Utvärdering av BeiDou vid statisk deformationsövervakning : En fallstudie på Gävle flygplats

Sammanfattning: Global Navigation Satellite System (GNSS) is nowadays a well-established and popular choice for various survey missions. Earlier studies indicate that BeiDou in combination with Global Positioning System (GPS), Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS) and Galileo contributes to a lower uncertainty in 3D. Earlier studies indicates that GNSS achieves good enough quality and is reliable for deformation monitoring. The purpose of the study is to examine the potential of BeiDou using static deformation monitoring in 3D at the millimeter level, both individually and in combination with other satellite systems. The study detects deviations in a local network and by connecting to an external reference station using single- and double frequency as well as broadcast- and precise ephemeris. Data were collected using static measurements for three sessions within 2 days. The observation time for session 1 was 9 h and for sessions 2 and 3 was 4 h, respectively. The measurements were carried out using 3 points with the average baseline length of 791 m. A simulated deformation was applied at 2 occasions were each displacement was 5 mm in plane and 4,8 mm in height. Data was processed in Leica Infinity. The measured deformation was compared with the true displacement and with the rest of the satellite constellations. The result of the study shows that BeiDou in combination with GPS/GLONASS/Galileo in a local network achieves deviations between 0,2–1,0 mm in plane and 0,1–1,2 mm in height for every setting. Regarding processing with only BeiDou in a local network with broadcast ephemeris and the B1 frequency, the result indicates deviations between 0,2–1,9 mm in plane and 0,4–1,0 mm in height. Further processing with precise ephemeris the deviations was calculated between 0,2–1,8 mm in plane and 0,9–4,6 mm in height. Larger deviations were obtained using the external reference station MAR6. The outcomes of this study indicate that there is a possibility to use BeiDou individually for deformation monitoring if broadcast- and precise ephemeris with frequency B1 are used. BeiDou in combination with GPS/GLONASS/Galileo indicates deviations at millimeter level (<1,2 mm) in 3D. BeiDou as a complement achieves equivalent deviations in comparison to GPS/GLONASS/Galileo. The conclusion indicates that BeiDou as a complement is useful for static deformation monitoring. Further conclusions indicate that an external reference station should not be used for deformation monitoring. BeiDou can, when using B1 frequency and precise ephemeris, detect millimeter displacements for shorter sessions.