Study On The Estimation Method Delay Of X-ray Pulsar Signal

Pulsar is a kind of neutron star with rapid self-rotation. The signal it radiates hasstable and precise period, which is the most remarkable property. The property enablesPulsar to offer position, velocity, and accurate time navigation information for spacecrafts in near-earth orbit, geostationary orbit, elliptic orbit or interplanetary orbit.Therefore, X-ray pulsar navigation plays an extremely important role in military affairsand engineering.As time delay of observed pulse profile and standard pulse contour template is onethe most important data of the XPNAV system, the time delay estimation method is cru-cial to related research. Thus, based on the long-term stability of the X-ray pulsar signal,this thesis compares various traditional delay estimation methods including Correlationmethod, correlation method, nonlinear least squares method and adaptive filter method,and proves the feasibility of using the time delay estimation method based on FractionalFourier transform in the field of the pulsar. Then in the simulation part, the pulsar sig-nals that procreant by ground simulation system and standard sinusoidal signal is usedto simulate both of the traditional and improved delay estimation method. At last, thereal X-ray pulsar signal acquired from REXE satellites is applied to validate the results.Simulation results show that the delay estimation method based on fractional Fouriertransform improve the performance of time delay estimation to a certain extent, and re-duce the positioning error of the spacecraft in the XPNAV directly.