Non-linear three-step filtering method for Mars atmosphere entry section

Abstract

The invention relates to a non-linear three-step filtering method for a Mars atmosphere entry section. The method comprises the following steps of: 1, establishing an engineering practice equation; 2, giving an initial value; 3, filtering a state quantity xk; 4, filtering a dynamic system deviation fk; 5, filtering an unknown measuring system error dk of a measuring system; 6, updating a correlation coefficient, correction state estimation and dynamic deviation estimation; 7, realizing an equation that k is equal to k+1 and returning the step 3 and performing the next steps until the k is equal to the time T corresponding to Mars atmosphere entry deadline, namely until a parachute is opened, so that the non-linear three-step filtering method for the Mars atmosphere entry section is finished. By adoption of the method, the problems about spacecraft position and speed estimation are integrally taken into consideration under the conditions of dynamic system deviation of a non-linear and non-Gaussian random system and the unknown measuring system error of the measuring system in the Mars real atmosphere entry process, and the position and speed estimation of a spacecraft at the Mars atmosphere entry section can be effectively guaranteed.

Description

technical field [0001] The invention relates to a nonlinear three-step filtering method for the Martian atmosphere entry section. It belongs to the technical field of aerospace navigation. Background technique [0002] The Kalman method is a very common method for determining the position and velocity of a spacecraft. It requires precise knowledge of the dynamical system and the measurement system. It is difficult to obtain the dynamic system and measurement system accurately in actual engineering. In the Martian atmosphere entry stage, due to the uncertainty of the state of the initial entry interface of the aircraft, the uncertainty of the time-varying parameters in the dynamic model, the uncertainty of the atmospheric density, and the uncertainty of the characteristics of the aircraft itself. These uncertainties make it difficult to accurately obtain the dynamical system, resulting in unknown bias input, and the ground-based deep space network and other measurement met...

AI Technical Summary

Problems solved by technology

Even if these deviations and errors have been calibrated on the earth, it will be difficult to apply or even generate new errors in the Martian environment, which is difficult to correct

So it is not very suitable for the Martian atmosphere entry segment

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