GEO-Mobile Radio Interface

GEO-Mobile Radio Interface (GEO stands for Geostationary Earth Orbit), better known as GMR, is an ETSI standard for satellite phones. The GMR standard is derived from the 3GPP-family terrestrial digital cellular standards and supports access to GSM/UMTS core networks. It is used by ACeS, ICO, Inmarsat, SkyTerra, TerreStar and Thuraya.

There are two widely deployed variants of GMR, both heavily modeled after GSM

GMR-1 is the technology used by Thuraya. GMR-1 3G is the technology used for TerreStar and SkyTerra. GMR-2 is used by Inmarsat iSatPhonePro.

GMR was developed by TIA and ETSI.

Versions of standard and cipher used: