Method for atmospheric entry section navigation of mars lander based on sampling point inheritance strategy

A technology of sampling points and landers, which can be applied to integrated navigators, navigation calculation tools, etc., and can solve the problem of low precision of landers

Inactive Publication Date: 2015-01-07
HARBIN INST OF TECH
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0005] In order to solve the problem of low precision when using the existing filtering method to estimate the state of the lander, the pre

Method used

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  • Method for atmospheric entry section navigation of mars lander based on sampling point inheritance strategy
  • Method for atmospheric entry section navigation of mars lander based on sampling point inheritance strategy
  • Method for atmospheric entry section navigation of mars lander based on sampling point inheritance strategy

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specific Embodiment approach 1

[0059] Specific implementation mode one: combine figure 1 Describe this embodiment mode, a kind of Mars lander atmospheric entry section navigation method based on the sampling point inheritance strategy of the present invention, the steps are as follows:

[0060] Step 1: In the initial period of filtering, according to the state x of the lander and the variance P of the state of the lander x , using the sampling point generation rule of the unscented Kalman filter to give sampling points and sampling point weights;

[0061] The specific process is as follows:

[0062] 2n+1 sampling points are:

[0063] χ i = x , i = 0 χ i = ...

specific Embodiment approach 2

[0109] Embodiment 2: The solutions of Q and S in Step 5 in this embodiment are obtained through the nonlinear constraint optimization numerical algorithm, which is calculated by the fmincon function in the Matlab software.

[0110] Other steps and parameters are the same as those in Embodiment 1.

specific Embodiment approach 3

[0111] Embodiment 3: The unscented Kalman filter described in steps 1 to 5 in this embodiment can be replaced by an integral point-based Kalman filter other than the unscented Kalman filter.

[0112] Other steps and parameters are the same as those in Embodiment 1 or Embodiment 2.

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Abstract

A method for the atmospheric entry section navigation of a mars lander based on a sampling point inheritance strategy relates to the technical field of navigation guidance and control, in particular to a method for the atmospheric entry section navigation of the mars lander. The invention aims at solving the problem that the precision is low when the status of the lander is estimated according to the conventional filtering method. The method comprises the following steps: in a filtering beginning cycle, providing a sampling point and a sampling point weight according to sampling point generating rules of unscented Kalman filtering; providing a lander status predicted value x' and a lander status variance Px according to a transmitted sampling point and a generated weight; calculating a measurement predicted value y', a variance Py and a covariance Pxy according to unscented Kalman filtering rules; updating measurement and correcting the estimate value of the lander status; estimating x'<+> and a lander status variance Px<+> according to the lander status, correcting the transmitted sampling point Xi and obtaining the sampling point Xi<+> with the corrected value. The method has higher status estimate precision and is suitable for navigation in the atmospheric entry section of the mars lander.

Description

technical field [0001] The invention relates to the technical field of navigation guidance and control, in particular to a navigation method for the atmosphere entry stage of a Mars lander. Background technique [0002] In order to maximize the scientific return of exploration missions, future Mars exploration missions will develop towards high-precision, fixed-point landings, which requires improving the navigation and control accuracy of the lander. Atmospheric entry is a stage that has a great impact on the final landing accuracy during the landing process, and it is also one of the most challenging stages in the Mars landing exploration mission. In this stage, the dynamic model has a strong nonlinearity. There are uncertainties in parameters such as point, aerodynamic parameters and atmospheric density, and many factors make it difficult to estimate the state of the atmosphere in the entry stage. [0003] At present, the estimation methods that can be applied in real ti...

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Application Information

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IPC IPC(8): G01C21/20
CPCG01C21/20G01C21/24
Inventor 田阳崔祜涛徐田来
Owner HARBIN INST OF TECH
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