An evaluation of range accuracy in the Super Dual Auroral Radar Network over-the-horizon HF radar systems

The Super Dual Auroral Radar Network (SuperDARN) of over-the-horizon BF radars forms a powerful diagnostic of large-scale ionospheric and magnetospheric dynamics in the Northern and Southern Hemispheres. Currently, the ground location of the HF radar returns is routinely determined by a simple range-finding algorithm, which takes no account of the prevailing HF propagation conditions. This is in spite of the fact that both direct E and F region backscatter and 1 1/2-hop E and F region backscatter are commonly used in geophysical interpretation of the data. Here BF radar backscatter which has been artificially induced by the high-power RF facility (ionospheric heater) operated by the European Incoherent Scatter Scientific Association at Tromso is used to provide a range calibration for the SuperDARN radars. The known ground range, the measured radar slant range, and the group path calculated by a ray-tracing simulation are compared. The standard algorithm for backscatter ground range location is found to be accurate to within 16 km and 60 kin for direct and 1 1/2-hop backscatter, respectively.