Simultaneous celestial positioning and orientation for the lunar rover

In order to obtain absolute heading angle and position, lunar rover needs the support of autonomous celestial navigation system (CNS). This paper proposes a sun observation based simultaneous celestial positioning and orientation (SCPO) algorithm for the lunar rover under stationary position. Firstly we measure the sun orientation by a sun sensor and the gravity orientation by an inclinometer; secondly combine them with sun ephemeris; finally solve this problem with quaternion estimation (QUEST). By analyzing affects of the sensorʹs system error (such as the installation errors, bias, etc.) and random noise under stationary conditions, these two types of errors can be eliminated using joint calibration. Executing the SCPO on the moon is demonstrated through simulation. The algorithm is carried out with an experiment on the earth surface, and results demonstrate the high consistency of our simulation.