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.
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:
- IGb08 definition (excluding sites affected by most recent large earthquakes);
- 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.
Receiver and Antenna tables
Site constraints file (sittbl)
Session table (sestbl)
The session table contains configuration parameters for the gamit run.
Earth Rotation Parameters (EOPs)
Solar, Lunar, Nutation, Leap Second Tables