Research on Search Laws of Image Guided Missile

When image guided missile adopts guided search and common search law to search ground targets, under some conditions the movement of image on the monitor screen will be dissymmetrical, which is harmful for shooter to acquire and capture targets. To remove the dissymmetry of the image movement, such common search laws as parallel search law, ＂X＂ style search law, search law of one-dimension visual effect and cone search law are improved and designed again. Simulation results show that the dissymmetry can be removed by adopting all the above four improved search laws, but the search track of improved cone search law has serious transmutation compared with the original search track. The other three improved search laws have little transmutation of the search track, and they all can keep the main characters of the original search law. Study resuits are helpful for image guided missile in adopting guided search to choose appropriate search law.

Optical flow based guidance system design for semi-strapdown image homing guided missiles

This paper focuses mainly on semi-strapdown image homing guided （SSIHG） system design based on optical flow for a six-degree-of-freedom （6-DOF） axial-symmetric skid-to-turn missile. Three optical flow algorithms suitable for large displacements are introduced and compared. The influence of different displacements on computational accuracy of the three algorithms is analyzed statistically. The total optical flow of the SSIHG missile is obtained using the Scale Invariant Feature Transform （SIFT） algorithm, which is the best among the three for large displacements. After removing the rotational optical flow caused by rotation of the gimbal and missile body from the total optical flow, the remaining translational optical flow is smoothed via Kalman filtering. The circular navigation guidance （CNG） law with impact angle constraint is then obtained utilizing the smoothed translational optical flow and position of the target image. Simulations are carried out under both disturbed and undisturbed conditions, and results indicate the proposed guidance strategy for SSIHG missiles can result in a precise target hit with a desired impact angle without the need for the time-to-go parameter.

Output-feedback based partial integrated missile guidance and control law design

An output-feedback based partial integrated guidance and control (IGC) law for missile interceptor is proposed with the smooth finite time convergence property. Firstly, a novel outputfeedback based smooth sliding mode control is proposed for a class of nonlinear systems in the presence of immeasurable state and disturbance. The finite time convergence property of this control scheme is proved based on the Lyapunov stability and homogeneous principle. Then, the proposed control method is applied to the design of partial IGC law. A kind of scaling methods is also developed to reach the rapid convergence of the system. An important dominance of this control scheme is the smooth characteristic, which may result in chattering free convergence. The simulation results indicate the high precision and smooth elevator deflection of the proposed output feedback base partial IGC law. © 2016 Beijing Institute of Aerospace Information.