Impact of IGS Orbit and Clock Product Types on PPP-Based GNSS Time Synchronization Performance

Halim Lee, Seunghyeon Park, Joon Hyo Rhee, Gyeongmin Kim, Chulsoo Lee, Jiwon Seo*

Precise time synchronization between geographically separated infrastructures is essential for terrestrial navigation systems, cellular networks, and distributed sensing networks. Precise point positioning (PPP)- based global navigation satellite system (GNSS) time transfer enables sub-nanosecond-level synchronization and requires precise satellite orbit and clock products, such as those provided by the International GNSS Service (IGS). Because these products (e.g., final, rapid, and ultra-rapid) differ in latency and accuracy, a trade-off exists between product latency and achievable synchronization performance, making product selection a key design consideration for operational systems. In this study, we investigate the impact of IGS product types on PPP-based time synchronization performance between two GNSS reference stations. Using RTKLIB-based PPP, identical RINEX datasets are processed while varying only the IGS products, and the inter-station time difference is derived from the estimated receiver clock offsets. Synchronization performance is evaluated in terms of the standard deviation (1σ) of the detrended time-difference series after removing long-term drift components. Experimental results indicate that the 1σ discrepancy among product types is marginal, with the difference between the IGS final and ultra-rapid products on the order of a few picoseconds. All configurations achieved sub-nanosecond synchronization precision. These results provide practical guidance for selecting appropriate IGS products in near-real-time GNSS timing applications.
Keywords: GNSS time transfer, precise point positioning (PPP), IGS orbit and clock products, time synchronization

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