A Closed-loop Guidance Method for Off-orbit Braking Satisfied with Re-entry Angle and Range Constraints

Abstract

The invention discloses a de-orbit braking closed circuit guidance method satisfying constrains on reentry angles and flying ranges. The guidance method comprises steps of firstly on the basis of a nominal de-orbit braking track of a two-body dynamics model design, correcting effects on the reentry angles imposed by a J2 item by iterating working time of an engine; correcting effects on the flying ranges imposed by the J2 item by designing a dynamics integral model; during a guidance process, according to current movement states and information of reentry points, calculating currently required speed and speed gain by use of a closed analytical expression; determining an instruction posture angle of the engine according to direction of the speed gain; and determining a turn-off instruction according to the fact whether the speed gain is zero. According to the invention, high-precision and strong-robustness de-orbit braking guidance can be achieved.

Description

technical field [0001] The invention relates to the technical field of guidance control, and can be applied to the guidance of off-orbit braking of spacecraft, especially the closed-circuit guidance of off-orbit braking of spacecraft satisfying the constraints of re-entry angle and voyage. Background technique [0002] De-orbit braking refers to the process of making the spacecraft leave the original orbit and return to the earth's atmosphere. De-orbit braking is the first stage of the spacecraft returning to the earth. In this stage, the spacecraft reduces the flight speed or changes the direction of the speed through the rocket engine, lowers the flight altitude, and enters the earth's atmosphere. [0003] The point at which the spacecraft reaches the boundary of the Earth's atmosphere is called the re-entry point. The angle between the flight speed at the re-entry point and the local horizontal plane is called the re-entry angle, and the re-entry angle is closely related...

AI Technical Summary

Problems solved by technology

The iso-velocity incremental shutdown equation and the constant-velocity inclination angle shutdown equation take into account the state of the re-entry point, which can guarantee the accuracy of the re-entry angle, but cannot guarantee the high accuracy of the voyage, and there are large initial position errors and initial velocity errors , The control accuracy of the flight range is especially low when the thrust error of the rocket engine

Since these three shutdown methods are all open-loop guidance methods, there are certain limitations in improving accuracy, so a closed-loop guidance method that satisfies the re-entry angle and range constraints is proposed

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