When cellular phones came in, they were touted as the phones you could carry and use everywhere. Well, almost. Until satellite phones came along. In India, licences to operate cellular phone services were given on the basis of circles. As a result, cellular phones had to be given different numbers in different places. Of course, there was no facility for global communication. Satellite phones, more than any other, facilitated global communication. There is a basic difference between the technology used in satellite phones and other satellite communication means.

All about low earth orbit satellites

These telephones can have a single access number. They can be used to communicate virtually around the world. That takes care of all such hassles like roaming, SIM cards, single number etc.

Initially, this technology may find very little takers because of the high access and use costs and certain technical drawbacks. The call rates, for one, are frightfully expensive. A global satellite call to a satphone subscriber will cost between Rs. 150 and Rs 300 per minute, depending on the distance. Besides voice telephony, these satellites can also offer data, fax and paging services. The handsets cost between Rs. 1.5 lakh and 2.75 lakh. This, and the activation fee of about Rs. 8000 and a monthly subscription of about Rs. 2000, makes this service a very expensive proposition.

Looking at a time-frame of five years for this service to consolidate, the picture that emerges from an MTA-EMCI (Malarkey Taylor Associates-Economic Management Consultants International) study is:

Express industry, international travellers, offshore and isolated locations would be the major users with about 28 per cent, 14 per cent and 10 per cent shares respectively. Globally, Asia Pacific (38 per cent), North America (29 per cent) and Europe (22 per cent) would be the major user areas.

Initial reports, however, suggest that all these projections have gone awry for the satphone companies. Iridium, with a projected subscriber base of about 27,000 world-wide, is now looking at a figure of just over 8,000. In India it had planned to have about 2,000 subscribers by end-March 1999, but has managed only 50. Consequently, Iridium's cash and revenue accruals have been disappointing.

Reasons for the dismal performance have been delays in commissioning and approvals and equipment problems. Iridium's global launch was in November 1998, but in India, it was delayed upto February 1999.

Iridium India's clients are mainly from mining, oil exploration and plantations segments.

Oil and Natural Gas Corporation, India Meteorological Society and the Andhra Pradesh government too are in the client list.

Technical hitches like PSTN connectivity to enable land phone-satphone link are yet to be solved. Clients are also complaining about bulkier handsets than normal cellphones and the fact that these sets need to be taken outdoors to be able to communicate.

Satphone companies are now reworking their estimates and marketing strategies to tackle these problems.

All about low earth orbit satellites

The conventional geostationary satellites fly at an altitude of about 36,000-km above the earth and are geostationary. Like the name indicates, they appear fixed over a particular spot on earth and take the same time to circle the earth as it takes for the earth to rotate once. The advantage is that these have a longer life. Communication signals are beamed from the earth station in the path ('footprints') of this satellite and then transmitted down to the receiving station.

The low earth orbit (LEO) satellites fly at far less altitudes (between 150 and 450 km) and travel at high speeds to avoid being pulled in by earth's gravitational force. These satellites are, therefore, short-lived. Using LEOs would mean that an entire battery of these satellites needs to be sent up to be able to cover the entire planet. For e.g. Iridium has a string of over 66 satellites for its network. But such a network assures global coverage and direct signal pickup.

Signals are beamed from the mobile communication unit and picked up by the nearest satellite and transmitted along the network to the satellite nearest to the destination communication unit.