The U.S. Space Force exercised its second contract option valued at approximately $737 million for the procurement of three additional GPS III Follow On (GPS IIIF) space vehicles (SVs) from Lockheed Martin on Oct. 22, 2021. This contract option is for GPS IIIF satellites 15, 16 and 17 (SV15-17).
GPS IIIF satellites build off the innovative design of Lockheed Martin’s next generation GPS III satellites (SV 01-10), which provide three times greater accuracy, up to eight times improved anti-jamming capability and increased resiliency, in addition to modernization, compared to legacy GPS satellites in today’s constellation. GPS III also adds a new L1C civil signal that is compatible with other global navigation satellite systems, such as Galileo.
“GPS IIIF satellites will add new capabilities and advanced technology to the GPS constellation, including Regional Military Protection (RMP); an upgraded Nuclear Detection Detonation System (NDS) payload; a safety-improving Search and Rescue payload; and an accuracy-enhancing Laser Retroreflector Array (LRA),” said Dave Hatch, Lockheed Martin’s GPS IIIF program management director. “The RMP capability further reinforces GPS III/IIIF as a warfighting system, providing up to 60x greater anti-jamming for our warfighters operating in contested environments.”
The GPS IIIF SV11-12 satellites were included in the original September 2018 GPS IIIF contract award to Lockheed Martin to build up to 22 GPS IIIF satellites. Under that contract, the government exercised the first GPS IIIF production option for SV13-14 in October 2020.
GPS IIIF SV13 and beyond will incorporate the company’s LM2100 Combat Bus, an enhanced space vehicle that provides even greater resiliency and cyber-hardening against growing threats, as well as improved spacecraft power, propulsion and electronics. This evolved bus incorporates many common components and procedures to streamline manufacturing. LM2100 Combat Bus vehicles are also capable of hosting Lockheed Martin’s Augmentation System Port Interface (ASPIN), which would allow for future on-orbit servicing and upgrade opportunities.
Today Lockheed Martin is close to finishing production on the original GPS III SV1-10 contract. GPS III SV01-05 have been launched and handed over to the Space Force for on-orbit operations. GPS III SV06-08 have been completed and placed in storage at the company’s facility waiting for the Space Force to call them up for launch. SV09 is a fully integrated space vehicle now going through final testing.
On October 26, 2021, the final GPS III satellite of the original GPS III contract – GPS III SV10 – completed an operation known as “core mate” to assemble it into a full space vehicle at Lockheed Martin’s GPS III Processing Facility. It will proceed into the vehicle testing campaign before year-end.
The U.S. Space Force’s Space Systems Command recently declared GPS III SV06, SV07 and SV08 satellites “Available for Launch.” Here, the space vehicles await official call up for launch in Lockheed Martin’s GPS III Processing Facility in Waterton, Colorado. (Photo: Lockheed Martin)
The U.S. Space Force’s Space Systems Command recently declared the eighth GPS III satellite as “Available for Launch.” This significant accomplishment officially marks the third space vehicle within the GPS III program to be declared available for launch in the past three months.
GPS III SV06, SV07, and SV08 are now awaiting official call up for launch in Lockheed Martin’s GPS III Processing Facility in Waterton, Colorado.
“SV06, SV07, and SV08 AFL milestones in just three months prove that GPS III production continues to benefit from efficiencies with each satellite delivery,” said Col. Edward Byrne, chief of SSC’s Space Production Corps’ Medium Earth Orbit Space Systems Division.
The first of the three recently completed satellites, SV06, is scheduled to launch in 2022 and will join the operational constellation of 31 GPS satellites.
GPS III satellites deliver enhanced performance and accuracy through a variety of improvements, including increased signal protection and improved accuracy. GPS III also expands the civilian L5 signal, dubbed the “safety-of-life” signal, currently broadcast by the 12 GPS IIF satellites, but not yet operational, and delivers a new L1C signal designed to grant interoperability to similar international space-based positioning, navigation, and timing systems around the world.
Space Systems Command, located at Los Angeles Air Force Base in El Segundo, California, is the U.S. Space Force’s Center of Excellence for acquiring and developing military space systems. SSC’s portfolio includes space launch, global navigation satellite systems, military satellite communications, a defense meteorological satellite control network, range systems, space-based infrared systems, and space domain awareness capabilities.
