The wideband global SATCOM (WGS) system is a high-capacity communication satellite, previously known as the wideband gapfiller satellite system.
It is principally designed and developed for the US Department of Defence (DoD).
"The WGS satellites operate in the programmed X and Ka-band frequency spectrum."
WGS systems feature digitally channelised transponded satellites that provide communication capacity, connectivity and flexibility to the US military forces.
These satellites operate in the programmed X and Ka-band frequency spectrum.
A team led by Boeing Integrated Defence Systems was awarded a contract to develop the WGS system in 2001. The contract was worth $160.3m, and is extendible up to $1.3bn.
Boeing’s team have agreed to supply the satellites, spacecraft, and payload control equipment under the deal, as well as logistics, training and sustained engineering support.
WGS systems enhance the DoD’s communication services currently provided by the defence satellite communications system (DSCS) satellites and the global broadcast system (GBS) operating at ultra high frequency (UHF).
The system provides two-way X-band and Ka-band communications, as well as Ka-band broadcast services to US armed forces and other allied forces worldwide X-band satellites transfer data, photos and videos to troops on the battlefield.
Boeing conducted ground test for a Ka-band SATCOM antenna system for installation in the spacecraft in January 2011.
The WGS satellite communication system has six satellites divided into two blocks. Block I contains WGS-1, WGS-2 and WGS-3 satellites, while block II satellites include WGS-4, WGS-5 and WGS-6.
The Australian Government provided A$927m (US$822.7m) in funding for ground infrastructure of the sixth WGS satellite under a memorandum of understanding (MoU) signed with the DoD in 2007.
In return, the Australian Defence Ministry was given access to the data sent by the sixth satellite, which was developed to increase the bandwidth capacity of US forces.
HX System (for mobiles and airborne / maritime communications) of Hughes Network Systems was granted Wideband Global SATCOM (WGS) certification by the US Strategic Command in November 2010.
Wideband Global Satcom (WGS) satellites
WGS systems comprise three main segments: space, terminal and control. The space segment refers to satellites in orbit; WGS-1 was launched into orbit on 10 October 2007 on the United Launch Alliance (ULA) Atlas V launch vehicle.
After the launch, the military designated the WGS-1 as USA-195, which entered service in April 2008. The WGS-1 satellite operates over the Pacific region.
Boeing successfully launched the WGS-2 into geostationary orbit on the Atlas V in April 2009. The WGS-2 satellite was designated as USA-204, and entered service in August 2009.
The satellite operates in the Indian Ocean region and provides high-capacity communication links to US troops in Iraq and Afghanistan.
Both satellites were launched from Space Launch Complex 41 of Cape Canaveral Air Force Base.
The WGS-3 satellite was delivered to Cape Canaveral Air Force Station, Florida, on 28 September 2009, and successfully launched in December 2009 on a ULA Delta IV vehicle from Space Launch Complex 41.
It is positioned over the Eastern Atlantic at an orbital slot of 12°> West longitude to operate in the Atlantic region.
The WGS-4 was launched atop the same vehicle and at the same location in January 2012 and was accepted by the US Air Force in April 2012. It was followed by the launch of the WGS-5 in May 2013 and that of the WGS-6 in August 2013.
The WGS-6 was delivered to the US Air Force in December 2013.
The block II satellites meet the bandwidth requirements of war-fighters, thereby providing information exchange, enabling execution of tactical command and control, communications and computers, intelligence, surveillance, reconnaissance (C4ISR), battle management and combat support information.
Boeing received a $182m order from the US Air Force in August 2010 for the seventh wideband satellite under WGS Block II programme.
The US Air Force extended the order value to $1.09bn in September 2011 to facilitate the production, launch and on-orbit activation of the seventh satellite, and also to procure the long lead materials for an eighth WGS satellite. The US Air Force subsequently exercised its option for two more satellites, WGS-8 and WGS-9, under a $673m contract in January 2012.
WGS-7 and WGS-8 were launched in July 2015 and December 2016, respectively while WGS-9 is expected to be launched in 2017.
WGS-9 is being funded through an international partnership consisting of the US Air Force, Canada, Denmark, the Netherlands, Luxemberg and New Zealand.
Block II satellites feature a radio frequency bypass capability, which is designed to support airborne intelligence, surveillance and reconnaissance platforms that require ultra-high bandwidth, as well as the data rates demanded by unmanned aerial vehicles.
The terminal segment refers to the users of the communication services provided by the WGS system.
Users of the WGS system include the Australian Defence Force and the US Army ground mobile terminals, the US Navy ships and submarines, and national command authorities for the nuclear forces, in addition to various national security / allied national forces.
The satellite operators come under the control segment. The 3rd Space Operations Squadron (SOPS) located at Schriever AFB, Colorado, manages bus commanding of the DSCS constellation.
Payload commanding and network control are managed by the army’s 53rd Signal Battalion at Peterson AFB, Colorado, with subordinate elements at seven locations.
