SpaceX details Starlink’s role in enhancing US PNT resilience amid FCC inquiry

Photo: SpaceX

SpaceX has submitted reply comments to the Federal Communications Commission (FCC) detailing how its Starlink low-Earth orbit (LEO) satellite system currently provides, and could further support, positioning, navigation, and timing (PNT) services. The filing is part of the FCC’s ongoing Notice of Inquiry (WT Docket No. 25-110), which seeks to promote resilient and diverse PNT capabilities across the United States in response to vulnerabilities associated with the nation’s reliance on GPS, such as the risks of jamming and spoofing.

The FCC’s initiative, titled “Promoting the Development of Positioning, Navigation and Timing Technologies and Solutions,” aims to explore both space-based and terrestrial alternatives to ensure the continuity of critical PNT functions for national security, public safety, and economic stability. The agency is soliciting input from stakeholders on technologies that could complement or serve as alternatives to GPS, with a focus on robustness, geographic coverage and resilience to interference.

In response, SpaceX noted in its comments: “One opportunity stands out as a particularly ripe, low-hanging fruit: facilitating the rapid deployment of next-generation LEO satellite constellations that can deliver PNT as a service alongside high-speed, low-latency broadband and ubiquitous mobile connectivity.”

SpaceX also states that it has already been working on a PNT system for its cellular Starlink service, which is currently in public beta and is set to launch through T-Mobile in July. SpaceX outlines several technical features of the Starlink system that they argue are relevant to PNT applications.

Starlink Architecture and Features  

SpaceX also noted that Starlink terminals can already provide nanosecond-level timing accuracy and meter-level positioning by using time-of-arrival measurements from its satellites. These capabilities allow the network to support precise timing applications, such as cellular network synchronization, without relying on external GPS sources. Timing signals are derived from the LEO constellation and synchronized through Starlink’s broadband infrastructure.

The filing highlights the Starlink system’s architecture, which includes thousands of satellites in low Earth orbit for global coverage and short signal travel times. SpaceX points to its phased-array user terminals, which use directional antennas to enhance signal integrity and mitigate interference. The company also notes that Starlink employs end-to-end encryption, making its timing and positioning information less susceptible to spoofing or tampering. According to SpaceX, Starlink is already in commercial use by a variety of customers and has been tested by U.S. military and civilian users in environments where traditional GNSS signals are degraded. The company emphasizes that these capabilities have been demonstrated under real-world conditions, not just in theory.

A Layered Approach to PNT

Addressing the FCC’s interest in a “layered” approach to national PNT resilience, SpaceX positions Starlink as one of several complementary solutions to enhance national PNT resilience. The company argues that using diverse, independently operated systems — both satellite and terrestrial — can provide redundancy and reduce dependence on any single technology or spectrum band.

SpaceX also responds to concerns from other stakeholders about whether Starlink qualifies as a PNT system, reiterating that the system was developed independently of government funding and can scale rapidly due to SpaceX’s vertically integrated manufacturing and launch model.

SpaceX confirms that Starlink operates in Ku- and Ka-band spectrum allocated for broadband services and is not proposing new spectrum allocations for PNT-specific use. It asserts that PNT functionality can be delivered within existing allocation.