The U.S. Space Force’s Space Systems Command recently declared GPS III SV06, SV07 and SV08 satellites “Available for Launch.” Here, the space vehicles await official call up for launch in Lockheed Martin’s GPS III Processing Facility in Waterton, Colorado. (Photo: Lockheed Martin)
The U.S. Space Force’s Space Systems Command has declared the eighth GPS III satellite “Available for Launch.” This milestone marks the third space vehicle within the GPS III program to be declared available for launch in the past three months.
The next three GPS III satellites — SV06, SV07 and SV08 — are now awaiting official call up for launch in Lockheed Martin’s GPS III Processing Facility in Waterton, Colorado.
“SV06, SV07, and SV08 AFL milestones in just three months prove that GPS III production continues to benefit from efficiencies with each satellite delivery,” said Col. Edward Byrne, chief of SSC’s Space Production Corps’ Medium Earth Orbit Space Systems Division.
The first of the three recently completed satellites, SV06, is scheduled to launch in 2022 and will join the operational constellation of 31 GPS satellites.
GPS III satellites deliver enhanced performance and accuracy through a variety of improvements, including increased signal protection and improved accuracy.
GPS III also expands the civilian L5 signal, dubbed the “safety-of-life” signal, currently broadcast by the 12 GPS IIF satellites, but not yet operational, and delivers a new L1C signal designed to grant interoperability to similar international space-based position, navigation and timing (PNT) systems around the world.
As a crucial technological foundation for internet, financial, transportation and agricultural operations, GPS delivers the gold standard in positioning, navigation, and timing services supporting U.S. and allied operations worldwide.
Space Systems Command, located at Los Angeles Air Force Base in El Segundo, California, is the U.S. Space Force’s Center of Excellence for acquiring and developing military space systems. SSC’s portfolio includes space launch, global positioning systems, military satellite communications, a defense meteorological satellite control network, range systems, space-based infrared systems, and space domain awareness capabilities.
Orolia Defense & Security delivers M-code-enabled timing and synchronization to Lockheed Martin
In September 2019, Lockheed Martin was awarded a contract to develop the U.S. Army’s Sentinel A4 radar system, an air and missile defense radar that will provide improved capability against dynamic threats.
The following November, Orolia Defense & Security announced the availability of M-code military GPS receivers in its flagship SecureSync — the first time server approved by the Defense Information Systems Agency.
Orolia is supplying SecureSync units for Lockheed Martin’s Sentinel A4 radar. (Photo U.S. Army)
This May, Orolia delivered a shipment of M-code-enabled SecureSync mission timing and synchronization units to Lockheed Martin, marking a key milestone for the Army program. SecureSync with M-code provides enhanced resilient positioning, navigation and timing (PNT) capabilities and improved resistance to existing and emerging GPS threats, such as jamming and spoofing.
Lockheed Martin selected Orolia’s SecureSync M-code as the A4 system’s resilient time and frequency reference solution in part due to its modular, open architecture – the same characteristics that are the cornerstone of the radar’s design – making integration a simple process and ensuring future upgrades.
“As a trusted Lockheed Martin partner, Orolia is proud to support the development of the Sentinel A4, which will be a key asset to our warfighters for decades to come,” said Hironori Sasaki, president of Orolia Defense & Security. “Making M-code available now in a readily configurable and scalable form factor is a critical step in advancing our forces out in the field, whether in the air or on the ground,” Sasaki added.
The next-generation of U.S. military systems are fortified with M-code, and Orolia leads the industry in M-code solutions for navigation warfare (NAVWAR) environments.
Orolia is supplying SecureSync units for Lockheed Martin’s Sentinel A4 radar. (Photo U.S. Army)Image: Orolia
SpaceX launched into orbit for the U.S. Space Force the fifth GPS III satellite (SV05) on June 17.
Photo: U.S. Space Force
GPS III SV05 eventually will replace one of the legacy GPS IIR satellites. Once GPS III SV05 is operational, about 16% of the 31-satellite constellation will be modernized with GPS III’s new capabilities.
