Local Area Augmentation System (LAAS)

The Local Area Augmentation System (LAAS) will augment the Global Positioning System to provide an all-weather approach, landing, and surface navigation capability. LAAS focuses its service on a local area (approximately a 20-30 mile radius), such as an airport, and broadcasts its correction message via a very high frequency (VHF) radio data link from a ground-based transmitter.

LAAS will have a profound impact on aviation navigation. LAAS will yield the extremely high accuracy, availability, and integrity necessary for Category I, II, and III precision approaches. It is expected that the end-state configuration will pinpoint the aircraft’s position to within one meter or less with a significant improvement in service flexibility and user operating costs. Curved approach paths, not possible using the current instrument landing systems, will be possible for Category I, II, and III precision approaches. Approaches will be designed to avoid obstacles, restricted airspace, noise sensitive areas, or congested airspace. Unlike current landing systems, LAAS will provide multiple precision approach capabilities to runways within the LAAS coverage area. Duplication of equipment solely for the purpose of serving multiple runways can be eliminated. Also, airports with the need for precise surface area navigation may use the accuracy of LAAS for the position determination of aircraft. Using this capability, controllers will know the location of all airport service vehicles and taxiing aircraft to assist in the prevention of runway incursions in low visibility conditions. Furthermore, aircraft operators will benefit from the reduction of expenses associated with purchasing a variety of radionavigation equipment. Potentially, WAAS and LAAS could use the same aircraft avionics to accomplish both the WAAS and LAAS missions, reduce avionics maintenance costs, and realize savings in air crew training.

The development efforts of the LAAS are focused on two main areas — the LAAS ground equipment and the LAAS avionics. On September 28, 1998, RTCA published the LAAS Minimum Aviation System Performance Standards (MASPS). This document allocated overall LAAS requirements between the ground equipment and the avionics. The development efforts of the avionics are captured in the LAAS Minimum Operational Performance Standards (MOPS), which was completed in February 2000. The development efforts of the ground equipment is captured in the LAAS specification, submitted to the FAA Specification Review Board in July 1999 and signed in November of that year. The FAA used a prototype LAAS ground station to perform validation testing of this specification. The LAAS Interface Control Document, which brings these two pieces together, was completed on September 28, 1998, along with the MASPS.

The FAA has already successfully demonstrated the feasibility of GPS-based Category III precision approaches and has completed the proposed architecture for LAAS. This architecture was successfully presented and approved by the International Civil Aviation Organization (ICAO) Global Navigation Satellite System (GNSS) Panel in February 1997.

To ensure that LAAS will be compatible with international standards, participation in the International Civil Aviation Organization’s (ICAO) Global Navigation Satellite System Panel (GNSS-P) has been ongoing. Standards and Recommended Practices (SARPs) for the Ground-Based Augmentation System (GBAS), for Category I only, have been approved by the ICAO Air Navigation Commission with an applicability date of November 1, 2001. The FAA is currently coordinating the Category II/III specification through the ICAO GNSS-P.

The FAA is pursuing an innovative approach to overall LAAS system production, fielding, testing and evaluation, and approval for public use. On April 7, 1999 and April 9, 1999, the FAA signed two separate cost-sharing partnerships with industry teams – one led by Honeywell and the other by Raytheon Systems Company - leading to the Government/Industry partnerships (GIP). The original FAA/Industry concept was to develop a LAAS Category I system using industry funds while FAA prepares all operational documentation, provides technical support, and conducts Type Acceptance or certification of the system. Due to additional FAA requirements, the current FAA concept is to leverage off these valuable GIP efforts and award an FAA development and procurement contract for LAAS Category I production systems (with additional requirements), followed later by a LAAS Category II/III system satisfying Category II/III requirements. Initial FAA Category I LAAS is scheduled to be operational by September 2003. Federal Category II/III development is scheduled to begin in FY03 with production in FY06. The FAA and the GIP partners will continue working toward a private/public use certified LAAS Category I system with the goal of transitioning to the Federal Category I procurement as soon as possible.

For futher information regarding LAAS, please contact:
FAA Satellite Navigation Product Team, AND-710
800 Independence Avenue, SW, Washington, DC 20591
Fax: 202-493-5031