Effects of solar cycle 24 activity on WAAS navigation

Abstract

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 U.S., 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 24–25 October 2011 storm as an example, we examine WAAS operational system coverage for the conterminous U.S. (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 Ionospheric Data Assimilation 4‐D, which show a local nighttime corotating persistent plume of plasma extending from Florida across central CONUS. We study the effect of scintillation on 9 October 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.

Comparative ionospheric impacts and solar origins of nine strong geomagnetic storms in 2010–2015

“…These maps are from the time period 19:30–19:45 UT, midday for the continental United States (near the peak of the local diurnal cycle). It is the large east‐west gradients associated with this plume that are responsible for the particularly severe WAAS outage during this storm [ Datta‐Barua et al ., ].…”

Automated Ionospheric Scattering Layer Hypothesis Generation for Detected and Classified Auroral Global Positioning System Scintillation Events

“…Losing lock on a satellite due to ionospheric scintillation can degrade the quality of the position estimate. This makes scintillation a navigation continuity and availability threat to GNSS users (Datta‐Barua et al, ).…”

The story of plumes: the development of a new conceptual framework for understanding magnetosphere and ionosphere coupling

“…What is now clear is that plumes connect the equatorial F region ionosphere to the dayside magnetopause and the nightside magnetotail plasma sheet (e.g., Su et al, 2001a, b;Horvath and Lovell, 2011;Walsh et al, 2014a, b;Foster et al, 2014). Through the formation and evolution of the different plumes, they impact wave generation and wave-particle interactions (e.g., Summers et al, 2008;Chen et al, 2012;Halford et al, 2015), particle precipitation (Spasojević and Fuselier, 2009;Yuan et al, 2011Yuan et al, , 2013, ion outflow (e.g., Zeng and Horowitz, 2008;Tu et al, 2007), local-time asymmetries in ULF wave field-line resonance (FLR) signatures (e.g., Archer et al, 2015;Ellington et al, 2016), satellite communication and navigation systems (Ledvina et al, 2004;Basu et al, 2005;Datta-Barua et al, 2014), and even the coupling efficiency of the solar wind to the magnetosphere (Borovsky and Denton, 2006;Borovsky et al, 2013;Ouellette et al, 2016;Fuselier et al, 2016). Though we now have a new appreciation and understanding of plumes, there are still many unanswered questions on their formation (e.g., Kelley et al, 2004;Horvath and Lovell, 2011;Zou et al, 2013Zou et al, , 2014Borovsky et al, 2014) and impact on global magnetospheric dynamics McFadden et al 2008;Walsh et al, 2014Walsh et al, , 2015.…”