Theia 和 HWO 上高精度差分天测量的校准
Calibrations for high precision differential astrometry onboard Theia and HWO
- Univ. Grenoble Alpes, CNRS, IPAG（格勒诺布尔阿尔卑斯大学，法国国家科学研究中心，行星与地球物理研究所）
- CNES（法国国家空间研究中心）
- Pyxalis（Pixalis）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
针对 Theia 和 HWO 任务对亚微角秒精度的需求，本文提出探测器表征、干涉校准和全局优化天体校准三项技术，共同支撑下一代高精度天测量任务。
AI中文摘要：
未来的空间天测量任务，如 Theia 以及宜居世界天文台（HWO）的天测量模式，需要前所未有的探测器校准和仪器表征水平，以实现亚微角秒级精度。本工作提出了三项互补的进展以满足这些要求。首先，我们报告了对 GIGAPYX-4600 背照式 CMOS 探测器的独立表征，评估了其线性度、读出噪声、暗电流、像素响应非均匀性、缺陷像素比例和像素间电容。结果表明该探测器性能优异，并确认其作为未来十亿像素焦平面候选者的适用性。其次，我们开发了一种基于杨氏条纹的干涉校准方法，用于测量像素质心位移，从而能够以适合星上实现的方式表征像素间响应变化。该方法通过数值模拟和使用 GIGAPYX-4600 探测器的实验测试平台进行了研究。最后，我们引入了一个天体校准框架，通过全局迭代优化联合估计恒星天测量参数、望远镜姿态、比例尺和光学畸变。尽管该校准方法仍在开发中，但模拟和实验室活动正在进行以验证其性能。总之，这些进展为下一代高精度天测量空间任务所需的技术和校准框架做出了贡献。
英文摘要：
Future space astrometry missions such as Theia and an astrometric mode of the Habitable Worlds Observatory (HWO) require detector calibration and instrumental characterization at an unprecedented level to achieve sub-micro-arcsecond precision. This work presents three complementary developments addressing these requirements. First, we report an independent characterization of the GIGAPYX-4600 back-side illuminated CMOS detector, evaluating its linearity, readout noise, dark current, pixel response non-uniformity, defective pixel fraction, and inter-pixel capacitance. The results demonstrate excellent detector performance and confirm its suitability as a candidate for future gigapixel focal planes. Second, we develop an interferometric calibration method based on Young's fringes to measure pixel centroid displacements, enabling the characterization of inter-pixel response variations with an approach compatible with onboard implementation. The method is investigated through numerical simulations and an experimental testbed using the GIGAPYX-4600 detector. Finally, we introduce an astro-calibration framework that jointly estimates stellar astrometric parameters, telescope attitude, plate scale, and optical distortion through a global iterative optimization. Although this calibration approach is still under development, simulations and laboratory activities are underway to validate its performance. Together, these developments contribute to the technological and calibration framework required for the next generation of high-precision astrometric space missions.
