Remote satellite links go broadband
- By William Jackson
- Jun 05, 2006
CHICAGO'Inmarsat PLC has launched a new satellite network service offering bigger pipes through smaller terminals that it hopes will be popular with the military and first responders.
'We launched new satellites that allowed us to concentrate a lot of power,' said Jack Deasy, Inmarsat's director of civil programs.
The satellite service provider is touting its Broadband Global Area Network, which offers speeds of up to 492 Kbps for data and switched-voice channels, at the GlobalComm trade show this week.
BGAN service was offered in Europe, Asia, Africa and the Middle East last year. The launch of a second fourth-generation satellite that is perched over Brazil enabled service in the Americas. Telenor Satellite Services, a subsidiary of Telenor of Norway, began retailing BGAN in the United States in May.
The companies are hoping that the service will be popular with first responders during the current hurricane season, because it will be able to provide high-speed voice and data communications independent of terrestrial infrastructure that can be put out of commission by severe weather.
In the federal market, 'it starts, as satellite always does, with DOD,' Deasy said.
The Defense Department's Joint Systems Integration Command in Suffolk, Va., is beta testing the service, he said.
BGAN is enabled by a new generation of satellites that can focus radio signals in three types of beams, with increasing strength as the area being covered is reduced. A global beam covers about one third of the Earth's surface. A regional beam, which is the size used by the eight satellites now in orbit from the previous generation, covers a continental area. A spot beam covers an area about 200 miles across.
Terminals connecting to the new satellites are detected by the regional beam, which is always on, and the user's area then is 'illuminated' by a spot beam to provide a high-speed connection. Each satellite can produce up to 193 spot beams and can concentrate up to one quarter of its total power on a single spot, depending on usage.
'Because we can concentrate the power, we can send the signal to a much smaller terminal and we can use the spectrum more efficiently,' Deasy said.
Previous terminals were luggable boxes with fold-out antennas. BGAN terminals are about the size of a notebook PC, with no external antenna. This link provides 492 Kbps of IP traffic and an Integrated Services Digital Network channel of up to 64 Kbps for circuit switched-voice or data traffic, enabling simultaneous voice and data communications.
Inmarsat wholesales the service and provided seed money to manufacturers of the new terminals. Each brand has different features for different markets. The largest model, the Hughes Network Systems 9201, features built-in WiFi, making it a WLAN access point for up to 11 users.
The L-band frequency used in the service is not affected by rain and blowing dust, making the signal stable in bad weather. The current BGAN services are portable; the equipment is easily moved, but is intended to be used while stationary. Inmarsat expects to follow up with a mobile service that can maintain connections at speeds of up to 60 mph.
The BGAN satellites, like the rest of the Inmarsat fleet, are geostationary, meaning that they orbit in a stationary position over the equator. With the two satellites now in orbit, Inmarsat claims coverage of more than 80 percent of the Earth's landmass and 90 percent of its population. The company is negotiating for a launch slot for a third satellite, probably next year.
Because the satellites orbit at the equator, they provide coverage only between 70 degrees north and south, eliminating the polar regions. The 70th parallel north cuts about halfway through Greenland and along Alaska's northern coast. The 70th parallel south cuts through some portions of Antarctica.
William Jackson is a Maryland-based freelance writer.