Behavioral model of ionospheric effects in HF radars

The sky wave and the surface wave radars can be impacted by the instabilities of the ionosphere while they perform continuous surveillance of very large and far-off areas. When long-term integration is performed, those instabilities are leading to an increased false alarm rate. This is the typical case when detecting slow targets such as vessels. In this paper, we will discuss the case of a hybrid mode of detection. Two phenomena can then occur: the fluctuation of the reflection on the ionosphere and the backscattering by irregularities. To do so, we will introduce probabilistic models of the ionospheric effects assuming that only the phase path fluctuation has a meaning in the radar point of view. A model has been implemented and applied to the radar processing. The latter is compared to actual data acquired with our high frequency surface wave radar deployed in the south-east of France. The obtained results will be presented during the EuCAP 2017 conference.