Abstract:  In the area of the underwater acoustics communication and detection, the modulation of binary phase shift keying (BPSK) is one of the commonly used modulation mode. As a result，the norr cooperative intercept processing of BPSK signal is an important research.The carrier frequency and
baseband waveform arc the critical information of BPSK signal intercept processing. Automatic extraction algorithms of these parameters in the noncooperation condition are needed to be achieved without any priori information, In the view of this problem, this paper presents a carrier frequency estimation method
based on presupposed frequency search and a baseband signal waveform estimation method using the carrier frequency information Both the estimation methods of the signal carrier frequency and the baseband waveform use the dowrrconversion processing. The carrier frequency estimation method based
on presupposed frequency search is achieved by using the changes in characteristics of the down-converted signal with different presupposed frequency. This estimation method is of high accuracy and has a good performance at low signal-to-noise ratio.After the carrier frequency estimation, judging the positive and
negative interchange of the down-convcrsion signal can recover the baseband waveform. For the down conversion processing,the initial phase and the arrival time of the received signal can brim adverse effects; the signal to noise rate reduces and the signal even tends to zero. And the estimation of the two
parameters is very difficult under non-cooperation condition, In order to ensure the stability of the estimation methods, we put forward two approaches:one is to select the largest amplitude of the down conversion signal both from the real and imaginary parts; another is based on the phase estimation.
Although these approaches are possible to lower the output signal-to noise ratio the decline rank is limited.They reduce the adverse effects of unknown parameters and we compare their performance through theoretical analysis and simulation tests, In order to verify the correctness of the earne
frequency and the baseband waveform estimation methods, we use Monte Carlo computer simulation approach to test. The simulation tests results show that the
carrier frequency estimation method has a better performance than the square law method and the power spectrum centroid method. And the
approach based on the largest amplitude selecting outperforms the approach based on the phase estimation for baseband waveform estimation when there exists the initial phase. At the signal-to-noise ratio of-5dB, the baseband estimation method still has a normalized error of less than 5%