Forecasting and correcting method for joining main deceleration stage and approaching stage

Abstract

The invention relates to a forecasting and correcting method for joining a main deceleration stage and an approaching stage. The forecasting and correcting method includes the steps of calculating main deceleration stage guidance parameters, conducting rapid adjustment stage terminal forecasting based on the main deceleration stage guidance parameters and current states of a detector, correcting a main deceleration stage guidance target based on approaching stage inlet conditions, judging whether main deceleration switching conditions are met or not, switching into rapid adjustment guidance if the approaching stage switching conditions are met, otherwise, executing the first step, the second step and the third step again until the main deceleration switching conditions are met, determining rapid adjustment stage guidance parameters according to switching time states, determining current guidance commands according to the rapid adjustment stage guidance parameters, planning approaching stage inlet guidance commands according to the current state, and when an included angle of rapid adjustment stage current guidance commands and the approaching stage inlet guidance commands is smaller than a set value, or the guidance time is completed, switching into approaching stage guidance. According to the forecasting and correcting method, requirements of an approaching stage inlet for gestures, heights, speeds and accelerated speeds are met, and the requirement of the detector for transiting from the main deceleration stage to the approaching stage is met.

Description

technical field [0001] The invention relates to a prediction and correction method connecting the main deceleration and the approaching section, which is mainly applied to deep space landing probes and belongs to the technical field of spacecraft guidance, navigation and control. It can be applied to deep-space celestial body exploration missions such as the moon, Mars, and asteroids, and has extensive application value and market prospects. Background technique [0002] The dynamic descent process of a deep-space celestial body’s soft landing can generally be divided into six task sections: (1) The main deceleration section: the height from the surface of the celestial body is from about 15km to about 3km. The speed reaches the preset value, and the altitude drops to about 3km. (2) Rapid adjustment section: The height from the surface of the celestial body is from about 3km to about 2.4km. The main task of this section is to quickly connect the main deceleration and the ap...

AI Technical Summary

Problems solved by technology

[0003] The Luna and Surveyor series lunar probes respectively adopt the nominal trajectory and gravity turn guidance; the Apollo main deceleration section and the approach section both use quartic polynomial guidance, and optimize the design parameters on the ground to meet the convergence of the thrust change process, but for the attitude Convergence is not considered; the U.S. return to the moon plan proposes to use PEG guidance in the main deceleration section and polynomial guidance in the approach section. The transition from the main deceleration to the approach section is realized through rapid attitude adjustment, and adaptive correction guidance with a connection function is not proposed. method

[0004] For the final stage of the main deceleration stage of power decline, the attitude of the detector is still close to the horizontal, the main engine is still working at the maximum thrust section, and the thrust acceleration also reaches the maximum; while the approaching section of power descent requires the attitude of the detector to be close to vertical, and the main engine works at low thrust. Horizontally, the height, speed and acceleration satisfy a certain relationship; it can be seen that it is difficult to directly connect the end state of the main deceleration section and the initial state of the approaching section

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