Patent ID: 6028549
Filing Date: 2000-02-22
Classification: G01S

Abstract:
A process for the detection and suppression of an interfering signal in SAR data, comprising:Fourier-transforming a time-domain noisy raw data signal U.sub.T (t) by range lines, into a raw frequency-domain spectrum U.sub.T (f);low-pass filtering the raw frequency-domain spectrum U.sub.T (f), according to a transmission-signal bandwidth B.sub.s, to yield a useful spectrum U.sub.T (f);in the time domain, determining an autocorrelation function (t) of the useful spectrum U.sub.T (f);using a weighting function w(t) further comprising a Parzen window w.sub.p (t), the Parzen window including a notch, to suppress portions of the useful signal in the autocorrelation function (t), thereby intensifying the interfering signal in relation to the autocorrelation function (t);Fourier transforming the resulting signal (t) into a power spectral density (f);calculating, with a MADMED function, a threshold value m from the power spectral density (f);calculating, with a comparator, an ideal notch filter frequency response W.sub.N ideal (f) from the power spectral density (f);generating a final notch filter W.sub.N (f) by Fourier-transforming the ideal notch filter frequency response W.sub.N ideal (f) into an ideal notch filter pulse response w.sub.N ideal (t), multiplying the ideal notch filter pulse response w.sub.N ideal (t) by a Kaiser-Bessel window w.sub.F (t), and subsequently inverse Fourier-transforming the product w.sub.N (t) thereof into a notch filter frequency response W.sub.N (f);multiplying the notch filter frequency response W.sub.N (f) by the useful spectrum U.sub.T (f); andFourier-transforming a resulting spectrum U.sub.T (f) into the time domain to generate a noise-free radar signal u.sub.T (t).