Satellite trackers are a means of communication via an orbiting satellite using GPS (Global Positioning System). They perform in a similar way to mobile phones, but are not dependent on being in range of a mobile phone network.
Mobile phone coverage is affected by your proximity to a mobile phone mast, and by physical obstructions such as buildings, hills and mountains. Signal is also likely to be weak or non-existent if working underground, and when travelling users may go in and out of signal. The weather also has a bearing on the strength of signal, particularly in heavy rain or snow. Even in a relatively smaller countries, there can remain significant areas where no signal is available.
Our satellite trackers by contrast work anywhere in the world. With 100% global coverage, users are able to to text, call and, most importantly, to send and receive data to control hubs and emergency systems.