A three-dimensional time-dependent algorithm for ionospheric imaging using GPS

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C. N. Mitchell
P. S. J. Spencer


Global Positioning System (GPS) satellite receivers provide a world-wide network of phase and group delay
measurements. The combination of two-frequency measurements can be used to derive the integral of the electron
concentration along each satellite-to-receiver path, a parameter known as the Total Electron Content (TEC). At this
stage these slant TEC data are diffi cult to interpret as they originate from a combination of a temporally changing
ionosphere and spatially changing observation geometry. In this paper TEC data are inverted to evaluate the underlying
distribution and time evolution of electron concentration. Accordingly, a new three-dimensional, time-dependent
algorithm is presented here for imaging ionospheric electron concentration using GPS signals. The inversion results
in a three-dimensional movie rather than a static image of the electron-concentration distribution. The technique is
demonstrated using simulated ground-based GPS data from actual measurement geometry over Europe.

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How to Cite
Mitchell, C. N. and Spencer, P. S. J. (2003) “A three-dimensional time-dependent algorithm for ionospheric imaging using GPS”, Annals of Geophysics, 46(4), pp. 687–696. doi: 10.4401/ag-4373.