Robust integrated navigation for Mars atmospheric entry with parameter uncertainties

Mars atmospheric entry is a key phase to actualize Mars pinpoint landing. In this phase, parameters including atmospheric density, ballistic coefficient, and lift-to-drag ratio are uncertain because of environmental complexity. Ignoring these uncertainties may probably cause negative effects on the navigation accuracy. Based on the desensitized unscented Kalman filter (DUKF), which obtains the state estimation by minimizing a cost function involving the trace of posterior covariance matrix and the weighted norm of the posterior state estimation error sensitivities, this paper further introduces parameter uncertainties into the radio beacons/inertial measurement unit integrated navigation scheme and establishes a robust integrated navigation for Mars atmospheric entry with parameter uncertainties. Numerical simulation results show that the robust navigation algorithm based on the DUKF effectively reduces the influence of parameter uncertainties and illustrates a better performance than traditional methods.