About GAMIT
GAMIT and GLOBK are a comprehensive suite of programs developed by MIT, Scripps Institution of Oceanography, and Harvard University for analyzing GPS measurements primarily to study crustal deformation, generating orbit/EOP products, and establishing and maintaining the reference frame. The GAMIT home page is available.
The SOPAC data archive GAMIT directory contains all of the setup files listed here.
Station lists (analyzed by SOPAC)
The International Terrestrial Reference Frame is defined by IERS and is updated every few years. The most recent reference frame is ITRF2014. The previous two frames were ITRF2005 and ITRF2008.
Based on ITRF 2014, IGS created a frame specific for GNSS technology, known as IGS14.
The derivation of ITRF is based on multiple modern space geodetic techniques, namely GNSS, SLR, VLBI, and DORIS.
The current SOPAC data analysis, since January 1, 1995 (GPS week 0782), is based on the IGS14 reference frame. IGS14 is derived from the analysis of GNSS only solutions contributed by IGS Data Analysis Centers while the core stations are constrained onto ITRF2014 defined stations. Therefore, its positions/velocities are completely consistent with IGS published orbits/clocks and earth orientation parameters (EOP), as well as all the physical models and model corrections, such as the antenna phase center model for receivers and satellites, the differential code biases (DCB), and various tidal loading displacements etc. SOPAC routinely processes a large volume of GPS data (about 3000 sites) collected from both global and regional networks.
The a priori coordinates used in SOPAC data processing come from three sources:
- IGS14 definition (major offsets caused by large earthquakes are considered);
- SOPAC multi-year solutions (if velocities are estimated);
- Most recent SOPAC weekly solutions (if velocities have not been estimated or affected by earthquakes).
The true of date a priori files containing the above mentioned a priori coordinates are date sensitive. They are updated weekly and are available as aprioriFile_YYYY_DOY.txt.
Station info
Receiver and Antenna tables
rcvant.dat html ftp
antmod.dat html ftp
igs_08.atx (absolute antenna phase centers) html ftp
Station coordinate constraints file (sittbl)
Session table (sestbl)
The session table contains configuration parameters for the GAMIT run.
sestbl.regional html ftp
sestbl.global html ftp
Earth Rotation Parameters (EOPs)
Multi-year EOP files: pmu.bull_f html ftp ; pmu.bull_a html ftp
UT1 (ut1.usno) html ftp
POLE (pole.usno) html ftp
Solar Ephemeris, Lunar Ephemeris, Nutation
The GAMIT tables below (soltab, luntab, nutabl) are replaced in 2021 by JPL Small-Body Database
JPL nbody tables (binary file)
SOLAR (historical)
2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985
LUNAR (historical)
2020
2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985
Nutation Tables (historical)
2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986