# Modeling and Simulation of Sky Survey
## 2 Related Work
### Sky Survey Planning Systems  
The sky survey planning system can bring together complete task setup, optimization scheduling, result output, and visual presentation in one software. It is extremely convenient for scientists who are not in the direction of algorithmic research to schedule their sky survey missions. Therefore, various spacefaring nations have developed related software and applied it in actual spacecraft launch missions. Table 2 summarizes some of the more representative software systems, according to [PERSON] et al. [32] and [PERSON] et al. [17].  
Spike planning and scheduling software [36], Sky Survey Planning Tool [17], and Multi-User Scheduling Environment [29] are applied in real satellite planning tasks with excellent optimization results. The Euclid telescope was able to achieve the science goal of covering an area of 15,500 deg\({}^{2}\) in 5.5 years, which also includes a 40 deg\({}^{2}\) deep-field observation area. With the Euclid Sky Survey Planning Tool (ESSPT), which was used by the Herschel satellite, Euclid is able to prioritize the observation of the areas of highest scientific value in the first year [17].  
In summary, there is still relatively little research on large-scale survey observations at home and abroad. Although the more mature Hubble telescope has both short-term and long-term planning algorithms, there are few detailed papers describing the algorithms in detail, and most of the research is carried out on simple survey missions, taking into account relatively few practical factors that do not have practical engineering use value. Thus, research on wide and deep survey algorithms becomes very urgent. To address the problem of the above research not being detailed and the model being in a black box state, this paper gives a wide and deep sky survey algorithm based on stage processing. Our main contributions are summarized as follows:  
* Various constraint analyses of the sky survey planning design are given in detail, which are divided into observation constraints and orbit constraints, and the multi-objective optimization model of the sky survey problem is established.
* The Staged Design Algorithm (SDA) is designed to prioritize the time efficiency and the difficulty of observation sky areas to maximize the efficiency of long-time observations.
* The model is solved using real data, and the obtained results are three years ahead of the predicted completion date of the sky survey mission, indicating that the algorithm performs well.  
The article is organized as follows. Section 3 expresses the specific problem of sky survey planning and analyzes the corresponding constraints and objective functions. Section 4 shows the Staged Design Algorithm (SDA) for solving the sky survey optimization model. Section 5 gives the results of the sky survey observations with real data and gives the comparison results of the algorithm for the efficiency of the sky survey observations with different parameter settings. In Section 6, a detailed summary of the paper is exhibited. In the last Section 7, the conclusions of this paper and directions for future research are given.