Predictor Corrector Reentry Guidance For Reusable Launch Vehicles

Since the year of1981, the space shuttle "Columbia" was sent up successfully,the space transportation systems caught more and more attentions. Reusable LaunchVehicles (RLVs) belong to the second generation of the space transportation, theyhave many advantages, such as: repeatability, economy, and safety. The whole flightprocess of the RLV could be divided into some phases: take off and rise, into orbit,orbiting flight, leave the orbit, reentry. The guidance precision of the reentryguidance is the most important thing among the whole flight process because ofmost complex environment in the reentry phase. The dissertation is focus on theguidance method for RLV, mostly use the method of predicted-correction. The mainresults of this article consist of the following parts:Firstly, the mathematical model in the reentry phase is established by the forceanalysis, to get the mass-point dynamics of the RLV. By the comprehensive researchof the constraints, the reentry corridor is obtained, that is a region that allows theRLV flight in the reentry phase.Then, the design of the reentry guidance is divided into the initial descentphase and the quasi-equilibrium-glide condition phase. The height and velocity atthe reentry point are both very high, but the aerodynamics force is very low, theflight trajectory is not in the reentry corridor. Then define the initial descent phase isfrom the reentry point to a point in the reentry corridor, it has its own feature, andthe design of the reentry guidance for this phase has the special demand.Lastly, the reentry guidance of the next phase is designed. Here divided thereentry guidance into longitudinal guidance and lateral guidance. The longitudinalguidance could be controlled by the magnitude of the bank angle, and the lateralguidance could be controlled by the sign of the bank angle. The results of numericalsimulation indicate that the design of the reentry guidance satisfies all theconstraints in the flight, and also it has robustness and adaptability to variousreentry missions.