The Research Of Radio Interference Cancelltion In High Frequency Radar Based On Olbique Projection Spatial-frequency Filtering

During the past years, ocean surveillance and coastal defense is important inmodern warfare. High frequency radar has been widely used in the detection andtracking of ships. Interference suppressing is a main issue of high frequency radar.Radio interference is one of the problems. In this paper, a new method ofinterference suppressing based on oblique projection technique, named collaborativespatial-frequency filter, is proposed. This filer makes the most of the differencebetween interference and target in the domain of space and frequency.This paper is organized as follows. First the signal receiving model and the jointsteering vector of space and frequency are established. The progress of signalfiltering with oblique operator is discussed. Performance analysis and simulationresults demonstrate that this method is valid. The expression of signal tointerference and noise ration and mean square error are given.The comparison between another two type of oblique projection filter: obliqueprojection spatial filter and oblique projection frequency filter is discussed. It isproved in theory that the propose collaborative spatial-frequency filter is better thanoblique projection spatial filter, oblique projection frequency filter and theirdouble-staged filter.It can be concluded that, collaborative spatial-frequency filter is a correctalgorithm for radio interference cancelation in high frequency radar. When there isdifference in spatial or frequency domain, the interference can be suppressed whilekeeping the target signal unchanged. However, when the parameters of target andinterference are very close, the existing noise will be amplified greatly. This is theproblem to be solved in future research.