Station Position Products

International GNSS Service (IGS) analysis centers currently provide station position and velocity solutions to NASA’s Crustal Dynamics Data Information System (CDDIS) on a daily basis; prior to mid-2012, these solutions were issued weekly. The analysis centers provide station position, velocities, daily length-of-day (LOD) and X, Y pole positions and rates, and geocenter position solutions. The IGS reference frame coordinator retrieves these solutions and produces a combined product, which is then in turn archived at CDDIS in Solution Independent Exchange (SINEX) format. These combination solutions are considered the official IGS products, which contribute to the International Terrestrial Reference Frame (ITRF).

Solution summary files are provided by the analysis centers in which they describe their analysis methods and strategies and list processing statistics. IGS provides descriptions of AC analysis procedures and models used.

All operational IGS GNSS products, including the station position solutions, are available in subdirectories by GPS week. The station positions and velocity files are stored in SINEX format.

In 2009, 2013, and 2020, the IGS initiated “reprocessing campaigns” (repro1, repro2, and and repro3 respectively). The IGS analysis centers re-processed the GNSS data from the global network of IGS stations (from 1994 to 2007 for repro1, from 1994 through 2012/2013 for repro2, from 1994 to 2022 for repro3) to produce a fully consistent set of products utilizing the most recent models and updated processing strategies. These reprocessed solutions are available within the weekly subdirectory structure as outlined below, in /repro1, /repro2, and /repro3 subdirectories.

The starting directories for these files (GPS and GPS+GLONASS solutions) are:

and for GLONASS-only solutions:

At the end of 2022, the IGS made the decision to change the name format going forward of many of its products archived at the CDDIS. A table is available on the IGS website which compares the old and new name formats. The table can be found on the following page:

Name Format Since GPS Week 2238

Append the following directory and file names to the starting directory:

as described in the table below.

Name Format Before GPS Week 2237

Append the following directory and file names to the starting directory:

as described in the table below.

The IGS combined, final station position solutions (GNSS only) are available on a weekly basis.

The starting directory for these files is:

https://cddis.nasa.gov/archive/gnss/products/   (GPS and GPS+GLONASS solutions)

Append the following directory and file names to the starting directory as described in the table below the list.