Li Ji

TL;DR: In this paper, an intelligent power dropping track online planning method is proposed to decide whether the condition that the propellants are in short supply or the postures are continuously out of the tolerance due to the fact that disturbance torque generated by a main engine is larger than control torque occurs in a main speed reduction stage or not.

Abstract: The invention discloses an IMU (inertial measurement unit) and distance-measuring sensor fusion method applicable to selenographic rugged terrains, which comprises the following steps: firstly, calculating the height of a lander respectively by using measuring information of an inertial navigation and a distance-measuring sensor; then, comparing the changes of the heights of the lander obtained respectively by the inertial navigation and the distance-measuring sensor in a period of time, determining the effectiveness of the distance-measuring sensor through a pre-designed e detection threshold changed with the height, and if an obtained result is consistent, confirming that the measurement implemented by the distance-measuring sensor is effective, and can be introduced for correction; in the process of correction, through taking the difference between the height calculated by the distance-measuring sensor and the height calculated by the inertial navigation as an innovation, correcting the position and the speed of the inertial navigation by using the optimal filtering coefficient matrix changed with the height. According to the method, the accuracy of distance-measuring signals introduced for correction can be greatly improved, the influence of f unknown uncertain terrains on a navigation system can be reduced, the optimality of navigation fusion can be ensured, and the accuracy and the security of landing navigation can be guaranteed.