It is confirmed by the field test that the power density of sea clutter received by the coherent radar varies in the Doppler domain

while the distribution of the amplitude of the Doppler frequency component can be mathematically modeled by the Rayleigh distribution or the Weibull distribution.A novel method for the constant false alarm rate (CFAR) detector with bi-thresholds is proposed.The proposed detector is implemented with a serial structure and has the ability for both threshold estimation and the CFAR.In addition

the proposed detector can tremendously outperform the traditional column window detector with nearly the same computational complexity.The simulation results show that the proposed method can achieve a gain of 9 dB in the term of the signal-to-noise ratio (SNR) compared to the column window detector with the false alarm probability of 10

-5

and the

detection probability of 90%.