SuperDARN Bistatic Measurements: Signals of Opportunity for Ionospheric Sounding

Abstract:

SuperDARN radars are well-known for their ability to provide measurements of plasma drift over a large region of the ionosphere from mid-latitudes to the pole on minute time-scales. These radars operate primarily in a monostatic fashion; transmitting and receiving their own signals. Shepherd et al. [2020] describe details of the first bistatic SuperDARN measurements whereby signals transmitted from a radar in Kansas propagate through the ionosphere before being received and analyzed by a radar located in Oregon. Three distinct bistatic modes of have been identified: a direct mode in which signals are communicated through radar side lobes along the great-circle path between sites; a bistatic ground scatter mode in which signals transmitted from one radar refract in the ionosphere back to the Terrestrial surface and are scattered back along a similar path to the other radar; and a bistatic ionospheric scatter mode in which signals propagate into the ionosphere and are scattered toward the other radar by irregularities in the plasma density. Details of these measurements provide valuable information about the ionosphere through which they travel. These initial results demonstrate the potential for ionospheric sounding using SuperDARN signals. Plans to expand the bistatic capability to other radars in the network and further develop the capabilities are currently being explored.