The satellite phones directly communicate with the low earth orbit satellites (LEOS). They are not only researched to be much faster, but also offer the user a better range of coverage.
Understanding the 'Ground' Work
The coverage is offered continuously, as the cellular phone user keeps moving, and enters from one cell range to another. When the instrument crosses over the borders, it actually transmits a signal to the Mobile Telephone Switching Office. The control channel in the database of the Mobile Telephone Switching Office (MTSO) helps the Satphone to relocate within the new cell area or coverage range. These phones use the LEOS that are registered for usage of a particular company. Whenever a Satphone is switched on, the instrument transmits a signal to the satellites of the designated or registered group, that the phone company is affiliated to.
The 'Satellite Angle'
While using a Satphone, when a person uses the handset, he or she unknowingly sends up a signal to the nearest orbiting satellite, which in turn, connects to the ground station or 'gateway'. The ground station then connects the call to the destination number. It is basically a mobile handset that enables the user to communicate via direct connectivity with the communication satellites orbiting the earth. The range or coverage offered by each of the Satphone companies, largely depends on the infrastructure and architecture of the particular system. The coverage may hence, be applicable anywhere around the globe or restricted to use within specific regions.
The Satphone mobile equipment is also referred to as the connecting terminal or ground station. It varies widely and the existent range of handsets come in a size and weight not very different from the earlier ones, but today they flaunt a retractable antenna. It is very popular on expeditions and journeys, in which they are taken to some remote areas. The users enjoy a connectivity with the outside world even in regions or areas where regular terrestrial cellular service is not available. The equipment also includes a fixed installation. The ship-board usually includes rack-mounted electronics and a steerable antenna. The purpose is to automatically track the overhead satellites.
The Satphones are not very popular with users for their indoor connectivity. The possibility of a consistent signal near a window exists, only if the roof is sufficiently thin. They come with 'connectors' for external antennae. These are installed in vehicles and buildings tops. These phones are connected via special 'country calling codes'. Some Satphones enjoy connectivity via satellites in the geo-synchronous orbit of the Earth and thus, a global coverage! The disadvantage of Geo-stationary system is that the required 'sight' between the phone and the satellite, is obstructed in the presence of hills and forest cover, and the user has to locate higher ground to be able to effectively use the phone. In the Low Earth Orbit service, the obstacle ceases to remain one, as soon as another satellite passes overhead.
The Satphone is built under license and contract, while the OEM operators influence the selling price. The cost of calls is usually quite high.