Motorola has founded a company, called Iridium, to launch their global cellular network. 47 countries have invested in Iridium, including China, the former Soviet Union, European nations, and many undeveloped countries lacking telecommunication infrastructures. Total investment so far is $1.5 billion. Iridium's current goal is to have 66 cellular communications satellites in Low Earth Destructive Orbit (LEDO). These satellites will route voice, data, and fax signals from cell phones, through the satellite network, to a ground based tracking station. The actual Iridium Phone weighs a mere 6 ounces and can contact any other Iridium Phone on the planet, as well as interface into existing phone systems via tracking station. Conveniently the Iridium Phone's also tap into the orbital GIS satellites.

Iridium proposes to have the network in place and operational by August of 1996! The fifteen month plan includes the construction of the space vehicles. In conjuction with Software Technologies Inc. (STI), Motorola and Iridium are claiming that the satellites can be produced from scratch in 5 days each, and can be put in LEDO no later than 8 days after that.

Their two week turnaround time requires launch from either a Soviet or Chinese rocket or high altitude drops from 747's with booster motors. Satellite life expectancy is only 3 to 10 years. STI is in charge of tracking and control of the satellite network. The software control package is STI's own, COMET. It is a GUI package that translates satellite tracking and operational data, as well as flight control through point and click operations. It is currently running on Sun Sparcstations using Solaris.

Headquarted in Melbourne, Florida, STI must intergrate Iridium's distributed geographical database of cellular coverage areas with the flight control software for real-time use. Each satellite has a unique frequency and must be able to route signals through other satellites to the appropriate ground station. This is further complicated by the fact that during transmission, each phone will only have an individual satellite overhead for 900ms. Over 300 gigabytes of data must be integrated before the system becomes operational. Control centers are being established in Washington DC, Hawaii, Florida, Italy, and Alaska. This still only allows for a very small window of time to bring control systems back on-line in the event of systems failure. Motorola is working on the not trivial task of creating circuitry for the Iridium Phones that will handle frequency shifting every 900ms. Complications have also arisen with the country of France. The French government has decided to have no part of the cellular global village, and are demanding that Iridium keep all such transmissions out of its airspace.

More information about Motorola can be found at URL:http://www.motorola.com/

Tim Van Devander

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