Real time large scale modelisation of the ionosphere with back scatter sounding-news results

Describes the development of a simple and direct method of real time inversion of the back scatter ionogram. The originality of the method lies in a double modelisation: that of the electron density profile, and that of the backscatter ionogram. This procedure offers the advantage of reducing each model to a few number of parameters among them it is possible to establish numerical relations. In practice the number of parameters describing the ionogram model is always smaller than the number of parameters describing the electron density profile, so the inversion is only possible if complementary data are available. The authors have shown that this can be done by using fixed frequency variable azimuth backscatter soundings (PPI), which allows us to find the bearing of horizontal gradients. The inversion method which has been developed ensures good stability of the solution.<>