the military and large commercial users. Automated receivers became available in the 1950s, but the same improved electronics also opened the possibility of new systems with higher accuracy. The U.S. Navy began development of Loran-B, which offered accuracy on the order of a few tens of feet, but ran into significant technical problems. The U.S. Air Force worked on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decca Navigator System
The Decca Navigator System was a hyperbolic radio navigation system which allowed ships and aircraft to determine their position by using radio signals from a dedicated system of static radio transmitters. The system used phase comparison of two low frequency signals between 70 and 129 kHz, as opposed to pulse timing systems like Gee and LORAN. This made it much easier to design receivers using 1940s electronics, and operation was simplified by giving a direct readout of Decca coordinates without the complexity of a cathode ray tube and highly skilled operator. The system was invented in the U.S., but development was carried out by Decca in the UK. It was first deployed by the Royal Navy during World War II for the vital task of clearing the minefields to enable the D-Day landings. The Allied forces needed an accurate system not known to the Germans and thus free of jamming. After the war, it came off the secret list and was commercially developed by the Decca Company and dep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Navigation
Radio navigation or radionavigation is the application of radio frequencies to determine a position of an object on the Earth, either the vessel or an obstruction. Like radiolocation, it is a type of radiodetermination. The basic principles are measurements from/to electric beacons, especially * Angular directions, e.g. by bearing, radio phases or interferometry, * Distances, e.g. ranging by measurement of time of flight between one transmitter and multiple receivers or vice versa, * Distance ''differences'' by measurement of times of arrival of signals from one transmitter to multiple receivers or vice versa * Partly also velocity, e.g. by means of radio Doppler shift. Combinations of these measurement principles also are important—e.g., many radars measure range and azimuth of a target. Bearing-measurement systems These systems used some form of directional radio antenna to determine the location of a broadcast station on the ground. Conventional navigation technique ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperbolic Navigation
Hyperbolic navigation is a class of radio navigation systems in which a navigation receiver instrument is used to determine location based on the difference in timing ( phase) of radio waves received from radio navigation beacon transmitters. Such systems rely on the ability of two widely separated stations to broadcast a signal that is highly correlated in time. Typical systems either broadcast short pulses at the same time, or continual signals that are identical in phase. A receiver located at the midpoint between the two stations will receive the signals at the same time or have identical phase, but at any other location the signal from the closer station will be received first or have a different phase. Determining the location of a receiver requires that the two synchronized stations be tuned in at the same time so the signals can be compared. This reveals a ''difference'' in time, corresponding to a relative distance closer to one station or the other. Plotting all the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CHAYKA
Chayka (russian: Чайка, lit. "seagull") also known as Radioteknicheskaya Systema Dalyoloiy Navigatsii abbreviated as RSDN (lit. Russian Hyperbolic Radio Navigation System) is a Russian terrestrial radio navigation system, similar to Loran-C. It operates on similar frequencies around 100 kHz, and uses the same techniques of comparing both the envelope and the signal phase to accurately determine location. The systems differ primarily in details. Chayka-Chains Chayka, like LORAN-C, uses different pulse repetition frequencies (Group Repetition Intervals, or GRIs) to allow the identification of different stations operating on the same frequencies. There are 5 Chayka chains in use: *GRI 8000 — Western (European) Russia Chayka Chain (1969, RSDN-3/10) *GRI 7950 — Eastern Russia Chayka Chain (1986, RSDN-4) *GRI 5980 — Russian-American Chayka Chain (1995) *GRI 5960 — Northern Chayka Chain (1996, RSDN-5) *GRI 4970 — North-Western Chayka Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operation Muskox
Operation Musk Ox was an 81-day military exercise organized by the Canadian Army in 1946. It involved the 48 members of the Army driving 11 4½-ton Canadian-designed snowmobiles ("Penguins"). They were joined by three American observers in a smaller American-made snowmobile called a "Weasel" as well as an observer from the Royal Canadian Navy and a number of scientists. The Royal Canadian Air Force provided airdrops of supplies. The main expedition, led by Patrick Douglas Baird, travelled , starting from Churchill, Manitoba, first to Baker Lake, Northwest Territories where the number of vehicles was reduced to ten. From there, the group travelled to Denmark Bay on Victoria Island, then south to Kugluktuk, Port Radium, Norman Wells, Fort Simpson, Fort Nelson, and Grande Prairie, and then by rail to Edmonton Edmonton ( ) is the capital city of the Canadian province of Alberta. Edmonton is situated on the North Saskatchewan River and is the centre of the Edmonton Metrop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area and the seventh most populous. Its capital is Brasília, and its most populous city is São Paulo. The federation is composed of the union of the 26 states and the Federal District. It is the largest country to have Portuguese as an official language and the only one in the Americas; one of the most multicultural and ethnically diverse nations, due to over a century of mass immigration from around the world; and the most populous Roman Catholic-majority country. Bounded by the Atlantic Ocean on the east, Brazil has a coastline of . It borders all other countries and territories in South America except Ecuador and Chile and covers roughly half of the continent's land area. Its Amazon basin includes a vast tropical forest, home to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intermediate Frequency
In communications and electronic engineering, an intermediate frequency (IF) is a frequency to which a carrier wave is shifted as an intermediate step in transmission or reception. The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process called heterodyning, resulting in a signal at the difference or beat frequency. Intermediate frequencies are used in superheterodyne radio receivers, in which an incoming signal is shifted to an IF for amplification before final detection is done. Conversion to an intermediate frequency is useful for several reasons. When several stages of filters are used, they can all be set to a fixed frequency, which makes them easier to build and to tune. Lower frequency transistors generally have higher gains so fewer stages are required. It's easier to make sharply selective filters at lower fixed frequencies. There may be several such stages of intermediate frequency in a superheterodyne receiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gee (navigation)
Gee, sometimes written GEE, was a radio navigation system used by the Royal Air Force during World War II. It measured the time delay between two radio signals to produce a fix, with accuracy on the order of a few hundred metres at ranges up to about . It was the first hyperbolic navigation system to be used operationally, entering service with RAF Bomber Command in 1942. Gee was devised by Robert Dippy as a short-range blind landing system to improve safety during night operations. During development by the Telecommunications Research Establishment (TRE) at Swanage, the range was found to be far better than expected. It then developed into a long-range, general navigation system. For large, fixed targets, such as the cities that were attacked at night, Gee offered enough accuracy to be used as an aiming reference without the need to use a bombsight or other external references. Jamming reduced its usefulness as a bombing aid, but it remained in use as a navigational aid in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post Office Position Indicator
Post or POST commonly refers to: *Mail, the postal system, especially in Commonwealth of Nations countries **An Post, the Irish national postal service **Canada Post, Canadian postal service **Deutsche Post, German postal service **Iraqi Post, Iraqi postal service **Russian Post, Russian postal service **Hotel post, a service formerly offered by remote Swiss hotels for the carriage of mail to the nearest official post office **United States Postal Service or USPS ** Parcel post, a postal service for mail that is heavier than ordinary letters *Post, a job or occupation Post, POST, or posting may also refer to: Architecture and structures *Lamppost, a raised source of light on the edge of a road * Post (structural), timber framing *Post and lintel, a building system * Steel fence post *Trading post *Utility pole or utility post Military *Military base, an assigned station or a guard post ** Outpost (military), a military outpost **Guardpost, or guardhouse Geography * Post, Iran, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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