Evaluation of real-time PPP techniques for seismic and structural monitoring

This contribution evaluates ability of Real-Time Precise Point Positioning (RT-PPP), Near RT-PPP, and Post-Processed (PP) RT-PPP to capture dynamic motions. Harmonic motions with different frequencies and amplitudes were generated on a shake table, along with ground-motion simulations of two major earthquakes and step functions. In both frequency and time domains, RT-PPP results from 20 Hz GPS observations were compared with Linear Variable Differential Transformer (LVDT) and PPP-Final references. Findings show that RT-PPP can successfully identify structural natural frequencies, seismic waveforms, and static or quasi-static displacements at the moment an event occurs in the field, immediately afterward, or one day later.