The Space Development Agency’s (SDA) plan to provide alternate positioning, navigation, and timing (PNT) signals to US military operators in GPS-denied environments faces uncertainty.
The Space Force is reevaluating its approach to the next set of Transport Layer data relay satellites, potentially impacting the SDA’s ability to deliver this crucial capability.
Organic PNT Capability: A Constellation Lifeline
SDA Director Gurpartap „GP” Sandhoo stated that the agency’s Proliferated Warfighter Space Architecture (PWSA) will feature „organic” PNT capability. This ensures the constellations can operate independently, even when GPS is jammed by adversaries. The PWSA comprises communications and missile tracking satellites in low Earth orbit.
Tranche 3 Transport Layer: A Question Mark for Warfighter Signals
However, Sandhoo acknowledged uncertainty regarding the delivery of these alternate PNT signals to warfighters on the ground if the Tranche 3 Transport Layer is cancelled. The SDA had planned to acquire 140 T3 Transport Layer satellites, launching in 2028, to provide worldwide routing of high volumes of data with low latency.
Navigation Layer: Leveraging Laser Links for PNT
The SDA’s planned Navigation Layer aimed to utilize laser links between PWSA satellites for two-way time transfer (TWTT) and ranging. This would maintain satellite operations, pinpoint GPS jamming, and provide space-based PNT services through a dedicated signal. The SDA Warfighter Council approved the inclusion of the Air Force Research Laboratory’s „Light Weight Service” in Tranche 3, designed to provide the alternate PNT signal.
MILNET: A Commercial Alternative?
As part of the fiscal 2026 budget planning, the Department of the Air Force and the Space Force are analyzing the possibility of replacing the T3 satellites with commercial services from SpaceX’s Starshield network under a program called MILNET. The Space Force’s FY26 budget request includes $277 million for this program, although reports suggest it is already underway.
