Elevation Filtering in Wide-Aperture HF Skywave Radar

Use of 2D arrays in HF skywave radar to provide elevation angle of arrival information has the potential to improve coordinate registration and provide for elevation filtering. This latter capability can be used to filter out propagation occurring off disturbed ionospheric layers which can introduce Doppler spreading in backscattered ground return, obscuring low radial speed targets. Filtering capability via a 2D wide-aperture HF receive antenna is demonstrated using real-world data with multiple ionospheric propagation paths.