A fuzzy variable coefficient variable structure guidance law is designed for intercepting high-speed maneuvering targets with terminal line-of-sight angle constraints. Firstly， an adaptive variable structure guidance law is proposed to adaptively adjust the velocity approaching the sliding mode surface according to the distance of the missile target. Then， the chattering is eliminated by replacing the switch term in guidance law with the saturation function. Simulation results show that the proposed guidance law can meet the requirements of line-of-sight angle constraint and miss distance for intercepting high-speed non-maneuvering and maneuvering targets， but it requires a large overload. To this end， a fuzzy control method is introduced and a fuzzy controller is designed to optimize the guidance coefficient in the variable structure guidance law. Finally， a fuzzy variable structure guidance law with a variable coefficient is obtained to satisfy the line-of-sight angle constraint and restrain the required system overload.

For the first time， Russia used the "Dagger" hypersonic weapon to destroy a large underground warehouse in Ukraine in combat， causing the world to pay more attention to hypersonic weapons and a growing sense of urgency. Hypersonic weapons have the advantages of fast flight speed， strong maneuver ability and difficult flight trajectory prediction， which makes the traditional missile defense system "paralyzed overnight". As countries around the world accelerate the weaponization of hypersonic technology， the hypersonic weapon defense system is also being built simultaneously. Aiming at the defense problem of foreign hypersonic weapons， the development status of foreign hypersonic weapons and the construction of hypersonic weapons defense system in the United States and Russia are analyzed in depth， and the development direction of foreign hypersonic weapons defense system construction is sorted out. The research results can promote the development of advanced defense technology.

In recent years， with the rapid development of hypersonic technology， all countries actively promote the research of hypersonic missile weapon system. While speeding up the development of offensive hypersonic missile weapons， they also step up the research of near space hypersonic missile defensive technology. The development layout of hypersonic offensive weapons and the general situation of hypersonic defense system abroad are analyzed in depth， and the application of hypersonic weapons in offensive and defensive operations is summarized. The challenges to national security are analyzed. We hope to promote the development of hypersonic offensive weapons and defense technology.