A fast maximum likelihood measurement for the time delay of pulse profile

In order to improve the measuring accuracy of the time delay of the pulsar integrated pulse profile and reduce computation complexity, a new method called fast maximum likelihood (FAIL) estimation is proposed to measure the time delay of the pulse profile relative to the standard pulse profile. This method distills the pulse profile by epoch folding first, and then creates a likelihood function. Finally, the time delay of the X-ray pulsar pulse profile is calculated by calculating the maximum of the likelihood function. A fast maximum likelihood time delay estimation based on narrowing the phase interval of the standard pulse profile is proposed as well. Compared with the measurement accuracy of the Taylor FFT algorithm, the experimental results show that the measurement accuracy of the FML algorithm is significantly higher.