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The Global AMDAR System: General Description
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The Global AMDAR System: General DescriptionThe Global AMDAR system consists of a number of data agreements between National Meteorological Services and their local airlines. The Global AMDAR system serves to coordinate the activities and data obtained from various sources, including overall quality monitoring and dissemination of data via the GTS in a timely manner. The WMO AMDAR Panel, and it’s successor ET-ABO (Expert Team on Aircraft Based Observations) serves to provide guidance and coordination to the National Meteorological Services to the overall benefit of the program. Aircraft based meteorological observation includes a number of data sources including AMDAR, MDCRS, ADS and AIREP, which are frequently noted separately in the literature and AMDAR documentation. Data is generally transmitted in either BUFR or FM 42 format. MDCRS (Meteorological Data Collection and Reporting System) refers to the US version of the AMDAR system and is jointly funded by the US government and the participating airlines. Most MDCRS data is transmitted in BUFR format. ADS-B (Automatic Dependent Surveillance- Broadcast) is a component of the next generation of air traffic management, and is intended to replace radar as the primary surveillance tool in many air traffic environments. In addition to accurate position, altitude and heading information, ADS-B may transmit current meteorological conditions. ADS-B requires additional avionics components; a certified GPS and a data transmitter –originally conceived as a modified Mode S transponder. Data is currently received by a relatively simple ground receiver usually collocated with VHF radio sites, although Iridium has committed to provide bandwidth for transmission on their next generation of satellite systems. ADS-C (Automatic Dependent Surveillance – Contract, may also be known as ADS-A: Automatic Dependent Surveillance - Addressed) ADS-C is a negotiated relationship between an aircraft and the ground facility requiring ADS information. It is typically used in areas without radar coverage, such as oceanic regions, and communication is typically via ACARS. AIREPs (Air Report) are automatic reports transmitted periodically from the aircraft at specific way point locations. BUFR (Binary Uniform Form for the Representation of meteorological data) is a standard format used for the transmission of some AMDAR data. FM 42 is a standard format for encoding AMDAR data. Within each system there are a number of possible routes that the data may follow from aircraft to forecaster. The general scheme for AMDAR Data Management is shown in Figure 3. Each country’s AMDAR program is somewhat different as are the data management facilities of each participant airline so the specifics vary. FANSIn 1983, ICAO began an initiative to develop the specifications for the next generation of ACARS using satellite data links and digital radio communications. This initiative was called FANS (Future Air Navigation System) and resulted in a number of technical and operational specifications. FANS equipment and procedures have led to a number of operational changes and improvements. Digital communications – the primary communications between an aircraft and air traffic control unit can be completed via digital radio communications or CPDLC (Controller- Pilot Data Link Communications). Both the pilot and controller have messages displayed on a screen reducing or eliminating the need for voice communications in routine operations. Navigation – There has been a near complete shift from inertial navigation systems to GPS position and navigation systems. The GPS systems are much more accurate and frequently incorporate deviation or limit alarms for the flight deck. Surveillance – There has been a change from voice position reports to automated positions reports using either ADS-C or ADS-B. All of these changes have resulted in lower pilot work load and greatly improved system capacity, particularly on congested trans-oceanic routes. System capacity is improved by allowing reduced separation between aircraft while efficiency improvements come from allowing more aircraft to fly at their most efficient altitude. Note that FANS and CPDLC data charges are being paid by the FAA in the US, and by Eurocontrol in Europe, because of the air traffic system efficiencies gained. 
Figure 3: General AMDAR Data Management scheme. (AMDAR Reference Manual, Painting, 2003) Directory: Documents Documents -> Concept stage Documents -> Concept stage Documents -> The great global switch-off Documents -> Nonprofit grant application Documents -> The Truth about the Rwandan Genocide Documents -> Annual InStructional unit plan Documents -> Chaos equipment included Download 3.89 Mb. Share with your friends:
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