Transmit and receive antenna array geometries for mode selective HF OTH MIMO radar

Use of multiple transmit waveforms to enable MIMO radar operation is a technology with strong application to HF over-the-horizon (OTH) radar. We consider the problem of target detection when the OTH radar is operating in an environment with a stable ionospheric propagation path supporting high quality Doppler spectra from backscattered signals and clutter, and a perturbed ionospheric propagation path which contaminates the signal with spread-Doppler clutter. In this case, efficient spread-clutter mitigation requires elevation and azimuth beampattern control via 2-D arrays. In addition, due to the propagation geometry, the beampattern control needs to range-dependent for both transmit and receive antenna arrays, mandating the use of the MIMO radar architecture. We examine the impact of antenna geometries on clutter mitigation performance. We also provide performance analysis for a specific configuration employing 1-D transmit and receive antennas which enables field experiments that validate MIMO OTH radar operations.