Space-baced Interception Trajectory Optimization And Ground-attacking Reentry Stage Guidance Methods Research

With the rapid development of aerospace science and weapon science, space resources are playing an increasingly important role in modern war, and space-based weapons gradually become an hot spot of research. Thanks to its unique location, space-based platform has high speed, wide range, strong concealment and other advantages. Space-based weapons system can both be used to attack and defend, whose two main functions are destroying satellites and striking the ground. Countries who own advanced technology of space-based platform can produce strong military deterrence to other countries besides occupying a huge advantage in future wars, so research on trajectory optimization and guidance of space interceptor and the key point of strike to the ground, reentry segment, has very important theoretical value and application prospect.First of all, the development history and the status of Space-based platform at homeland and abroad is summarized, which proves the great military value and development potential of space-based platform, and also proves this subject has important value. Some basic theories of space-based platform, including two-body problem, modified equinoctial elements and Lambert theorem are introduced.Secondly, two methods of intercepting satellites by space-based weapons, the space-based same orbit interception and the space-based direct ascend interception,are studied. Same orbit interception can use impulse orbit transfer or continuous thrust case, which are compared in advantages and disadvantages in this paper, besides, optimal trajectory of continuous thrust orbit transfer in condition of minimum-fuel, is solved and be verified by matlab. Direct ascend interception uses Lambert transfer method, which applies to interception tasks with time constraints, and algorithms that cost least fuel are given under the constraints of prescribed launching time or prescribed interception time.Then, the study focuses on trajectory optimization of the reentry phase of space-to-ground strike. Building the model of reentry segme nt, and choose the final velocity of the kinetic weapon as performance, the falling point and initial parameters as constraints. In this way, the space-to-ground trajectory optimization problem is translated into a typical optimal control problem, and a t rajectory optimization method based on gaussian pseudo-spectral method is designed, which is verified by simulation.Finally,the guidance of the reentry phase is studied. Based on three dimensional analytical of the reentry phase under the condition of z ero-incidence, an analytical predictive guidance method is desigened, whose feasibility proves to be right by the simulation results of matlab.