Satellite phone
Therefore, they can work in most geographic locations on the Earth's surface, as long as open sky and the line-of-sight between the phone and the satellite are provided.
Satellite phones provide similar functionality to terrestrial mobile telephones; voice calling, text messaging, and low-bandwidth Internet access are supported through most systems.
The advantage of a satellite phone is that it can be used in such regions where local terrestrial communication infrastructures, such as landline and cellular networks, are not available.
[3][4] A fixed installation such as one used aboard a ship may include large, rugged, rack-mounted electronics, and a steerable microwave antenna on the mast that automatically tracks the overhead satellites.
Smaller installations using VoIP over a two-way satellite broadband service such as BGAN or VSAT bring the costs within the reach of leisure vessel owners.
Internet service satellite phones have notoriously poor reception indoors, though it may be possible to get a consistent signal near a window or in the top floor of a building if the roof is sufficiently thin.
The satellites orbit at an altitude of 35,786 kilometres (22,236 mi) above the Earth's surface; a noticeable delay is present while making a phone call or using data services due to the large distance from users.
Both systems, based in the United States, started in the late 1990s, but soon went into bankruptcy after failing to gain enough subscribers to fund launch costs.
They are now operated by new owners who bought the assets for a fraction of their original cost and are now both planning to launch replacement constellations supporting higher bandwidth.
The service is aimed to provide dead-zone cell phone coverage across the US using existing midband PCS spectrum that T-Mobile owns.
[10] T-Mobile has offered to extend the offering globally if cellular carriers in other countries wish to exchange roaming services via the T-Mobile partnership with SpaceX, with other carriers working with their regulators to enable midband communications landing rights on a country-by-country basis.
[10] LEO systems have the ability to track a mobile unit's location using Doppler navigation from the satellite.
Satellite phones are sometimes subsidised by the provider if one signs a post-paid contract, but subsidies are usually only a few hundred dollars or less.
Since most satellite phones are built under license or the manufacturing of handsets is contracted out to OEMs, operators have a large influence over the selling price.
Rates from landlines and mobile phones range from $3 to $14 per minute with Iridium, Thuraya[18] and Inmarsat being some of the most expensive networks to call.
Some satellite phone networks provide a one-way paging channel to alert users in poor coverage areas (such as indoors) of the incoming call.
[19] Their signals will usually bypass local telecoms systems, hindering censorship and wiretapping attempts, which has led some intelligence agencies to believe that satellite phones aid terrorist activity.
Most mobile telephone networks operate close to capacity during normal times, and large spikes in call volumes caused by widespread emergencies often overload the systems when they are needed most.
In the early 2020s, manufacturers began to integrate satellite connectivity into smartphone devices for use in remote areas, out of the cellular network range.
Three years later, in 2021, Thuraya launched its second bi-type satellite plus cellular phone, the XT Lite, a reviewed of the X5 model.
[51][52][53][54] In 2022, AST SpaceMobile started building a 3GPP standard-based cellular space network to allow existing, unmodified smartphones to connect to satellites in areas with coverage gaps.
Scheduled for launch in 2026, the service provides messaging, emergency communications and IoT for devices like cars, smartphones, tablets and related consumer applications.
