SCIPION: a flexible ionospheric digital sounder. Illustration of its capabilities for spatial coherence studies of Es and F regions

SCIPION is a new state of the art digital sounder that has been developed by France Telecom-CNET for ionospheric monitoring and research. Extensive data processing using DSP technology has resulted in a low power, low cost and full featured system for both vertical and oblique soundings. SCIPION provides numerous sounding capabilities. In a standard mode of operation, the amplitude ionogram is displayed together with the full channel scattering function at each sounding frequency. Antenna diversity can be performed using up to 8 antennas for spatial coherence and drift measurements, with only one receiver needed. Furthermore, by means of the SCIPION system, impulse response sequences of the ionospheric transmission channel can be measured and stored, in order to be used for simulation purposes. In this paper the system is described and some illustrative examples of its capabilities obtained during actual experimental situations are shown. Particular attention is given to spatial coherence studies of the F and Es ionospheric layers. Results are presented from an experiment performed over a short link in Brittany. It can be concluded that, in this case, the received signal was coming from two distinct sporadic E layers having different vertical velocities with very closed group paths and Doppler shifts