WGS-2 is operated by 3rd SOPS at 50th Space Wing, Schriever AFB, under the operational command of JFCC SPACE at Vandenberg.
Capacity of WGS satellites
WGS system provides 4.875GHz instantaneous switchable bandwidth. Around 500MHz of X-band and 1GHz Ka-band spectrum is allocated to WGS.
Each satellite of WGS system provides 2.1Gbps to 3.6Gbps of data transmission rates, based on the mix of ground terminals, data rates and modulation schemes employed,. Each WGS system also has the capacity to supply data transmission rates ten times faster than DSCS service life enhancement programme (SLEP) satellites.
Connectivity of the US satellites
The breakage of uplink bandwidth into approximately 1,900 independently routable 2.6MHz subchannels by a digital channeliser has increased the connectivity between uplink and downlink coverage areas.
Both the X and Ka bands are interconnected through a digital channeliser and provide better connectivity in WGS. The digital channeliser also offers multicast and broadcast services to support the network protocol.
The WGS satellites were built on a Boeing 702 spacecraft with 13kW of power and flexible coverage areas.
The Boeing 702 uses advanced technologies in propulsion, power generation and thermal control, and has the ability to connect X-band and Ka-band users within the coverage field of view via reconfigurable antennas and a digital channeliser.
Rocket launcher and orbital launch vehicles used
Atlas V is equipped with 4m-diameter payload fairing, two solid rocket motors and a single-engine Centaur upper stage, attached to a single common core booster (CCB) powered by a RD-180 engine.
Delta IV is an orbital launch vehicle equipped with 5m-diameter payload fairing and three CCBs, which are powered by a Rocketdyne RS-68 engine. It is available in different medium models: medium+ (4,2), medium+ (5,2). medium+ (5,4) and heavy.
The models are differentiated depending on the specific payload size and weight ranges.
Ground station for the US Wideband Global Satcom (WGS) satellites
The satellites launched into orbit are controlled through four army wideband satellite operations centres (WSOCs) on the ground, using ground equipment hardware and software developed by Boeing, ITT Industries and Raytheon.
"A team led by Boeing Integrated Defence Systems was awarded a contract to develop the WGS system in 2001."
Three satellites operating in X-band and Ka-band can be controlled and tracked by a global satellite configuration and control element (GSCCE), using a telemetry tracking and command links (TT&C) system.
The telemetry tracking and command system is a technology primarily used to locate and control the satellite from deviating its orbit.
The third SOPS controls the spacecraft platform via unique software and databases designed by Boeing, and fitted on the command and control segment consolidated (CCS-C) systems supplied by Integral Systems.
Boeing’s team of contractors includes Harris Corporation, ITT Industries, Logicon and SAIC.
Harris provides satellite communications ground terminals, and terminal and payload interfaces, while ITT Industries supplies communications network and control systems.
Logicon provides communications software and SAIC extends engineering and communications architectures.
CAPE CANAVERAL — An antenna-covered communications spacecraft that will bring more bandwidth and capacity to the U.S. military’s global information grid than any single satellite ever before was successfully launched Wednesday atop a Delta 4 rocket.
United Launch Alliance delivered the Wideband Global SATCOM satellite No. 8 into space for the U.S. Air Force following a 42-minute flight of the powerful rocket.
The two-stage Delta 4 was fueled during an uneventful afternoon countdown, then lit its hydrogen-fed main engine and four side-mounted solid-propellant boosters to depart Cape Canaveral right on schedule at 6:53 p.m. EST (2353 GMT).
Two burns of the cryogenic upper stage achieved a highly elliptical super-synchronous orbit stretching more than 27,000 statute miles in altitude, releasing the 13,000-pound payload while flying above the western Indian Ocean, just off the coast of Madagascar.
It marked the 107th successful launch in a row for the Delta program since 1999, the 360th success overall since 1960 and the 34th for a Delta 4.
United Launch Alliance also extended its mission record to 114 and completed its 45th mission for the Air Force in the past 120 months.
“As a former airman, I truly understand the importance of delivering national assets like the WGS 8 satellite to orbit safely,” said Laura McGinnis, United Launch Alliance’s vice president for Custom Services.
“We are proud of our partnership with the Air Force and proud to be entrusted by them to again deliver one of our nation’s most critical assets to orbit.”
Built by The Boeing Co., this latest WGS satellite features a technology advancement — the first Wideband Digital Channelizer at the heart of its communications package — that nearly doubles its capacity compared to the previous sister-spacecraft in the series.
“The channelizer on WGS 8 essentially performs the same function as WGS 1 through 7. It is a router in orbit. It basically takes radio frequency input from the ground, converts that to digital and then is able to route and move things around,” said Rico Attanasio, director of Boeing’s MILSATCOM programs.
“On WGS 8, we were able to transition the channelizer from its predecessor to the next-generation ASIC technology…provided by IBM to us. That improved our processing capability on board the spacecraft and we were able to open up more availability and routes of information through that router. By opening up those additional routes, we provided additional flexibility and more available bandwidth to the user.”
