A Fast X-ray Pulsar Time Delay Estimation Method Based on Bispectral Feature Points and Cross-Correlation

In order to improve the accuracy and real-time performance of X-ray pulsar time delay estimation over short-time observation interval, a method based on bispectral feature points and cross-correlation is proposed in this paper. Firstly, calculate the self-bispectrum of the standard pulsar profile, extract the bispectral feature points by PSO algorithm, and store it in the spacecraft. Secondly, the pulsar photons are received in real-time and get the observation profile by epoch folding. Thirdly, calculate the cross-bispectrum at the bispectral feature points, construct the objective function of time delay estimation, and solve the extremum. Finally, the pulsar time delay estimation is obtained by screening the extreme points using cross-correlation. Simulation experiments based on Insight-HXMT observations of the Crab pulsar show that, the average running time of the proposed algorithm is 41.59ms on Matlab R2017b, and the average estimation error at observation interval below 2.5s is 0.1858ms, which is better than the traditional bispectrum method and the selected bispectrum method.