Bear wrote:
This would be called "ADS-B". See:

http://adsb.tc.faa.gov/ADS-B.htm
http://www.ads-b.com/

FLARM is more than ADS-B!
It also warns when approaching static obstacles. That is the main reason
why REGA (Swiss Air-Rescue) installed FLARM in their helicopters.

No, you got it backwards, ADS-B is much more than FLARM. ADS-B has
always had provision for fixed transmitters for obstacle avoidance.
Ground stations have the capability to broadcast locations of known
obstacles using datalink capability, along with real-time weather data,
etc. Plus, ground stations will retransmit traffic data derived from
ATC radar, allowing ADS-B equipped aircraft to receive traffic warnings
for mode C/S transponder equipped aircraft.

That said, ADS-B is horribly over-designed, and the current units are
large, power-hungry, and expensive. Hopefully, this will not be true in
5 years or so...

Marc