PPT Slide
? Sun light forms free electrons and positively charged ions. Maximum disturbances occur at about 300 km height (Ionosphere)
? Free electrons alter the speed that electromagnetic waves travel through the ionosphere. The effect is frequency dependent and disrupt communications
? The differential effect on the two GPS frequencies may be applied to measure the distribution of free electrons
? TEC is highly correlated with the location of the sun
GPS Derived Total Electron Content (TEC)
http://www.grdl.noaa.gov/GRD/GPS/Projects/TEC