1. Ground-Based Global Navigation Satellite System Observation Summary Data (30-second sampling, daily files) from NASA CDDIS
  2. temporal
YearFile Count
199214838
199324076
199420289
199525734
199639707
199748415
199859998
199966591
200092745
200183971
2002100116
2003114289
2004120404
2005124211
2006134253
2007137135
2008140814
2009147428
2010160155
2011171492
2012243382
2013276059
2014347635
2015330830
2016412023
2017190003
2018259414
2019287766
2020249323
2021196511
2022245495
2023229505
2024212400
2025192888
2026118677