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Pixel frequency based star sensor high accuracy calibration method

A technology of star sensor and calibration method, which is applied in the field of aerospace measurement and can solve the problems of reducing the working accuracy and so on

Inactive Publication Date: 2007-08-08
BEIHANG UNIV
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  • Claims
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Problems solved by technology

In the current star sensor calibration process, the systematic error problem of the centroid algorithm is often ignored, and it is simply regarded as random noise, which reduces the working accuracy

Method used

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  • Pixel frequency based star sensor high accuracy calibration method
  • Pixel frequency based star sensor high accuracy calibration method

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Embodiment Construction

[0043] The present invention will be described in further detail below.

[0044] Star sensor centroid algorithm.

[0045] The star sensor completes the attitude calculation by photographing and identifying stars. Since the opening angle of ordinary stars is much smaller than the corresponding angle of one pixel, the result of focused imaging will be imaged in one pixel. In order to improve the centroid positioning accuracy of the star sensor to the sub-pixel level, defocusing technology is usually used to make the star point form a diffuse circular spot on the target surface of the image sensor. The distribution of the star image on the target surface of the image sensor is called the point spread function. Figure 2 is a schematic diagram of point diffusion in the X direction, and I represents the radiation energy distribution. The sub-pixel precision star point position coordinates are obtained by calculating the centroid of the diffuse circular spot. By analyzing the defoc...

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Abstract

The invention relates to the space technology, and to the improvement of the star sensor calibration method. The invention uses the calibration system which including air cushion platform, single-star starlight simulator, star tracker, two-dimensional axial turntable platform and data-processing computer, its steps being: establishing point spread function model, establishing a centroid algorithm formula, establishing a centroid algorithm pixel frequency error model, and data acquisition. The invention provides a more practical point spread model; improving satellite sensor calibration precision; the calibration model is simple and easy to calculate.

Description

technical field [0001] The aerospace measurement technology of the invention relates to the improvement of the star sensor calibration method. Background technique [0002] The star sensor is an aerospace measurement instrument that uses star observation to provide high-precision attitude information for spacecraft. Before the star sensor is put into use, its internal parameters such as principal point, focal length and distortion coefficient must be accurately measured, which is called star sensor calibration. There are two common ground calibration methods for star sensors: one is to use a star simulator in a starlight laboratory with a high-precision 2-axis turntable for data collection and calibration; Shoot to get data and calibrate. Figure 1 is a schematic diagram of the star sensor calibration system inside the laboratory. The calibration system mainly consists of an air cushion platform, a single star simulator, a star sensor, a 2-dimensional axial turntable and a ...

Claims

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Application Information

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IPC IPC(8): G01M19/00B64G3/00G01M99/00
Inventor 张广军郝雪涛江洁
Owner BEIHANG UNIV
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