This sounds like a bit of a mixture of ideas. The GPS helps with time for the gateway but it doesn’t add to the data from the devices. It’s not expected that gateways are moving.
Which limitations of TTN are you thinking of?
As for Tago, it doesn’t connect to a gateway, almost nothing does, the gateway is a radio receiver that passes whatever it hears on to the network server it’s been told to talk to. Tago will connect to an application / device which is sending data through the TTN network:
If your devices have a location (from GPS or other means), Tago can put it on a map: