Terra aims to build satellite-free positioning by using FM radio broadcasts as fixed reference points, while relying on internet-connected reference receivers to share timing. A demo has already run in Denver, and the project is open-source—meaning anyone can
GPS and GLONASS have made “where am I?” feel effortless. It’s easy to forget how much precision is hiding behind the scenes: reference transmitters, extremely accurate timing, and receivers that do the math.
Terra is betting that the same kind of precision can be achieved without satellites—or the usual network of dedicated ground transmitters. The plan starts with a different cast of characters: instead of relying on systems built around fixed land-based reference transmitters like LORAN and Decca Navigator. Terra uses FM broadcast transmitters as its fixed points.
At first glance, the approach sounds almost backwards. Those classic systems work because they transmit timing information that client receivers can use directly. Terra, by contrast, doesn’t assume access to the transmitters’ timing in the normal way. The workaround is to use the internet as a backhaul.
Rather than broadcasting timing information to every client, Terra depends on a set of reference receivers that share timing online. Client receiver software then uses that shared timing information to calculate position. So far, Terra has run a demo in Denver.
What makes the idea spread beyond a lab, though, is the way it’s built. Terra is open-source, and it doesn’t ask for specialized infrastructure. A relatively inexpensive software defined radio receiver and a computer are enough to operate the system.
If that holds up under wider testing, the implications are immediate and personal. Positioning systems wouldn’t be locked behind government-only access to dedicated networks. Instead, anyone with a group of internet-connected friends could set up reference receivers and build their own local positioning system.
The project also takes its cues from earlier navigation experiments. Terra’s makers have even pointed back to LORAN as a reference point for where the thinking comes from—an acknowledgment that this is an old problem approached with new connectivity.
Terra FM navigation satellite-free positioning GPS alternative software defined radio open-source navigation LORAN Decca Navigator internet backhaul reference receivers Denver demo
So like… it’s GPS but just using radio towers instead? Cool I guess.
I don’t get it—if it’s “satellite-free” then how does it know where you are? Sounds like it still needs some network somewhere. Also open-source doesn’t automatically mean it’s accurate…
Wait, they said FM broadcasts as fixed points so wouldn’t every city have the same signal timing? Like if you tune your radio you should get the location automatically, right? This sounds backwards to me. Denver demo or not.
Open-source positioning is gonna be wild or a disaster depending on how close they are to accurate timing. People are gonna try to DIY this and then act surprised when their “GPS” points to the wrong street. I also saw something about LORAN/Decca in there so now I’m thinking this is just an old system remixed with internet, which feels kinda sus.