Multi-constellation programmes increasingly qualify their navigation chain against both GPS and Galileo signals, which means injecting simulated constellations rather than relying on live sky. The RF shielded enclosure is what allows that to be done indoors. Coupling is held between 4 and 6.5 dB across the band, tight enough that measurements taken across a production run can be compared directly. The same fixture supports outward measurement for acceptance testing, so one article covers both receive-chain verification and the RF functional check that closes out integration. The hat mounts on interface features already present on the antenna, needs no bracket on the spacecraft, and dismounts without tooling. The envelope is 97 x 97 x 40 mm (3.8 x 3.8 x 1.56 in) at 245 g, with an SMA female interface, rated -70 to +100 °C operating and storage. CSA-L-004-RH is the matching antenna.