Nearly 50 years ago, there were no smart phones, no GPS-guided weapons, no turn-by-turn direction systems in automobiles.
That’s when the U.S. Air Force launched the first two Navigation Technology Satellites, NTS-1 and NTS-2, to expand and improve the nascent positioning capability provided by GPS forerunner programs such as Transit and Timation. NTS-1, launched in 1974, and NTS-2, launched in 1977, weren’t part of the original GPS constellation but were instead orbiting testbeds for various technology systems such as clocks and solar cells.
Since 1977 and today, of course, satellite positioning has become an integral part of everyday life, and certainly an integral part of military operations. This was amply demonstrated in Ukraine, when an attack with an unmanned surface vessel on Russian targets failed because of a lack of satellite connectivity. It’s a technology that’s increasingly on every vehicle and in every pocket.
Ground Control to NTS-3
Braxton Science & Technology Group provided the ground control systems for NTS-3 (the company was acquired by Parsons Corp. in 2020).
NTS-3 will use a tailored version of Parson’s hybrid cloud ground control architecture, similar to DARPA’s Blackjack satellite and the National Oceanic and Atmospheric Administration (NOAA)’s Polar Operational Environmental Satellites.
One goal, according to AFRL, is to move from stove-piped command and control systems, each designed for a single mission, to one that can support multiple Department of Defense (DoD) satellites.
The ground control system is also using commercially available services and products, including ground antennas and monitoring receivers, according to AFRL, as well as incorporating the government-certified cloud platform.
“The NTS-3 control segment allows for easier data sharing, enhanced situational awareness, and collaboration across multiple program partners across the United States,” according to the AFRL. “By demonstrating ways of effectively managing system complexity across space, ground control, and user equipment segments, NTS-3 will develop lessons learned and meaningful test data to transition to future DoD programs.”
The NTS-3 user segment includes MITRE’s Global Navigation Satellite System Test Architecture (GNSSTA) for software-defined receivers, or SDRs, that, according to AFRL, can take full advantage of the ability to reprogram the signal on orbit. The architecture allows users to receive both legacy GPS signals and advanced signals from NTS-3.
NTS-3 will demonstrate new SDR features, including various signal modulations, transmitting data in different ways and changing broadcast parameters on a pre-defined schedule.
“In the future, warfighters equipped with SDRs capable of receiving and processing reprogrammable SATNAV signals will be able to access accurate PNT data and enhanced flexible anti-jam and anti-spoof protections,” according to AFRL.
In January, the AFRL team successfully generated signals on the actual spacecraft and received them with the experimental GNSSTA equipment, Dr. Joanna Hinks, the NTS-3 principal investigator, said at a media day event in January.