We at NextNav care deeply about helping solve an urgent national security issue that makes us all vulnerable. I’m talking about the growing threats to GPS. It’s a system we rely on every day, often in ways we don’t even realize.
GPS helps to power our public safety networks, secure our energy grid, synchronize financial transactions and even navigate from point A to point B.
Yet, at any moment, a range of natural or man-made events could disrupt the GPS satellite network. Around the world, GPS disruptions are no longer hypothetical. Incidents of GPS jamming and spoofing have become routine in places like the Middle East and the Baltic states and the increasing severity of these disruptions is spilling over into civilian life, putting us all at risk.
We’ve seen the consequences here at home, too. Major airports have experienced man‑made GPS disruptions of unknown origin, and farmers have seen how even temporary GPS loss can upend precision agriculture.
Whether caused by jamming, spoofing or natural disasters, the vulnerabilities are real and growing.
I am encouraged by the ongoing dialogue between industry and government to support a system-of-systems approach to resilient positioning, navigation and timing (PNT). Building layers of space and ground-based complements and backups to GPS is the only way to overcome the risks relying on a single point of failure in GPS causes to everyday life.
It’s a problem so big that a one-day GPS outage could cost the U.S. economy an estimated $1.6 billion per day.
NextNav is on a mission to enable a terrestrial PNT solution to help solve this problem, and that is why we feel it’s so important to respond to those who are more focused on problem-finding than problem-solving.
By ignoring both the urgency of the threat and the strength of the engineering analysis supporting near-term solutions such as 5G-powered 3D PNT, the Z-Wave Alliance argues that the U.S. can afford to wait. At NextNav, we strongly disagree.
The Federal Communications Commission (FCC) is working to enable resilient PNT. Among the solutions that the Commission is examining is NextNav’s ground-based 5G-powered 3D PNT complement and backup to GPS. We are serious about solving an urgent national security problem and we will continue to do the hard work necessary to support the FCC’s fact-based, engineering-driven decision-making.
The FCC is the expert authority on commercial spectrum issues and we believe it has all of the information it needs to take the next step in this process. The appropriate venue for resolving any remaining technical questions is a Notice of Proposed Rulemaking, where the world’s best spectrum engineers can put these competing claims to the test.
In the meantime, here are the engineering receipts that should make anyone suspicious of entities like the Z-Wave Alliance, who don’t want the FCC to put their technical claims to the test.
Unlicensed Part 15 Operations Can Continue Operating Across the Entire 902-928MHz Band
We have filed multiple comprehensive engineering studies demonstrating that 5G operations in the Lower 900MHz band will not cause unacceptable interference to unlicensed devices. Those studies specifically examined five different unlicensed technologies, including Z-Wave technology. To ensure this discussion is fact-based, we’d like to set the record straight.
First, let’s start by talking about the 900MHz band as it is today. Unlicensed lower 900MHz devices today successfully coexist with a wide range of unlicensed users that operate without coordination or interference protection.
How? Part 15 devices are resilient because of the mechanisms that are used daily, including frequency hopping, bursty transmissions, adaptive modulation, redundancy paths (meshing), and self-healing, among other features.
This includes coexistence with bandwidth-intensive use cases such as HaLow devices supporting 4K video streaming, wideband point-to-point and point-to-multipoint connectivity supporting up to 20MHz, and wireless cameras streaming live video.
These devices pose more serious coexistence challenges to each other than NextNav’s proposed 5G operations because unlicensed devices are more prone to collocation or being situated in close proximity. And these devices today coexist with multiple licensed operations, such as tolling and NextNav’s authorized M-LMS deployments.
The technical record before the FCC demonstrates that unlicensed devices can continue to operate in the presence of 5G, using the same core coexistence principles.
Hidden and Unrealistic Assumptions Lead to Deeply Flawed Results
The studies from Pericle Communications and Plum Consulting cited by Mr. Rosenthal do not hold up under scrutiny and contain a number of fundamental technical errors. As we’ve outlined in detail, NextNav’s comprehensive technical analysis has identified significant flaws in the Pericle paper, including fundamental errors in its assumptions and methodology.
For instance, Pericle’s predicted 5G emission levels exceed levels found in theoretical free-space conditions — an impossibility that undermines the entire paper. The Pericle paper also seems to ignore how 5G positioning signals work, failing to mention comb patterns and muting that are core to the technology and thereby further inflating perceived 5G emission levels.
Attempts to reproduce Pericle’s simulations with Pericle’s stated methods and parameters yield dramatically different results, which serve as clear evidence of computational errors or faulty execution of the depicted scenario.
Perhaps most remarkably, no credible analysis could replicate Pericle’s conclusion that 5G interference would occur more than 50% of the time when the ostensibly interfering transmitter operates only 50% of the time.
The same lack of technical rigor is true of the FCC submission by Plum Consulting. A technical filing from NextNav confirms that 5G operations will not cause unacceptable interference to unlicensed Part 15 devices in the lower 900MHz band, and that unlicensed operations can continue across the entire lower 900MHz band. NextNav has also thoroughly rebutted the Plum submission in the record.
A National Security Vulnerability We Can Fix Together
We are serious about solving an urgent national security problem and we will continue to do the hard work necessary to support the FCC’s engineering-driven decision making.
There’s a clear choice between choosing to be part of the problem, or part of the solution. From the outset, NextNav has been committed to being part of the solution. We hope others will follow our lead. We should all work together to solve this critical national security problem.
Renee Gregory is the vice president of regulatory affairs at NextNav.
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