Integrated navigation for the approach phase of Mars probe

Abstract

Considering the navigation for the approach phase of the Chinese Mars probe TIANWEN-1, we present an integrated navigation method based on the data fusion of the ground measurement and optical observation. This method combines the measurements of space and control stations on Earth and the optical observation of the camera carried by the probe. Taking an on-the-ground filter as a subfilter to deal with the data of ground measurement and uploading the results with communication delay considered, we proposed a data fusion method for the uploaded results and optical data. First, a dynamic model for the approach phase of the Mars probe is introduced, and the computational accuracy and efficiency of the orbital integration are analyzed. The measurement models are then subjected to visibility analysis. Second, the algorithms of extended Kalman filter and unscented Kalman filter are formulated for data uploading and fusion. Finally, a simulation is performed under the prior position estimation as 100 km and Priori velocity estimation as 0.1 m/s. Results show that the integrated navigation method has better convergence speed and navigation accuracy.