The GPS Expansion for the Onion Omega is a USB-based expansion that allows your Omega to pinpoint its location using both GPS as well as China’s Beidou satellite positioning systems. It comes with an on-board GPS antenna as well as a built-in u.FL connector to attach your own antenna. Provides up to 1.8m accuracy, 66 search channels, 22 tracking channels, and -165 dBM sensitivity. Up to 10Hz update rate.
The datasheet for the GPS unit can be found here.