A single WGS satellite can support data processing at 6 gigabits per second, and WGS 8 with its advanced channelizer will support over 11 Gbps, officials said.
The WGS 8 satellite is valued at $426 million, including the new channelizer for the capacity upgrade.
All of that extra bandwidth can be utilized by any user within the satellite’s footprint.
“The capacity is available to any tactical warfighter and it’s up to the operators, who are the Army, to assign the use of bandwidth. That’s exactly the same (way) that we utilize WGS 1 through 7,” said Charlotte Gerhart, the Air Force’s WGS 8 program manager.
“So we’re simply making more bandwidth available and it will go to the users who are in that area. There’s no specific user who is targeted and there’s no specific area. Wherever WGS 8 is and whatever capacity is requested, the system will provide it.”
WGS is the backbone of the military’s global communications infrastructure for troops on the ground, aircraft in the sky, ships at sea, the White House Communications Agency and the State Department.
The system transmits high-priority communications such as the exchange of war-fighting information between battlefield commanders on the ground and senior defense officials.
“The WGS constellation provides wideband communications to Soldiers, Sailors, Airmen and Marines and international partners (for) broadcast, multicast and point-to-point connections anytime, anywhere around the world,” said Thomas Becht, civilian deputy director and business manager for the Air Force’s Military Satellite Communications Systems Directorate at the Space and Missile Systems Center in Los Angeles.
“WGS is unique among military satellites because it can simultaneously support X- and Ka-band communications and seamlessly connect the two bands.”
WGS uses the Boeing 702HP satellite design, which includes a xenon-ion propulsion system, highly efficient triple-junction gallium arsenide solar cells and deployable radiators with flexible heat pipes.
The WGS satellites place shaped, steerable spotbeams of bandwidth wherever requested across its field-of-view for Ka- and X-band frequencies, plus the onboard capability to switch signals from one band to the other.
Each satellite has electrically-steerable, phased array antennas for X-band transmitting and receiving, mechanically-steered Ka-band antennas and a fixed full-Earth-coverage beam also in X-band.
The antennas provide 19 independent coverage areas — 10 Ka-band and 8 X-band spotbeams, plus the full-Earth footprint.
WGS 8 will spend the next three months being maneuvered from its current transfer orbit into a circular one by controllers at Boeing’s satellite facility in El Segundo, California. The orbit raising activities will use both conventional hydrazine engines as well as ion propulsion thrusters.
Boeing will oversee the craft’s solar array and antenna deployments, plus complete an initial round of testing before WGS 8 is handed over to the Air Force for its own round of checkouts and final positioning in orbit.
The solar arrays will stretch 135 feet tip-to-tip, a wingspan larger than a Boeing 737 but smaller than a Boeing 747.
This satellite will operate at a yet-undisclosed location in geostationary orbit 22,300 miles above the equator, matching Earth’s rotation and remaining in lockstep over a specific spot of the globe.
“The information age has resulted in an explosion of communications demand capability for everyone globally. And for our armed forces and DOD users, wideband communications is vitally important to executing missions that defend and protect the people of the United States and our interests. More and more, WGS is called upon to deliver reliable, high-data-rate communications anywhere in the world, sometimes in contested environments,” said Attanasio.
“In addition to the technical advancements made on WGS 8, the entire WGS system is currently undergoing resilience upgrades that are being enabled across the fleet to better protect communications from interference and signal jamming.”
Those upgrades have involved uplinking new operating software to the orbiting satellites and modifying the ground segment. And the phased arrays enable operators shape the beams and control power to avoid intentional or accidental interference.
The first five WGS satellites formed a constellation for global coverage. The subsequent spacecraft have beefed up and expanded capacity of the network with overlapping orbital slots.
Two more WGS craft, each carrying the upgraded channelizer, will be launched by Delta 4 rockets in the next two years to punctuate the constellation.
WGS 9, built by international funding from Canada, Denmark, the Netherlands, Luxembourg and New Zealand, is preparing for shipment from its Los Angeles factory to Cape Canaveral for launch in March.
The allies bought the satellite in exchange for access to the entire constellation, similar to the groundbreaking deal with Australia that paid for the construction and launch of WGS 6.
“In accordance with the terms of the partnership, the international partners gained access to the WGS constellation upon enactment in 2012,” said Lt. Gen. Samuel Greaves, the Air Force’s program executive officer for space.
The final satellite — WGS 10 — has been manufactured and will soon start system-level testing for a late 2018 liftoff aboard the last “single-stick” Delta 4-Medium+ vehicle.
“You only need to look at the headlines today to see the events that will continue our military’s engagement across the globe. The enhancement of the WGS constellation will ensure that the U.S. and its allies can meet their committments,” said Walt Lauderdale, the WGS 8 launch vehicle lead and the technical director of the EELV generation and operations division within the Air Force’s Launch Systems Enterprise Directorate at the Space and Missile Systems Center in Los Angeles.
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