M-Code Requirement Met
GPS III SV05 is the 24th M-code satellite on orbit, completing the constellation’s baseline requirement to provide U.S. military forces a more-secure, harder-to-jam and spoof GPS signal.
GPS III SV05 is the fifth Lockheed Martin-built, next-generation GPS III space vehicle. The SpaceX Falcon 9 rocket is the first U.S. Space Force mission to reuse a previously-flown booster, the company said.
The U.S. Space Force contracted Lockheed Martin to design and build GPS III/GPS IIIF satellites to help modernize today’s GPS satellite constellation with new technology and advanced capabilities. Lockheed Martin said the GPS III provides three-times greater accuracy, eight times improved anti-jamming capability for U.S. military forces; a new L1C civil signal to the constellation that is compatible with other GNSS; and a new modular design that allows new technology and capabilities to be added in the future to better address changing mission needs and emerging threats.
Future GPS III Satellites
GPS III Space Vehicles 06, 07 and 08 already are complete and waiting to be called up for their launch dates, which are to be determined.
In addition, GPS III SV09 was core-mated, meaning it reached a major production milestone in which two major satellite components — the mission module and the propulsion core — are paired to form one space vehicle. The GPS III SV10 currently is in the component build up stage.
Lockheed Martin has been contracted to design and build up to 22 additional GPS III Follow On – or GPS IIIF – satellites (SV11-32), with even more capabilities. Contract options for the first four GPS IIIFs, SV11-14, have been exercised so far.
The U.S. Space Force contracted Lockheed Martin to design and build GPS III/GPS IIIF to help modernize today’s GPS satellite constellation. Photo: Lockheed Martin
The fifth GPS III satellite was encapsulated within a SpaceX payload fairing on June 9 in preparation for its June 17 launch.
The U.S. Space Force’s Space and Missile Systems Center’s Lockheed Martin-built GPS III Space Vehicle 05 satellite was encapsulated within a SpaceX payload fairing at Astrotech Space Operations Florida facility on June 9 in preparation for launch, scheduled for June 17 from Cape Canaveral Space Force Station.
The 15-minute launch window opens 12:09 p.m. EDT. If SpaceX provides a live feed to view the launch, it will be available here.
Encapsulation of the satellite within the payload fairing protects the satellite from the impact of dynamic pressure and aerodynamic heating during its harrowing journey through the earth’s atmosphere, and supports the ability to communicate with the satellite until separation from the launch vehicle on orbit.
“The GPS III program continues to make strides in modernizing the GPS constellation for the United States Space Force, maintaining the ‘gold standard’ for position, navigation and timing,” said Col. Edward Byrne, Medium Earth Orbit Space Systems division chief, “SV05 is not only the first-ever USSF satellite launched on a previously flown booster, but also is the 24th military-code (M-xode) satellite introduced to our constellation, the last needed to bring M-code to full operational capability.”
GPS III SV05 will join the current 31-satellite operational constellation to continue to provide the gold standard in positioning, navigation and timing services for more than four billion users worldwide.
The Space and Missile Systems Center, located at Los Angeles Air Force Base in El Segundo, California, is the U.S. Space Force’s center of acquisition excellence for acquiring and developing military space systems. Its portfolio includes the development of advanced space and launch capability and systems, global navigation satellite systems, military satellite communications, defense meteorological satellites, space launch and range systems, satellite control networks, space-based infrared systems, and space situational awareness capabilities.
GPS III SV05 is encapsulated within a SpaceX payload fairing at Astrotech Space Operations Florida in preparation for its June 17 launch. (Photo: Lockheed Martin)
GPS III Space Vehicle (SV) 05 was transported from the Lockheed Martin facility in Waterton, Colorado, to the Space Coast Regional Airport in Titusville, Florida, by a C-17 Globemaster III crew from Joint Base Lewis-McChord, Washington. Lockheed Martin is the contractor for construction of the GPS III satellites.
Now that the satellite has arrived at the Astrotech Space Operations facility, the latest addition to the GPS constellation modernization effort will begin final testing and checkout before the launch. While at Astrotech, it will undergo final post-ship functional testing, be fueled with onboard propellant, and then be encapsulated for launch.
