Abstract
The accuracy of X-ray pulsar-based navigation is greatly affected by the Doppler effect caused by the spacecraft orbital motion and the systematic biases introduced by the pulsar directional error, spacecraft-borne clock error, etc. In this paper, an innovative navigation method simultaneously employing the pulse phase (PP), the difference of two neighbor PPs (DPP) and the Doppler frequency (DF) of X-ray pulsars as measurements is proposed to solve this problem. With the aid of the spacecraft orbital dynamics, a single pair of PP and DF relative to the spacecraft’s state estimation error can be estimated by using the joint probability density function of the arrival photon timestamps as the likelihood function. The systematic biases involved to the PP is proved to be nearly invariant over two adjacent navigation periods and the major part of it is eliminated in the DPP; therefore, the DPP is also exploited as additional navigation measurement to weaken the impact of systematic biases on navigation accuracy. Results of photon-level simulations show that the navigation accuracy of the proposed method is remarkably better than that of the method only using PP, the method using both PP and DF and the method using both PP and DPP for Earth orbit.
Highlights
Pulsars are strongly magnetized and rapidly rotating neutron stars emitting signals that are unique and highly periodical [1,2]
Unlike some current applications for spacecraft navigation, such as Deep Space Network and Global Navigation Satellite System, which suffer from low performance outside their effective coverage and rely extensively on ground-based operations, the X-ray pulsar-based navigation (XPNAV) has the same accuracy throughout the solar system and has much more autonomy [7,8]
In this paper, inspired by the study in [9], we develop an innovative X-ray pulsar-based navigation method considering both the spacecraft orbital motion effect and the systematic biases introduced by the ephemeris errors and the satellite-borne clock error, of which the pulse phase (PP), the difference of two neighbor PPs (DPP) and the Doppler frequency (DF) of X-ray pulsars observed at the spacecraft are utilized as the navigation measurements
Summary
Pulsars are strongly magnetized and rapidly rotating neutron stars emitting signals that are unique and highly periodical [1,2]. Along with their spatial diversity about the galactic disk, pulsars have been suggested as a natural lighthouse for spacecraft navigation. Unlike some current applications for spacecraft navigation, such as Deep Space Network and Global Navigation Satellite System, which suffer from low performance outside their effective coverage and rely extensively on ground-based operations, the XPNAV has the same accuracy throughout the solar system and has much more autonomy [7,8]. It can be used to augment the current navigation systems to improve their performance by introducing pulsar measurements [9,10]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
