Research On Terminal Guidance Law Of Small Cruise Missile

The cruise missiles have been an extremely important component of precision-guided weapons in every country because of its great power and influence on the battlefield in modern warfare.With the development of modern warfare concepts and the advancement of weaponry defense systems,the cruise missiles need to satisfy the multi-constraint conditions,including the impact angle,and achieve high attack accuracy at the same time.The missile terminal guidance law is studied in this paper based on the small ground-to-ground cruise missiles.Firstly,the coordinate system for studying missile motion is defined and the mutual transformation relation between coordinate systems is deduced;the kinematics equation,dynamics equation,angle relations equation,other correlation equations and the missile-target relative motion equation are established;the classical terminal guidance laws are classified and the characteristics of several traditional guidance laws are analyzed in this paper.Secondly,based on the most widely-used proportional navigation guidance law,the influences of different proportional coefficients on guidance performance are analyzed in subduction plane.The characteristics of the over-gravity compensated proportional navigation guidance law are studied in order to achieve the effect of larger impact angle,and the maximum impact angle is reached on the premise that the target is always in the field-of-view.A bias proportional guidance law with impact angle control is designed to solve the problem that the over-gravity compensated proportional navigation cannot control the impact angle accurately,and the simulation results show that the bias proportional guidance law can control the impact angle effectively.The above two modified guidance laws are simulated in monte-carlo method,the attack and control accuracy with two kind of random interference factors of the guidance system are analyzed.Finally,the constraint conditions are transformed into terminal constraint problems of state equations by using the LQR optimal control theory and the relative motion state equations are established in the line of sight coordinate system.The optimal guidance law with impact angle and terminal normal overload constraint based on the delay-free system is deduced by solving the riccati equation.In order to solve the problem that the target moved out of the field-of-view in the guidance process,a switch correction term for field-of-view is added to the optimal guidance law,and the simulation results show that the modified multi-constraint optimal guidance law can ensure that the target is always in the field of view of the seeker.The attack and control accuracy with two kind of random interference factors of the guidance system are analyzed based on the monte-carlo method.