Displacement Monitoring of CORS Reference Stations Using GNSS Precise Point Positioning in Bangladesh

Displacement monitoring is useful for understanding the nature of geological hazards, such as earthquakes and landslides. It can also be used to monitor the stability of manmade structures such as buildings, bridges, nuclear plants and dams. Now a days, GNSS technology is considered as an effective tool for monitoring the displacement of the Earth's crust resulted from the effect of natural forces and human activities. This study estimated the displacement of six GNSS CORS reference stations in Bangladesh with the GNSS Precise Point Positioning (PPP) method. GNSS PPP is a competent tool in landslide monitoring which used un-differenced pseudorange and carrier-phase measurements along with precise satellite orbit and clock correction. In order to estimate the displacement, uninterrupted three days measurements data of each year of Six GNSS CORS stations were chosen during the period of 2012-2015. IGS final orbits and clock products were used in the data processing and the data processing was performed by high precision Bernese 5.0 scientific software package. Three dimensional coordinate's accuracy and the displacements of the four years have been presented in this paper. The results indicated that the horizontal trend increased towards the north-east direction about 5.34 cm/year and the vertical trend decreased 4.84 mm/year with some uncertainties. After four years, the estimated horizontal position was moved on about 16.00 cm and the vertical 1.452 cm. The presented accuracy in this study proven that it is possible to achieve millimeter-level accuracy of the displacements in the three dimensional coordinate components. It is evident that displacement monitoring with PPP is highly appropriate which can helps to minimize the landslide hazards, reduces costs and logistics which is particularly useful for remote areas or developing countries.