As Rugged relied on Orekit for the frames computation, Orekit must be properly initialized for Rugged to run.
The simplest way to configure is to first retrieve the example orekit-data.zip file from Orekit files section and to unzip it in a known fixed location on your computer (let’s assume it is on your home folder, and it creates an orekit-data subfolder there).
Then near the start of your main program, and before Orekit is called for the first time, you will add the following code snippet:
File home = new File(System.getProperty("user.home"));
File orekitData = new File(home, "orekit-data");
DataProvidersManager.getInstance().addProvider(new DirectoryCrawler(orekitData));
This is sufficient to start working.
Note that some of the data in the orekit-data folder needs to be updated, typically the UTC-TAI.history file, which is updated about once every 18 months by IERS, and the files in the Earth-Orientation-Parameters folder which are updated regularly by IERS. The update frequency depends on which file you use.
The data provided in the example archive from Orekit site are example only and are not kept up to date. The real operational data are live, and remain under the responsibility of the user.