6. Manufacturers of satellite phone systems

Some of the major manufacturers of satellite phone systems include

a. Globalstar: Globalstar satellite phone system that consists of 48 LEO satellites was specifically designed to meet the needs of those who travel extensively. Therefore, a phone that is a compact, tri-band handset, that is able to operate on both the cellular CDMA and AMPS networks as well as the Globalstar network was designed.

Advantage: The Globalstar LEO constellation is only 700 miles from earth, and allows better quality communications.

b. Inmarsat: Inmarsat was the first mobile communications satellite system conceptualized and brought to reality. Inmarset originally designed their satellite phones for the maritime industry, but they now offer phone services to a wide range of industries.

Inmarsat uses four geo-stationary satellites set at different locations over the equator. Inmarsat delivers voice, fax, real-time ISDN and MPDS data services to the user.

Disadvantage: The satellite is so far away (approx. 22,000 miles) that a comparatively large antenna system is required for signal transmission and reception.

c. Iridium: The Iridium System is a satellite-based, wireless personal communications network providing a suite of voice features to virtually any destination anywhere on earth.

Iridium uses 66 satellites that orbit the earth on six different planes. Since the satellites are in LEO, the signal delay for communication is very low. Individual Iridium satellite is able to orbit the earth once every 100 minutes.

Advantage: Iridium handsets can receive and make satellite phone calls from anywhere on the planet, thus creating a reliable connection.

d. Thuraya: Thuraya is an advanced geo-synchronous mobile satellite system that provides satellite telephony and data services to Europe, The Mediterranean, Northern Africa and the Middle East region covering more than 120 countries.

Advantage: Thuraya satellite phones are capable of Internet connectivity, and data is available at no extra charge.

Disadvantage: Thuraya uses geostationary satellites and hence delay in voice communications may be felt.

A general comparison chart is given below

7. Advantages and Disadvantages of satellite phones

The advantages of satellite phones are

1. Wide network coverage

2. Uniform performance irrespective of location

3. Uniformity in phone number

4. No installation/setup required

5. Highly useful in disaster response

The disadvantages are

1. High cost of the phone as well as call cost

2. Large antenna size

3. Delay in voice communications conversations, particularly when using networks based on geosynchronous orbits.

4. Low data bandwidths for Internet access etc.

5. Local government regulations may also prevent one from using satellite phones without prior permission.