A Precise Acoustic Distance Measuring System for Tectonic Plate Motion

This paper proposes a new distance measuring system to monitor tectonic plate motions. The method is based on estimation of phase shift between two acoustic signals. The measurement error of plate displacement is determined by the phase estimation error. Phase estimation is performed with a conventional quadrature phase estimator in this paper. Simulation results show that under ideal conditions, the root-mean-square (RMS) error of the displacement estimation is within 1 millimetre when the signal-to-noise ratio (SNR) equals OdB. This error can be further reduced if we use a longer transmission pulse. Measurement errors caused by environmental factors such as ocean currents are also addressed. Reciprocal transmission is suggested to reduce this effect.