Abstract: Sea clutter can be removed from radar signals by accurately determining sea velocity in a coverage area of a radar scan, updating a median value for the coverage area, and selecting a clutter rejection filter for the coverage area biased on the median value for the coverage area. Preferably, a median sea velocity is stored for each coverage area, as the median value. When processing begins for a coverage area, a previously stored median sea velocity is retrieved and updated. The median sea velocity is updated by converting the median sea velocity into a median phase difference between two echo signals, based upon carrier frequency and the time between receipt of two echo signals, which is preferably more than one interpulse period. The difference in phase between the two echo signals is compared with the median phase difference and the median sea velocity is increased if the median phase difference is smaller and decreased if the median phase difference is larger.