Ionosphere Scintillations and their Effect on the Positioning Errors
Beniguel, Y; Adam, J-P
IEEA

This paper deals with the problem of phase and intensity ionospheric scintillations and their influence on the positioning errors for a navigation system.

The ionospheric scintillations are caused by the fluctuations of the electronic density with the appearance of bubbles randomly distributed. These bubbles move due to the ionosphere E x B term. The corresponding medium behaves as a moving random screen. As a consequence the signal crossing this medium is affected by scintillations. These scintillations may reach 30 dB peak to peak in the worst case, in the L band. Loss of lock may appear in that case. The ionospheric scintillations may be significant at low and high latitudes : -20° to + 20° and above 60° of magnetic latitude. It exists a climatology for their appearance related to the solar activity, the magnetic activity, the season and the local time.

In this presentation we will resume the scintillation characteristics : indices, spectrum, probabilities, … We will present some results of a measurement campaign realized in the frame of an ESA / ESTEC activity, the effects of the scintillations at receiver level and the consequences for the positioning errors. This will include the case when one or several links are disrupted due to strong scintillations.