Trajectory Re-planning

Abstract

The launch vehicle will deviate from its intended trajectory during flight due to flight deviations and malfunctions, and the launch vehicle’s flight trajectory needs to be re-planned when the flight state is abnormal. Two approaches are available for launch vehicle trajectory re-planning under the condition of satisfying constraints and residual capabilities: off-line re-planning and on-line re-planning. For off-line planning, the optimal parking and standby orbits are designed in advance considering the residual orbit entry and control capabilities of various failures. The optimal target orbit matching the current capability is chosen based on the current flight state and fault level under the condition of satisfying constraints and residual capabilities. Finally, the optimal guidance strategy is selected to complete the flight mission. For on-line planning, it is required to assess the launch vehicle’s residual orbit entry and control capabilities in real time, to achieve autonomous rapid planning using optimal trajectory planning control technology, to achieve dynamic processing of constraints during flight and relaxation of some constraints to ensure that on-line planning problems are solved and converged for on-line solving of optimal problem with the least fuel consumption or the largest radius of degraded orbit.