1. Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
2. School of Earth and Planetary Sciences, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia
3. Department of Computer and Geospatial Sciences, University of Gävle, Gävle SE-80176, Sweden
4. Geodetic Research Division, Lantmäteriet (Swedish Mapping, Cadastre and Registry Authority), Gävle SE-80182, Sweden
5. Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm SE-10044, Sweden