(a) Locations of the earthquake and GNSS stations. (b) and (c) are observations and synthetics in PPP and RP. S1-S2 represents the RP waveform with S2 as the reference station. While precise PPP requires a delay of as much as 1–2 weeks, RP offers rapid, near real-time waveform (S1–S2) with comparable accuracy. PPP waveforms can be directly matched with synthetics, whereas RP waveform should be matched with differential synthetics.