Doppler frequency history characteristics for azimuth traveling waves

To show the effect of ocean wave and system parameters on the velocity bunches that affect SAR images of azimuth traveling ocean waves, the Doppler frequency histories of surface points are obtained and investigated. The results obtained show that velocity bunch locations migrate in frequency (i.e. in the along-track direction) approximately linearly with time when the processor is focused for static targets. It is shown that velocity bunch locations remain at approximately constant Doppler frequencies if the focusing function uses the velocity v_a-v_W/2 rather than v_a, where v_a is the SAR platform velocity and v_W is the wave phase velocity. Several sets of parameters are considered to illustrate the effects of changes in parameters such as the ocean wave height and the velocity used for the focusing function