## 4 Results
### PPP Time Transfer in the Kinematic Model Using HAS Service  
To further explore the performance of kinematic PPP time transfer based on the Galileo HAS service, Figure 10 presents the receiver clock offsets for the PTBB station calculated using GPS PPP in dynamic mode, while Figure 11 illustrates the receiver clock offsets for six other stations derived from GPS PPP in the kinematic model. Upon examining the data presented in the two figures, a few key takeaways emerge. Firstly, akin to the static scenario, the receiver clock offsets across all stations maintain a consistent trend regardless of whether they are determined by static or kinematic PPP, a pattern largely attributable to the benchmarks of the GPS satellite clock products within the HAS service. Secondly, it becomes evident that the receiver clock offsets derived from kinematic PPP exhibit greater noise compared to those from static PPP. This increase in noise is likely due to the pronounced correlation between the receiver clock offset parameters and the vertical coordinate during the dynamic PPP solution process, a relationship well-documented in the scholarly literature. Lastly, it is observed that the kinematic PPP-derived receiver clock offsets undergo multiple instances of frequent re-convergence, a phenomenon not observed in the static PPP calculations. This susceptibility to re-convergence in kinematic PPP is primarily a consequence of the challenges posed by an insufficient number of satellites during the solution process, leading to more frequent re-initializations of the clock offset estimates. Solving this problem might be possible through the establishment of a receiver clock offset model [30], which will also be part of our future research work. In our quest to delve deeper into the receiver clock offsets, we conducted an in-depth analysis focusing on the Galileo and Galileo/GPS integrated PPP kinematic model. Figures 12 and 13 present a comparative analysis of the receiver clock offsets, with Figure 12 highlighting the data from the PTBB station and Figure 13 extending this analysis to encompass six additional stations. This visual representation of data provides a comprehensive overview of the performance characteristics of the PPP kinematic model across diverse stations, offering valuable insights into the behavior of receiver clock offsets in kinematic conditions. Mirroring the preceding results, it is observed that the kinematic scenario notably amplifies the noise associated with receiver clock offsets. Moreover, the Galileo-only PPP, which relies on the Galileo HAS service, experiences quite frequent instances of re-convergence in its receiver clock offsets when operating in the kinematic mode, a phenomenon particularly pronounced at the TWTF station. The underlying causes for this  
Figure 10: The receiver clock offset from GPS PPP in the kinematic model for the PTBB station. behavior have been elucidated in the earlier sections and will not be reiterated here. What is particularly exciting is that the Galileo/GPS combined PPP solution demonstrates the ability to maintain a smooth and continuous time series under kinematic conditions, devoid of any significant re-convergence events. This robust performance can be attributed to the enhanced spatial configuration and increased satellite count that results from the integration of multiple GNSS systems. From these observations, we can confidently conclude that for the implementation of PPP time transfer in kinematic scenarios facilitated by the Galileo HAS service, the combined Galileo and GPS PPP solution is the recommended approach. This recommendation is based on its superior performance in maintaining precision and continuity in time transfer, which is crucial for applications requiring high-precision timing information during movement.