An Adaptive Trajectory Planning Method for Atmospheric Entry Guidance

Abstract

The invention discloses a self-adaptive planning method for an atmosphere entrance guidance trajectory. The method comprises the following steps: (1) acquiring a change rule of a flight longitudinal range and a cross range along with a heeling angle; (2) sectioning a whole entrance process, and determining a guidance law of each stage; (3) setting different entrance point initial longitudinal ranges, judging whether parachute-opening states in different entrance points satisfy given constraints, if so, positively increasing the initial longitudinal range or negatively decreasing the initial cross range, until a certain constraint is not satisfied, and determining a limit range of the initial longitudinal range which can be adjusted by the above guidance law; (4) in a actual flight process,judging whether the initial entrance point longitudinal range is within the above limit range, if so, using the guidance law in the step (2) to control; if not, executing the step (5); and (5) calculating a deviation value of the actual initial longitudinal range exceeding the limit range, correcting a longitudinal range reference value of a reference ground track, and substituting a corrected value into the guidance law in the step (2), to obtain a new guidance law, and using the new guidance law to control.

Description

technical field [0001] The invention belongs to the field of guidance for the entry process of a small lift body into a thin atmosphere in a deep space exploration planetary surface landing project, and relates to an analytical prediction correction method based on a nominal trajectory. Background technique [0002] my country's first planetary exploration mission will implement planetary orbiting, landing and patrol detection through a single launch. The key to the mission is to successfully implement a soft landing on the surface of the planet. However, 18 planetary landing exploration missions have been implemented in the world at present, and only 7 of them are completely successful, with a success rate of less than 39%. It can be seen that the planetary landing exploration mission is very difficult. Among them, the entry, descent and landing process (EDL, Entry, Descent, and Landing) is the biggest challenge faced by planetary landing exploration missions. [0003] The...

AI Technical Summary

Problems solved by technology

[0004] At present, the published literature at home and abroad mainly focus on the guidance accuracy and the amount of misses as the primary control objectives, and rarely pay attention to the spread of parachute opening height.

And when the flight capability of the probe is very limited, if the landing accuracy is blindly pursued, it is likely that all the control capabilities will be used to control the accuracy of the landing point, and the ability to adjust the height will be lost.

The final parachute opening altitude will not meet the parachute opening constraints, and the parachute cannot be deployed smoothly, resulting in the failure of the landing mission

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