Motorola´s IRIDIUM system: low-Earth orbit global cellular communications network

Summary form only given. The technical parameters which led to Motorola´s announced IRIDIUM system were discussed. The IRIDIUM system is a worldwide, satellite-based, cellular, personal communications system primarily intended to provide commercial, low-density, mobile service via portable, mobile, or transportable user units, using low-profile antennas, to millions of users throughout the world. Calls can be made and received anywhere in the world with a personal, portable unit. Small smart satellites are internetworked to form the network´s backbone. Small, battery-powered, cellular-telephone-like user units communicate directly to the satellites. Gateways (Earth stations) provide the interface from the satellites to the individual postal, telephone, and telegraph authorities. The system is intended to be compatible with terrestrial cellular telephone systems installed, or being installed, in densely populated areas by providing a similar service everywhere else in the world.<>