Oblique Backscatter Sounders

Abstract

Having discussed sounders which transmit and receive RF energy at vertical incidence to the ionosphere in the previous chapter, we now turn our attention to a class of sounders which direct RF energy at oblique angles to the ionosphere. By Oblique Backscatter Sounders (OBS) we include any technique which uses HF through UHF radio waves coherently backscattered from ionospheric irregularities either directly or via reflection from the surface of the earth to deduce properties of ionospheric irregularities. Examples of recently or currently deployed OBS systems are the STARE (Scandinavian Twin Auroral Radar Experiment, Greenwald et al. 1978) the SABRE VHF radar (Nielsen et al. 1983), the HF phased array radar located at Goose Bay, Labrador (Greenwald et al. 1985), the Cornell University CUPRI Radar (Riggin et al. 1986) Swedish/French SAFARI radar in Scandinavia (Hanuise et al. 1981) and the PACE (Goose Bay and Antarctic HF radars Baker et al. 1989). Table 4.4 lists all the known currently operating OBS systems.