How Globalstar Works
Globalstar phones look and act like mobile or fixed phones with which you’re familiar. The difference is that they can operate virtually anywhere, carrying your call / data over an exceptionally clear, secure Code Division Multiple Access (CDMA) satellite signal.
Like “bent-pipes”, or mirrors in the sky, the Globalstar constellation of Low Earth Orbiting (LEO) satellites picks up signals from over 80% of the Earth’s surface, everywhere outside the extreme polar regions and some mid-ocean regions. Once the second-generation constellation is fully deployed and operational, several satellites can pick up a call, and this “path diversity” helps assure that the call is not dropped even if a phone moves out of sight of one of the satellites.
As soon as a second satellite picks up the signal and is able to contact the same terrestrial gateway, it begins to simultaneously transmit. If buildings or terrain block your phone signal, this “soft-handoff” prevents call interruption. The second satellite now maintains transmission of the original signal to the terrestrial “gateway”.
Additional advantages of using Low Earth Orbiting (LEO) satellites within the Globalstar system include no perceptible voice delay (latency) and lighter / smaller all-in-one phones.
Gateways process calls, then distribute them to existing fixed and cellular local telephone networks or the Internet. Terrestrial gateways are an important part of Globalstar’s strategy to keep key technology and equipment easily accessible and to integrate our services as closely as possible with existing local telephony networks. This helps makes the Globalstar system and its services easier to manage, expand and improve.
Gateways are an integral part of the Globalstar ground segment. In addition to the gateways the ground segment includes the Ground Operations Control Center(GOCC), Satellite Operations Control Center (SOCC), and Globalstar Data Network (GDN).
Each gateway, which is owned and managed by the service provider for the country in which the gateway is located, receives transmissions from orbiting satellites, processes calls, and switches them to the appropriate ground network.
A gateway may service more than one country. Gateways consist of three or four dish antennas, a switching station and remote operating controls. Because all of the switches and complex hardware are located on the ground, it is easier for Globalstar to maintain and upgrade its system than it is for systems that handle switching in orbit.
Gateways offer seamless integration with local and regional telephony and wireless networks. They utilize a standard T1/E1 interface to the existing PSTN/PLMN systems. Encryption ensures voice and signaling security for individual transmissions.
Ground Operations Control Center (GOCC) Is responsible for planning and controlling the use of satellites by gateway terminals and for coordinating with the Satellite Operations Control Center (SOCC). The GOCC plans the communications schedule for the gateways and controls the allocation of satellite resources to each gateway.
Satellite Operations Control Center (SOCC) Manages the Globalstar satellite constellation. The SOCC tracks satellites, controls their orbits, and provides telemetry and command (T&C) services for the constellation. Globalstar satellites continuously transmit spacecraft telemetry data that provides on-board health and status reports for the satellites. The SOCC also oversees satellite launch and deployment activities. The SOCC and GOCC facilities remain in constant contact through the Globalstar Data Network (GDN).
Globalstar Data Network (GDN) Is the connective network, which provides wide-area intercommunications facilities for the Gateways, Ground Operations Control Center, and Satellite Operations Control Center.
The Globalstar second-generation constellation will consist of 32 Low Earth Orbiting (LEO) satellites.
The Globalstar satellite is simple; Each consists of a communications system of both S and L-band antennas, a trapezoidal body, two solar arrays and each satellite operates at an altitude of 1,414km (approximately 876 miles). The second-generation satellites are manufactured by Thales Alenia Space.
The satellites utilize “bent-pipe” architecture. On any given call, several satellites transmit a caller’s signal via CDMA technology to a satellite dish at the appropriate gateway where the call is then routed locally through the terrestrial telecommunications system.
The system’s software resides on the ground, not on the satellites, which means fast and easier system maintenance and upgrades.
The Satellite Operations Control Center (SOCC) manages the Globalstar satellite constellation.
Globalstar – Simulation of Fully Functional Satellite Network