Ocean clutter suppression for an HF ground wave radar

At HF frequencies, the sea echo or clutter return is quite significant and can mask signals from targets travelling at or near the same Doppler of the resonant (Bragg) ocean waves. This paper presents a systematic method of reducing clutter signals so as to enable detection of targets travelling at speeds near the Bragg Doppler. The algorithm uses a Hankel rank reduction method that assumes that targets and ocean clutter can be modelled as time varying sinusoids. Several examples of clutter suppression are shown from data that was collected at the Cape Race facility. A cooperating vessel was used to show that a clutter supression algorithm may be used to enhance target detection when the target's speed is near the Bragg Doppler frequency.