Application of RADAR imaging analysis to SuperDARN observations

Recently, Universal Software Radio Peripherals were installed at the McMurdo, Antartica, and Kodiak, Alaska, Super Dual Auroral Radar Network (SuperDARN) radars to replace existing synthesizer and receiver electronics. Each antenna in the radar arrays was connected to its own Universal Software Radio Peripherals input, which enables controlling the phase of the transmitted signal and sampling the received signals on each antenna. Received data are written to disk and simultaneously combined using beam forming to produce the standard SuperDARN data stream. The raw signal data from the individual antennas is retrieved from the radar sites and analyzed using an algorithm that fits a model signal based on the assumption of individual plane waves arriving from discrete angle bins in the field of view. With this analysis the target amplitudes and Doppler frequencies can be determined as a function of angle. In this paper, the theory behind the algorithm is developed, and synthetic test data are presented, as are real observations. Finally, the line-of-sight velocities determined from the data are used to estimate maps of the vector velocity field that produced them.