Improved GPS-based coseismic displacement monitoring using high-precision oscillators

The determination of high-frequency displacements using Global Navigation Satellite Systems (GNSS) observations with sampling frequencies > 1 Hz has attracted much interest in recent years, e.g., in seismology. We propose a new concept for GPS Precise Point Positioning (PPP) that takes advantage of a highly stable oscillator connected to the GPS receiver by modeling its behavior. We show that the high-frequency noise of kinematic GPS height estimates can be reduced by a factor of up to 4 to the level of 2-3 mm and the overall standard deviation including systematic long periodic errors by a factor of up to 2 to the 1 cm level. Consequently, valuable small and currently hidden vertical displacements can be detected that are not visible with classical PPP. Using data of the 2010 Chile earthquake, we demonstrate that coseismic vertical displacements with an amplitude of only 5 mm can be recovered using PPP with the proposed clock modeling strategy.