双星敏感器在轨相对热变形分析及修正

摘要

为了获取高质量的对地观测遥感图像,除了有效载荷成像的高分辨率外,还需要卫星平台姿态具有高精度.在双星敏联合姿态确定时,星敏感器之间的相对热变形会对姿态确定带来不利影响,需对热变形误差进行辨识与修正.通过对某遥感卫星在轨遥测数据进行分析,建立了星敏感器在轨结构热变形模型,并对星敏感器热变形进行了在轨修正.采用辨识得到的傅里叶级数的热变形模型参数,对星敏热变形进行在轨修正后,提高了星敏感器的测量精度,减小了星敏感器之间的热变形误差对姿态确定精度的影响,对得到高质量的对地观测遥感图像具有很大的工程应用价值.%A high-accuracy satellite platform is required to obtain remote-sensing images that meet the requirements of high image quality and high resolution for payload imaging.In practical engineering applications,the thermal deformation error caused by the thermal environment of star sensors is always neglected.Therefore,relative thermal deformation between star sensors will negatively affect altitude determination by dual sensors.Thus,the thermal deformation error must be identified and corrected.In this study,the thermal deformation model is established on the basis of satellite remote-sensing data and then corrected.The parameters of the thermal deformation model established using the Fourier series reflect the real results of on-orbit thermal deformation,and the magnitudes of sinusoidal and cosine functions in the Fourier series are determined.Then,the estimated parameters are used to compensate for the output of star sensors.Comparing the altitude error of star sensors before and after correction revealed that measurement precision improved by 40％ after correction.Results showed that the proposed method for thermal deformation correction can improve the measurement precision of star sensors and reduce the influence of slow-frequency error on the precisions of altitude determination.The proposed method has potential engineering applications for obtaining high-quality images.