Research On The Gravitational Perturbations’ Influence And Compensation Of Missile’s Ascent

Disturbing gravity is an important factor which affects the cutoff pointprecision and the hit accuracy of long-range ballistic missile while its affects on thecutoff point in the ascent are more remarkably. Disturbing gravity ballistic impacthas become the most important part of guidance error, this item of km point errorcaused by the order of magnitude. This paper in order to improve the precision ofballistic missile cutoff point as the background, for a long-range ballistic missilemost application the feature of inertial guidance system, analyses the influence ofgravity disturbance on the ascent, and carry out the fast assignment and disturbinggravity compensation method research.This article in view of the disturbing gravity to the influence of the ascent,missile is discussed in chapter2on the motion model, gives the analysis of theballistic missile movement common coordinate system and euler angles of therelationship between them, using vector to describe the kinematics equation of themass center of missile, more accurately describes the missile on the motion law.In the third chapter, first of all, through the pitching angle design program hasbeen a range of8000km of ballistic missile on the trajectory and the cutoff pointparameters, and then introduces the basic principle of iterative guidance, combinedwith the optimal control problem is put forward, its control equation is deduced,gives the solution of the derivation of the optimal control problem, the iterativeguidance is given and the calculation method and calculation process.In the fourth chapter puts forward the three aspects of the disturbing gravityeffect on ballistic and disturbing gravity compensation to improve the necessity ofmissile accuracy, and then put forward for the application to the gravity modelrequires accurate characterization of the high frequency components in gravitydisturbance caused by the gravitational potential change request. By introducing thestate space perturbation method, was deduced on the movement of the perturbationequation, the analytical solutions are presented and the state transition matrixmethod. Respectively using ballistic perturbation integral differential and state spaceequation of state of two kinds of methods to solve the cutoff point deviation,compare the calculation accuracy, from the simulation result, the state spaceperturbation method to calculate the efficiency is very high, can reduce thecomputing time. Finally, the influence of gravity on the ascent track disturbancecharacteristics are analyzed, summarized the disturbing gravity change with terrain,heigh.In the fifth chapter puts forward the existing method of accurate calculation of the gravity disturbance exists large amount of calculation and difficult to achieve,etc, on the basis of put forward the importance to study gravity disturbance rapidassignment methods. Summary of the current commonly used in a disturbing gravityrapid assignment methods advantages and disadvantages, and taken the aboveapproximation of finite element interpolation method is proposed. Introduced thebasic idea of this method and unit division and building method, and gives thespecific calculation steps of finite element interpolation approximation method.Through the simulation analysis, proves that the method has high approximationaccuracy and less data storage and fast computing speed, effectively improve theefficiency of the guidance, effectively control the cutoff point error, is a kind ofeffective and feasible method.