Method and apparatus for radar surveillance and detection of sea targets

In a radar system using a radar clutter map comprising a plurality of range-azimuth cells containing parameter data values indicative of time averaged echo returns for affecting alarm threshold levels at range-azimuth locations scanned by the radar system antenna, a method for detecting comprising the steps of obtaining from the radar clutter map a first parameter data value associated with a given cell under test (CUT); determining a second parameter data value using parameter data values of other cells from the plurality of range-azimuth cells from the radar clutter map; comparing the first parameter data value associated with the CUT with the second parameter data value; and generating a signal indicative of a target detection when the first parameter data value exceeds the second parameter data value by a given threshold corresponding to a target false alarm rate.