Influence of azimuth angle and water surface roughness on sar imagery of a bridge

The influence of the azimuth angle and water surface roughness determined by wind speeds on the SAR imaging of a metallic bridge over water was simulated after the identification of the double- and triple-bounced radar returns. Different bounced returns were caused by interactions of the bridge surface and water surface. In the simulation, the radar wavelength was L-band. The azimuth angle was between 0 and 45°. The wind speed was from 0 to 40m/s. The Pierson-Moskowitz spectra were used to model the spatial spectral energy distribution of the sea surface. The Kirchhoff approximation algorithm was used to compute the backscatter. With the noise level of a SAR system at −30dB, three regions were delineated. In region I, both double- and triple-bounced returns existed. There were only double-bounced returns in region II. None of the double- and triple-bounced returns was in region III.