VIAVI Solutions adds a box between the antenna and receiver

De Falcis

VIAVI Solutions — with corporate headquarters in Chandler, Arizona, and offices in 22 countries — makes a wide array of testing solutions for network operators, equipment manufacturers, enterprises, government, aerospace, and railways. I spoke with Nino De Falcis, Senior Director, Global PNT Business Development.

What problem are you addressing?

A GNSS clock is a single point of failure and is at risk of cyber-attacks that are on the rise, such as jamming and spoofing. In a typical configuration, a GNSS legacy clock includes an antenna, a receiver, a holdover oscillator and fan-out input/output. The GNSS antenna is the point of attack for many bad guys. That’s the problem we are addressing in the critical infrastructure that we are serving, including defense, 5G, public safety, utilities, data centers, financial systems and transportation. Bad guys now have also demonstrated that they can jam or even, in Russia’s case, shoot down GNSS satellites, which makes GNSS even more vulnerable, both in space and on the ground. GNSS constellations do not have spoofing detection or mitigation through authentication, except for Galileo’s Open Service Navigation Message Authentication (OSNMA). Additionally, their signals are not encrypted, so they are easy to spoof and do not work indoors.

What is your solution?

Instead of replacing the hundreds of thousands of legacy GNSS clocks that are deployed, we are just adding our box in line between the antenna and the receiver, as an accessory. We call it the zero-trust multisource PNT clock, and it is our new SecurePNT-6200 product. Additionally, we offer our new suite of SecureTime services, which combines multiple signals of opportunity, coupled with the 6200 clock. We already have Iridium LEO and Inmarsat GEO sources and will soon add support for other future satellites as well as terrestrial sources. You can even aggregate a stand-alone cesium clock into our resilient 6200 clock. Then, we output the legacy signal to feed it to the GPS receiver.

Our resilient multi-source clock aggregates all those signals of opportunity, and then AI sensor fusion weighs, cross-verifies, authenticates, qualifies. It does a lot of processing to select the best uncompromised source. The source is then converted to the legacy GPS L1 signal before feeding it to the GPS receiver. We call it a transcoder and have a patent on this technology. We are the only company offering this solution, though we allow third parties to do the same.

How are you processing your data?

We’re inputting all the constellations — almanacs, ephemerides, etc. — and fusing all those internal and external sources, weighing their quality and estimating the PNT state. We then apply the zero-trust, AI-based jamming and spoofing detection and mitigation. So, we’re doing the authentication, the verification, the qualification, the learning of patterns using all the data sets that we are accumulating between those different sources from GNSS, LEO, GEO or cesium clocks. We can also aggregate sources from the ground, such as eLoran or any terrestrial source that could be activated in the next two or three years. When we switch from one source to another — in the sky, in space, and/or on the ground — we go quickly into holdover so that we don’t have a phase hit during the switchover.

What is your timing source?

Our ground control stations are connected to the NIST to provide a GNSS-independent timing source. So, our solution doesn’t depend on GNSS and its coverage is global and traceable to UTC.

How do LEO and GEO complement each other?

Through Iridium LEO, we’re addressing the encryption, jamming protection, and indoor antenna capabilities that GNSS does not have. However, there are still two missing pieces: spoofing detection and authentication. To address those two gaps of Iridium, we have Fugro Inmarsat GEO, both in L-band and Ku band. Some end users have already approached us and will receive a combination of all three sources — GNSS, LEO and GEO. By the time you get all of those, if anything happens in a critical infrastructure, you’re covered. It is just a matter of your risk profile and how much you want to pay for these services. There is not one service that fits all. The pros and cons of each service are presented in the table above.

What unique capability does VIAVI offer?

We are the only company today that can provide multi-orbit, multi-constellation, multi-band capability. All the solutions — GPS, Iridium and Inmarsat — are L-band, but we are going to come out with Ku band capability, too. Jamming and spoofing Ku band will be much, much more difficult than doing it in L-band, which has already been jammed and spoofed in known warzones, because the frequency is so high and if you get jammed, you can easily switch to a different transponder, and there are many of them. For the defense applications that we are serving, this capability can be the difference between winning or losing a war. We have many engagements with defense accounts, as well as commercial and government accounts and our solution has been embraced very successfully so far.

What performance have you achieved?

We have built spoofing detection into our product for defense-in-depth attacks. We are offering 5 ns accuracy to UTC and can go down to 1 ns accuracy using our new SecureTime eGNSS service. That is breakthrough performance. If you look at GPS, we are at 15 ns with a high-end receiver, but typical receivers are in the 20 ns to 30 ns range, so we’re at least 15 times better than that.

To detect jamming and spoofing, we see all the different signals from space and ground, if any, and map them into our AI fusion software platform that we have, which is our new TrustedPNT technology. These services have been tested and proven in live-sky battlefield scenarios at USAF’s NAVFEST 2024 Test Event in May 2024, including successfully providing assured PNT in a simulated warzone with complete denial of GPS and GNSS services. When attacked, our solution switched from GPS to LEO source and then from LEO to GEO, while surviving the various jamming and spoofing attacks. Once the attack stops, we fail back to GPS. If we add more sources, we will be able to switch from one to another depending on the relevant weaknesses, while amalgamating the different sources to create a solution that is higher in performance than any one constellation by itself.

In conclusion?

Adding an accessory costs a lot less than replacing your legacy clock. Additionally, adding diversified sources from multiple orbits and bands can significantly bolster the robustness and survivability of your overall PNT solution.

Learn more about VIAVI’s new solutions below.