| 摘要 |
<p>The invention relates to a method, usable in diverse ways, for determining periodic structures in a digitised amplitude spectrum, for example a Doppler spectrum of a radar echo. In this case, with the aid of fuzzy set theory, a residual spectrum is formed and the desired periodic structure in the original spectrum is determined at each (residual) spectral line present in the residual spectrum by making a histogram. The method is, in particular, usable for recognising aircraft, for example helicopters having periodically moving components, for example rotors, which generate a periodic structure in a (Doppler) spectrum. <IMAGE></p> |
