Abstract:The automatic landing system based on the LQG/LTR method has good robustness, which can resist strong wind shear. This paper gave a brief introduction to the principle of the LQG/LTR method and presented an LQG/LTR automatic landing controller design for a commercial airplane. Simulation results show that the LQG/LTR method works well on nonminimal system under certain conditions. The autolanding system designed can maintain good control effect with the presence of several disturbances such as wind shear and model uncertainty, hence achieving good robust stability.