I. Introduction
With the continuous development of modern warfare, research on advanced guidance and control for high-speed flight vehicles, especially hypersonic missiles, has received worldwide attention. The traditional method is based on the separation theory[1][2], designing the guidance loop and control loop separately. The outer loop generates acceleration commands to guide the inner loop, while the inner loop generates control variables including attack angle and sideslip angle, enabling hypersonic missiles to adjust trajectory and track targets[3]. Proportional navigation guidance law is widely adopted in the design of the outer loop[4], which generates acceleration commands based on changes of the sight line angle of missile-target, so that the miss distance will converge to zero. However, on the one hand, additional control loops are required to calculate the rudder angle command based on acceleration requirements with such method, resulting in large time delays and inability to effectively strike high maneuvering targets; On the other hand, the actual aerodynamic model of hypersonic missiles is a nonlinear model with strong coupling between different directions, which greatly limits the acceleration generated by hypersonic missiles, and a suitable rudder angle to meet the requirements of the guidance loop cannot always be found in the control circuit. As a result, it is hard to accurately strike the target, which is an unavoidable drawback of the double-loop structure. Thus, more and more scholars are conducting researches on integrated guidance and control[5][6]