Jane's International Defence Review report on the recently launched first GPS-III Satellite and the 32-sat. constellation that it will eventually be a part of.
GPS III - 1 launched
GPS III - 2 to be launched in 2019
GPS III - 3 to be launched in 2019
GPS III - 4 through 7 - to be launched by 2021
GPS III - 8 through 32 (Sat. 11-34 are IIIF satellites) - to be launched by 2034GPS III brings new capabilities to space-based navigation
GPS III-1 is the first of a planned 32-satellite constellation to be placed into orbit over the next two decades. GPS III-1 represents the first of an entirely new design of GPS satellite meant to help the USAF modernise the legacy GPS constellation with new technology and advanced capabilities. GPS III is to have three-times better accuracy and up to eight-times improved anti-jamming capabilities, according to prime contractor Lockheed Martin.
GPS III also includes a new military code (M-Code) designed to enable military receivers to operate closer to jammers and under trees, enhancing their ability to track the GPS satellites, support a more secure and flexible cryptography architecture, detect and reject false signals, and provide higher power with comparable availability and accuracy improvements.
The GPS III programme also provides navigation and timing to a broad spectrum of civil users, which will include the three civil signals (L1C/A, L2C, and L5) flown on previous satellites. It will also transmit a new fourth civil signal, L1C, which is compatible with the European Galileo satellite navigation system signal. L1C is compatible with those signals planned for broadcast on Japan's Quazi-Zenith Satellite System (QZSS): a system meant to augment GPS services.
Once implemented, the common civil signal will be jointly broadcast by up to 60 satellites from GPS and Galileo constellations, further increasing the accuracy and availability of user PNT solutions.
The Government Accountability Office (GAO) said in a December 2017 report on GPS that operational need for the first GPS III satellite is June 2021, as the current GPS satellites are expected to remain operational longer than previously projected. The GAO believes that the USAF is likely to meet this GPS III operational requirement date because there are seven of the next-generation satellites scheduled to be launched by June 2021. This will also help the service to resolve any development issues with the new satellites.
GPS III spacecraft life will extend to 15 years, which is 25% longer than any of the 31 GPS satellites currently on orbit.
The USAF had originally contracted with Lockheed Martin for eight satellites with an option for two more. That option has since been exercised. A few months ago, the air force awarded satellites 11–32 to Lockheed Martin and dubbed those GPS IIIF for follow-on.
In August 2018 the USAF declared GPS III-2 available for launch and, in November, declared the spacecraft ready for 2019 launch. Lockheed Martin spokesperson Chip Eschenfelder said on 17 December that GPS III-3 is expected to be declared available for launch towards mid-2019.
GPS III-4 has completed thermal vacuum testing and GPS III-5’s navigation payload has been fully integrated and is beginning environmental tests. GPS III-6 has its navigation payload and is being prepared to be integrated while GPS III-7 and GPS III-8 are in component build-up. Eschenfelder said GPS III-9 and -10 will start up as soon as work cells are available.
As part of the USAF’s GPS modernisation effort, the new GPS next-generation Operational Control System (OCX) is meant to improve cyber security protection so GPS could operate through cyber attacks.
OCX, built by Raytheon, is to support up to 63 satellites on orbit, almost twice as many as the legacy system. Not that the government is going to build that many satellites, Bill Sullivan, vice-president of Raytheon’s GPS OCX programme, told Jane’s, “but the more they put on [orbit] basically provides better accuracy for any particular receiver whether it is on your smartphone or a smart weapon.”
Raytheon has also automated OCX to handle some of what Sullivan said are the more mundane activities associated with contacting the satellite. Taking those tasks out of the hands of air force operators will enable the ground station to communicate with the satellite more often each day.
“The more we can talk to the satellite the more often we can update its position, navigation, and timing information. The more you do that the more accurate the data signal will be coming to the ground,” Sullivan said.
OCX appears to have overcome a troubled history, most notably in 2016 when it breached a congressional cap that exceeded the 25% cost overrun threshold known as a Nunn-McCurdy breach. At the time the USAF said that inadequate systems engineering and software with high defect rates led to the cost growth. Further, corrective actions by Raytheon took longer than anticipated, according to the USAF.
Now, OCX is set to help the air force reduce operation costs by reducing crew size by about 40%, Sullivan said.
“The [USAF] will be able to do it with a [smaller] crew, which allows them to use their resources on more high-order warfighting capabilities as opposed to the manual work associated with contacting the satellite,” Sullivan said.
Raytheon’s layered defence gives OCX manoeuvring ability to address emerging cyber threats, Sullivan added. “We all know the cyber threat changes on a daily basis. We have a lot of flexibility there to be able to address threats as they come through the life of the GPS III mission and obviously of GPS OCX,” he said.
OCX is the first space ground control system to implement the 'DoD 8500.2 IA Defense in Depth’ information assurance standards, which provide the procedures for applying an integrated layered defence for DoD information systems and networks.
“I think that was a challenge for both us and the air force to not only just interpret those standards but then develop an implementation plan, actually imperilment it, test it, and then verify it,” Sullivan said. “That is all behind us at this point. I consider it a monumental achievement by Raytheon and our air force partner.”
The first GPS OCX Block 0 ground system was delivered to Schriever Air Force Base (AFB), Colorado, in 2017 and is in operation today at the Master Control Station. A back-up system is in place at Vandenberg AFB, California. Raytheon is also working on the second OCX delivery, known as Block 1, which will deliver full navigation capability for the entire GPS III and the currently deployed GPS II constellations. Block 1 is scheduled to be delivered in June 2021.
Block 0 will send commands up to and receive telemetry down from the satellite. However, before launch, OCX has been receiving telemetry from the satellite. Raytheon will monitor the state of the satellite up through launch and then through boost phase.
“Once the satellite gets into space, we will make first contact through the air force’s satellite control network, or AFCN, and we will start issuing commands to the satellite to basically get it into the correct orbit and that takes a couple of weeks to do,” Sullivan said.
It is Raytheon’s understanding that there will be some technology upgrades in the GPS IIIF block of satellites. A study is expected to begin shortly, bringing together Raytheon, Lockheed Martin, and the USAF to work collaboratively to determine what those technology changes will be.