The satellite phones that use satellites in Geostationary orbit are called as Geosynchronous satellite phones. This satellites remain in a fixed position in the sky. In this system the communication for the network can be maintained using only three to four satellites.So,the launching cost is less in this arena. The satellites used for this service is too heavy like 5000 kg and expensive to build and launch. Because of the large distance from user there is a noticeable time delay in voice communication. The amount of Bandwidth is high in this case, so voice and data communication rate is higher than the low earth orbit system.
The disadvantage in Geosynchronous Satellite phone service is that in a place where there is a large sky, in this areas also some times because of no line of sight calls cannot be made because of the hill and forest. The user must need to go to a area to make a call where the line of sight is possible. But in the LEO satellite this does not happen. Though the signal is got stuck by an obstacle another satellite in the system will cover this and send signal to the satellite phone.
Below are some Geosynchronous satellite phone service company and their operation regions descriptions:
Aces: This provider is comparatively small. This provider provides voice and data communication sercives.The operating region is east Asia. The service is provided by a single satellite.
Inmarsat: This is the oldest satellite phone service provider. This company started their service in the year 1979.The main business was the installation for the ships. But after that they started a joint venture with AceS to the handheld services. This company is operating with total 12 satellites.Last one was launched in 2010.Coverage for this provider is almost all the regions in earth except the polar areas.
Thuraya: This system is based in UAE.Currently three satellites are providing coverage for this network.It covers most of the regions in euro Asia, Africa and Australia.
MSAT: This is an American based company. This uses equipment similar to Inmarsat,Thuraya but planning to launch a hand held service in Americas like Thuraya.
Terrestar: This satellite phone service is based on North America.
ICO Global Communication: A company which just launched one satellite in the geostationary orbit but the service is not started yet.