GNSS Library

A. The Local Area Augmentation System (LAAS) is a satellite navigation system being developed by the FAA. LAAS uses signals from the Global Positioning System (GPS) to develop an extremely accurate navigation signal that focuses its service on the airport area (approximately a 20-30 mile radius).   

A. Like the Wide Area Augmentation System (WAAS), LAAS relies on GPS for basic navigation signals. However, with WAAS, GPS-corrected navigation signals come from space, broadcast from WAAS geostationary satellites. With LAAS, the GPS-corrected navigation signal is broadcast from a LAAS VHF data broadcast transmitter at or near the airport. Although LAAS and WAAS will operate independently, LAAS will complement WAAS by providing GNSS Landing System (GLS) landing service for Category II/III precision approach operations. LAAS will also provide GLS Category-I capability at locations where WAAS service may not be available. Other differences between WAAS and LAAS include the manner in which the availability of the systems are computed, the manner in which avionics receive information on approach procedures, and the vertical alert limits (VAL) associated with each system.   

A. Yes. LAAS was directed back to a research & development program in February 2004 to lower overall program risk and resolve integrity issues. The U.S. air carrier/cargo users want a seamless worldwide navigation capability and continue to support LAAS. The preferred instrument approach procedure types in the terminal area for air carriers are Performance Based Navigation or Required Navigation Performance (RNP) and GLS precision approach provided by LAAS. LAAS also supports the FAA strategic plans to transition to satellite navigation.   

A. The FAA is pursuing a Non-Federal Category I LAAS system. The FAA currently has a contract with Honeywell for the development of LAAS. Additionally, Honeywell has entered into an agreement with Airservices Australia (ASA) to complete the development, certification and joint commercialization of a Ground-Based Augmentation System (GBAS). [GBAS is the international term for LAAS.] ASA will develop a certifiable system to be installed at Sydney under a separate Honeywell contract.

This GBAS development will be a jointly-sponsored FAA and ASA effort. The FAA will sponsor new processor redesign, GPS reference receiver hardware development (DO-254, Level B), and operating system upgrades. ASA will sponsor everything else.

The goal is to get the Memphis system approved as an ICAO Non-Federal Standards and Recommended Practices (SARPs) compliant Category I system in late 2008, the same time the ASA system would be approved in Sydney.

Honeywell will apply for regulatory approval of the SLS-4000 LAAS ground facility at Memphis. The FAA will conduct test & evaluation activities at the FAA Technical Center. FedEx will submit an application for specials approval at Memphis.

The FAA will also complete facility and service approval plans to ensure the operational and user requirements are in place. FAA’s Aviation Systems Standards organization (AVN) is designing and flight inspecting 8 straight-in Category I Instrument Landing System (ILS) overlay approaches at Memphis. The FAA is also doing research on developing Terminal Area Path (TAP) procedures using existing RNP and RNAV criteria. A TAP is a curved path procedure that can begin at the fringes of the terminal area and end in a Category I LAAS approach, while maintaining the most stringent RNP equivalent values. The FAA will determine the feasibility of TAP as a potential implementation of RNP/RNAV and conduct flight testing at the FAA Technical Center and in Memphis to validate performance.   

A. LAAS can provide Category I precision landing to all runway ends with one system while eliminating most ILS critical areas. The eventual goal for LAAS is Category II/III service.   

A. One LAAS system supports multiple runway ends. LAAS eliminates ILS critical areas. LAAS can support curved path approaches. LAAS provides guided missed approaches and departures.  

A. The FAA Technical Center, in conjunction with Boeing and other FAA entities, are developing the high level requirements for a Category II/III LAAS. In addition, the FAA is examining the possibility of using advanced navigation and landing technologies onboard newer digital aircraft to augment existing Category I LAAS technology to attain Category II/III functionality for these specific aircraft.   

A. Rockwell Collins recently received FAA certification approval for their multimode receiver (MMR). Boeing has incorporated this LAAS/GLS functionality on their 737-800 NG series aircraft. Qantas Airlines has purchased several of these LAAS capable Boeing aircraft in anticipation of a future LAAS ground station at Sydney. Continental Airlines has retrofitted nine of its 737-NG with GLS in anticipation of a LAAS System being installed in Guam and a German Air Carrier recently purchased a new LAAS equipped Boeing 737-NG to fly against a new LAAS system in Bremen, Germany. Airbus plans to offer GLS functionality on several of its airframe types to include the new Airbus A380.   

A. The most important part about the survey is that the runway ends have been surveyed in accordance with FAA No. 405, “Standards for Aeronautic Surveys and Related Products”, which describes the accuracy of the runway coordinates. If a survey was done to support WAAS or other precision NAVAID installations, it should be OK.   

A. A new airport survey won’t be needed to support LAAS if it is replacing an ILS, but where a new service or approach is being introduced, a new obstacle survey may be needed. The LAAS installer will need to survey the LAAS reference locations, but it should be possible to do that from existing benchmarks.