## 6 Precise Orbit Determination Methods
The findings suggest that increasing the number of observation satellites from two to six can significantly enhance the observation accuracy from the kilometer level to the decimeter level [90]. Due to the rapid increase in the number of space debris, precise orbit determination and prediction for space debris cluster have become another hot spot [91]. Building upon the investigation of factors influencing the growth of space debris, [PERSON] et al. proposed a method to quantitatively estimate the density and quantity of space debris. However, it does not provide a method to estimate the orbits of space debris [92]. [PERSON] et al. conducted a dedicated study on the selection of dynamic models in the orbit prediction of space debris. They systematically examined the influence of disturbance factors, including gravity field models, atmospheric drag, three-body gravity fields, and solar radiation, on the orbit prediction accuracy of space debris. The research offers quantitative insights into the selection of dynamic models in the precise orbit prediction processes for space debris in different orbital regimes. However, it primarily relied on established initial value problem integrators for recursive calculations and did not specifically delve into the investigation of the orbit estimation model [93]. In addressing the challenges of low computational efficiency with numerical methods and low accuracy with analytical methods in the precise orbit determination process, [PERSON] proposed an analytical method for solving the orbit propagation problems with both rapidity and high precision. This method employs numerical integration method with large step size to compute the mean orbital elements of space targets, utilizes an analytical algorithm to reconstruct the short-period terms of the targets, and finally recombines the mean orbital elements and short-period terms to determine orbits fast and accurately [94]. [PERSON] et al. presented a method for orbit prediction in large-scale space debris clusters. They categorized the debris cluster into nominal and correlated debris. Numerical integration was employed for a small number of nominal debris to ensure accuracy in the prediction. For a larger quantity of correlated debris, a semi-analytical method based on Taylor expansion was utilized to enhance the computational speed while maintaining prediction accuracy. This approach achieved a balanced consideration between computational efficiency and accuracy [95]. 7 Challenges and Development Trends in Orbit Determination Methods for Space-Based Optical Platforms  
The rapid increase in the quantity of space objects and space debris has heightened the need for improved speed and precision in orbit determination for space targets. Effectively addressing the challenge of enhancing the efficiency and accuracy of existing orbit determination methods within space situational awareness systems is of paramount importance. Furthermore, the development of strategies to swiftly and accurately predict the orbits of satellite constellations or extensive space debris resulting from space collisions has become a central concern for contemporary space situational awareness systems. Given the current