## 3 Proposed Methods
### Multi-Subsystems Coupling Relationship Analysis of Earth Observation Satellite
In Figure 4, the \(X\)-axis represents the roll angle of the satellite, the \(Y\)-axis is the angle between the position vector of the ground station and the orbit plane, and the \(Z\)-axis represents the length of the data transmission time window. It can be seen from the figure that the smaller the satellite's roll angle and the closer the ground station is to the subsatellite point, the longer the data transmission time window duration that the satellite can obtain. Meanwhile, when the satellite's attitude is pointing toward a ground station, the satellite can obtain more data transmission within the time window duration. Due to this coupling relationship, some targets may be distributed far away from the ground stations, causing the satellite to have less data transmission time or no data transmission time while observing these targets. When the subsequent data transmission time and the memory capacity are sufficient, observing these targets will not affect the data recording or  
Figure 4: Influence diagram of the satellite attitudes and ground station distribution on the data transmission time. Figure 3: Schematic diagram of the data transmission window with different satellite attitudes. (**a**) Satellite attitude pointing to the ground station. (**b**) Satellite attitude not pointing to the ground station. downloading. In contrast, when the subsequent data transmission time or memory capacity is insufficient, the lack of data transmission time or the lack of memory capacity will result in fewer target observations and data downloads. At this time, choosing targets close to the ground stations may obtain more data transmission time and a higher total profit. Hence, this situation reflects the conflicting relationship between the observation subsystem and the data transmission subsystem. The state variables that reflect the main limiting factor between observation and data transmission includes the volume of observation data, the amount of transmission data, and the capacity of on-board memory. The observation subsystem is the main limiting factor when the data transmission time is sufficient for the data download while the memory capacity is sufficient to the store observation data. In this case, the path should be scheduled to allow the satellite to perform more target observations. Conversely, when the data transmission subsystem is the main limiting factor, the path should be scheduled to enable the satellite to have more data transmission time. Additionally, we analyzed the relationship between the observation subsystem and the electricity subsystem. The choice of observation path and the amount of satellite electrical energy determine the number of target observations. The variables that determine the available electrical energy of the satellite include the initial electrical energy satellite carriers, the electrical energy consumed by the satellite observation, data transmission, and normal operation, and the supplementary electrical energy from the solar arrays. The initial electrical energy was determined by the initial conditions, while the electrical energy consumption of the normal operation was determined by the normal electrical power consumption of the satellite. Furthermore, the electrical power consumption of the satellite observation and data transmission was determined by the number of observable targets and the amount of data transmitted. The supplementary electrical power from the satellite's solar arrays is related to the charging power of the solar arrays and also to the angle between the normal vector of the solar arrays and the Sun vector. In other words, the satellite charging electrical power is related to the choice of observation path. Then, we examined the coupling relationship between the satellite charging electrical power and the observation path by analyzing the available electrical power under different attitude conditions.