09-05-2013, 02:54 PM
SATELLITE PHONES
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INTRODUCTION
What is satellite phone?
A Satellite phone is a phone, which uses satellite for communication. Satellite phone enables you talk to anybody from anywhere in the world. A number of competing Mobile Satellite Services (MSS) plan to blanket the globe with satellite phone coverage from a constellation of over 1,000 satellites by 2004. It has great advantages over ordinary mobile phones.
Why satellite phones have been developed?
As developments in business, travel and technology have led to the increased human exploration of such 'remote and wild corners', the demand for a system of communication, beyond that of cellular phones, has arisen. It is for this reason that satellite technology has been developed.
Applications
The major applications of satellite phones are in
1. Marine Engineering (Ship etc)
2. Aviation (aero planes etc)
3. Business field
4. Disaster Relief organizations etc.
IRIDIUM SATELLITE SERVICE
The Iridium System is a satellite-based, wireless personal communications network providing a robust suite of voice and data services to virtually any destination anywhere on earth.
Motorola established iridium in 1960. Initially the aim was to use 77 satellites for communication. So the name iridium comes. (Iridium is the 77lh element in the periodic table). But later it was planned to use 66 satellites. In 1997, Iridium starts its service by using 66 satellites. But at that time, because of propagation of mobile phones and also the high cost of satellite phones, Iridium would not get the customers. But later in 2001,it start's its service and now it have a good position in satellite communication service.
Satellites in Iridium Service
The 66 satellites for iridium service circles around the earth along the low earth orbit (LEO). The satellites are about 750 Km away from the earth surface. It completes its motion around the earth in each 6 hours.
Since the satellites are in LEO, the signal delay for communication is very low. Also it has also some advantage is that only a small power is required for transmission and reception of data's. Also the size of the phones can be reduced.
The communication between satellite and phone (or gateways) is through L band (1616MHz) and the communication between two satellites is by using Ka band (19GHz).
Iridium Voice Services
If you work, live or travel in areas outside cellular coverage or in areas with inadequate landline service, Iridium is for you. Eighty-six percent of the world's land mass and all of its oceans are in areas with inadequate landline service. Iridium addresses these situations by providing coverage in all ocean areas, air routes and all land masses The Iridium system provides true global voice services by covering areas that cellular and landline do not. Voice services are supported using the 9500 handset or the smaller, lighter 9505 handset. The excellent signal strength provided by the Iridium constellation supports reliable connectivity across wide ranging landscapes and situations.
GLOBALSTAR SATELLITE SERVICE
Globalstar service has also a great position in satellite phone service. It uses 48 satellites for communication. Globalstar provides a high quality, affordable and reliable satellite communication.
Globalstar satellite telephone service is delivered through special multi-mode phones, which work just like traditional cellular phones when you are in an area with cellular coverage. When you need to communicate from outside the area covered by ground-based systems, the phones easily switch to Globalstar satellite mode. Satellite and cellular communications are both at your fingertips.