On Saturday, January 31, 2015 at 4:23:22 PM UTC-8, 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.


According to the Flarm technical guys I've spoken to this is not a correct statement.

They have told me directly that the position prediction happens on the transmit side not the receive side. This makes Flarm less prone to errors due to latency and dropped packets - unlike ADS-B. This is one reason why if a Flarm receives a Flarm packet and and ADS-B packet from the same aircraft, it ignores the ADS-B packet.

In any case - you can buy a Flarm now and then wait and see whether Garmin decided to implement glider-specific anti-collision algorithms. Might be a long wait.

Hope is hardly ever a very good strategy.

9B