The U.S. Global Positioning System (GPS) Standard Positioning Service (SPS) consists of spacebased

positioning, navigation, and timing (PNT) signals generated from space vehicles orbiting the

earth and delivered free of direct user fees for civil, commercial, and scientific uses worldwide. The

Wide Area Augmentation System (WAAS) provides an augmentation signal to GPS, delivered free

of direct user fees, that provides correction and integrity information intended to improve

positioning navigation and timing (PNT) service over the United States (U.S.) and portions of

Canada and Mexico. WAAS is the first operational implementation of an International Civil Aviation

Organization (ICAO) compliant Space Based augmentation System (SBAS). This WAAS

Performance Standard (WAAS PS) specifies the levels of navigation performance that will be

available to suitably equipped users who use both the GPS SPS broadcast signals and the WAAS

augmentation signal. The U.S. Government is committed to meeting the minimum levels of service

specified in this WAAS PS. Refer to the GPS SPS PS for specific information regarding the USG

commitment for the GPS SPS.

Since WAAS was commissioned in 2003, actual performance has typically met and exceeded the

minimum accuracy, integrity, continuity, and availability performance requirements specified in this

WAAS PS and users can therefore generally expect improved performance over the minimum

levels described here. Actual real-time performance, statistical performance and real-time data are

provided on-line by the Federal Aviation Administration (FAA). Quarterly Performance Analysis

Reports for both GPS and WAAS are also available at the FAA Technical Center WAAS Test Bed

web site (http://www.nstb.tc.faa.gov/). Interested readers are encouraged to refer to this site and

other sources for updated GPS and WAAS performance information. Note that the number of

WAAS-based Localizer Performance with Vertical (LPV) guidance procedures now exceeds the

number of Instrument Landing System (ILS) procedures in the United States.

GPS will provide three new modernized civil signals in the future: L2C, L5, and L1C. With the

additional signal on L5, airborne receivers will be able to correct for the line of sight ionospheric

propagation delay error. This dual frequency (L1/L5) mode of operation will allow changes to be

made in the delivery of GPS-based augmentation services, such as WAAS, but this Performance

Standard does not consider those future changes. This WAAS Performance Standard only applies

to WAAS augmented GPS SPS users of the L1 (1575.42 MHz) Coarse/Acquisition (C/A) signal and

the WAAS Signal-In-Space (SIS) broadcast by a geostationary satellite (GEO).

The WAAS PS will be updated as required to reflect substantial changes to WAAS augmentation

services. In addition to the WAAS PS, readers are referenced to the GPS SPS PS and FAA

Technical Standard Order (TSO)-145/146 for details in both the fundamental GPS SPS service and

WAAS receiver equipment. WAAS also meets or exceeds the ICAO Annex 10, Standards and

Recommended Practices (SARPs) for Global Navigation Satellite System (GNSS) Satellite Based

Augmentation System (SBAS).

1st