Precision of Global Navigation Satellite Systems Based Earthquake Observations

In this study, accelerometer and GNSS observations were carried out for different earthquakes on the shake table and the differences between the observations and the actual input were examined in both time and frequency domains. When the waveforms obtained from the measured GNSS and acceleration displacement waveforms are compared with the actual input, the Root Mean Square (RMS) error values of GNSS vary between 4 and 9 mm while the RMS values of the displacement waveforms obtained from the acceleration records vary between 1 and 110 mm. Besides, the average RMS values of the GNSS displacement waveforms are around ~6 mm. In the signal coherence analysis, the coherence between the acceleration measurements and the actual input signal is observed only at frequencies higher than 2-3 Hz verifying that the coherence at lower frequencies is low for accelerometers whereas the coherence between GNSS and the actual input signal is observed to be flat at low frequencies up to 1 Hz