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

On Thursday, May 28, 2015 at 10:26:08 AM UTC-5, wrote:

I would hope that glider pilots choose to install a transponder BEFORE they add a FLARM to their aircraft.

I would hope that glider pilots choose to install a PowerFLARM BEFORE they add a transponder to their aircraft, unless they routinely fly in airspace with lots of airliners (TCAS-equipped).

Why? Because with a PowerFLARM, the glider pilot can actively avoid transponder and ADS-B (mode S-ES) equipped aircraft, as well as other PF-equipped gliders that are likely to join him in a thermal. With only a transponder, your protection is entirely up to the OTHER aircraft, and in the case of most VFR traffic, will provide almost NO protection.

Of course, the best solution is to have both a transponder and PF....

Kirk

There is no "predictive" algorithm. See my previous post, and there are no
differences according to the people that for many years have been using both
technologies.
The assertion "do not have the predictive algorithm that Flarm does."
reminds me of old detergent advertising campaign.

The other thing you say "As I understand it the Easter Egg was to ensure
that users were on reasonably
up-to-date Firmware." makes me instead ask you : what if Bosch would have
placed a similar "easter egg" in their ABS BREAKING SYSTEM of you car?
Because this is exactly the same.

How long have you been using a Flarm, Tim?

"Tim Newport-Peace" wrote in message
...

At 12:22 28 May 2015, pcool wrote:
Oh?

Even if Flarm did open their encoding, DSX is still not Flarm-compatible.
The

The differances are too great.

When you say "straw manning" you are talking about yourself, right?
Because In my previous post I have pointed you to a real predictive code,
and explained why there is no prediction but a simple projection in a flarm.


"Andy Blackburn" wrote in message
...

On Thursday, May 28, 2015 at 5:22:47 AM UTC-7, pcool wrote:

Who is incompatible with who? You have the freedom to choose a device
manufacturer.

Well, there is one device that is installed in 25,000 gliders worldwide and
one that is installed in...how many? 500? People can decide which is the
tail and which is the dog when it comes to wagging. I think if I showed up
in most European countries with an electrical device requiring 110 volts I
would not get agreement that the entire continent is incompatible and needs
to change to 110 volts.

The TAdvisor, and probably the OGN devices soon, are not worst than flarm
to do this job.

That isn't even how they talk about themselves.

Here is what T-Advisor says about the themselves: "The functioning idea of
the T-Advisor is not the one of an Anticollision or Collision Avoidance
System, rather the one of the Traffic Advisor, an Early Warning System."

OGN's main purpose is tracking, not collision detection. Here is what they
say about themselves: "The objective of the Open Glider Network is to create
and maintain a unified tracking platform for gliders and other GA aircraft.
Currently OGN focuses on tracking aircraft equipped with FLARM,
FLARM-compatible devices or OGN tracker."

Hair-splitting and straw-manning are not a productive ways to advance the
conversation.

9B

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 7:35:51 PM UTC+1, pcool wrote:
There is no "predictive" algorithm. See my previous post, and there are no
differences according to the people that for many years have been using both
technologies.
The assertion "do not have the predictive algorithm that Flarm does."
reminds me of old detergent advertising campaign.



Each Flarm unit broadcasts a prediction of its own flight path over the next 20 seconds or so. It isn't a simple projection of the current instantaneous vector. It will be straight or curved or circling depending on how Flarm analyses the current mode of flight. There are also airspeed dependent vertical "buffers" e.g. a slow moving glider is unlikely to zoom up but could dive whereas a very fast moving glider can zoom up a long way. Each Flarm unit within range compares its own predictive flight path with others that it receives. Unfortunately Flarm's new website no longer holds their original Power Point presentation that, amongst other things, explains this pictorially.

The DSX T-Advisor manual (referenced again below) explains on page 3 why they do not follow the same predictive approach as Flarm and hence they confirm that they understand the difference even if pcool does not. DSX claim that "prediction of the trajectory of a glider at times 10 or 20 seconds after the present one, can be too often unreliable". The experience of 25,000 Flarm units show that this is not the general perception of pilots although everyone using Flarm needs to understand the limitations - e.g. that Flarm alerts are related to track and not heading so in a strong crosswind and flying at slow airspeed on a ridge the direction of a threat may be coming from a rather different direction to that shown on a simple Flarm LED display. The increasing use of Flarm "radar" displays helps by giving additional situational awareness of other Flarm equipped gliders

http://www.soaringwear.com/uploadz/0...r_07_12_19.pdf

We did a study of original Swiss Flarm in 2007 in Scotland which is still generally relevant - albeit out of date as regards the hardwa

http://old.gliding.co.uk/bgainfo/saf...larmreport.pdf


John Galloway

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 11:41:49 AM UTC-7, pcool wrote:
When you say "straw manning" you are talking about yourself, right?

Are we in 4th grade?

I was referring mostly to Lucas' misinformed and obfuscating rant, but also to your inaccurate comments minimizing the difference between traffic advisory and path-dependent collision warning. It is quite a big difference.

9B

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