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A broadband global network area is to be expanded with the construction of three satellites for a fourth generation broadband satellite network known as the Inmarsat I-4. Inmarsat has awarded the contract for the construction of the satellites to Astrium. Inmarsat owns and operates a global satellite network, and has operating licenses in 171 countries. The satellites will be able to communicate with a variety of terminals as small as personal digital assistants in what Inmarsat refers to as its Broadband Global Area Network or B-GAN.

The network will enable Inmarsat to deliver higher bandwidth services on the internet and intranet content and solutions, video-on-demand, video conferencing, fax, Email, voice and LAN access at speeds up to 432Kbps (kilobits per second) anywhere on the globe via notebook or palm top computers. Two of the I-4 satellites will be launched in 2003, the remaining one will be an on-ground spare. The satellites and B-GAN system will be operational in 2004. The system will cost about $1.7 billion. Of this $700 million will be spent on launching the satellites, earth stations, telecommunications infrastructure, distribution and billing and support systems. It will also be compatible with third generation (3G) mobile systems.

The I-4 satellites will be 100 times more powerful than Inmarsat's current world global mobile 64Kbps network. In addition, the new Broadband Global Area Network (B-GAN) will provide at least ten times the capacity for new users. The new network will be interoperable with Inmarsat's current I-3 satellite network allowing existing users to migrate on to the new system and take advantage of new enhanced capabilities.

Recent forecasts indicate that the mobile satellite market will be worth over US$4 billion in 2004, doubling to over US$8 billion in 2009. The B-GAN has been designed in response to the dramatic rise in customer demand for bandwidth. This growth has been driven by a number of forces, including that of B2B eBusiness, which is forecast to be a US $1.1 trillion market by 2003. Data communications over Inmarsat's satellite network has grown by an average of 50% year-on-year since 1995, and it is expected that data traffic will use 70% of its current network by 2003.


The satellites will be positioned at 54° West (the western Atlantic slot) and 64° East (the Indian Ocean slot). Each satellite will carry about 200 spot beams, which will allow them to cover North and South America, Europe, Africa and Asia. Each of the satellites will require one earth station and a backup earth station for interconnection with terrestrial lines. The satellites will have about 10.5kW power and a payload power of about 9kW. The satellites' effective isotropic radiated power will be 68dbw and the I-4 system will communicate with three classes of terminal. A briefcase-size terminal will run at 432Kbps to and from the satellite. A 'nominal' terminal will weigh 1,000g (2 lbs, 3 1/4 oz), will fit into the carrying case for a personal computer and cost about $1,000. It will run at 432Kbps from the satellite to the terminal and 144Kbps from the terminal to the satellite. A PDA-size terminal will measure about four by five inches, weigh 700g (1 lb, 9 oz), cost about $700 and run at 144Kbps to and from the satellite. The I-4 system is seen as a logical extension of the work that has been done with the ACeS (Asia Cellular Satellite) and the Middle Eastern Thuraya systems.

Astrium plans to manufacture the satellite buses in its plant at Stevenage and the payloads in its Portsmouth plant in the United Kingdom. The integration and testing will be done in Toulouse, France. The company has previously been involved in the construction of three Marecs satellites, part of the original maritime satellite system and four Inmarsat 2 satellites, and supplied the advanced payload for the five Inmarsat 3 spacecraft.

With a project of this size, there are a number of contractors and sub-contractors. Thrane & Thrane won a £30 million contract to build the satellite communications equipment, and awarded a £6 million contract to Logica in September 2001 to develop higher bandwidth communications. Ericsson will provide the call routing and mobility management network for the ground stations.