Possible WAAS Reference Station Locations In Alaska To Increase LPV Availability

E. Carolipio, H. Go, H. Wan

Abstract:	As the Wide Area Augmentation System (WAAS) nears an initial operating capability, upgrades to the system are starting to be planned. One proposed extension is to guarantee a useful availability of Lateral Precision with Vertical Guidance (LPV) service in Alaska. With only three WAAS reference stations (WRSs) in Alaska, LPV is unavailable for most of the day for nearly the whole state. Alaska is a region where augmentation systems such as WAAS are cost-effective solutions to increasing the safety of approaches at many airports. This paper explores how significant availability of LPV service can be achieved through the addition of three WRSs in the region. The Service Volume Model (SVM) software can estimate the availability of LPV service and is used to conduct the analysis. The SVM includes models for the GPS satellite motion and for the integrity algorithms in the fielded WAAS, though the software unfortunately can not simulate the effect of ionospheric irregularities that affect LPV service significantly and are common in Alaska. A two-step approach is taken to optimize the station locations. Candidate locations are scored at five “critical points” then scenarios are assembled from the bestscoring candidates to identify a set of three locations that maximizes LPV coverage. Simulations indicate about half the state will have LPV service for 90% of the day, primarily over regions where the service likely is most useful.
Published in:	Proceedings of the 2003 National Technical Meeting of The Institute of Navigation January 22 - 24, 2003 Disneyland Paradise Pier Hotel Anaheim, CA
Pages:	195 - 202
Cite this article:	Carolipio, E., Go, H., Wan, H., "Possible WAAS Reference Station Locations In Alaska To Increase LPV Availability," Proceedings of the 2003 National Technical Meeting of The Institute of Navigation, Anaheim, CA, January 2003, pp. 195-202.
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