Research, On-the-horizon Radar (othr) Anti-transient Interference And Sea Clutter Suppression

Over-the-horizon radar (OTHR) detects target by reflecting propagation from ionosphere. It has the features of long-distance detection, large areas surveillance, anti-stealth, and so on. Many counties pay great attention to it. Since OTHR works in HF band, there exist the strong clutter, radio interference, lightning, meteor trails and some other transient interference in the band. Therefore OTHR needs a lot of effective signal processing to assure its advantages of long-distance detection, anti-stealth and early warning ability. In order to reach its performance, OTHR needs to suppress all kinds of interference and clutter. This thesis mainly studies the following topics: the model of transient interference, the model of clutter, the clutter suppression, and the method of high-resolution spectral estimation.First of all, the thesis discusses the model of transient interference, the land clutter and the ocean clutter by all kinds of imformation, comparing them to the actual data to validate them.Afterwards, it studies the method of ocean clutter suppression. The ocean clutter is suppressed by the MTI method, the subspace method, the singular value decomposition based method, the modified subspace method, the adaptive filter method, the traditional ocean clutter cancellation and the FFT phase estimate ocean clutter cancellation. The thesis gives the simulation results of these methods, estimates the complexity of computation.Then this thesis introduces some high-resolution spectral estimation method. Computer simulations and complexities of computation of the methods are gived.Finally, the signal processing of ocean clutter suppression in OTHR are applied in the ADSP—21160 DSP processor ,and some result is shown.