Contract modification will also see new reference stations in Alaska, Canada and Mexico
Raytheon is to increase the availability of precision approach guidance using the GPS wide-area augmentation system (WAAS) under a new agreement with the US Federal Aviation Administration. Under a modified contract, the WAAS prime contractor will deploy full lateral precision with vertical guidance (LPV) performance, allowing instrument landing system (ILS) -like approaches.
Since WAAS was commissioned in July 2003, LPV approach availability has exceeded 95% across more than 98% of the lower 48 US states, says Raytheon. The contract modification, which includes four new WAAS reference stations in Alaska and redundant geostationary satellites to broadcast the signal, will increase availability to more than 99% across much of North America, the company says.
WAAS compensates for the effect of the ionosphere on GPS signals, and Raytheon will enhance the integrity algorithms to increase LPV approach availability during weather disturbances, including solar flare activity.
The company also intends to increase the capacity, redundancy and security of the communications backbone linking the WAAS ground stations.
Canada has agreed to install four reference stations in Gander, Goose Bay, Iqaluit and Winnipeg to expand LPV coverage throughout much of Canada and increase availability in the northern USA, while Mexico plans to install five stations at La Paz, Meridia, Mexico City, Puerto Vallarta and Tapachula to expand LPV coverage into Mexico and increase availability in the southwest USA.
Last month, Garmin International received the first certification for a GPS/WAAS receiver providing ILS-like LPV precision approach guidance (Flight International, 2-8 November).
GRAHAM WARWICK / WASHINGTON DC
Source: Flight International
