In article , "Karl Osen" wrote:
Hello,
Is anyone aware of anti-collision systems (projects or products) for gliders
based on GPS and short range radio? Such systems broadcast position at
random times, allowing equipped vehicles (e.g. gliders) to be informed when
they have a dangerous trajectory relative to other equipped gliders).

May be ADS-B is such a system you are looking for.
See http://www.upsat.com/air_home.shtml
But have a look at the prices!

Peter Nyffeler
Tel P 01 363 62 42, Tel G 01 632 43 60, Fax G 01 632 10 21