Quality Control in Using GNSS CORS Network for Monitoring Plate Tectonics: A Western Australia Case Study

Abstract

A comprehensive quality-control approach is presented when monitoring motion of tectonic plates using Global Navigation Satellite System (GNSS) measurements of Continuously Operating Reference Station (CORS) networks. The approach was used in a case study in which changes of coordinates with time in a dynamic datum of the newly established CORS network in Western Australia were used to determine the rate of horizontal motion of this part of the Australian Plate. Biweekly data spanning 3 years were used. Quality control started in the preprocessing stage by multipath analysis of all sites and screening of data for outliers, cycle slips, and clock jumps. Possible error sources in the observations were addressed in the processing software. The stability of CORS networks was evaluated by checking changes of their coordinates in a static datum. The computed positions were checked for their consistency, precision, and repeatability. The few problematic data were replaced by better neighboring data sets. The final positions that passed the quality-control process were used for assessment of the Australian Plate movement. Results showed that this plate had a rate of motion in a grid Universal Transverse Mercator (UTM) projection of International Terrestrial Reference Frame ITRF2008 that was 6.84 cm/year with a precision of 2 mm/year and an azimuth of 29.6° on average.