Monitoring the Ionosphere with GPS

A.J. Coster, J. Foster, and P. Erickson


This article discusses the effects of geomagnetic storms on GPS observations and
measurements and focuses on one in particular, the March 31, 2001, storm. The
first of the articles four sections presents a brief background of space weather
and its effects on GPS.  This section also reviews how GPS observables are used
to measure TEC. The second section presents a map of the TEC over North and
South America based on GPS data and collected during the geomagnetic storm. The
TEC map clearly illustrates a phenomenon known as storm enhanced density (SED),
which is driven by processes in the Earth's magnetosphere and is associated with
large gradients in the ionospheric and plasmaspheric TEC.  The next section
presents data from additional sensors that support the GPS TEC observations and
connect the observed SED phenomenon with other space weather processes.  The
final section discusses some specific effects on GPS observations that arose
from the march 31 storm. 

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GPS World, 14(5), 42-49, 2003