Parameter Optimization for an All-Time Star Sensor Based on Field of View Gated Technology

Abstract

The intense atmospheric background in near-earth space has huge interference on the star detection for all-time star sensors. To observe and track stars, traditional all-time star sensors with narrow field of view (FOV) must be installed on turntable platforms, which cannot achieve autonomous celestial attitude measurement. The innovative all-time star sensor based on FOV-gated technology controls the microshutter and microlens array, enabling rapid switching to subdivide the wide FOV and gate a narrow FOV. This system ensures the detection of multiple stars simultaneously by suppressing atmospheric background radiation, thereby achieving autonomous attitude determination. For the all-time star sensor, the accuracy of attitude measurement is not only related to system parameters but also to atmospheric radiation and transmission. Current parameter optimization methods are constrained by specific observation conditions, limiting their applicability across diverse scenarios and temporal variations. To overcome these limitations, we developed an analytical model that accounts for the distribution of spatiotemporal observation conditions, including the probability distribution of the solar zenith angle. Based on this model, the attitude accuracy of the star sensor under all spatiotemporal conditions is weighted and employed as the global optimization objective. An optimal design scheme was provided through optimization, leading to the fabrication of an actual optical lens, which was subsequently used to assemble a prototype. A ground-based experiment was conducted to validate the accuracy of the star detection model, followed by a simulation that confirmed the proposed design satisfies the requirements in the entire celestial sphere.