Pulsar is a kind of neutron star with extraordinary high temperature, super-high pressure, ultra-strong magnetic field and excellent stable period. Pulsar is honored as space laboratory with extreme condition, and the most stable clock in the world. In the half century since the discovery of pulsar, the research mainly focuses on astronomy and physics. Recent years, with the development of space technology, people are gradually concerned about the use of pulsar in deep space navigation. XPNAV (X-ray Pulsar-...