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)

Global list

Regional list


Reference Frame Definition and Date Specific a priori Coordinates

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:

  1. IGS14 definition (major offsets caused by large earthquakes are considered);
  2. SOPAC multi-year solutions (if velocities are estimated);
  3. 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

The file station.info contains the history of GNSS metadata (e.g., antenna heights and antennas) for global and regional stations. Direct from SOPAC Oracle database) html ftp

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)

sittbl.refined html ftp

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, Leap Second Tables

SOLAR

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

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

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


Leap Second File

leap.sec html ftp