Study On The Key Technique Of The Small Smart Bomb Terminal Guidance System

The Small Smart Bomb (SSB) is a kind of light and smart symmetrical guided bomb with high aspect ratio and stand off attacking ability. SSB adopts a method of compound guidance with INS/GPS for navigation phase and TV seeker for terminal phase. In this dissertation, some key technique of SSB guidance and control system designing for terminal phase are studied. The thesis mainly consists of the following five parts:(1)At the beginning of this dissertation, the system concept of SSB, TV guidance technique and Bank-To-Tum (BTT) control technique is studied. On the basis of these results, four key technique of system designing for SSB terminal guidance phase are concluded and analyzed.(2)Aiming at the issue of TV guidance for SSB, the thought of target tracking algorithm is made clear. Firstly, an improved correlation matching algorithm with high precision and robustness is proposed by using the methods of template partition and weighted similarity correction; after that, the real time ability and robustness for high mobility targets are both improved by using Kalman filtering for motion estimation; a self-adaptive template updating strategy and an occlusion detecting method is also proposed, and the complete target tracking algorithm is designed. The experimental results have shown the high robustness for interference such as noises, brightness change, target rotation and occlusion. Finally, the tracking algorithm is recompiled and written into embedded system of C64xDSP by software/hardware designing and system optimizing.(3)The issue of autopilot designing for SSB is analyzed, the mathematical model of SSB is established and two BTT autopilots are designed based on different control theory. By introducing a coordinated loop to constrain the coupling among the three channels, a PID decoupling autopilot is constructed based on classical control theory. By using linear quadratic regular (LQR) method in inner loop, the error between actual model and nominal model is bounded; by using mixed weight sensitivity H?state feedback controller in outer loop, a robust H?autopilot is constructed. The combining simulation results of three-channel at multiple characteristic points have indicated that both of the two controllers satisfy the requirement on the whole trajectory. Finally, advantages and disadvantages of the two controllers are analyzed.(4)By analyzing the affection of TV guidance and BTT control method for terminal guidance system, a three-dimensional BTT guidance law for SSB is proposed. By constructing relative motion equations of SSB in 3D space, a 3D pure proportional law (3DPPNG) and BTT acceleration commands with gravity compensation are derived. Aiming at the frame angle constraint problem, a line of sight (LOS) rate biased item based on the thought of time-varying is proposed. By using this biased item in the 3DPPNG, the frame angle constraint is realized. Simulation results have indicated that the proposed guidance law can satisfy capability requirements.(5)The TV guidance SSB mathematical model including TV seeker,6DOF motion model, BTT autopilot, guidance law for terminal phase is constructed. By simulating TV guidance commands, adding signal noises and delay, adding wind disturbance and setting different battlefields, different 6DOF simulations are conducted. The results have indicated that the control and guidance system can satisfy the capability requirements and is suitable for SSB.The achievements of this dissertation have established the foundation of SSB system design and provided the necessary technique supports.