## 4 Results and Analysis
### Results of the Real Data Set  
In this subsection, real data are utilized to validate how our approach performs when data interruption occurs. The real-time stream interruption occurs occasionally under unknown conditions. The real-time stream CLK 81 is employed here. The investigation is performed from DOY 147-158, 2018. The monitoring system records the data interruption at some times. The abnormal data are stored to verify the new algorithm. Because the time reference of real-time satellite clocks is not a continuous clock or time scale, the clock solution of a single station is not reliable when evaluating the new model. For this reason, only a link result can be used for the stability evaluation with the purpose of removing the uncertainty of the reference. Four links are calculated with the real data set. One link is demonstrated in below. In the real data section, all the time transfer experiments are obtained with BRUX as the pivot.  
Figure 8: Allan deviation of scheme 1 (**blue**) and scheme 2 (**red**) at six stations for observation interruptions of 60 and 90 min.  
Figures 10 and 11 show, first, that the clock difference time series of scheme 2 is smoother than that of scheme 1. Second, the non-convergence caused by the observation interruption occurs in scheme 1, causing the appearance of a system error. It influences the stability of the time link. Third, the tendency of scheme 2 is in accordance with the complete data, i.e., the data show that scheme 2 avoids re-convergence when the data are interrupted. The data show that scheme 2 works well for the real time data and for the simulation data.  
Figure 10: Clock offset time series of scheme 1 (**blue**) and scheme 2 (**red**); the yellow colour represents the solutions of the complete data with the between-epoch constraint model; the bottom figure is a partial amplification of the top figure.  
Figure 9: Improvement of the frequency stability (percent) of scheme 2 compared to scheme 1.  
Figures 12 and 13 illustrate more about the link stability. All the stations are equipped with an H-maser. The discrepancy in the different types of external frequency standard can be neglected. For the selected four links, the data show that the time series in scheme 2 is more stable than that in scheme 1. The maximum percentage of improvement is greater than 50%, while the minimal percentage of improvement is 5%. In other words, the frequency of stability is boosted at each averaging time, especially in the link BRUX-PTBB, where a distinct enhancement is demonstrated at each averaging time. The maximum percentage is greater than 50% at 100 s. A strong correlation may exist in the adjacent epoch for the PTB's H-MASER. The application of the between-epoch constraint clock model makes full use of the correlative information to achieve more stable results. Moreover, the data show that the magnitude of the improvement is not correlated to the distance between the stations.  
Figure 11: Clock difference time series of scheme 1 (**blue**) and scheme 2 (**red**) with respect to the results of the complete data with the between-epoch constraint model when 10 min of data interruption occurs; the bottom figure is a partial amplification of the top figure.  
Figure 12: Allan deviation of scheme 1 (**blue**) and scheme 2 (**red**) on four links.