Detection of sea surface features by coherent radar

To measure surface currents on the sea a synthetic aperture radar (i.e. a moving radar with high resolution) is operated with two receive antennas, thus providing two temporally separated coherent radar images. The phase difference between pixels in the pair of images is interpreted as being proportional to the velocity of the sea at the pixel position. It is of interest to relate this technique to the Doppler power spectrum of the sea backscatter and to assess the effect of spectral shape on the velocity estimate distribution. The authors analyse this problem and indicate the parametric dependence of the results on the antenna separation