Wide Area Multilateration

	Wide Area Multilateration Wide area multilateration (WAM) is a cooperative aircraft surveillance technology based on the same ''time difference of arrival'' principle that is used on an airport surface. WAM is a technique where several ground receiving stations listen to signals transmitted from an aircraft; then the aircraft's location is mathematically calculated -- typically in two dimensions, with the aircraft providing its altitude. Aircraft position, altitude and other data are ultimately transmitted, through an Air Traffic Control automation system, to screens viewed by air traffic controllers for separation of aircraft. It can and has been interfaced to terminal or en-route automation systems. System performance WAM provides performance that is comparable to secondary surveillance radar (SSR) in terms of accuracy, probability of detection, update rate and availability/ reliability. Performance varies as a function of the location of aircraft in relation to the ground sensors. WAM is adaptable to int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Multilateration Trilateration is the use of distances (or "ranges") for determining the unknown position coordinates of a point of interest, often around Earth (geopositioning). When more than three distances are involved, it may be called multilateration, for emphasis. The distances or ranges might be ordinary Euclidean distances (slant ranges) or spherical distances (scaled central angles), as in '' true-range multilateration''; or biased distances (pseudo-ranges), as in ''pseudo-range multilateration''. Trilateration or multilateration should not be confused with ''triangulation'', which uses angles for positioning; and ''direction finding'', which determines the line of sight direction to a target without determining the radial distance. Terminology Multiple, sometimes overlapping and conflicting terms are employed for similar concepts – e.g., ''multilateration'' without modification has been used for aviation systems employing both true-ranges and pseudo-ranges."Multilateration (MLAT) Conc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	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, 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), Mode S, TCAS and ADS-B are similar modern methods of secondary surveillance. Overview Primary radar The rapid wartime development of radar had obvious applications for air traffic control (ATC) as a means of providing continuous surveillance of air traffic dispositio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Mode S The aviation transponder interrogation modes are the standard formats of pulsed sequences from an interrogating Secondary Surveillance Radar (SSR) or similar Automatic Dependent Surveillance-Broadcast (ADS-B) system. The reply format is usually referred to as a "code" from a transponder, which is used to determine detailed information from a suitably equipped aircraft. In its simplest form, a "Mode" or interrogation type is generally determined by pulse spacing between two or more interrogation pulses. Various modes exist from Mode 1 to 5 for military use, to Mode A, B, C and D, and Mode S for civilian use. Interrogation modes Several different RF communication protocols have been standardized for aviation transponders: Mode A and Mode C are implemented using air traffic control radar beacon system as the physical layer, whereas Mode S is implemented as a standalone backwards-compatible protocol. ADS-B can operate using Mode S-ES or Universal Access Transceiver as its transport ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	ASTERIX (ATC Standard) ASTERIX (short for ''All Purpose Structured Eurocontrol Surveillance Information Exchange'') is a standard for the exchange of air traffic services (ATS) information. It is developed and maintained by the European ATS organization Eurocontrol. ASTERIX is surveillance data format which is being adopted by the world users community as the universal standard in this domain today. ASTERIX is an extensible standard with a number of different categories, each of which deals with one particular kind of information. These include target reports from surveillance sensors such as radars as well as processed information such as aircraft tracks and various system status messages. Each category defines a number of data items which can be transmitted in a message. Which of these items are transmitted is defined in a User Application Profile (UAP), usually the default UAP provided by the standard document for the category, but optionally a more specialised UAP negotiated between sender and receiver ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Footnotes A note is a string of text placed at the bottom of a page in a book or document or at the end of a chapter, volume, or the whole text. The note can provide an author's comments on the main text or citations of a reference work in support of the text. Footnotes are notes at the foot of the page while endnotes are collected under a separate heading at the end of a chapter, volume, or entire work. Unlike footnotes, endnotes have the advantage of not affecting the layout of the main text, but may cause inconvenience to readers who have to move back and forth between the main text and the endnotes. In some editions of the Bible, notes are placed in a narrow column in the middle of each page between two columns of biblical text. Numbering and symbols In English, a footnote or endnote is normally flagged by a superscripted number immediately following that portion of the text the note references, each such footnote being numbered sequentially. Occasionally, a number between brack ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]