1. School of Electronic Information and Engineering, Yangtze Normal University, Chongqing, China
2. Department of Mathematics, Research Group of Ionospheric Determination and Navigation based on Satellite and Terrestrial Systems (IonSAT), Universitat Politècnica de Catalunya, Barcelona, Spain
3. Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
4. NorthWest Research Associates, Inc., Boulder, CO, USA
5. NASA Goddard Space Flight Center, Greenbelt, MD, USA
6. Department of Signal Theory and Communications, Centre for Language and Speech Technologies and Applications (TALP), Universitat Politècnica de Catalunya, Barcelona, Spain
7. Institut d’Estudis Espacials de Catalunya-Universitat Politecnica de Catalunya (IEEC-UPC), Barcelona, Spain
8. Geodesia Espacial y Aeronomia (GESA), Universidad Nacional de La Plata (UNLP), La Plata, Argentina
9. Department of Computers Architecture, High Performance Computing Group and Sustainability, Technology and Humanism (CAP-STH), Universitat Politècnica de Catalunya, Barcelona, Spain
10. European Space Agency, European Space Research and Technology Centre (ESTEC), Noordwijk, AZ, The Netherlands