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The Local Area Augmentation System (LAAS) is an all-weather aircraft landing system based on real-time differential correction of the GPS signal. Local reference receivers located around the airport send data to a central location at the airport. This data is used to formulate a correction message, which is then transmitted to users via a VHF Data Link. A receiver on an aircraft uses this information to correct GPS signals, which then provides a standard ILS-style display to use while flying a precision approach. The International Civil Aviation Organization (ICAO) calls this type of system a Ground Based Augmentation System (GBAS). ==History== The Ground-Based Augmentation System (GBAS) with aviation standards identified in International Civil Aviation Organization (ICAO) Standards and Recommended Practices (SARPS), Annex 10 on Radio-frequency Navigation provides international standards for augmentation of GPS to support precision landing. The history of these standards can trace back to efforts in the United States by the Federal Aviation Administration to developed a Local Area Augmentation System (LAAS). Many references still refer to LAAS, although the current international terminology is GBAS and GBAS Landing System (GLS). GBAS monitors GNSS satellites and provides correction messages to users in the vicinity of the GBAS station. The monitoring enables the GBAS to detect anomalous GPS satellite behavior and alert users in a time frame appropriate for aviation uses. The GBAS provides corrections to the GPS signals with a resulting improvement in accuracy sufficient to support aircraft precision approach operations. For more information on how GBAS works, see GBAS-How It Works.〔http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/laas/howitworks/〕 Current GBAS standards only augment a single GNSS frequency and support landings to Category-1 minima. These GBAS systems are identified as GBAS Approach Service Type C (GAST-C). Draft requirements for a GAST-D system are under review by ICAO. A GAST-D system will support operations to Category-III minima. Many organizations are conducting research in multi-frequency GBAS. Other efforts are exploring the addition of Galileo corrections for GBAS. Honeywell has developed a Non-Federal CAT-1 GBAS which received System Design Approval (SDA) from the Federal Aviation Administration (FAA) in September 2009 (). The GBAS installation at Newark Liberty International Airport achieved Operational Approval on Sept. 28, 2012.〔http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/mobileAll/GBAS_Newark.pdf〕 A second GBAS installed at Houston Intercontinental Airport received Operational Approval on April 23, 2013.〔http://www.fly2houston.com/0/3921086/0/83280/〕 Honeywell systems are also installed internationally, with an operational system in Bremen, Germany. Additional systems are installed or in the process of being installed. Operational approval of several more systems is expected shortly. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Local Area Augmentation System」の詳細全文を読む スポンサード リンク
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