Next-gen satellite to transform military PNT capabilities

Anticipated to launch in late 2023, Navigation Technology Satellite-3 (NTS-3) will be the US Department of Defense’s first experimental, integrated navigation satellite system in nearly 50 years.

Just as NTS-1 and NTS-2 served as the foundation for today’s global positioning system (GPS) constellation in the 1970s, NTS-3 is on track to transform current US military positioning, navigation and timing (PNT) capabilities and lay the foundation for multilayer PNT resiliency.

As the space domain is increasingly contested, there is an urgent need to demonstrate transformative capabilities to ensure warfighters can operate successfully in GPS-degraded or -denied environments. The Department of the Air Force (DAF) has prioritised NTS-3 as one of its four Vanguard programs to do exactly that, with aerospace and defence technology company L3Harris chosen to lead the design, development, integration and test of the next resilient PNT mission solution.

“If you watch the news today, it’s easy to see that the threats posed by our adversaries are becoming bolder, more frequent and more sophisticated,” said L3Harris Fellow Tara Solorzano. “Our goal is to show that NTS-3’s technology will not only address these evolving threats, but it will also provide our warfighters with a responsive and flexible capability to ensure mission success.”

The NTS-3 is an experimental platform designed to prove resilient, robust and reprogrammable PNT functionality in space. It is also said to be the first satellite that can simultaneously broadcast and receive GPS information, which will allow US forces to operate successfully in GPS-denied environments and areas prone to spoofing.

Not only does NTS-3 have the ability to focus powerful beams to ground forces, it’s also able to minimise the impacts of GPS jamming through rapidly reprogrammable signal waveforms, frequency agility and increased signal strength. The experimental satellite’s embedded software and firmware is reprogrammable on orbit. When paired with agile and reprogrammable user receivers, this will allow the US Air Force (USAF) and US Space Force (USSF) to react in real time as threats change on the battlefield. Additionally, NTS-3’s enhanced processors can support more complex signals, now and into the future.

“Think of NTS-3 as GPS’s next-generation wingman that will provide our forces with uninterrupted PNT,” Solorzano said. “This technology is designed to defeat the threat that contested, degraded and denied PNT poses to our national security.”

Satellite testing was recently conducted at Edwards Air Force Base’s Benefield Anechoic Facility (BAF), understood to be the largest anechoic test facility in the world. The BAF provides shielding effectiveness that allows GPS tracking and jamming tests without frequency management or regulatory agency approval.

“The BAF is large enough and has enough infrastructure around it,” said Arlen Biersgreen, NTS-3 Program Manager, Air Force Research Laboratory (AFRL). “It is a quiet enough chamber that protects the aircraft and other GPS users outside of the facility. We needed to have a shielded, large enough area to keep the energy of the testing inside the facility. Across the board, the BAF really fit the bill in a way no other facility in the United States really could.”

“We are testing when a satellite sends out a signal, we can actually receive that signal and it’s the correct one,” added Amarachi Egbuziem-Ciolkosz, an engineer with the 772nd Test Squadron. “You don’t want a satellite to send you back a signal that your house is 10 miles away when it’s actually right in front of you.”

NTS-3 will demonstrate technologies and techniques to augment the GPS constellation to help maintain access to GPS in contested environments. Testing at the BAF is an important step in ensuring that the AFRL team is ready to successfully conduct on-orbit experiments.

“The value of all of this is to allow for everything to be synchronised together,” said Thomas Roberts, NTS-3 Chief Engineer, AFRL. “Whether it be airline schedules, take-offs/landings at the airports or military operations, NTS-3 is taking this a step further because we are using clocks, but we are also doing a demonstration of advanced signals and signal flexibility. Our ability to get that job done is dependent on the success of this testing facility.”

Once all testing is complete, the NTS-3 will launch into space in late 2023 aboard United Launch Alliance’s new Vulcan Centaur rocket. The satellite will remain in a near-geosynchronous orbit for another year of testing, during which it will broadcast navigation signals from its phased array antenna. But before this happens, a few more steps in the NTS-3’s journey need to be made.

“After we are done here at the BAF, we will transport the satellite to Kirtland Air Force Base and get it back into our integration and test facility,” Biersgreen said. “We have thermal vacuum testing where we will be simulating the environment the satellite will be operating in. We also have testing to show that the ground system is compatible with the satellite. After that, we have a long training campaign for our operations crew so everyone on the team is ready to conduct this experiment after we launch.”

The AFRL has already scheduled more than 100 experiments for NTS-3, which will help the USAF and USSF decide on the best ways to use the complementary satellite, ground and user equipment technologies to modernise the military’s PNT architecture.

“We’re incredibly excited about the upcoming launch,” Solorzano said. “Once NTS-3 is in orbit, we’ll be able to prove its performance and showcase the benefits of this game-changing technology. The experiments performed by AFRL will shape the way our military uses this technology to protect our nation’s warfighters.”

Image caption: Artist’s concept for NTS-3 in geostationary orbit. Image credit: 1st Lt. Jacob Lutz.