Mobile phones have become a vital part of our daily life and we just arvel at the idea of how we even coped without them for so many years. Mobile phones offer some really impressive benefits especially to world travelers. But on the other hand, they also present certain challenges, like when travelling from one place to another will they even work properly. This is due to the incompatible and differing nature of the various mobile phone systems, which often define the entire continents or regions.
In contrast to the conventional mobile phones, satellite phones connect to orbiting satellites instead of the terrestrial cell sites. So whether you’re reporting news from the mountains or just keeping in touch with your office during a trip, satellite phones can be simply the choice for you when you absolutely need a phone in the far off places of the world.
Like with most satellite communications you need line-of-sight communication in satellite phones as well. So when using a mobile satellite phone you need at least about 80% of the view of the sky to receive good service. Obstructions such as buildings, trees and vehicles roof can block the signals from the satellite from reaching the device. So the more you’re cut off from the view of the sky, the more possibility of having dropped calls and no service.
A satellite phone utilizes two sorts of networks basically:
- Geosynchronous orbit services
- Low earth orbit services
A geosynchronous orbit satellite completes one revolution in the same time that the earth completes one rotation. It rotates with the earth and thus appears to remain fixed, or stationary, over a particular location. It offers a greater bandwidth compared to low earth orbit services.
A low-Earth-orbit satellite, or LEO, circles the planet in 90 minutes to 2 hours. LEOs allow for use of smaller dishes and handheld devices, so they are well-suited for interactive conferencing. However, because a LEO remains above the local horizon for about only 20 minutes, large numbers of these satellites, in several different orbits, are required to maintain service. Generally LEOS offers a greater battery power life compared to geosynchronous services.
Currently, there two companies that are powered by LEO and that offer the satellite phone services, namely: Iridium and GlobalStar.
Iridium uses a network of 66 satellites that orbit the poles they travel from pole to pole giving coverage practically everywhere on the globe. If an Iridium user phone is calling another Iridium user phone then the call is not sent to the gateway and it’s entirely handled by the networked satellites.
Globalstar uses a network of 48 satellites that orbit the central hemisphere of the earth covering over 120 countries. If a phone user of the Globalstar is calling another Globalstar phone user the call goes to the ground station then back up the satellite network then down to the other Globalstar phone.
In near future, Globalstar plans to send their satellite signals over terrestrial cellular towers allowing the signals to break through obstacles like building and vehicles. So a satellite phone would be in terrestrial mode when line-of-site to the satellite is blocked by an obstacle and when the phone gets hold of line-of-site to the satellite network then the phone would be switched to the satellite mode.
Although satellite phone services can be really expensive and there are fewer providers to choose from the satellite communication industry is a growing and ever changing field. Over the last few years there has been a remarkable growth in the satellite phone market and the future for the satellite phones looks really bright. As the technology progresses customers will enjoy additional services offered never before.