| 摘要 |
PURPOSE:To eliminate the out-of-focus condition of a reproduced picture in the direction of distance resulting from a rangewalk geometrical distortion contained in received signals of a synthetic-aperture radar, by performing convolutional integration of interpolatory kernel in the direction of distance when the distance is compressed. CONSTITUTION:When the out of focus at a distance (d) is eliminated, the out of focus in a specific path dc is eliminated by means of a distance compressing section 5 by using the data of a received signal file 1 and the parameter of the specific distance dc. Then a parameter precisely-estimating section 6 analyzes the power spectrum and phase of this output in the direction of azimuth and corrects a Doppler FM ratio (KD) and Doppler frequency (fD) which are the output of a parameter roughly-estimating section 3 at the distance dc. An interpolatory function (interpolatory kernel WCt) is found from the corrected values and the parameter value at the specific distance dc. The distance-compressed signal is Fourier-transformed in the direction of azimuth by an azimuth compressing section 8 and subjected to azimuth compression after it is resampled by means of the interpolatory function and geometrical distortion is removed. |