Once these tasks are accomplished, SV05 will be horizontally integrated with the first-ever SpaceX Falcon 9 launch vehicle to be reflown for a National Security Space Launch (NSSL) mission.
“SV05 is the third GPS III satellite shipped to the Cape in the last 14 months and marks a key step to our larger goal of GPS constellation modernization,” said Col. Edward Byrne, SMC’s Space Production Corps Medium Earth Orbit Space Systems Division chief. “As the fourth GPS III launch campaign with SpaceX, this NSSL mission is historic both for the first reflight of a Falcon 9 rocket and for being the 24th military-code (M-code) satellite introduced to our constellation, the last needed to bring M-code to full operational capability.”
Slated to launch in June, GPS III SV05 will join the operational constellation of 31 GPS satellites, delivering enhanced performance and accuracy through a variety of improvements.
Improvements include increased signal protection, L1C signal interoperability, and the newest civilian signal, L5. As a crucial technological foundation for internet, financial, transportation and agricultural operations, GPS delivers the gold standard in positioning, navigation and timing services supporting U.S. and allied operations worldwide.
The U.S. Space Force’s Space and Missile Systems Center, located at the Los Angeles Air Force Base in El Segundo, California, is the center of excellence for acquiring and developing military space systems. SMC’s portfolio includes space launch, global positioning systems, military satellite communications, a meteorological satellite control network, range systems, space-based infrared systems, and space situational awareness capabilities.
Lockheed Martin, the prime contractor for GPS III/IIIF, selected L3Harris in 2018 to design and build the first two fully-digital MDUs, the heart of the satellite’s navigation payload. (Artist rendering: Lockheed Martin)
L3Harris Technologies has received contracts totaling $137 million for four navigation payload Mission Data Units (MDU) for future GPS III Follow-On (GPS IIIF) satellites.
Lockheed Martin, the prime contractor for GPS III/IIIF, selected L3Harris in 2018 to design and build the first two fully-digital MDUs, the heart of the satellite’s navigation payload. The MDU generates more powerful GPS signals and assures clock operations for GPS users, L3Harris said.
“The digital MDU is flexible enough to adapt to advances in GPS technology and future changes in mission needs,” said Ed Zoiss, president, Space and Airborne Systems, L3Harris. “The new MDU will also support a smooth transition for the U.S. Space Force’s GPS OCX ground control segment.”
The U.S. Space Force expects the first GPS IIIF satellite, which builds on GPS III adding new capabilities and technology, to be available for launch in 2026. According to L3Harris, the GPS IIIF MDU will provide improved capabilities over L3Harris’ 70-percent-digital MDU on the first ten GPS III satellites. The first four GPS III satellites have successfully launched and are now operational in the GPS constellation.
L3Harris Technologies is a global aerospace and defense technology innovator, delivering end-to-end solutions that meet customers’ mission-critical needs. The company provides advanced defense and commercial technologies across air, land, sea, space and cyber domains.
The fourth GPS III satellite, space vehicle (SV) 04, received United States Space Force’s Operational Acceptance approval on Dec. 1.
Operational acceptance marks another significant milestone for the GPS III program, Space and Missile Systems Center and USSF, according to the Space Force. This is the fourth GPS III satellite delivered into the operational constellation in the past 12 months and the second in the past three months.
Also, this is the first GPS III vehicle delivered to the warfighter through an expedited satellite control authority transfer process, which cuts 10 days off the previous operational acceptance timeline.
One more to go for M-code capability
“With the onset of SV04, the GPS constellation continues moving forward in next generation modernization,” said Capt. Collin Dart, the 2 SOPS DOA flight commander. “The 2nd Space Operations Squadron is one step closer to providing military code (M-code) capability for the entire 24 satellite baseline.”
“The highly encrypted M-code to protect GPS signals from jamming and spoofing is currently enabled on 22 GPS satellites of various generations; 24 are needed to bring the M-code to the next level of operational capability,” Dart explained. “SV04 brings the constellation to 23 M-code capable vehicles. SV05 will launch no earlier than July 2021. This will add the 24th M-code capable vehicle.”
“M-code signals are more-secure, harder-to-jam and spoof, and are critical to helping our warfighters complete their missions, especially in contested environments,” said Tonya Ladwig, Lockheed Martin’s vice president for Navigation Systems. “GPS III is a warfighting system and we are proud to be helping bring this critical capability to the men and women protecting our nation.”
