How we built satellite SOS for Pixel Watch 4

Last summer, members of the Pixel Watch 4 team took a few exciting field trips in the name of research. “We had teams testing in national parks and someone even took a Pixel Watch 4 on a whale watching trip,” says Sharath Ananth, a lead engineer on Pixel Watch who focuses on systems engineering. These outings were part of the research and testing to bring emergency satellite communications to Pixel Watch 4, so people in even the most remote locations can get help when they need it, all from their wrists. ¹

Pixel Watch 4 (LTE) is the first smartwatch on the market to have stand-alone satellite communications. ¹ Bringing this technology to such a small device was complex. “First we thought ‘is this feasible?’” Sharath says. “And once we realized it was, then we thought ‘does it make sense for a watch? Is there value for people?’” Those answers, it turns out, were also yes.

Building satellite SOS for a smaller surface for the first time

The development process was no small feat, and that’s because the device itself was precisely that: small. Normally, a piece of technology that connects to a satellite has multiple antennas, and it can simultaneously connect to terrestrial communications like GPS, Wi-Fi or Bluetooth, even when attempting to connect to a satellite. But given its size, Pixel Watch 4 has fewer antennas than a phone, so it can’t leave all connections on and connect to a non-terrestrial network at the same time. Sharath says the team designed the system to work around this limitation.

The product team designed a system so that if a person attempts to call 911 and terrestrial service is unavailable, the watch automatically switches over and offers the satellite option. If that person then opts for satellite, an initial questionnaire gathers vital information about the emergency.

Once satellite SOS starts, you see a clear demonstration of how to orient the watch for a successful connection and the device will also use audio cues to guide you. After the watch transmits the necessary information, you receive haptic confirmation via vibration, and a "check replies" button guides you to re-establish connection for updates from emergency services as needed.

Tools like the positioning interface, audio cues and haptic feedback are meant to make satellite SOS easy to use, even in stressful situations. As Sharath notes: "What if you're in some kind of position where you can't see the display? We had to take that into account.”

And once you enter satellite mode, you have to finish the process — you’re locked out of other apps while using satellite SOS. (If you accidentally enable it, you simply hit “end satellite mode” to stop the process.) “You can't have any other app running and you can’t just back out — emergencies can be stressful, so we wanted to make it easier to focus on getting help,” Sharath explains. You eventually end the session by selecting the option that says “help has arrived” or “I don’t need help anymore.”

Bringing emergency help to more people

In addition to the aforementioned national parks and whale watching excursions, team members went all around the U.S. to test in different weather conditions and environments, simulating worst-case scenarios in places with little satellite connectivity. This helped them fine-tune the experience to work better in more conditions.

This new feature will certainly offer peace of mind to adventurers. But Sharath believes they aren’t the only ones who benefit from it. But Sharath believes they aren’t the only ones who’ll benefit from it — getting help after a car accident was top of mind for the team during development. “Large parts of the country aren’t fully covered by LTE,” he explains. “I think about getting stranded somewhere, anywhere, and if your phone isn’t working or if you’re injured, this allows you to still activate satellite SOS from your wrist.” Pixel Watch 4 (LTE) means that however an emergency happens, there’s a way to call for help. ¹