Initial results from an experimental skew-fire Mode-Selective over-the-horizon-radar

The use of skywave over-the-horizon radar for the detection and tracking of ships is significantly more challenging than the equivalent task for aircraft. This is due in large part to multi-path and Doppler disturbed propagation through the ionosphere. In this paper we report initial results for a newly proposed class of radar called Mode-Selective OTHR that is able to selectively isolate each of the multiple ionospheric paths between the radar and surveillance region. The radar contains several innovations including the use of multiple waveforms and a skew-fire array geometry. The results show that mode-selection can be achieved with multiple modes isolated simultaneously. We conclude that this new class of OTHR can provide significant improvement for the detection and tracking of surface vessels.