| With the development of space technologies, Mars explorations have become the focus of the deep space exploration. The conventional dead-reckoning based navigation systems can't meet the accuracy requirement for the future Mars missions. The purpose of this thesis is to research the innovative navigation schemes for Mars entry precision landing. It's mainly described as follows:Firstly, several reference frames which would be used in the following developments are developed. Then, a 3-DOF design model is presented, which is the foundation of the subsequent navigation schemes design.Secondly, based on the analyzing of the mission characteristics and task requirements, three different navigation schemes are proposed. The first scheme only utilizes IMU data as external measurements, the second and third scheme add one and two radio-range measurement to the IMU-based navigation respectively. Then the simulation results of these three schemes are analyzed.Finally, aiming at various uncertainties in real navigation system, a multi-model adaptive estimation algorithm is proposed in this paper. Simulation results show that the proposed algorithm can identify the parameters of dynamic model on line and achieve the fusion of each filter output. |
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