Calculation Method And Its Implementation Of Doppler In X-ray Pulsar Navigation

Pulsar is a kind of star,which constantly radiates electromagnetic pulse signals,and it’s one of the four found in the 1960s.X-ray pulsar in particular,makes pulsar-based navigation possible,because of its steady rotation period and detectability.In recent years,X-ray pulsar-based navigation(XPNAV)has become a hot spot on the research of space navigation.But when the probe detects pulsar signals,the probe is not stationary relative to the pulsar,so it will cause the Doppler effect,and which would adversely affect navigation.To eliminate this,the value of Doppler should be calculated first.This paper discussed the cause of the Doppler effect in XPNAV,studied its calculation and realized the calculating of the value of Doppler in X-ray pulsar-based navigation.This algorithm consists of pulsar observational data receiver module,the pulsar theoretical data producing module,as well as the algorithmic module.Receiving part uses Universal Serial Bus to transfer data,pulsar theoretical data is produced by DSP,DSP and the FPGA work together to achieve the Doppler value calculations.After simulation and testing,the algorithm is working properly and the result achieved the expected requirements.