Publication Date:
2013-12-13
Description:
[1] This paper reviews the effects of geomagnetic activity of solar cycle 24 from 2011 through mid-2013 on the Federal Aviation Administration's Wide Area Augmentation System (WAAS) navigation service in the US, to identify a) major impacts and their severity compared with the previous cycle, and b) effects in new service regions of North America added since last solar cycle. We examine two cases: a storm that reduced service coverage for several hours, and ionospheric scintillation that led to anomalous receiver tracking. Using the October 24-25, 2011 storm as an example, we examine WAAS operational system coverage for the conterminous US (CONUS). The WAAS algorithm upgrade to ionospheric estimation, in effect since late 2011, is able to mitigate the daytime coverage loss, but not the nighttime loss. We correlate WAAS availability to maps of the storm plasma generated with the data assimilative model IDA4D, which show a local nighttime co-rotating persistent plume of plasma extending from Florida across central CONUS. We study the effect of scintillation on October 9, 2012 on the WAAS reference station at Fairbanks, Alaska. Data from a nearby scintillation monitor in Gakona and all-sky imaging of aurora at Poker Flat corroborate the event. Anomalous receiver processing triggered by scintillation reduces accuracy at Fairbanks for a few minutes. Users experiencing similar effects would have their confidence bounds inflated, possibly trading off service continuity for safety. The activity to date in solar cycle 24 has had minor effects on WAAS service coverage, mainly occurring in Alaska and Canada.
Print ISSN:
1539-4964
Electronic ISSN:
1542-7390
Topics:
Geosciences
,
Physics
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