Robust Mars atmospheric entry integrated navigation based on parameter sensitivity

A robust integrated navigation algorithm based on a special robust desensitized extended Kalman filtering with analytical gain (ADEKF) during the Mars atmospheric entry is proposed. The robust ADEKF is realized by minimizing a new function penalized by a trace weighted norm of the state error sensitivities and giving a closed-form gain matrix. The uncertainties of the Mars atmospheric density and the lift-to-drag ratio are modeled. Sensitivity matrices are defined to character the parameter uncertainties, and corresponding perturbation matrices are introduced to describe the navigation errors with respect to the parameter uncertainties. The numerical simulation results show that the robust integrated navigation algorithm based on the robust ADEKF effectively reduces the negative effects of the two parameter uncertainties and has good consistency during the Mars entry.