About that Starlink jamming…

ACK

Shout out to Elon Musk and Starlink for shipping Starlink terminals to the conflict zone. These are a fantastic resource in areas of the world without direct Internet access or in areas that have lost connectivity due to natural or man-made disasters. We hope he continues this practice in the future.

We have thoughts on their “safe” use well beyond what Musk has already tweeted, and we will be covering that in detail in blog posts later this week.

We note this article from the Washington Post that cites Elon as stating that at least some of these terminals are falling out of operation due to jamming and his tweet on the subject.

Our hope is that this is a by-product of other jamming and not direct targeting of the Starlink system itself. All the players in this region have extensive electronic warfare capability, so any of them could be engaging in this action. If Starlink itself is being targeted, that is an indication of much larger issues and a dire security warning for its users.

We suspect that what is actually happening is that the Starlink terminals are unable to get an accurate “self-location fix" due to jamming of one or more of the navigational satellite constellations. Most modern VSAT terminals need a new “self-location fix" whenever they are moved. This is especially true of the Starlink system, which uses a phased array antenna to steer beams as various Starlink satellites pass overhead. This requires a precise self-location fix (as compared to a BGAN VSAT which only "sort of" needs to know where it is).

In other words, Starlink terminals need to know precisely where they are on the Earth. To determine this, they likely use one of the existing navigational satellite constellations.

Starlink probably does this (although it’s also possible that Starlink could be using its own satellite constellation for geolocation, but we don’t believe that is the case). Since we don’t have a Starlink terminal in our possession, we can’t say for sure if it limits its geolocation to just the US GPS (Navstar) system or if it also has the ability to use any or all of the other 5 systems: the EU's Galileo system, Russia's GLONASS system, China’s BeiDou system, India’s IRNSS system plus any of the GNSS augmentation systems (WASS, EGNOS, SDCM, GAGAN, BDSBAS, MASAS, QZSS).

Our belief is that Musk’s tweet contains the answer to this riddle. If Starlink were being directly jammed, it’s unlikely that any software update would be able to fix that problem. More than likely, they shifted the terminal’s dependency from a single satellite navigation constellation, either by shifting to another one entirely or by using all of them in a "super-constellation.”

Both of these methods, including support for the “big three” of GPS, GLONASS, and Galileo, are commonly supported by most “GPS” chips. The “super-constellation” solution is a good strategy, because most military systems of the world depend on their “native” system. It’s unlikely they would jam all of the systems at once. This may change in the future, but for now, that’s likely what’s going on.

The other possibility is that the firmware update told the terminal to use its last fix if it hasn’t been moved. This is also a good solution to this problem, although we haven’t seen any updates on the Starlink website addressing this. If they made that change, we would encourage them to inform users of this fact.

It would also be good to know just how far a terminal can be safely moved without requiring a new self-location fix. Is it tens of feet (meters), inches (centimeters), or literally any movement at all?

Similarly, if the terminal isn’t moved, can it be powered off (and for how long) without needing a new fix? This also raises the issue of the “cold start” geolocation process. “Back in the day,” this could take fully 15 minutes, but most devices now take 2–3 minutes.

A further final possibility is that the Starlink terminals were always doing a “cold start,” and the firmware update changed this to “hot” or “warm.” We don’t think this is likely, but we can’t say for sure.

Questions, questions. If you’ve read this far, please be on the lookout for the next post on “safely” using Starlink.

Vitali Klitschko, Mayor of Kyiv, and his brother Wladimir with Starlink terminals in Kyiv. Source: Kyiv City Council

FIN