More than 100 experiments will be conducted with the Navigation Technology Satellite-3 (NTS-3), set to launch next year, according to a U.S. Air Force official and reported by FedScoop.
“We’re really excited to push the state of the art with more than 100 experiments on this little [NTS-3] spacecraft and we’re looking at ways that we can solve warfighters’ problems in the contested environment,” Maj. Gen. Heather Pringle, commander of AFRL, told reporters April 6 at the 37th Space Symposium in Colorado Springs.
Maj. Gen. Heather Pringle
Set to launch in 2023, NTS-3 is designed to push the boundary of today’s position, navigation and timing (PNT) technology to pave the way for a more flexible, robust, and resilient architecture for satellite navigation technology.
NTS-3 is a product of the Air Force Research Laboratory (AFRL) and industry, designed to test advanced techniques and technologies to detect and mitigate interference to PNT capabilities and increase system resiliency for military, civil, and commercial users.
Unlike the GPS medium-Earth-orbit satellites, NTS-3 will operate for one year in geosynchronous Earth orbit. Ultimately, NTS-3 will identify key aspects for new GPS receivers that incorporate multiple signals and readily adapt to warfighter needs.
The NTS-3 experiments will also involve ground equipment and terminals such as command and control stations and software-defined radios. Specific improvements to the ground segment will enable experimentation with automated “lights-out” operations, control station failover, and near-real time environment sensing and generation of error correction and tailored waveforms. Onboard systems will monitor clock accuracy and orbit parameters to mitigate errors and notify the user.
NTS-3 will test a new digital signal generator that can be reprogrammed on-orbit, enabling it to broadcast new signals, improve performance by avoiding and defeating interference, and adding signatures to counter spoofing.
AFRL also will explore antenna configurations to provide Earth coverage and steerable regional beams in multiple frequencies and signal codes. The NTS-3 satellite will be equipped with 110 antennas to help counter attempted GPS jamming.
Ultimately, NTS-3 is expected to provide users with enhanced signal stability, availability, integrity and accuracy.
L3Harris plans to deliver NTS-3 later this year. The company is assembling the satellite at its Palm Bay facility near Cape Canaveral, Florida. The plant was expanded in 2021 to accommodate the NTS-3 program.
The Navigation Technology Satellite-3 (NTS-3) program is making major strides in developing a new navigation spacecraft for in-space demonstration. The NTS-3 is scheduled to launch to geosynchronous orbit from Cape Canaveral in 2023.
This summer, Northrop Grumman Corp. delivered the ESPAStar-D spacecraft bus to L3Harris Technologies of Palm Bay, Florida.
“The transfer of the bus allows L3Harris to move forward building the NTS-3 spacecraft,” said 2nd Lt. Charles Schramka, the program’s deputy principal investigator. “L3Harris will perform tests and begin integrating the NTS-3 PNT payload onto the bus. Together the bus and payload will form the NTS-3 spacecraft.”
Following L3Harris’s work, the Air Force Research Laboratory (AFRL) will test the bus with the NTS-3 ground control and user equipment segments, and will perform its own integrated testing on the overall NTS-3 system architecture.
Northrop Grumman has successfully delivered an ESPAStar-D spacecraft bus to L3Harris in support of the NTS-3 mission. (Photo: U.S. Air Force)
NTS-3 in the Vanguard. In 2019, the U.S. Air Force designated NTS-3 as one of three Vanguard programs — priority initiatives to deliver new capabilities for national defense. The NTS-3 mission is to advance technologies to responsively mitigate interference to position, navigation and timing (PNT) capabilities, and increase system resiliency for GPS military, civil and commercial users.
“This is the first time an ESPAStar bus has been built and delivered as a commercially available commodity,” said Arlen Biersgreen, NTS-3 program manager. “NTS-3 is using a unique acquisition model for the ESPAStar line that fully exercises the commercial nature of Northrop Grumman’s product line, in order to provide the bus to another defense contractor for payload integration using standard interfaces.”
The ESPAStar-D bus, built in Northrop Grumman’s satellite manufacturing facility in Gilbert, Arizona, includes critical subsystems such as communications, power, attitude determination and control, in addition to configurable structures to mount payloads.