GPS III SV04 is encapsulated in its protective launch fairings. (Photo: 45th Space Wing Public Affairs)
Faster handover from contractor
SV04 also sets a new standard for handover from contractor Lockheed Martin’s launch team to operational acceptance, setting the satellite healthy to the global user community approximately 30 days post launch, according to Dart. “Moving forward with future GPS III launches, the timeline between launch and the satellite being set healthy will be at a minimum,” he said.
SV04 was launched on a SpaceX Falcon 9 Block 5 vehicle on Nov. 5. The Air Force has been flying 31 operational satellites for years to ensure the United States’ commitment to have 24 operational GPS satellites available 95% of the time.
GPS III SV04 joins this operational constellation of 31 GPS satellites orbiting in medium-Earth orbit. The system delivers improved accuracy, advanced anti-jam capabilities and increased resiliency for the GPS III constellation.
Lockheed Martin’s production proceeds
The Space Force declared GPS III SV05 “Available for Launch” in May. The satellite is waiting to be called up”for launch.
GPS III SV06, 07 and 08 are now fully assembled and going through environmental testing at Lockheed Martin’s GPS III Processing Facility in Denver.
GPS III SV09 and 10 are in component build up.
Lockheed Martin is also under contract for up to 22 additional GPS III Follow On (GPS IIIF) satellites, which introduce further technology and capabilities. In May, Lockheed Martin completed its Critical Design Review for the GPS IIIF and in July, the Space Force declared that GPS IIIF fulfilled “Milestone C,” which means the production phase of the program has officially begun.
“The operational acceptance of GPS III SV04 is another significant milestone for GPS Modernization, delivering critical new capabilities to our Military and Civil Users. We now have a total of 23 M-code spacecraft for our Warfighters. For our billions of civil users, it brings the count up to 23 L2C spacecraft and 16 L5 spacecraft,” said Col. Ryan Colburn, director of the SMC Portfolio Architect Office’s Spectrum Warfare Division. “For professional users with existing dual-frequency operations, L2C enables faster signal acquisition, enhanced reliability, and greater operating range. L5 is broadcast in a radio band reserved exclusively for aviation safety services. It features higher power, greater bandwidth, and an advanced signal design. Future aircraft will use L5 in combination with L1 C/A to improve accuracy (via ionospheric correction) and robustness (via signal redundancy). The operational acceptance of this spacecraft is another display of the fantastic teamwork across SMC’s Corps, Space Delta 8, National Geospatial-Intelligence Agency, Department of Transportation, Federal Aviation Administration, our industry partners and many others who work together to make these missions possible.”
GPS satellites provide position, navigation, and timing to more than four billion military and civilian users worldwide.
A Falcon 9 carrying GPS III SV04 lifts off from Cape Canaveral Air Force Station, Florida, Nov 5. (Photo: SpaceX via USAF)
UPDATE: The U.S. Space Force, Space and Missile Systems Center (SMC) and its mission partners successfully launched the fourth GPS III satellite at 6:24 p.m. EST Nov. 5 from Space Launch Complex 40 at Cape Canaveral Air Force Station, Florida.
The Lockheed Martin-built satellite was carried to orbit aboard a Space Exploration Technologies Corporation (SpaceX) Falcon 9 launch vehicle.
“The launch of GPS III SV04 is a testament to SMC’s ability to rapidly and safely deliver new capabilities on orbit,” said Cordell DeLaPena, Air Force program executive officer for SMC’s Space Production Corps. “At SMC, we are proud to deliver our fourth GPS III satellite and will continue to operate at an accelerated pace to enhance the capabilities of the billions of users worldwide.”
“I’m proud of my team’s 83rd successful National Security Space Launch and look forward to our future missions with SpaceX,” said Col. Robert Bongiovi, SMC’s Launch Enterprise director. “Ultimately, our ability to embrace innovation with our launch providers advances warfighter’s capabilities while lowering costs to the U.S. Government and its taxpayers.”
GPS III SV04 separated from its upper stage approximately 90 minutes after launch. Engineers and operators at Lockheed Martin’s Waterton Facility will now begin on-orbit checkout and tests, which are estimated to complete in approximately one month. Operational use is expected to begin in a few months.
