BPS basics. A TV tower broadcasts the tower’s location and each communication frame’s emission time within the frame. (Graphic: National Association of Broadcasters)

More than 20 years ago, in these pages, we referred to television broadcast signals as “signals of opportunity” that might be used for positioning, navigation and timing (PNT). Since then, several other signals with a different primary purpose have also been considered as sources of PNT, and some have been used routinely for years now, such as WiFi routers for indoor navigation. On Feb. 26, 2025, the National Association of Broadcasters (NAB) filed a petition for rulemaking with the Federal Communications Commission (FCC) for television to transition to a new standard, ATSC 3.0, that enables what they call Broadcast Positioning System (BPS), as a way to enhance GPS resiliency. I asked NAB’s chief technology officer and executive vice president, Sam Matheny, to answer a few questions about the organization’s proposal. In next month’s issue, we will present a different perspective on it.

Question: Briefly, what is the history of the relevant standards?

Answer: The Advanced Television Systems Committee (ATSC) is an international standards development organization. ATSC developed ATSC 3.0 as the “next-gen” standard, and the International Telecommunications Union (ITU) adopted it as a recommended digital broadcast standard in 2020. Broadcasters in the United States began experimental ATSC 3.0 transmissions in 2016, and there are currently more than 100 transmitters broadcasting in 80 markets. Other nations currently using or considering ATSC 3.0 include Brazil, India, South Korea, Canada, Mexico, Jamaica and Trinidad and Tobago. NAB’s petition to the FCC requests permission to fully transition to ATSC 3.0 by 2030.

Q: Briefly, what is the history of the BPS project/proposal?

A: BPS is a datacast application that uses ATSC 3.0. We at NAB authored a seminal paper on BPS in 2021 and built our first prototype in 2022. We put our second prototype on the air in 2023. We signed a Cooperative Research and Development Agreement (CRADA) with the National Institute of Standards and Technology (NIST) in 2024 and published our first joint paper earlier this year. The paper concludes that “the stability of BPS time transfer is comparable to or better than GNSS, making BPS a viable complementary PNT solution when GNSS is unavailable.”

Our petition to the FCC highlights a transition to ATSC 3.0 that enables the nationwide deployment of BPS.

Q: What is the motivation for broadcasters to implement BPS? What’s in it for them?

A: BPS will further secure television broadcasters’ role in the fabric of U.S. telecommunications. We also witnessed the innovation around GPS, with more than 7 billion GPS receivers being built into myriad devices. We’d like to see BPS experience similar innovation, which will bring new business opportunities. We believe that there is an opportunity for a public-private partnership with the government to deploy BPS for economic and national security.

Q: What have your tests so far shown regarding the timing accuracy of your signals? How much more R&D is required?

A: We’ve completed a wide variety of testing over the years, but probably of most interest is the work done with NIST. They ran common-view experiments using the BPS signal transmitted from KWGN, a TV station in Denver. Receivers were placed at two different facilities equipped with NIST timescale. Their Boulder facility is 30 km away with non-line-of-sight (NLOS) propagation, and their Fort Collins facility is 106 km away with line-of-sight propagation. A 21-day-long test showed that the time deviation (TDEV) statistics were better than 2 ns for all intervals. NIST also tested the stability of the NLOS signal alone at the Boulder facility and found that the TDEV statistics were better than 3 ns.

Q: How can BPS help improve GNSS resilience and integrity?

A: BPS functions completely independent of GNSS, so in the event of an acute GNSS disruption or catastrophic outage, BPS can be a resilient secondary source of timing for critical infrastructure (CI). Integrating BPS into CI applications also makes GPS a less attractive target for intentional disruption. Additionally, being independent means that BPS and GPS can work together in a hybrid mode, where, for example, BPS can help detect jamming and spoofing of GPS.

Q: What are the main benefits of BPS?

A: The key benefits of BPS include:

• Existing infrastructure: BPS leverages existing television transmission…