Symmetry measurement of radar echoes and its application in ship and chaff discrimination

Chaff is a typical passive interference, which is commonly used when a ship is under the attack of anti-ship missiles (ASM). Firstly the paper gives a symmetry analysis of ship and chaff echoes, redefines a measurement function of symmetry, and studies two problems: one is how to select the axis of symmetry; the other is how to select the symmetry zone. Secondly, the paper designs an algorithm to discriminate ships from chaff clouds. Frequency agility (FA) and no alignment of the receive gate (NARG) when pulses are accumulated are two problems in engineering, so the influences of FA and NARG on echo symmetry are analyzed. At last, simulation results validate the correctness and validity of the algorithm.