On 10/29/2010 12:51 AM, Andy wrote:
On Oct 28, 9:19 pm, wrote:

Also, to clarify, ADS-B does no path estimation of its own. That
function either would have to be added into an ADS-B unit by the OEM,
similar to the way Flarm does today - unlikely to be done in a glider-
specific way IMO - OR, it would have to be done by a separate external
device, perhaps a navigation computer/software like Oudie, WinPilot,
SN-10. For it to be effective manufacturers would all have to agree to
use the same algorithm, which also seems unlikely, unless they all
adopt the Flarm algorithm. That seems somewhat unlikely too, since I
don't think Flarm would want to start splintering how their algorithms
get used by splitting out the Flarm link technology from the collision
algorithm (which would have to be modified to accommodate the
differences in how path estimations get generated - with unpredictable
results). PLUS the external device OEM's would have to adapt to using
ADS-B inputs - another standards issue.

No matter how hard I try, it seems highly improbable that you will be
able to stitch together a satisfactory collision avoidance system for
gliders using ADS-B technology developed for general aviation. You'd
have to be satisfied with the simple functionality offered by ADS-B -
which would be fine if you generally come into conflict with GA and
airliners more often than other gliders, but there are a bunch of us
for whom the opposite is true. Then the problem becomes some gliders
using Flarm and others using ADS-B, you lose some of the Flarm
benefits of path estimation for the non-Flarm gliders.

9B

9B


You are probably correct that no one is going to beat FLARM in an
optimized collision avoidance solution for high density glider
environments. That's obviously their focus and they are good at it.

However, most recreational, non-contest pilots, primarily need a system
that will reliably alert them to other aircraft in their general
vicinity. If I enter a thermal and know that there are 3 other aircraft
in the area, and I only see two, I'm going to abort and go elsewhere. A
contest pilot obviously wants more data.

What is interesting about the Parowan situation is that this was not a
gaggle of gliders. It was two gliders who apparently did not have a
proper appreciation that they were near each other. A simple graphical
display that showed their relative positions, with a very simple
collision avoidance algorithm, or some form of auditory announcement
could have prevented this accident. That's not to say that the FLARM
simulation was not impressive.

--
Mike Schumann