The bus will “provide affordable, rapid access to space,” according to Northrop Grumman. Its configuration, using an Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA), allows multiple separate experimental payloads to be stacked together on one launch vehicle. AFRL developed the ESPA ring to transport space experiments, allowing for lower cost and more frequent trips to space for government and industry users.
Besides the bus delivery, there are other advances in the program.
GNSSTA receiver. In June, AFRL took delivery of an experimental receiver — GNSS Test Architecture (GNSSTA). The receiver was developed by the AFRL unit the Sensors Directorate, located at Wright-Patterson Air Force Base in Ohio, and Mitre Corporation. GNSSTA is a reprogrammable software-defined signal receiver that will allow the Air Force to receive both legacy GPS and advanced signals generated by NTS-3.
AFRL will continue its integration efforts through 2022 to ensure all parts are working together for the fall of 2023 NTS-3 launch.
“With the delivery of the bus we are entering into the next phase of payload integration,” Biersgreen said. “These recent breakthroughs allow the program to continue to move forward and prepare for launch of the first U.S. integrated satellite navigation experiment in over 45 years.”
Artist’s concept for NTS-3 in geostationary orbit. (Artist’s concept: 2d Lt. Jacob Lutz, AFRL)
The NTS-3 experimental satellite will be launched in 2023, according to reports from C4ISRNET and Space News. The United States military will use the satellite for positioning, navigation and timing (PNT) as a supplement to GPS.
The satellite was originally set to launch in 2022.
The Air Force Research Laboratory (AFRL) plans to use the additional time to reduce risks and conduct more ground testing.
Navigation Technology Satellite 3 will help guide future GPS satellites, a priority area for the military as the technology has become easier to spoof and jam. Among other features, NTS-3 will have steerable beams for regional coverage and a software-defined payload that can be reprogrammed on orbit.
AFRL discussed the delay in a media roundtable held Wednesday, reports C4ISRNET. AFRL Commander Brig. Gen. Heather Pringle said that shift was out of the lab’s control since the satellite will launch as a rideshare with a U.S. Space Force payload, and that launch had been pushed back.
AFRL plans to experiment with the satellite in geosynchronous orbit for one year, testing PNT signals and architectures as well as ground-based command and control systems and software-defined radios. Following testing, NTS-3 will transition to the U.S. Space Force and integrate into the service’s other PNT capabilities.
Satellite NTS-3 above Earth. (Illustration: Lt. Jacob Lutz, AFRL Space Vehicles Directorate)
L3Harris Technologies is on track to begin building the U.S. Air Force’s first Navigation Technology Satellite-3 (NTS-3) after completing the program’s critical design review.
According to L3Harris, it will integrate the program’s experimental payload with an ESPAStar Platform, planned for launch in 2022. The system is designed to augment space-based position, navigation and timing (PNT) capabilities for warfighters.
The NTS-3 payload features a modular design, and the experiment will demonstrate capabilities that can be accomplished through a stand-alone satellite constellation or as a hosted payload.
“Collaboration with our customers has enabled us to move rapidly through important milestones to design this experimental satellite,” said Ed Zoiss, president, space and airborne systems, L3Harris. “Our goal is to deliver new signals to support rapidly evolving warfighter missions.”
The Space Enterprise Consortium selected L3Harris for the $84 million contract in 2018 as the prime system integrator to design, develop, integrate and test NTS-3. The NTS-3 will examine ways to improve the resiliency of the military’s PNT capabilities. It will also develop key technologies relevant to the GPS constellation, with the opportunity for insertion of these technologies into the GPS IIIF program, L3Harris said.
The program is a collaboration with the Air Force Research Laboratory, Space and Missile Systems Center, U.S.Space Force, and Air Force Lifecycle Management Center.
Satellite NTS-3 above Earth. (Illustration: Lt. Jacob Lutz, AFRL Space Vehicles Directorate)
Harris Corporation has been selected as the prime contractor to build Navigation Technology Satellite-3, the next-generation experimental positioning, navigation and timing (PNT) spacecraft. The satellite, called NTS-3, is expected to launch in 2022, with one year of experimental operations.
The Air Force Research Laboratory and the Space and Missile Systems Center selected Harris on Dec. 20, 2018, and announced it on Jan. 17.
