adaptive mitigation of spread clutter in high frequency surface-wave Radar

High frequency surface-wave (HFSW) radars are cost-effective systems for maritime surveillance and sea-state mapping of ocean areas in the Exclusive Economic Zone (EEZ). The effective mitigation of disturbances, either from interference sources or unwanted radar echoes scattered from the ionosphere, is fundamental to ensure the successful operation of such systems. This paper addresses the mitigation of ldquoionospheric clutterrdquo spread in delay (i.e. range) and Doppler frequency by adaptive spatial filtering for the problem of target detection in surveillance applications. An alternative adaptive processing method that jointly exploits the spatial and temporal information of range-gated signals, over receivers and pulses, is proposed and applied to experimental data from an Australian HFSW radar. Target detection performance is compared against conventional and standard adaptive beamforming techniques. The author thanks the High Frequency Radar Branch of the Defence Science and Technology Organization (DSTO), Australia, for supporting this work and making the experimental data available.