Novel algorithm for frequency estimation of coherent sinusoidal pulse train

Frequency estimation of coherent sinusoidal pulse train was addressed with coherency. The frequencies of all monopulse signals were estimated respectively, and the mean value of these estimates was considered as a reference frequency to down-conversion the coherent pulse train. All of the baseband signals were accumulated in intrapulse and a sinusoidal signal was acquired, of which the frequency is the difference between the carrier and the reference frequencies, the duration is the pulse train duration and the signal-to-noise ratio(SNR) is N times that of the SNRin. Accordingly, it is possible to get high accurate frequency estimate of the sinusoid. Then the frequency of coherent pulse train was obtained by the reference frequency plus the difference. A formula of minimum SNRin needed was presented. Simulation results show that the performance approaches closely to the Cramer-Rao lower bound under the condition that the SNR is above the SNR threshold.