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.


Site Lists

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 ITRF2008.

Based on ITRF 2008, IGS created a set site list specific for GNSS technology, known as IGb08. IGb08 evolved from IGS08 and IGB08. The lower case 'b' is intended to differentiate from the previous IGB08. IGb08 reference URL.

The GPS site positions and their velocities defined by the above mentioned reference frame is currently IGb08.ssc, and previously ITRF2005_GPS.SSC.txt and ITRF2008_GNSS.SSC.txt.

The derivation of ITRF is based on multiple modern space geodetic techniques, namely GNSS, SLR, VLBI, and DORIS.

The current SOPAC data analysis, since Oct 7, 2012 (GPS week 1709), is based on the IGS08 reference frame, which is closely related to ITRF2008. IGb08 is derived from the analysis of GNSS only solutions contributed by IGS Data Analysis Centers while the core stations are constrained onto ITRF2008 defined stations. Therefore, its positions/velocities are completely consistent with IGS published orbits/clocks and 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 classes of sources:

  1. IGb08 definition (excluding sites affected by most recent large earthquakes);
  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

station.info is the gps site equipment setup file used by gamit

GPS processing metadata files (xml) for global and regional sites generated daily (Note: large size, SOPAC-processed sites only).
XSD schemas
station.info (direct from SOPAC DB) html ftp

Receiver and Antenna tables

rcvant.dat html ftp
antmod.dat html ftp
igs_08.atx (absolute antenna phase centers) html ftp

Site 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, Lunar, Nutation, Leap Second Tables

SOLAR

2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 20042003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 19911990 1989 1988 1987 1986 1985


LUNAR

2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 20042003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 19911990 1989 1988 1987 1986 1985


Nutation Tables

2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 20042003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 19911990 1989 1988 1987 1986


Leap Second File

leap.sec html ftp