On Sunday, February 1, 2015 at 8:51:09 AM UTC-8, Dave Nadler wrote:
On Saturday, January 31, 2015 at 7:23:22 PM UTC-5, Mike Schumann wrote:
There is nothing inherent in FLARM that makes it superior
to ADS-B in terms of its capability to detect potential glider
to glider collisions. Both technologies transmit the aircraft
location once per second. The resolution of both is limited by
the accuracy of the GPS source. What currently makes FLARM
superior are the collision detection algorithms in the receiver,
which are specifically designed for a glider environment.
There is nothing preventing software developers from developing
similar solutions for use with ADS-B receivers.

The above is utter nonsense.
FLARM transmits the PROJECTED PATH of the aircraft using knowledge
of aircraft type and maneuvering.
ADS-B cannot possibly ever match the collision-avoidance performance
of FLARM for gliders, for this and numerous other reasons.

For anybody interested in actual FACTS as opposed
to authoratively-spoken nonsense on RAS, please see:
http://www.gliderpilot.org/Flarm-WhatDoesItDo

Good Grief...

Thank Dave (who wrote the Flarm software for those out of the loop).

Anyone who has been in close quarters with one or more other gliders can understand the importance of not having multi-second lags in likely flight path conflicts. The prediction engine on the transmitting aircraft is the only way to sort in-close traffic (as opposed to 5mi/1000' traffic).

Mike is right in the sense that the appropriate solution depends on the kind of flying you do. If you fly your glider like a power plane - mostly constant cruise altitude, long straight flight paths, 5mi/1000' separation from other traffic, then ADS-B (when available for installation) might be just fine. But if that's how you fly it might be debatable whether you are a glider pilot in practice.

9B