Iteration SKF (Schmidt Kalman Filter) method of multi-source information integrated navigation of Mars power descent stage

Abstract

The invention discloses an iteration SKF method of multi-source information integrated navigation of the Mars power descent stage, which comprises the following steps: 1, utilizing the kinetics equation of the Mars power descent stage; 2, building the measurement equation of the Mars power descent stage; 3, discretizing the kinetics equation and the measurement equation, and then linearizing the kinetics equation and the measurement equation so as to obtain the novel kinetics equation and measurement equation; 4, outputting navigation information through utilizing the SKF filtering algorithm. Through the four steps, the kinetics equation and the measurement equation are built, and then the influence of errors in the measurement information is eliminated through utilizing the iteration SKF filtering algorithm to ensure the stability of the filtering algorithm, so that the purpose that navigation state of a detector is estimated efficiently and in real time. The method efficiently corrects the influence on the filtering caused by errors in the measurement equation, corrects the filtering errors caused by the truncation error caused by the Taylor series by utilizing the iteration method, improves the navigation precision, and enhances the stability of the filtering process, so that the navigation state of the detector can be estimated efficiently and in real time.

Description

technical field [0001] The invention relates to an autonomous navigation method for combined navigation of Mars power descent section, in particular to an iterative SKF method for multi-source information combination navigation of Mars power descent section, and belongs to the technical field of aerospace autonomous navigation. Background technique [0002] To make a soft landing on the surface of Mars, the Mars rover must go through three stages: entry stage, descent stage and landing stage (EDL for short). Although the entire EDL process is only 6-10 minutes, it is one of the most dangerous and important processes of the entire Mars exploration mission. [0003] The power descent phase begins when the Mars rover is 6-12 kilometers above the ground. At the beginning, the supersonic parachute was opened, but due to the high Mach number at this time, the heat shield could not be thrown away immediately, so this section still cannot use other sensors, and can only rely on the...

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Problems solved by technology

[0004] The integrated navigation system based on IMU and MCAV has problems such as the unknown constant drift of the gyroscope and accelerometer of the IMU and the deviation of the altitude and speed provided by MCAV. The existing filtering methods cannot solve this problem well.

Peng Yuming introduced the constant value drift of the gyro and accelerometer of the IMU into the estimated state and used the extended Kalman filter (EKF for short) to estimate, but there is a constant position error in the X and Y directions, and the drift estimation of the gyro and accelerometer The effect is not good, and the unscented filtering method (UKF for short) is too large due to the expanded state, which cannot meet the real-time requirements (see Peng Yuming, "Research on New Mars EDL Navigation, Guidance and Control Technology", Master Thesis, Nanjing Aviation Aerospace University, 2011.)

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