Abstract
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.
Highlights
The ionosphere results from the interaction of solar emissions with the Earth’s atmosphere
In the final model the peak height to the north of the image was increased to 370 km, the scale height to 140 km and the peak electron concentration was increased to 20 ¥ 1011 m-3
Nb i (binvi where biri are the 750 (Nb) vertical Total Electron Content (TEC) found by integration through the IRI model represented on the 30 latitude ¥ 12 longitude grid used for the inversion and binv are the corresponding values found by integration through the electron concentrations in the inversion
Summary
The ionosphere results from the interaction of solar emissions with the Earth’s atmosphere. In the case of conventional ionospheric tomography, TEC measurements are made from dual-frequency trans-ionospheric signals along many intersecting raypaths between a LEO satellite and a chain of ground-based receivers. These TEC data are subsequently analysed and inverted using a suitable mathematical algorithm to produce two-dimensional images of electron concentration. A time-dependence has been incorporated into the inversion, allowing for changes in electron concentration throughout the imaging period This allows the algorithm to invert multi-directional slant TEC data derived from GPS signals over a period of typically one hour into movies of electron concentration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
