论文标题
船上的精制天文统计
Refined Astrometry on Board a CubeSat
论文作者
论文摘要
Cubesat上的光导航必须依赖于从机上图像中一些信标的方向的最佳提取。我们在欧洲航天局（ESA）的立方体OPS-SAT上介绍了一个实验，该实验将描述该目标的机上算法，称为基于角度的相关性（ABC）。 OPS-SAT是一个具有态度确定和控制系统（ADC）的3单位立方体，并且成像仪已证明其可靠性，其可靠性在Cubesat量表上的典型性能。我们选择了几个星场，它们都在10中呈现出足够的可见恒星？视场。当我们的实验运行时，OPS-SAT当时指向最方便的星场。在那里，根据ADC报告的态度 - 争论，从每个星星的预期位置周围的图像中提取了星形场，并从图像中提取了子窗口。 ABC重建了中央体的绝对方向，原则上未知，这是实验中尖锐的恒星。该方法强烈使用四元代数。标准位置首先在视野中与ABC合并。然后，景色领域再次与ABC相对。与发现的信标方向相关的协方差。我们对OPS-SAT的实验管理指向和成像仪，并处理拍摄的图像。然后，它下载了计算的绝对方向及其协方差，将其与实际说明进行比较。在大量使用实验的活动之后，将建立算法的统计性能并将其与机上计算的协方差进行比较。作为奖励，将获得对OPS-SAT的惯性指向稳定性的评估。 ABC理论上可以摆脱平台的态度控制错误（ACE）以及ADC估计的态度知识错误（AKE），并有可能收敛到（...）
Optical navigation on a CubeSat must rely on the best extraction of the directions of some beacons from on-board images. We present an experiment on OPS-SAT, a CubeSat of the European Space Agency (ESA), that will characterize an onboard algorithm to this aim, named Angle-based Correlation (AbC). OPS-SAT is a 3-unit CubeSat with an Attitude Determination and Control System (ADCS) and an imager that have proved their reliability with typical performance at CubeSat scale. We selected a few star-fields that all present enough visible stars within a 10 ? field of view. When our experiment is run, OPS-SAT is pointed to the most convenient star-field at that time. There, the star-field is imaged and subwindows are extracted from the image around the expected location of each star, based on the attitude-quaternion reported by the ADCS. The AbC reconstructs the absolute direction of the central body, in principle unknown, which is the pointed known star in the experiment. The method intensively uses the quaternion algebra. The beacon location is first consolidated in the field of view with the AbC. Then, the field of view is finely positioned against the sky, again with the AbC. A covariance is associated with the found beacon direction. Our experiment with OPS-SAT manages the pointing and the imager, and processes the taken images. Then, it downloads the on-board computed absolute directions and their covariances, to be compared with the actual directions. After a campaign of intensive use of the experiment, the statistical performance of the algorithm will be established and compared to the on-board computed covariances. As a bonus, an assessment of OPS-SAT's inertial pointing stability will be available. The AbC can theoretically get rid of the Attitude Control Error (ACE) of the platform and of the Attitude Knowledge Error (AKE) estimated by the ADCS, and potentially converge to (...)
