Overall Design of Nano Star Sensor

Nano type star trackers（NST） are high-precision attitude measurement devices specifically designed for micro/nano satellites. Its core components include an optical lens system, a light shield, an electronics system, and other components. The design and manufacturing of these components require meticulous processing and debugging to ensure their performance and stability.

The optical lens system and the light shield are the two main components that make up the optical unit. The optical lens system is composed of multiple lenses, whose function is to gather starlight into the core device CCD imaging plane for detecting components. The design and manufacturing of these lenses require precise processing and polishing to ensure their optical performance and stability. The function of a light mask is to reduce the impact of stray light from celestial bodies such as the Earth and the Sun on the imaging of optical lenses. It is usually installed in front of the optical lens and adopts special materials and structural design to minimize the interference of stray light.

To obtain a star map, it is first necessary to convert the sky area electrical signal corresponding to the field of view of the star sensor on the observed instantaneous satellite into a grayscale signal through a detection unit. This process is completed by an electronic system. The electronic system adopts single-chip integration technology and flexible circuit board technology to integrate multiple circuit boards together, forming a miniaturized and low-power electronic system. Adopting a simplified circuit architecture based on a single chip SoC and APS CMOS image detector, a pipelined working mode is adopted on a single chip SoC to achieve functions such as control, star map capture, data processing, attitude calculation, and communication of APS CMOS image detectors. The circuit board adopts a design method of combining rigid and flexible printed circuit boards (Flexible Rigid PCB), which not only improves system reliability but also isolates the external connection with the circuit board where the photosensitive device is located, ensuring system accuracy.

In the process of obtaining star maps, the processing module of star trackers plays a crucial role. This module is responsible for a series of processing of star maps, including star extraction, star map recognition, and attitude calculation. Through these processing processes, we can obtain the attitude information of the inertial coordinate system in the star sensor. This information can be used to control the attitude and orbit of satellites, achieving precise control and operation of satellites.

The research and development of nano star trackers is a complex engineering task. It requires knowledge and technology from multiple disciplines, including optical design, mechanical design, electronics, computer science, etc. During this process, researchers and developers need to conduct extensive experiments and tests to verify the performance and stability of nano star trackers. They need to use advanced testing equipment and technology to conduct detailed testing and evaluation of various components of the nano star sensor.