## 2 Materials and Methods
### Error Model Analysis
Furthermore, the satellite's cross-sectional size is not constant; when the attitude changes, the projected area perpendicular to the velocity vector fluctuates over time. As a result, in orbit determination, the product \(C_{\mathit{D}}.\frac{s}{m}\) is often handled as an unknown quantity to be estimated with the satellite's state variables. The present atmospheric density models are primarily dependent on years of observational data, and each model has a limited range of applications. In this part, the DTM-94 atmospheric density model, the initial set of six orbital elements, the EIGEN-6C gravity field model, Earth Orientation Parameters (EOP), and other necessary inputs are utilized to simulate the satellite's orbital state under actual operational conditions. This orbit is used as a reference trajectory to assess the performance of different atmospheric density models. The orbit is then determined using the DTM-78, MSISE-90, and NRLMSISE-00 models, and the results are compared. The results are presented in Table 3. \begin{table}
\begin{tabular}{c c} \hline
**Perturbing Forces** & **Acceleration Magnitude (m/s2)** \\ \hline Two-Body Problem & 8.6 \\ Non-Spherical Earth Gravity & \(1.5\times 10^{-6}\) \\ Moon’s Gravitational Influence & \(1.0\times 10^{-8}\) \\ Solar Gravity & \(4.0\times 10^{-7}\) \\ Solid Tides & \(1.5\times 10^{-7}\) \\ Solar Radiation Pressure & \(3.0\times 10^{-8}\) \\ Atmospheric Drag & \(5.0\times 10^{-7}\) \\ \hline \end{tabular}
\end{table} 
Table 2: Typical magnitudes of perturbative forces acting on LEO satellites. In addition to atmospheric density, the solar panel area has an impact on atmospheric drag during satellite operation. Satellites in LEO occasionally travel into the Earth's shadow. The software determines the solar panel's effective area based on satellite, Earth, and Sun locations. This section uses the DTM-94 atmospheric model to simulate an orbit with a solar panel area of 2 m\({}^{2}\) as the reference value. To evaluate the impact of panel area variation on orbit determination findings, we performed a comparative accuracy investigation using area parameters of 4 m\({}^{2}\) and 6 m\({}^{2}\). The results are presented in Table 4.  
The results indicate that the orbit determination accuracy achieved from various atmospheric density models is relatively similar. This is due to two main reasons: first, the differences between these models are relatively small for LEO satellites; second, while there are differences between the models, the addition of atmospheric drag parameters and empirical force model parameters for radial, tangential, and normal directions allows these empirical parameters to account for the majority of the unmodeled atmospheric drag. As a result, the accurate orbit determination results are remarkably consistent. This study focuses specifically on the effect of solar panel area variation on orbit determination accuracy. The simulation results reveal that changes in panel area can dramatically increase atmospheric drag, resulting in orbit inaccuracies of up to a meter--far beyond the discrepancies reported across various atmospheric density models. These findings highlight the vital relevance of precisely modeling solar panel properties in orbit determination, and they also validate the effectiveness of empirical force parameters in adjusting for unmodeled disturbances.