Radio Direction Finding and Superresolution (Ieee Electromagnetic Waves Series)

Enlarged and revised second edition. Modern direction finders, capable of measuring elevation angles as well as azimuth angles on the components of multi-ray wavefields, have become powerful tools for research in ionospheric physics and HF radio propagation. The complexity of the problem of resolving closely-spaced rays requires the combined use of wide aperture antenna arrays, multichannel receiving systems and sophisticated digital processing techniques.