The ITU (International Telecommunications Union) provides antenna contours for ITU member satellite antennas. These antenna contours are used to generate antenna patterns in STK. These antenna patterns are called GIMROC patterns and can be loaded in as antennas using the .gxt file extension. To obtain these patterns, you must subscribe to the ITU GIMS dataset.
http://www.itu.int/en/ITU-R/software/Pages/gims.aspx
The Graphical Interference Management System for PC, or GIMS, is a PC-based software package which allows the capture and modification of graphical data (service areas, antenna gain contours, and gain towards the geostationary orbit) relating to the electronic notification of geostationary satellite networks in the space radio communications services.
It also allows for carrying out Power Flux Density (PFD) calculations using graphical data captured via this product either by using the digitiser or by importing a file in the GXT format. The captured diagrams may be exported in the GXT format for use in STK as antenna patterns using the GIMROC antenna pattern option.
As of version 8.0, GIMS can also handle graphical data for non-geostationary satellite networks in the forms of images, primarily for the purpose of perusal.
The ITU-R Space Radio Stations (SRS) database used to be a separate database on the SRS CD. Now it is a part of the collection of data sold as the BR-IFIC DVD. The old application program name was GIMROC and the new name is GIMS.
Users have to install the SRS database and the GIMS application program. The GIMS application program interfaces with the database. Users run the GIMS program and view/search the satellites and the onboard transponders. Select any transponder and then "Export" the EIRP coverage contours in the *.gxt file format.
STK can import the *.gxt file format data and process the antenna information.
Further information can be found here:
http://help.agi.com/stk/Content/comm/GIMROCAntennaPattern.htmand here:
http://help.agi.com/stk/Content/comm/CommRadarA-02.htm#TechAntGIMROC
