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

On Thursday, May 28, 2015 at 9:00:06 AM UTC-4, Tim Newport-Peace wrote:


Even if Flarm did open their encoding, DSX is still not Flarm-compatible.
The do not have the predictive algorithm that Flarm does.


That's not true (logically). One need only have open transmission of 3D location, velocity, turn rate. The predictive element of things is done on the receiving end and need not be symmetric. Better predictive capability yields fewer nuisance alarms.

Most US guys, I think, never heard of DSX until this thread. Did DSX and Flarm have an agreement or did they just hack the protocol?


regards,
Evan Ludeman / T8

On Thursday, May 28, 2015 at 6:29:35 AM UTC-7, Tango Eight wrote:
On Thursday, May 28, 2015 at 9:00:06 AM UTC-4, Tim Newport-Peace wrote:


Even if Flarm did open their encoding, DSX is still not Flarm-compatible.
The do not have the predictive algorithm that Flarm does.


That's not true (logically). One need only have open transmission of 3D location, velocity, turn rate. The predictive element of things is done on the receiving end and need not be symmetric. Better predictive capability yields fewer nuisance alarms.

Most US guys, I think, never heard of DSX until this thread. Did DSX and Flarm have an agreement or did they just hack the protocol?


regards,
Evan Ludeman / T8

Actually, the Flarm engineers told me that the prediction is done on the transmit side for Flarm. I'm told this is helpful because it is more accurate in the event of dropped packets, which can happen for a variety of reasons.. Obviously it doesn't work this way for ADS-B traffic. Collision detection and warning is done on the receive side.

There is a bit of benefit in having a consistent algorithm - for instance, in a head-to-head scenario having both systems determine that the traffic is slightly to the right wouldn't be all that great. Glider flying is dynamic and consistent dynamic behavior with humans in the control loop is important. There are other more subtle issues with respect to Stealth mode that also require a single system. Interoperability is generally better if you have a single system design rather than having to rely on adherence to standards.

9B

On Thursday, May 28, 2015 at 7:04:44 AM UTC-7, Andy Blackburn wrote:

There is a bit of benefit in having a consistent algorithm - for instance, in a head-to-head scenario having both systems determine that the traffic is slightly to the right wouldn't be all that great.

[[[[ Sorry, meant to say one says to the left and one says to the right. Dyslexia ]]]]]]

- 9B

On Thursday, May 28, 2015 at 10:04:44 AM UTC-4, Andy Blackburn wrote:
On Thursday, May 28, 2015 at 6:29:35 AM UTC-7, Tango Eight wrote:
On Thursday, May 28, 2015 at 9:00:06 AM UTC-4, Tim Newport-Peace wrote:


Even if Flarm did open their encoding, DSX is still not Flarm-compatible.
The do not have the predictive algorithm that Flarm does.


That's not true (logically). One need only have open transmission of 3D location, velocity, turn rate. The predictive element of things is done on the receiving end and need not be symmetric. Better predictive capability yields fewer nuisance alarms.

Most US guys, I think, never heard of DSX until this thread. Did DSX and Flarm have an agreement or did they just hack the protocol?


regards,
Evan Ludeman / T8

Actually, the Flarm engineers told me that the prediction is done on the transmit side for Flarm. I'm told this is helpful because it is more accurate in the event of dropped packets, which can happen for a variety of reasons. Obviously it doesn't work this way for ADS-B traffic. Collision detection and warning is done on the receive side.

Ah, I made an inference I should not have based on some other conversation. Yes of course: you need data over time to establish trends and projections. And so it absolutely has to be done on the transmission side. Limited range, spotty reception, also less processor demand (processing two dozen other gliders in a thermal might be a little intensive!). Thanks.

-Evan

On Thursday, May 28, 2015 at 7:23:16 AM UTC-7, Tango Eight wrote:

....also less processor demand (processing two dozen other gliders in a thermal might be a little intensive!).

Good add - everyone responsible for their own prediction - do it only once and consistently for everyone in range. Otherwise everyone in a thermal gets a slightly different track prediction based on what data they receive - or algorithm they use. Imagine the dynamic effects as pilots react differentially based on slightly different predictions and create new tracks and predictions, all based on slightly different interpretations of where others are headed. Emergent behavior, possibly not stable, probably unpredictable to a greater extent than normal thermal flying.

9B

Interesting podcast on FLARM.

"In this episode we talk with Gerhard Wesp, Development Manager Avionics at Flarm Technology GmbH about FLARM, a collision avoidance system for gliders and general aviation. We talk about the history of the FLARM system as well as about newer developments such as the PowerFlarm. Mostly, however, we talk about how FLARM works and how PowerFlarm integrates with Transponders and ADS-B systems."

Omegatau - omega tau covers a mix if topics from engineering and science; the selection of topics is guided by our own interest (as well as listener suggestions). Since we have German and English language episodes, the tag cloud is a mix of German and English words. Click on a tag to get to the respective episodes.


http://omegataupodcast.net/2014/03/1...ce-with-flarm/

A look from the engineering point of view.

Dan

I will not be signing the petition.
FLARM is a private enterprise and deserves to reap the rewards of its work.
FLARM is a optional instrument for pilots, not a mandated piece of equipment. The issue with contest pilots being required to use FLARM is an SSA matter.
I would hope that glider pilots choose to install a transponder BEFORE they add a FLARM to their aircraft.

On Thursday, May 28, 2015 at 4:26:08 PM UTC+1, wrote:
I will not be signing the petition.
FLARM is a private enterprise and deserves to reap the rewards of its work.
FLARM is a optional instrument for pilots, not a mandated piece of equipment. The issue with contest pilots being required to use FLARM is an SSA matter.
I would hope that glider pilots choose to install a transponder BEFORE they add a FLARM to their aircraft.

Out of ignorance and curiosity, what are the relative proportions of glider collisions in the US between gliders versus between gliders and CA/GA aircraft?

John Galloway

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