PNT Testbed
As a unique testbed in geosynchronous orbit, NTS-3 will integrate several advanced technologies to demonstrate resiliency and new concepts of operation to include experimental antennas, flexible and secure signals, increased automation, and use of commercial ground assets.
Technologies matured and knowledge gained from NTS-3 are expected to transition to future generations of GPS and augmentation layers for national PNT capabilities.
Satellite NTS-3 closeup. (Illustration: Lt. Jacob Lutz, AFRL Space Vehicles Directorate)
“The National Defense Strategy tells us we must evolve our nation’s Position, Navigation, and Timing capabilities to be more resilient,” said AFRL Space Vehicles Director Col. Eric Felt. “NTS-3 is all about resiliency, and I am incredibly excited about the resiliency experiments our SMC, AFRL, and Harris team will be able to conduct with NTS-3’s innovative and flexible hardware, software, and waveforms.”
Agile Waveform Platform
In support of NTS-3, Harris plans to develop the Agile Waveform Platform, a digital signal generator that can be reprogrammed on-orbit, enabling operators to quickly develop and deploy new signals to meet rapidly-evolving needs on the battlefield.
Additionally, Harris’ electronically steerable phase-array antenna will support simultaneous broadcast of multiple waveforms in both Earth-coverage and spot-beam configurations.
NTS-3 will use Northrop Grumman Innovation System’s ESPAStar bus, building on AFRL’s EAGLE spacecraft that launched in April 2018.
The NTS-3 Space Experiment
Navigation Technology Satellite – 3 (NTS-3) was selected as the Space Vehicle Directorate’s next major integrated space experiment in 2015, and it represents AFRL’s first PNT flight experiment to prototype a more resilient PNT multi-layer architecture in accordance with the Space Enterprise Vision (SEV) and the Space Warfighting Construct (SWC).
Satellites NTS-1, 2 and 3. (Illustration: Lt. Jacob Lutz, AFRL Space Vehicles Directorate)
NTS-3 builds on a heritage of Department of Defense (DoD) satellite navigation (SATNAV) success that began in the 1970s with the predecessors of the modern GPS constellation. NTS-1 was developed by the Naval Research Laboratory (NRL) and launched in 1974 with two rubidium-vapor frequency standards that advanced the timing and navigation precision demonstrated by the earlier TIMATION satellites.
NTS-2 launched in 1977 as the first NAVSTAR GPS Phase I satellite, and demonstrated cesium frequency standards and a worldwide network for data acquisition. There has been no major DoD SATNAV developmental program for experimentation since then, until NTS-3.
In 2017, AFRL restructured NTS-3 to emphasize mission objectives to demonstrate disaggregated, resilient PNT in a multi-layer space architecture, as outlined by the SEV and the SWC. NTS-3 will provide space qualification for core technologies such as on-orbit digital signal reprogrammability and solid-state amplifiers. In addition to new signals, onboard experiments include improvements to timing accuracy and integrity, including ensembling to improve long- and short-term stability. NTS-3 will demonstrate key tactics, techniques and procedures (TTPs) for multi-layer PNT through all three segments of the SATNAV system: space, control, and user.
Ground Control
Braxton Technologies was selected in June 2017 to handle NTS-3 SATNAV ground control, while demonstrating and maturing innovative and affordable ground-based command and control capabilities to ensure resilient PNT in contested and denied environments.
Braxton experts also will demonstrate satellite ground-control technologies to inform future GPS ground-control systems. They will use the Multi-Mission Space Operations Center (MMSOC) open architecture standard, as well as the Air Force Satellite Control Network (AFSCN) for primary direct and secure communications with the future NTS-3 space payload.
Satellite NTS-3 in space. (Illustration: Lt. Jacob Lutz, AFRL Space Vehicles Directorate)
Ground control segment (GCS) objectives include commanding of multiple antennas to form high-gain regional beams in conjunction with traditional Earth coverage beams, and processing the subsequent impact on phase center bias and pattern variation.
The GCS will also incorporate commercial antennas for TT&C and experiment with automation of common functions to reduce the level of manual control that GPS requires. GCS development will emphasize cyber security and compatibility with Enterprise Ground Services (EGS).
Collaborators Wanted
AFRL/RV is seeking collaboration from industry, government agencies, and universities in developing experimental concepts and participating in the flight experiment.
