@ranlvor TTIG https://www.thethingsindustries.com/docs/gateways/thethingsindoorgateway/
In my case in a 3D-printed outdoor enclosure, though it also works reasonably well when placed indoors. I think it's one of the most affordable solutions available at the moment.
@derf how do you calculate the distance?
@nicoduck Gateway GPS location(s), which is conveniently part of the MQTT uplink messages. So ± a few km, but sufficiently accurate for this use case.
@derf What gateway-hardware do you use? Asking for a project of mine that is stalled by bad coverage in my area.