A maximum a posteriori estimation based method for estimating pulse time delay

The accuracy of the classical time delay estimation algorithms cannot exceed Cramér-Rao bound (CRB), and it is difficult to obtain a higher precision estimation. In order to break through the limitation of CRB, this paper integrates prior information into estimation algorithm. Through combining priori information with pulsar observation, the pulse time delay estimation algorithm based on maximum a posteriori (MAP) estimation is derived, thereby presenting the lower bound of the proposed estimator. Experimental results based on observational data for the Crab pulsar show that the estimation precision of the proposed estimator is not only 2 orders of magnitude higher than that of the classical algorithms, but also asymptotically efficient, providing more accurate observation for X-ray pulsar navigation.