Mars Autonomous Navigation Scheme Design And Analysis

Nowadays,the navigation information of Mars probe is mainly provided by the deep space network(DSN).However,maintaining and operating the DSN are expensive and requiring great labors.In order to satisfy the requirement of increasingly blooming Mars exploration missions,conducting research on the autonomous navigation scheme is conducive to reducing the expense.Moreover,the autonomous navigation system can make the probe free from depending on the earth and enhance the ability of autonomous decision and control.As for china,no intact infrastructure such as DSN has been placed.Hence,it would be meaningful and urgent for our country to investigate autonomous navigation scheme for future Mars exploration missions.This thesis mainly delves into the autonomous navigation scheme of Mars final approach phase,the orbiting-around phase and the entry,descent and landing(EDL)phase.To beign with,specific navigation scheme is proposed and system designing parameters are designated.Then,the system optimization strategy and parameters are determined according to the observability analysis theoey.After that,nonlinear optimization methods or intellectual optimization methods are applied to optimize these parameters.In the end,numerical analysis and navigation simulations are used to verify the results from optimization.As for Mars final approach navigation scheme,the fixed Mars surface beacons and orbiters are used as the measurement objects and specific navigation scheme and system designing parameters are proposed.According to the recursive propagation theory of the Fisher information matrix,the observability optimization object function is proposed and optimized using the particle swarm optimization(PSO)algorithm.Based on range measurements between the probe and beacons,the optimal geometrical configuration is obtained according to the Fisher information index.Numerical analysis and navigation simulations corroborate these optimization results.The scheme that uses Mars probes formation is proposed to fulfill autonomous navigation around Mars.The optimization problem is proposed according to the nonlinear observability matrix,and the optimal formation description parameters are obtained using nonlinear optimization methods.Considering the navigation scheme using one deputy and two deputy,the optimal configuration description parameters are obtained through constrained optimization methods.In addition,in view of the two-deputy navigation scheme,the optimal parameters are obtained according to the Fisher information theory.Numerical analysis and navigation simulations corroborate these optimization results.Considering available navigation schemes proposed by other researchers,the range and velocity measurements are used in the entry navigation system.The relative observability of each states are compared using the entry dynamincs as the system dynamical equation.Considering the kinematic equation of inertial measurement unit,the entry navigation scheme is simulated.The adavantages of aforementioned two models are compared.