Cancellation of Es layer clutter in a HF Surface Wave Radar using auxiliary horizontal Dipole antennas

This paper presents the results of a preliminary study of an adaptive system using horizontal antennas for the cancellation of Es layer clutter in HF surface wave radar (HFSWR). Four horizontal dipoles, configured as two separate crosses, were added to a HFSWR system that normally uses vertically polarized antennas (VPAs). The data received from the horizontal antennas were correlated with the data received from the vertically polarized antennas (VPAs) to estimate and cancel the clutter adaptively in the VPAs. Suppressing the Es layer clutter after each coherent integration interval, about 25 dB signal-to-clutter ratio is expected with the experimentally derived data. The study also compared the effectiveness of the adaptive technique using one, two or four horizontal dipole antennas. This comparison indicates that the cancellation was more effective when all four horizontal dipoles were used.