Acknowledgements
Thanks to the following organizations who provide publicly available base station data:
[CDDIS] http://cddis.gsfc.nasa.gov
[CORS] http://www.ngs.noaa.gov
[ALTCORS] http://alt.ngs.noaa.gov
[EPN] http://www.pecny.cz
[FLEPOS] https://www.agiv.be/producten/flepos
[IGE] http://www.ign.es/ign/main/index.do
[IGNI] http://ign.fr
[SOPAC] http://garner.ucsd.edu
[AUSLIG] http://www.ga.gov.au
[GSI] http://terras.gsi.go.jp
[ASI] http://geodaf.mt.asi.it
[OLG] http://www.oeaw.ac.at
[BKGE] http://igs.bkg.bund.de
[BKGI] http://igs.bkg.bund.de
[DUT] http://gnss1.tudelft.nl
[ROB] http://gnss.be
[UNAVCO] http://www.unavco.org
[SPICC] http://icc.cat
[TRIGNET] http://trignet.co.za
[LINZ] http://www.linz.govt.nz
[RBMC] http://ibge.gov.br/home/