Accuracy enhancement of GPS displacements measured on a large steep slope and results of long-term continuous monitoring

Abstract

  GPS displacement monitoring has been done on a large steep slope. Measurement environment of this slope was so severe, namely, with narrow sky view over GPS antennas and large relative height of measurement points to reference point, that low measurement accuracy was expected. However, employing appropriate error correction methods, this study got a successful measurement result as accurate as the measurement in a flat open field. Using these error correction methods, the slope monitoring has been stably continuing for three years. The measurement result shows that the GPS system can detect the three-dimensional movements of landslide with high sensitivity. Sudden large displacement of the slope due to heavy rain was successfully measured with high accuracy as well as small steady displacement of about 15mm/year.