Design and Analysis of a Four-way Star Sensor Assembly

In order to improve the accuracy of on-orbit geometric calibration, high precision attitude measurement and control of remote sensing satellites is one of the key steps. star sensors is the most precise attitude measurement component, and it is of great significance to improve the on-orbit pointing accuracy of star sensor. The pointing error of the star sensor is mainly caused by the deformation of the star sensor frame under the space environment. Aiming at the pointing accuracy less than 2 for a remote sensing satellites star sensor, a four-way star sensor bracket is designed in this paper. The installation interface of three star sensors can realize the integrated installation. The structure and thermal stability of the bracket are studied. The stiffness is analyzed by the finite element method, and the deformation of the optical axis is analyzed by the least square method. The results show that: the base frequency of the star sensor bracket is 119Hz; the maximum response of the installation interface of star sensor under the vibration condition of the whole camera is below 8gn,showing that the bracket can provide a good mechanical environment for the star sensor; the maximum temperature fluctuation of the star sensor bracket is less than 0.5℃, and the pointing accuracy of the star sensor is 1.2″. The four-way star sensor assembly can meet the requirements of high precision positioning of remote sensing satellites, giving a good reference for future designs.

This article designs a four way star sensing bracket for a remote sensing satellite with a star sensing direction less than 2 “, which uses aluminum based silicon carbide with a lower expansion coefficient to design the star sensing heat dissipation surface, reducing the impact of large deformation of the heat dissipation surface on the deformation of the star sensing bracket. The main body of the star sensing bracket is cast with high thermal conductivity aluminum alloy, ensuring the stability, uniformity, and support stiffness of the star sensing bracket, The least squares method was used to fit the variation in the orientation of the star sensor mounting surface. The results show that the first-order fundamental frequency of the star sensitive bracket and the star sensitive combination is 119Hz, and the dynamic environment of the star sensitive installation surface is good. At the same time, under harsh external heat flow conditions, the temperature fluctuation of the star sensitive bracket does not exceed ± 0.3 ℃, and the maximum change of the star sensitive bracket installation surface is 1.2 ″, achieving the need for star sensitive angular second level pointing and meeting the high-precision image positioning needs of satellites. This article adopts a four way structure to install multiple star sensors on the same bracket while ensuring the stiffness of the star sensor bracket, providing an implementation method for improving the accuracy of star sensor attitude determination. This method can provide reference for the design of other star sensitive scaffolds.