How do satellite phones work?

We are all familiar with the convenience of mobile phones and landlines to make a phone call. And it certainly seems that they work almost anywhere in the world. However there are certain areas or circumstances were this convenient service is not available. That is when a satellite phone is the only method of communication.

Unlike mobile phones which use a localized phone tower to connect calls; a call from a satellite phone is sent through a satellite constellation, then sent back to Earth via the nearest satellite gateway. Then the call is routed through traditional voice networks to reach its destination.

A call that is made from one satellite phone to another will be completely routed through the satellite constellations. This way the call will not be affected by any technical difficulties on the ground. This is why satellite phones are essential for communications during a disaster such as a hurricane, earthquake or winter storm where landline communications can be destroyed.

Satellite phones rely on a direct line of sight to the satellite constellation. To use a satellite phone properly you will need a clear view of the sky, so it is important to ensure that the phone signal is not obstructed by trees, mountains, buildings or other large structures.

To choose the right satellite phone, you may want to consider the type of satellite constellation that is used. Iridium and Globalstar use a LEO (low earth orbiting) constellation. This style of satellite constellation covers the entire globe including the Polar Regions. A LEO satellite is also moving quickly from horizon to horizon, so there is the possibility of a dropped call when it is being transferred to the next satellite. Companies like Inmarsat and Thuraya use a geostationary satellite constellation. These satellites move with the Earth’s rotation, so from our prospective on the ground the satellite doesn’t appear to be moving. These satellites are in a higher orbit so you may notice latency or delay with the call, but there is a slim chance that the call would be dropped.

For more information on the different satellite phones available and their style of handsets view our previous comparison blog here.