PNT by Other Means: Satelles

An exclusive interview with Dr. Michael O’Connor, CEO, Satelles. For more exclusive interviews from this cover story, click here.

How many Iridium satellites carry your system?

Mike O’Connor

Iridium has 66 active satellites. There are also several spares on orbit. The satellites were all launched between 2016 and 2018, so they are all relatively new. They cover the entire globe, 24 hours a day, seven days a week, so they have universal coverage.

How will your constellation grow?

Today, our Satellite Time and Location (STL) service is offered only over the Iridium satellites. There’s nothing else that we’re discussing publicly. It could expand over time to other satellites. The signal and the capability are flexible. In terms of how Iridium could change, that’s more for Iridium to discuss than us.

Who makes chipsets that can use your system? And how does that work?

We work with partners. For example, with Adtran (through their Oscilloquartz product line), Jackson Labs (now VIAVI Solutions), Orolia (now Safran Trusted 4D). Companies like that provide the solutions that are favored by critical infrastructure providers today. We provide them either reference designs or effectively referenced designs. They ultimately integrate our STL capability into their solutions. We help them to do that. They can use our reference designs or create their own custom designs based on our reference designs. So, that’s the model that we use.

Is the STL receiver on top of a traditional GNSS receiver and passing certain data to it?

STL is used in two ways. In some cases, users are trying to do positioning or timing in an environment where GNSS signals will not reach, such as indoors, or are otherwise unavailable. In those cases, it wouldn’t be overlaid with GNSS, it would just be a standalone solution.

In many other cases, the goal is having a solution that is resilient to an outage, interference, jamming, spoofing, those sorts of things. In that case, the receiver card that might be provided by one of our partner companies would have both GNSS and STL capabilities and would take the best of both worlds. If GPS is jammed or there’s interference, then the STL signal alone would be sufficient to do PNT. However, whenever both signals are available and can be authenticated, then it would use both and leverage the benefits of having two systems.

Does the location calculation take place in a GNSS chip or separately in the STL?

The chain to take measurements of the STL satellite signals is different. It’s not a single chip that’s measuring both satellites, it’s ultimately two chips that are making those measurements. Then how the position calculation and the integration of those signals is done is left to our partners. In some cases, it is proprietary to the partners that are doing that integration work. It can be integrated loosely or tightly.

When it’s just the STL chip, is that usually for timing purposes, or both timing and location?

Generally, an STL-only solution is best suited for timing. It’ll do timing at about 100 ns, depending on what kind of oscillator is being used and the exact configuration of the product.

What positional accuracies can you achieve?

Generally, in the 10 m to 20 m range, depending on the product configuration.

Most of the correction services refer to variables that are not relevant to your system.

That’s right. There are other techniques, such as integrating with other sensors, that can improve the accuracy. The primary uses for STL today are in delivering timing in environments where GNSS is not able to do so today, such as for national critical infrastructure. That’s been our commercial focus as a company.

Who currently uses the STL receivers? Which markets are you targeting first?

Most of our users are in the data center space. Stock exchanges around the world are also using our service as a source of resiliency, and now wireless infrastructure. So, think 5G infrastructure. As 5G networks are rolling out, they need about five to ten times more nodes to cover a geographic area than 4G networks. GNSS has been used for years to time 4G networks, but most 5G network sites — such as femtocells and picocells — are indoors or in places where GNSS is challenged. We deliver that timing service indoors, outdoors, everywhere. So, those are the three commercial markets where we have the highest adoption rates.

You still have plenty of room for expansion in that market before you must start thinking about expanding into other areas.

Yes, there’s plenty of room for expansion into those markets, so I wouldn’t say that they’re fully saturated. We are also looking into other opportunities. We’ve seen interest in the energy area. I think the industry is a little bit slower moving, but the need is ubiquitous, right? We all recognize that a black swan event in our society would really represent a bad day and we want to avoid that.

There are several companies across the industry that are trying to solve that important problem. Everyone involved in critical infrastructure that requires a timing reference — which is anything that is associated with a network activity — should have an alternative or augmentation to GNSS as a timing source. It’s great that we’re seeing tailwinds from the U.S. Government, from the European Union, and from others to try to encourage that adoption. However, there’s still a long way to go before we really feel that that’s been sufficiently covered.

What, if any, have been the major developments in the past year or so?

One of the most interesting things that has happened over the last year and a half has to do with our capability regarding STL. We’ve been demonstrating more publicly, and with more independent authorities, the capabilities, resiliency, and operational characteristics of our service.

For example, the JRC study.

It started with the U.S. Department of Transportation (DOT) a couple years ago, but there’s also been some work done by the Department of Homeland Security and with the National Institute of Standards and Technology (NIST). We’ve been working directly with NIST to do some validations, as well as with UK and European organizations. They have subjected STL to rigorous third-party, hands-off technology evaluations. They confirmed the timing accuracy specifications to UTC and validated the operational characteristics of STL, such as the resilience in the absence of GNSS, the ability to receive the signal indoors, and having global availability.

We’re delighted to see the third-party operational evaluation of things that we’ve known all along but are now being evaluated and confirmed by these government sources. Beyond that, of course, there are always going to be technology advancements, both with our company and with other companies.

The real focus of industry right now is on adoption. All the providers of these capabilities ultimately need adoption in industry to remain active and viable. These are good people trying to do the right thing to protect our society. There are many great technology solutions out there to do it. Hopefully, many of these solutions are adopted in the near term. That’s what our focus has been. Our focus has not been on squeezing an extra five nanoseconds out of performance, although, of course, we’re always doing that. I think the important focus of industry should be driving adoption. There are solutions available today, including ours, that are ready to go and are being proven operationally in use.

Can you say more about the study by the European Commission’s Joint Research Centre (JRC)?

If you look at the summary, all these technologies that were demonstrated worked. Both the DOT report and the JRC report effectively summarize that there are multiple technologies out there today that are ready to go.