GPS - IIF Military Satellite

The next-generation Global Positioning System (GPS) IIF military satellites are built byBoeing to provide improved war fighting capabilities for the US Department of Defense(DoD) and its allied defense forces.

GPS III (Global Positioning System III) is a military communication satellite designed andbeing manufactured by Lockheed Martin Space Systems (LMSS) for the United States AirForce (USAF).

The satellite will provide modern anti-jam potentialities, superior system security,accuracy, reliability and meliorated position, navigation and timing (PNT) services.

The integration of an international civil signal (L1C) will allow the spacecraft to beinteroperable with global navigation satellite systems.

The GPS IIF satellite features a central aluminum core mounting six aluminum honeycombpanels.

The satellites provide increased capability, improved mission performance and accuracyand enhanced anti-jamming capability and security in hostile environments.

Each satellite is 2.23m high, 2.48m wide, 2.03m deep and weighs 3,230lb on-orbit. It isdesigned for a lifespan of 12 years and provides variable power options.

The thermal control systems include thermal coatings, radiator blankets and electrically-controlled heaters.

The space-ground link system (SGLS) uses S-bands for both up-link transmission anddown-link reception.

The GPS IIF satellites are powered by two Aero jet Rocket dyne engines.

The propulsion system also consists of 320lb hydrazine (N2H4) monopropellant, twelve 1lbrocket engine assemblies (REAs) and four 5lb REAs.

The satellite can operate at an altitude of about 10,898nmi.

The satellite is also equipped with NiH2 rechargeable battery system and three-panelimproved triple junction GaAs solar arrays, which produce a power of 1.9kW.

The GPS III will be equipped with a nickel hydrogen rechargeable battery, bipropellanthydrazine propulsion system, NTO oxidizer, 100lbs liquid apogee engines, unified S-bandtransponder, network communication element (NCE), navigation payload element (NPE),hosted payload element and antenna subsystem element.

The GPS IIF satellite is equipped with two radiation-hardened rubidium atomic clocks andone cesium clock with high stability timing to provide superior navigational accuracy.

The navigation payloads also include a radiation-hardened 32-bit (RH-32) central processor,ADA HOL, full message encoding and processing techniques.

GPS III will use the A2100 satellite bus, a fully redundant flight proven spacecraft busdesigned and being built by Skunk Works at the Astro Space East Windsor facility, in NewJersey.

The A2100 will provide mobile communications, direct broadcast, multimedia, high-speedbroadband and business services. The bus will house an attitude control system, electricalpower system, thermal control system, propulsion system and mechanical system.

http://www.airforce-technology.com/projects/gps-iii-military-satellite/

http://www.airforce-technology.com/projects/global-positioning-system-gps-iif-military-satellite/

http://www.lockheedmartin.co.in/us/products/gps.html

http://en.wikipedia.org/wiki/GPS_(satellite)