## 4 Verification and Accuracy Analysis of Single-Frequency Occultation Processing
### Reconstruction Excess Phase Doppler Correctness Verification
Similar to the consistency analysis of reITEC change rate in Figure 3, [PERSON]'s correlation coefficient is also used as a statistical indicator in the consistency analysis of reconstructed excess phases Doppler. Figure 6 shows the statistical results of [PERSON]'s correlation coefficient histogram of the excess phase Doppler between the reconstructed B\({}_{3}^{*}\) and the actual B\({}_{3}\) observed by FY3E satellite on 4 January 2022, with the histogram interval of 0.05. The figure shows that the Spearman correlation coefficients of the data are all above 0.5, and most of the correlation coefficients are concentrated near 1.0, showing strong correlations. The proportion of Spearman correlation coefficients greater than 0.8 (that is, those showing extremely strong correlations) exceeds 90%, while those with correlation coefficients greater than 0.95 make up nearly 78%. Therefore, the correlation between the reconstructed excess phase Doppler and the actual excess phase Doppler is significant and highly consistent. Figure 4: The comparison between the excess phase Doppler of reconstructed B\({}_{3}^{*}\) and that of the actual observation B\({}_{3}\), (**A**) is occultation event 1 and (**B**) is occultation event 2. Figure 5: Consistency comparison between the excess phase Doppler of the reconstructed B\({}_{3}^{*}\) and the excess phase Doppler of the actual observation B\({}_{3}\), (**A**) is occultation event 1 and (**B**) is occultation event 2. In addition to the above-mentioned analysis, the relative average deviation and relative standard deviation of the reconstructed excess phase Doppler are also calculated. Figure 7 shows the histogram of the relative average deviation and relative standard deviation distribution of the excess phase Doppler between the reconstructed \(\text{B}_{3}^{*}\) and the actual \(\text{B}_{3}\). The horizontal axis of Figure 7A is the percentage of the deviation between the excess phase Doppler of the reconstructed \(\text{B}_{3}^{*}\) and that of \(\text{B}_{3}\). The horizontal axis of Figure 7B is the relative standard deviation percentage of the excess phase Doppler of the reconstructed \(\text{B}_{3}^{*}\) and the actual \(\text{B}_{3}\). The figure shows that the relative average deviation of the single-frequency measurement of the reconstructed \(\text{B}_{3}^{*}\)'s excess phase Doppler is less than 1%, the absolute value of most of the relative average deviation is less than 0.2%, and the deviation amplitude is low. The relative standard deviation is less than 1%, and most deviations are around 0.5%. Compared with the excess phase Doppler measured by dual-frequency, the data quality of the excess phase Doppler reconstructed by single frequency is nearly ideal. To sum up, the reconstructing excess phase \(\text{B}_{3}^{*}\) is verified by considering the excess phase Doppler. By the analysis of four aspects: direct plot the excess phase Doppler (Figure 4), y = x consistency comparison (Figure 5), Spearman correlation coefficient histogram (Figure 6), and plot the relative average deviation and relative standard deviation (Figure 7). All results show that the reconstructed excess phase Doppler and the dual-frequency excess phase Doppler not only have good consistent frequencies but  
Figure 6: Spearman correlation coefficient histogram between the excess phase of the actual \(\text{B}_{3}\) and the excess phase of the single-frequency occultation reconstructed \(\text{B}_{3}^{*}\). Figure 7: Relative average deviation and relative standard deviation distribution histogram of the excess phase Doppler of the reconstructed \(\text{B}_{3}^{*}\), (**A**) is relative average deviation and (**B**) is relative standard deviation. also have strong monotonic correlations. The standard deviation and average deviation of the reconstructed excess phase Doppler are very low, indicating that the quality of the reconstructed excess phase Doppler is good.