Optimization of optical systems for low Earth orbit satellites observation under strong background radiation conditions.

Strong sky background radiation and the angular motion of satellites are the key challenges that limit the daytime observations of low-orbit Earth satellites. To enhance the capability of satellite observation, a theoretical method for optimizing the optical system is proposed in this study. Firstly, the degradation of the satellite optical signal due to angular motion is characterized by an effective magnitude based on the theory of satellite photometric characteristics. Then, the analytical relationship of the satellite observation signal-to-noise ratio with exposure time is derived. Meanwhile, considering the constraint of the full well capacity of the image sensor on the exposure time, a theoretical framework for maximizing the signal-to-noise ratio of satellite observations under strong background radiation was established. Based on this theory, the optimal design of the satellite's optical system parameters was achieved. The theory was verified through numerical simulation and experiments. The results show that under various optical system parameters, background light intensity and dynamic conditions, the proposed model can accurately provide the optimal exposure time and the maximum detection signal-to-noise ratio for satellite observations. This research provides a theoretical basis and parameter optimization guidance for the development of low-cost and portable space target observation equipment, thereby enhancing the observation capability of low-orbit Earth satellites under strong background radiation conditions.