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Precision Approach Radar
Precision approach radar or PAR is a type of radar guidance system designed to provide lateral and vertical guidance to an aircraft pilot for landing, until the landing threshold is reached. Controllers monitoring the PAR displays observe each aircraft's position and issue instructions to the pilot that keep the aircraft on course and glidepath during final approach. After the aircraft reaches the decision height (DH) or decision altitude (DA), further guidance is advisory only. The overall concept is known as ground-controlled approach (GCA), and this name was also used to refer to the radar systems in the early days of its development. PAR radars use a unique type of radar display with two separate "traces", separated vertically. The upper trace shows the elevation of a selected aircraft compared to a line displaying the ideal glideslope, while the lower shows the aircraft's horizontal position relative to the runway midline. GCA approaches normally start with the controller ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transponder
In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a flight transponder is an automated transceiver in an aircraft that emits a coded identifying signal in response to an interrogating received signal. In a communications satellite, a satellite transponder receives signals over a range of uplink frequencies, usually from a satellite ground station; the transponder amplifies them, and re-transmits them on a different set of downlink frequencies to receivers on Earth, often without changing the content of the received signal or signals. Satellite/broadcast communications A communications satellite’s channels are called transponders because each is a separate transceiver or repeater. With digital video data compression and multiplexing, several video and audio channels may travel through a single tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Index Of Aviation Articles
Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Articles related to aviation include: A Aviation accidents and incidents – Above Mean Sea Level (AMSL) – ADF – Accessory drive – Advance airfield – Advanced air mobility – Advanced technology engine – Adverse yaw – Aerial ramming – Aerial reconnaissance – Aerobatics – Aerodrome – Aerodrome mapping database (AMDB) – Aerodynamics – Aerofoil – Aerodrome beacon – Aeronautical Information Manual (AIM) – Aeronautical chart – Aeronautical Message Handling System – Aeronautical phraseology – Aeronautics – Aeronaval – Aerospace – Aerospace engineering – Afterburner – Agile Combat Employment (ACE) – Aileron – Air charter – Air defense identification zone (ADIZ) – Air freight terminal – Air traffic flow management – Air-augmented rocket – Airband – Airbase (AFB) – Airborne colli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ICAO
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] |
Theodolite
A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and infrastructure construction, and some specialized applications such as meteorology and rocket launching. It consists of a moveable telescope mounted so it can rotate around horizontal and vertical axes and provide angular readouts. These indicate the orientation of the telescope, and are used to relate the first point sighted through the telescope to subsequent sightings of other points from the same theodolite position. These angles can be measured with accuracies down to microradians or seconds of arc. From these readings a plan can be drawn, or objects can be positioned in accordance with an existing plan. The modern theodolite has evolved into what is known as a total station where angles and distances are measured electronicall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flight Inspection
Flight inspection refers to the periodic evaluation of navigational aids used in aviation, such as flight procedures and electronic signals, to ensure they are safe and accurate. Unlike flight tests, which analyze the aerodynamic design and safety of the aircraft itself, flight inspection comprises reviewing flight procedures (such as routes, approaches and departures) to ensure navigational support is sufficient, there are no obstacles and the procedure is reliable. Flight inspectors originally tested the accuracy of light beacons sighted while flying. These beacons allowed pilots to fly at night with visual guidance. Radio navigation systems followed, with inspectors testing the radio transmitters while airborne, and then GPS. Customized aircraft are used for flight inspection, with dedicated receivers and sensors to collect data from the navigational aids being inspected. Computers decode the data and compare to the real aircraft position, with results displayed to the insp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rain Fade
Rain fade refers primarily to the absorption of a microwave radio frequency (RF) signal by atmospheric rain, snow, or ice, and losses which are especially prevalent at frequencies above 11 GHz. It also refers to the degradation of a signal caused by the electromagnetic interference of the leading edge of a storm front. Rain fade can be caused by precipitation at the uplink or downlink location. It does not need to be raining at a location for it to be affected by rain fade, as the signal may pass through precipitation many miles away, especially if the satellite dish has a low look angle. From 5% to 20% of rain fade or satellite signal attenuation may also be caused by rain, snow, or ice on the uplink or downlink antenna reflector, radome, or feed horn. Rain fade is not limited to satellite uplinks or downlinks, as it can also affect terrestrial point-to-point microwave links (those on the Earth's surface). Rain fade is usually estimated experimentally and also can be calculated t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L-band
The L band is the Institute of Electrical and Electronics Engineers (IEEE) designation for the range of Frequency, frequencies in the radio spectrum from 1 to 2 gigahertz (GHz). This is at the top end of the ultra high frequency (UHF) band, at the lower end of the microwave range. Applications Mobile service In Europe, the Electronic Communications Committee (ECC) of the European Conference of Postal and Telecommunications Administrations (CEPT) has harmonized part of the L band (1452–1492 MHz), allowing individual countries to adopt this spectrum for terrestrial mobile/fixed communications networks supplemental downlink (MFCN SDL). By means of carrier aggregation, an LTE-Advanced or UMTS/HSDPA base station could use this spectrum to provide additional bandwidth for communications from the base station to the mobile device; i.e., in the downlink direction. In the Americas, mobile services are operated between the 1.7 GHz to 2.1 GHz range in the Personal Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Surveillance Radar
Secondary surveillance radar (SSR)''Secondary Surveillance Radar'', Stevens M.C. Artech House, is a radar system used in air traffic control (ATC), that unlike primary radar systems that measure the bearing and distance of targets using the detected reflections of radio signals, relies on targets equipped with a radar Transponder (aviation), transponder, that reply to each interrogation signal by transmitting encoded data such as an identity code, the aircraft's altitude and further information depending on its chosen mode. SSR is based on the military identification friend or foe (IFF) technology originally developed during World War II; therefore, the two systems are still compatible. Monopulse secondary surveillance radar (MSSR), Secondary surveillance radar#Mode S, Mode S, TCAS and ADS-B are similar modern methods of secondary surveillance. Overview Primary radar The rapid World War II, wartime development of radar had obvious applications for air traffic control (ATC) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transponder Landing System
A transponder landing system (TLS) is an all-weather, precision landing system that uses existing airborne Transponder (aviation), transponder and instrument landing system (ILS) equipment to create a precision approach at a location where an ILS would normally not be available. Description Conventional Instrument landing system, ILS systems broadcast using a number of "single purpose" antennas. The localizer array consists of 8 to 14 or more antenna elements and is typically located 2000+ feet from the runway approach threshold, which is often beyond the departure end of the runway and provides a fan-shaped signal for azimuth direction (side to side). The other antenna array is located beside the runway and provides elevation to indicate a standard glideslope. This complex set of antennas is expensive to install and maintain and is often difficult to site in areas with uneven terrain or obstacles that could interfere with its guidance signals. Function The TLS facility ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
