ADAPTIVE CANCELLATION OF NONSTATIONARY INTERFERENCE IN HF ANTENNA-ARRAYS

The paper statistically analyses and compares temporal variability in the spatial structure of two HF interference signals propagated from k nown locations via ionospheric channels with different spatial and tem poral characteristics. The impact of the particular ionospheric paths propagating HF interference on the cancellation performance of various adaptive beamforming algorithms is investigated using data collected by the receiving antenna array of the Jindalee Facility Alice Springs OTH radar in Alice Springs, Australia, Measurements and analysis stati stically confirm that the spatial properties of HF interference signal s, and the actual performance improvements gained through the use of a daptive beamforming techniques, are highly dependent on the spatio-tem poral characteristics of the prevailing ionospheric circuits linking t he particular source location to the receiving array at the selected o perating frequency.