“The GPS III program continues to make strides in modernizing the GPS constellation for the U. S. Space Force while maintaining the gold standard for position, navigation and timing,” said Col. Edward Byrne, Medium Earth Orbit Space Systems Division chief.
GPS III SV04 will join the current GPS constellation comprised of 31-operational spacecraft. GPS III, the newest generation of GPS satellites, brings new capabilities to users, including three times greater accuracy and up to eight times improved anti-jamming capabilities.
A Falcon 9 carrying GPS III SV04 lifts off from Cape Canaveral Air Force Station, Florida, Nov 5. (Photo: SpaceX via USAF)
GPS constellation status
According to the U.S. Space Force Second Space Operations Squadron (2 SOPS), the satellite is designated SVN-77/PRN-14 in the GPS almanac. GPS III SV04 (SVN-77/PRN-14) will replace SVN-44/PRN-28 in the B plane at slot 03. 2 SOPS will issue a Launch NANU after on-orbit checkout when control of SVN-77 is transferred from Lockheed Martin to 2 SOPS for insertion into the GPS control segment.
GPS III SV-2 (SVN 75), launched Aug. 22, 2019, replaced SVN 45/PRN-21 at D3 and was set healthy on April 1, 2020. As a result, SVN 45 is being re-phased from D3 to D2F replacing SVN 46/PRN 11 and will arrive sometime in November of this year. SVN 46 will be taken out of the operational constellation before the January 2021 launch of GPS III SV05 (SVN-78) and sent to Launch, Anomaly, Resolution, and Disposal Operations (LADO), making PRN-11 available.
GPS III SV-03 (SVN 76, PRN-23) launched June 30, 2020, and was set operational and healthy on October 1.
SVN-46, launched October 7, 1999, has been an “iron bird” workhorse in the D-plane and has successfully served the world’s GPS users for more than 20 years, 12 years past its designed service life. It outlasted (and in many cases, outperformed) many of its peers on-orbit, testament to quality engineering and the diligent efforts of the men and women of the U.S. Air Force.
Screenshot: SpaceX
The fourth GPS III satellite (GPS III SV04) is scheduled to launch today at 06:24 p.m. EST (~15 minute launch window) from Cape Canaveral Air Force Station, Florida, on a SpaceX Falcon 9 rocket. The new launch window follows an aborted launch with two seconds to go on Oct. 2.
Built by Lockheed Martin, GPS III satellites are designed to help the U.S. Space Force modernize the current GPS constellation with new technology and advanced capabilities. GPS III provides three times greater accuracy and up to eight times improved anti-jamming power over satellites in the current constellation. GPS III also adds a new L1C civil signal compatible with Europe’s Galileo global navigation satellite system, which will provide greater civil user connectivity in the future.
After adding GPS III SV04, the four GPS III satellites on orbit will represent about 12 percent of the 31 satellites in the GPS constellation.
GPS III SV04 is the 23rd M-code-enabled satellite in the constellation, only one short now of the 24 needed for global coverage. M-code is a more-secure, harder-to-jam or spoof signal invaluable to U.S. and allied military forces.
GPS III SV03, which lifted off from the Cape on June 30, was set operational on Oct. 1. The next satellite — GPS III SV05 — was declared “Available for Launch” in May 2020. The satellite is now waiting to be called up for a launch date in 2021. Five more GPS III satellites are in production, three of which are fully assembled and in testing.
Lockheed Martin is also under contract to build up to 22 additional GPS III Follow On (GPS IIIF) satellites, which add additional technology and advanced capabilities to this warfighting system, including a new Regional Military Protection Capability, which will increase anti-jam support in theater to ensure U.S. and allied forces cannot be denied access to GPS in hostile environments; an accuracy-enhancing laser retroreflector array; a fully digital navigation payload; and a new search and rescue payload.
In July, the Space Force declared that the GPS IIIF program had fulfilled Milestone C, which means the start of the production phase. Lockheed Martin has introduced augmented reality tools into the GPS IIIF production process to drive even-greater efficiency into the production process.
