Abstract: A method for spectral estimation of the clutter of a haline liquid medium received by an oceanographic radar, such as a lake, a river, a sea or an ocean, from an array of antennas including at least three antennas. The method includes forming at least two sub-arrays of antennas from the array of antennas, each of the sub-arrays including at least one antenna less than the array of antennas, calculating a beam in one direction for each sub-array of antennas, locating in azimuth all the sources included in the beam from data of the beam coming from each of the sub-arrays, estimating the energy of each of the located sources, selecting a source, referred to as preferred source, among a plurality of sources according to a predetermined criterion when the beam includes a plurality of sources.

Abstract: A frame synchronization method and device. The method determines the frame start position D. That position D is the same as a position of a window H sliding along the received frame Tr. For various possible positions of the window H and for various blocks Bi of the window H, the method computes a syndrome Sd(i), and the start position D of the received frame Ti is that for which the number of null elements of a syndrome Sd(i) is highest.

Abstract: A frame synchronization method and device. The method determines the frame start position D. That position D is the same as a position of a window H sliding along the received frame Tr. For various possible positions of the window H and for various blocks Bi of the window H, the method computes a syndrome Sd(i), and the start position D of the received frame Ti is that for which the number of null elements of a syndrome Sd(i) is highest.