SpaceX's Starlink broadband satellites could be used for GPS navigation – Space

> much closer to Earth than GPS in geosynchronous orbit at nearly 23,500 miles (37,800 km).

GPS does not operate in geosynchronous orbits. They’re actually about half that, in Medium Earth Orbit at around 20,000km.

https://www.gps.gov/systems/gps/space/

The article and the statement are frustratingly light on details, but this appears to be an application of the primary author's prior work on navigating by observing the Doppler shifts in LEO satellite constellation frequencies: https://escholarship.org/content/qt9p86d5fk/qt9p86d5fk.pdf

It blows my mind that a private company could create their own GPS service.

I wonder if Tesla vehicles could contain starlink receivers that give Internet access plus geolocation service.