Attitude correction method using speed measurement sensor in Mars landing process

Abstract

The invention relates to an attitude correction method using a speed measurement sensor in a Mars landing process. The method comprises the following steps of: adopting a parallel attitude determination frame, using traditional inertial navigation extrapolation at a foreground to obtain an inertial position, a speed and an attitude, and obtaining a projection of a gravitational force direction under a body coordinate system by using the inertial position and the attitude; carrying out benchmark reconstruction in the background by using a speed measurement sensor and an inertial measurement unit to obtain the projection of another gravity direction in the system; and monitoring and comparing the gravitational force direction of the background and the gravitational force direction of the foreground in real time, once the gravitational force directions exceed a certain threshold value, rotating the gravitational force direction of the foreground according to the Euler rotation principle, so that the gravitational force direction of the foreground can coincide with the gravitational force direction of the background so as to achieve the purpose of posture correction. According to the method, the problem of filtering divergence caused by incomplete observability of speed measurement attitude correction is avoided, the inertial navigation attitude precision in a large dynamic flight environment can be improved, and the landing index is improved.

Description

technical field [0001] The invention relates to an attitude correction method using a velocity sensor during the Mars landing process, and belongs to the technical field of spacecraft autonomous navigation and attitude determination. Background technique [0002] The Entry, Descent, and Landing (EDL) section of the Mars exploration mission is the last 6 or 7 minutes of the Mars probe’s journey of nearly 700 million kilometers. It is the key stage of the Mars surface exploration mission and the most difficult stage. EDL technology is also one of the key technologies for Mars surface exploration missions. From the time the Mars probe entered the Martian atmosphere at a speed of 20,000 kilometers per hour, it went through a series of stages such as atmospheric deceleration, parachute drag, and power deceleration, and finally in order to ensure a safe and accurate landing on the surface of Mars. [0003] Most of the failure cases of Mars exploration are due to the accident of ...

AI Technical Summary

Problems solved by technology

Under extreme pull-off conditions, the reduction in the accuracy of the inertial navigation extrapolation attitude error will make it difficult for the horizontal speed during landing to meet the index requirements

Since the speed sensor can provide information on the vertical attitude, if the Kalman filter algorithm is used to directly use the speed sensor to correct the extrapolated attitude of the inertial navigation, due to the incomplete observability of the system, it is difficult to ensure the convergence of the filter

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