Continued investment in GPS is important. Besides the military applications, the U.S. economic benefit of GPS is estimated to be over $300 billion per year and $1.4 trillion since inception.
The first launch attempt on Oct. 2 from Cape Canaveral was halted due to an “unexpected pressure rise in the turbomachinery gas generator,” said SpaceX CEO Elon Musk on Twitter, referring to a part in the rocket’s Merlin engines.
SpaceX test-fired the Falcon 9 rocket for the GPS mission on Saturday at 7 p.m. on pad 40 at Cape Canaveral Air Force Station to verify that corrective actions have resolved the issue, according to SpaceX and reported by SpaceFlightNow. The fourth GPS III satellite was not aboard during the test.
GPS III SV04 first rolled out to Cape Canaveral’s Space Launch Complex 40 on Sept. 27. The satellite was originally scheduled for launch Sept. 30, then Oct. 1, but that launch was delayed because of a “traffic jam” at the launchpad caused by launch delays of other rockets.
The satellite was almost launched at 9:43 p.m. EDT on Oct. 2 until the launch was stopped at T– 2 seconds.
The Lockheed Martin-built GPS III SV04 will be launched aboard a SpaceX Falcon 9 rocket — the third National Security Space Launch (NSSL) mission on a Falcon 9 rocket, the second U.S. Space Force (USSF) first-stage booster recovery, and the sixth USSF launch.
A live feed will begin 20 minutes before the launch and conclude approximately 45 minutes afterward. A simulcast of the broadcast can be viewed at www.spacex.com.
GPS III SV04 will be launched to augment the current GPS constellation comprised of 31 operational spacecraft. GPS satellites operate in Medium Earth Orbit (MEO) at an altitude of approximately 20,200 km (12,550 miles) in six orbital planes. Each satellite circles the earth twice per day.
GPS III brings new capabilities to users such as the new L1C civilian signal, which opens the window for future interoperability with international satellite navigation systems.
GPS III SV04 rests atop a Falcon 9 rocket, waiting to be sent into orbit. (Photo: SpaceX)
Partnering with the U.S. Coast Guard Navigation Center (NAVCEN), U.S. Space Force and Lockheed Martin Space have released the GPS IIR/IIR-M satellite antenna patterns for worldwide public use.
Additionally, the Institute of Navigation has offered a related ION journal article free to the public to accompany the antenna patterns.
The GPS Block II Replenishment (IIR) space vehicle (SV) began improving upon its baseline design in 2003 with the launch of the first Block IIR SV retrofitted with a redesigned antenna panel. This is the Earth-facing panel providing the GPS L-band broadcast signal. The improved antenna panel includes redesigned L-band elements mounted on the SV Earth-facing structure in the same manner as the original antenna panel.
The Earth Terrestrial Service Volume is the near-Earth region up to 3,000 km altitude. (Diagram: NAVCEN/Lockheed Martin)
Spacecraft Navigation
The use of GPS signals for spacecraft navigation has increased in general over the last few decades. Navigation employing GPS observations for spacecraft in low-Earth orbit is now considered routine.
However, the situation is quite different for spacecraft that fly in the Space Service Volume above the GPS constellation, including medium-Earth orbit (MEO), geostationary orbit (GEO) and high-Earth orbit (HEO) satellites, as well as missions to the Moon and beyond.
For these spacecraft, reception of GPS transmit antenna side lobe signals is essential to improve availability and performance of on-board navigation and timing. In this context, the knowledge of the full antenna pattern (main lobe and side lobes) from the transmitting antennas of each of the GPS satellites is essential.
These published antenna patterns and associated ION citation describe both IIR and IIR-M antenna panel versions, their broadcast signal patterns, the performance observed in factory testing, and their on-orbit performance.
Chart: NAVCEN/Lockheed MartinChart: NAVCEN/Lockheed MartinChart: NAVCEN/Lockheed Martin
These patterns represent the current capability of the GPS IIR/IIR-M Space Vehicles. Receiver designers should consult the IS-GPS-200 specifications for use in receiver design and not base design on current signal performance.
GPS technical documents are also available at the NAVCEN website and linked from the GPS.gov website.
Legacy antenna panel on the GPS IIR satellite. (Photo: NAVCEN/Lockheed Martin)
