Study On Trajectory Design And Guidance Algorithm For Boost-glide Missile

With the advantage of far range, strong maneuverability and precise strike, the boost-glide missile gradually became the hot spots of research and development in the global offensive weapons for the military powers. In the new era of offensive and defensive systems, the boost-glide missile also became the key investigation object of defense system. A kind of lower trajectory model, which remain the vehicle inside the atmosphere and use the curvature of the earth to shield, can reduce the enemy defense system response time and increase the missile survival probability and the probability of penetration. At the same time, to meet the higher requirements of autonomy, security and reliability, the fast generation optimal ascent trajectory algorithm, the closed-loop atmospheric guidance algorithm and the reentry guidance algorithm were studied in this paper.The way of fast generation optimal ascent trajectory can reduce launch costs, reduce the prepared time, increase the flexibility of the task, and provide service for guidance technology, which is one of the key technologies in vehicle design. The mathematical model of the boost-glide missile in the ascent period is Strong-nonlinearity, Strong-coupling and exits a variety of constraints, which makes the direct trajectory optimization algorithm of the initial value selecti on be difficult and slow. On the other hand, the indirect trajectory optimization algorithm is difficult to solve the path constraints in the flight. So, this paper presents finite element method(FEM) to obtain the optimal ascent trajectory without constraints, and treats the value as the initial value of direct trajectory optimization algorithm to obtain the optimal ascent trajectory satisfied the constraints. The simulation results show that the advantages of the hybrid optimization algorithm.The traditional way of the atmospheric guidance is open loop, which has the advantages of low cost, good stability and so on. But this guidance method can’t modify the trajectory deviation which is caused by aerodynamic force or thrust, so the open loop guidance way can’t meet the precision of the boost-glide missile injecting the shift point. Combining with the flight characteristic of the boost-glide missile, on the one hand, this paper uses the feedback linearization technology to design the closed-loop guidance method based on the nominal trajectory; on the other hand, it also uses the finite element numerical trajectory optimization algorithm to generate the new reference trajectory online and designs the real-time prediction and correction of the close-loop guidance method. The comparative analysis of the simulation results show that the two closed-loop guidance methods can meet the demand, and the closed-loop guidance based on finite element numerical trajectory optimization method has higher precision.A strong online trajectory planning method for reentry guidance problem is researched. This paper proposes a numerical prediction method based on quasi equilibrium glide condition to solve the longitudinal trajectory online, which treats the flight altitude as the integral independent variable, and design the flight path angle profile to meet the constraint of the reentry flight distance, then design the angle of attack profile to meet the terminal velocity constraint, finally calculate the flight bank angle which can keep the balance-glide flight with the help of quasi equilibrium glide condition, at the same time, the flight constraints is changed into the bank angle constraint. This paper transforms the complex 3D reentry guidance problem into a lateral control problem and a longitudinal guidance problem, the longitudinal guidance technology uses the static planning based on model prediction to obtain guidance command, and the lateral control uses reverse strategy of heading error corridor to control the flight direction. The simulation results show that this method is applicable to reentry guidance for the boost-glide missile, and the results of Monte Carlo targeting also show that this guidance method has stronger robustness for the initial state error and aerodynamic parameters uncertainty.For unpowered reentry vehicle of the guidance presicion degradation problem caused by the difference between the theoretical data and actual aerodynamic characteristics, this paper uses kalman filter algorithm, which has good convergence, high computation efficiency and less resource-intensive, to identify the aerodynamic parameters online, and then proposes a reentry guidance method based on the aerodynamic parameter identification. This paper adopts the first-order Gaussian Markov process and noise compensation technology to describe the variation of aerodynamic parameters to be identified. The angle of attack and bank angle are revised by the deviation between the estimated parameter and nominal value, and the longitudinal reference trajectory is tracked by using the principle of linear quadratic regulator. The simulation results show that the aerodynamic parameter identification algorithm has fast convergent rate, and the reentry guidance algorithm has better guidance effect for the aerodynamic parameter perturbation.