Help us with this petition for security on anti-collision systems

At 18:35 28 May 2015, pcool wrote:
There is no "predictive" algorithm.

This does appear to be true.. The previous flarm protocol is
documented here

http://tinyurl.com/opgtogo

I haven't personally verified (all) of it, but it certainly has all the
marking that it is correct, and there really doesn't appear to be any
'prediction' there at all. A similar document for the new protocol exists
too, it shouldn't be too hard for you to find it.

I would like comments from those who said there was prediction. What
made you think there was, how does this change your thinking and
have you heard the tale of the Emperor's New Clothes?

On Thursday, May 28, 2015 at 9:00:06 PM UTC+1, Buddy Bob wrote:
At 18:35 28 May 2015, pcool wrote:
There is no "predictive" algorithm.

This does appear to be true.. The previous flarm protocol is
documented here

http://tinyurl.com/opgtogo

I haven't personally verified (all) of it, but it certainly has all the
marking that it is correct, and there really doesn't appear to be any
'prediction' there at all. A similar document for the new protocol exists
too, it shouldn't be too hard for you to find it.

I would like comments from those who said there was prediction. What
made you think there was, how does this change your thinking and
have you heard the tale of the Emperor's New Clothes?

This link concerns the radio protocol for communication between Flarms - the proprietary nature of which is what the OPs petition is about - but that is a separate issue from what Flarm units actually broadcast.

At 20:11 28 May 2015, wrote:
This link concerns the radio protocol for communication between
Flarms -
the proprietary nature of which is what the OPs petition is about - but
that is a separate issue from what Flarm units actually broadcast.


and 5 mins before that you wrote

Each Flarm unit broadcasts a prediction of its own flight path over
the nex=
t 20 seconds or so. It isn't a simple projection of the current
instantane=
ous vector.

Please can you rationalize this in the context of the published protocol
specification?

On Thursday, May 28, 2015 at 4:00:06 PM UTC-4, Buddy Bob wrote:
At 18:35 28 May 2015, pcool wrote:
There is no "predictive" algorithm.

This does appear to be true.. The previous flarm protocol is
documented here

http://tinyurl.com/opgtogo

I haven't personally verified (all) of it, but it certainly has all the
marking that it is correct, and there really doesn't appear to be any
'prediction' there at all. A similar document for the new protocol exists
too, it shouldn't be too hard for you to find it.

I would like comments from those who said there was prediction. What
made you think there was, how does this change your thinking and
have you heard the tale of the Emperor's New Clothes?

Two flarm equipped gliders fly parallel to one another at 80 kts with 300' separation and -- as long as the flight paths are not convergent -- flarm gives no alarm. If the paths become convergent, alarms result very quickly. As soon as the paths become parallel or divergent, the alarms cease. The same two gliders now fly a head on approach, again at 80 kts. Flarm gives a warning at significant range... over a mile... and the warning ceases almost immediately when one glider changes his track. From this I believe it should be clear to anyone that the way flarm works is most likely just how they've said it works: by estimating what airspace any given glider is capable of occupying in the next +/-30 seconds and looking for potential conflicts.

-Evan Ludeman / T8

On Thursday, May 28, 2015 at 2:16:55 PM UTC-7, Tango Eight wrote:
On Thursday, May 28, 2015 at 4:00:06 PM UTC-4, Buddy Bob wrote:
At 18:35 28 May 2015, pcool wrote:
There is no "predictive" algorithm.

This does appear to be true.. The previous flarm protocol is
documented here

http://tinyurl.com/opgtogo

I haven't personally verified (all) of it, but it certainly has all the
marking that it is correct, and there really doesn't appear to be any
'prediction' there at all. A similar document for the new protocol exists
too, it shouldn't be too hard for you to find it.

I would like comments from those who said there was prediction. What
made you think there was, how does this change your thinking and
have you heard the tale of the Emperor's New Clothes?

Two flarm equipped gliders fly parallel to one another at 80 kts with 300' separation and -- as long as the flight paths are not convergent -- flarm gives no alarm. If the paths become convergent, alarms result very quickly. As soon as the paths become parallel or divergent, the alarms cease. The same two gliders now fly a head on approach, again at 80 kts. Flarm gives a warning at significant range... over a mile... and the warning ceases almost immediately when one glider changes his track. From this I believe it should be clear to anyone that the way flarm works is most likely just how they've said it works: by estimating what airspace any given glider is capable of occupying in the next +/-30 seconds and looking for potential conflicts.

-Evan Ludeman / T8

Yes. I'm surprised this is even coming up, except as a deliberate effort to obfuscate important differences between the various technologies and why they may not be compatible.

Anyone with a rudimentary knowledge of aircraft dynamics and even a single day's flying with FLARM has to conclude that it is making path-dependent collision prediction estimates. You have to fly in a few thermals to pick up that the path prediction is curved when you are turning.

Flarm engineers have told me explicitly that the prediction is done on the transmit side and I can see why this would work better for the reasons previously raised. The specification may or may not need to specify this as a communications protocol generally needn't include a specification of the data payload or the algorithm to create or interpret it.

9B

oh com'on, at the beginning of this thread I stated I did not sign the
petition. There is no deliberate action of any kind.
Simply you keep calling prediction what is really a projection.
If you are turning, it projects accordingly . It doesnt predict you are
turning.
"prediction" is a marketing word here. There is no computational power to
predict anything, inside the flarm.
But let it go, it does work, this is out of any question. We have been using
it since 2005.


"Andy Blackburn" wrote in message
...

On Thursday, May 28, 2015 at 2:16:55 PM UTC-7, Tango Eight wrote:
On Thursday, May 28, 2015 at 4:00:06 PM UTC-4, Buddy Bob wrote:
At 18:35 28 May 2015, pcool wrote:
Two flarm equipped gliders fly parallel to one another at 80 kts with 300'
separation and -- as long as the flight paths are not convergent -- flarm
gives no alarm. If the paths become convergent, alarms result very
quickly. As soon as the paths become parallel or divergent, the alarms
cease. The same two gliders now fly a head on approach, again at 80 kts.
Flarm gives a warning at significant range... over a mile... and the
warning ceases almost immediately when one glider changes his track. From
this I believe it should be clear to anyone that the way flarm works is
most likely just how they've said it works: by estimating what airspace
any given glider is capable of occupying in the next +/-30 seconds and
looking for potential conflicts.

-Evan Ludeman / T8

Yes. I'm surprised this is even coming up, except as a deliberate effort to
obfuscate important differences between the various technologies and why
they may not be compatible.

Anyone with a rudimentary knowledge of aircraft dynamics and even a single
day's flying with FLARM has to conclude that it is making path-dependent
collision prediction estimates. You have to fly in a few thermals to pick up
that the path prediction is curved when you are turning.

Flarm engineers have told me explicitly that the prediction is done on the
transmit side and I can see why this would work better for the reasons
previously raised. The specification may or may not need to specify this as
a communications protocol generally needn't include a specification of the
data payload or the algorithm to create or interpret it.

9B