Broadcasters Looking at BPS to Justify ATSC 3.0 Transition
LAS VEGAS -- A proposal to use ATSC 3.0 stations to create a U.S. backup to GPS is more about justifying a speedy transition to the new standard than directly monetizing it, broadcasters and broadcast engineers told us at the NAB Show 2025. The U.S. is the only major power without a backup solution for GPS, and the Broadcast Positioning System proposed by NAB and Sinclair is the most promising candidate in two decades, said Patrick Diamond, a member of the National Space-Based Positioning, Navigation and Timing Advisory Board. For the proposed BPS system to work optimally, “the more towers, the better,” said Tariq Mondal, NAB's vice president-advanced technology.
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“We want our spectrum,” said Harvey Arnold, Sinclair Broadcast's senior vice president-engineering. “We want the commission to say, and the public to think, broadcasting is an important thing to have.” Broadcasters need public television stations to participate in ATSC 3.0 and BPS to provide the needed coverage, and the BPS proposal could be an angle in the fight over public TV funding, he said.
The BPS proposal is based on the fact that ATSC 3.0 broadcasts create a precise time stamp for the emission of each broadcast frame, which can be used along with the location of multiple ATSC 3.0 transmitters in a given area to calculate a precise position, comparable in accuracy to GPS. The ability to count time in precise increments down to nanoseconds and even smaller is essential for telecommunications, the U.S. power grid and the stock market, Diamond said. If the GPS system were taken down -- whether by interference or foreign government anti-satellite weapons -- U.S. infrastructure “would just die in 30 days,” he said. Under the plan, U.S. TV stations would switch to ATSC 3.0 and all be upgraded to provide a BPS signal, which requires minimal spectrum and power. Funding could come from the U.S. government to help fund the upgrades, Diamond said.
At NAB Show 2025, Sinclair unveiled developments for BPS that make it more viable as a GPS backup. Engineers are testing a “leader-follower” system that would reduce the cost of upgrading ATSC 3.0 stations to BPS because it would mean only some stations would need expensive cesium atomic clocks, Arnold said. These “leader” stations would transmit a signal to the much more numerous “follower” stations, which would each require only rubidium atomic clocks. Cesium clocks cost around $100,000 each, while rubidium clocks are in the $20,000 range. The leader-follower system would make upgrading all ATSC 3.0 stations to provide BPS much more cost effective, Arnold said.
Sinclair, UrsaNav and NAB also held a demonstration combining BPS with a ground-based positioning system called eLORAN (enhanced long-range navigation) to provide timing precision comparable to GPS. It's descended from LORAN, a now-defunct navigation system developed during World War II. Combining the two systems creates a backup to GPS with “survivability” that could provide continuity of operations if something were to knock out the GPS system, said UrsaNav CEO Charles Schue. Under the proposal to combine the two systems, 10 eLORAN towers and the bulk of the nation’s TV stations running on ATSC 3.0 would be enough to provide a nationwide backup to GPS, Schue said. The eLORAN facilities could be built on federal sites that used to house LORAN sites or on AM masts, he said.
Advocates for the proposal said multiple federal agencies have shown interest in BPS. “ATSC 3.0 and BPS are immediately useful” for transferring precise timing information without GPS, said Jeffrey Sherman, a supervisory physicist at the National Institute of Standards and Technology, during a BPS-focused session at NAB Show 2025.