The highly advanced ICEBEAR-3D E-region coherent imaging radar

ICEBEAR (Ionospheric Continuous-wave E-region Bistatic Experimental Auroral Radar) employs advanced software defined radio (SDR) and aperture synthesis radar imaging to produce unambiguous high resolution (1--2~km) 3-dimensional (range, azimuth, elevation) coherent E-region observations.  ICEBEAR-3D operates in the VHF at 49.5~MHz observing the auroral zone of the ionosphere from western Canada (58N, 106W geographic).  The receiver antenna array was re-configuration in 2019 to a non-uniform co-planar T-shaped double interferometer layout to complete the ICEBEAR design and allow for unambiguous, highly detailed, high-resolution coherent radar E-region observations.  We present the antenna array re-configuration; the novel and advanced synthesis aperture radar imaging technique; a low elevation angle accuracy and reliability solution; validations and calibrations of ICEBEAR-3D using celestial radio sources (Cygnus A) and interferometer closure angles; as well as some initial E-region and meteor trail observations and analysis.