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#21
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Meeting to discuss FLARM in the USA
"Eric Greenwell" wrote in message news:LOsUi.39$MW.24@trndny05... Mark Dickson wrote: On Oct 26, 8:32 am, 5Z wrote: I understand FLARM does a good job of recognizing which gliders in the gaggle may pose a threat. Correct? -Tom Incorrect. Flarm is merely a distraction in gaggles. Its value is between thermals and approaching them. The makers obviously believe this aswell because it has a 5 minute mute facility specifically intended for use gaggles. Does it warn you when a new glider approaches to join the gaggle? That would be useful, even if the gliders already in the gaggle were muted. -- Eric Greenwell - Washington State, USA * Change "netto" to "net" to email me directly * "Transponders in Sailplanes" http://tinyurl.com/y739x4 * "A Guide to Self-launching Sailplane Operation" at www.motorglider.org Keep in mind that Flarm, and for that matter ADS-B, are basically systems for aircraft to exchange position information in real time. What the receiving aircraft does with that information is determined by software. Software, by its nature, is constantly under development. This means that we can expect constant improvement in how traffic conflict is determined and how that information is displayed. We're still very early in this game. Bill Daniels |
#22
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Meeting to discuss FLARM in the USA
As someone else noted, ADS-B is purely a way to broadcast the position,
speed, direction, and altitude of all aircraft. The ability to interpret this data and display or announce it in a way that is meaningful to a pilot will vary greatly from one potential implementation to another. Obviously, gliders need some very specialized collision avoidance algorithms on the receiving end, as we tend to intentionally fly in close proximity to one another. However, that does not mean that the system should be turned off in a gaggle. Rather it means that we need more intelligence in glider specific ADS-B units, so we can determine if there is a collision threat in a gaggle, or if there is an orderly structure to the gliders in the thermal that does not pose any issues. There are lots of times that I am in a gaggle and lose sight of the other glider(s). It would be great to have a way to know where the gliders are that I can't see, in a way that does not provide sensory overload. It would be very interesting if someone could come up with a low cost ADS-B transceiver that had an interface to a PDA (if desired) to handle the processing and display of inbound traffic and weather data. That would make it easy for a lot of different people to get very creative with innovative collision avoidance software, without incurring the big costs associated with hardware development and with certification issues. Mike Schumann "5Z" wrote in message ups.com... On Oct 25, 1:57 pm, "Mike Schumann" mike-nos...@traditions- nospam.com wrote: We don't need FLARM. What we need is a low cost version of ADS-B that is affordable for glider pilots. I agree. But... I doubt ADS-B will have the smarts to provide intelligent warnings and ignore false alerts due to the close proximity we fly in. I understand FLARM does a good job of recognizing which gliders in the gaggle may pose a threat. Correct? -Tom -- Posted via a free Usenet account from http://www.teranews.com |
#23
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Meeting to discuss FLARM in the USA
If you mute Flarm it mutes all contacts. The problem
with it in a gaggle (all Flarm equipped) is that it is constantly going off and it is difficult if not impossible to be sure who it is warning you about; it would certainly not be possible to tell whether the conflict was in the gaggle or joining (at least not with my Swiss Flarm). That said, I don't mute mine and it is a valuable aid to lookout. When thermalling alone or with one other glider it gives early warning of other gliders approaching your thermal and overall it is a valuable addition to a good lookout; as long as others have it. I have only had limited use of mine and my experiences may well be contradicted by others. At 21:18 26 October 2007, Eric Greenwell wrote: Mark Dickson wrote: On Oct 26, 8:32 am, 5Z wrote: I understand FLARM does a good job of recognizing which gliders in the gaggle may pose a threat. Correct? -Tom Incorrect. Flarm is merely a distraction in gaggles. Its value is between thermals and approaching them. The makers obviously believe this aswell because it has a 5 minute mute facility specifically intended for use gaggles. Does it warn you when a new glider approaches to join the gaggle? That would be useful, even if the gliders already in the gaggle were muted. -- Eric Greenwell - Washington State, USA * Change 'netto' to 'net' to email me directly * 'Transponders in Sailplanes' http://tinyurl.com/y739x4 * 'A Guide to Self-launching Sailplane Operation' at www.motorglider.org |
#24
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Meeting to discuss FLARM in the USA
We have been using Flarm devices for the last two seasons and are very
satisfied with its performance, between thermals, near airports and in gaggles. Yes it does warn you of threats in a gaggle and it tends to be surprisingly appropriate (risque de resource intempestive for instance). There may be situations where alarms bother more than they inform, but it's not very frequent, and I personally don't care the extra noise. It's always a shock when you pass a glider coming from the front without having the warning (because it is not equipped with flarm); and despite looking out you surprise yourself not having noticed that particular glider. Don't hesitate: try it in different situations, and you will see how effective the algorithms are. I have been using it for x-country flights, competitions and passenger flights near the airport, at home and abroad (France): not without any more on a day with hundreds of gliders in the air. In addition, cables, towers and other obstacles are listed; flying in the Alps knowing the flarm will tell you about these terrible dangers is so much better. No, you can't rely entirely on flarm warnings, but it does add a lot to your own vigilance. Pascal Duport Geneva Groupe genevois de vol à voile - Montricher |
#25
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Meeting to discuss FLARM in the USA
Aviation Consumer's current issue has an article on traffic-detection
systems. It points out that mode S is already going away and ADS-B in only just beginning to be installed. and that a defect of ADS-B is that several seconds may elapse between the time aircraft A replies to the radar facility, the facility processes the signal and calculates vector information, and then broadcasts this. So this isn't going to help as much as we'd like in gaggles, never mind that it won't be available everywhere for a long time. It sounds as though FLARM is available and functional. It might be possible for pilots to cooperatively use it without an FAA imprimateur, though the FTC will have jurisdiction over the use of frequency. Dan On Oct 26, 4:53 pm, "Mike Schumann" mike-nos...@traditions- nospam.com wrote: As someone else noted, ADS-B is purely a way to broadcast the position, speed, direction, and altitude of all aircraft. ... ...we need more intelligence in glider specific ADS-B units, so we can determine if there is a collision threat in a gaggle, or if there is an orderly structure to the gliders in the thermal that does not pose any issues.... On Oct 25, 1:57 pm, "Mike Schumann" wrote: We don't need FLARM. What we need is a low cost version of ADS-B that is affordable for glider pilots. I agree. But... I doubt ADS-B will have the smarts to provide intelligent warnings and ignore false alerts due to the close proximity we fly in. -Tom |
#26
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Meeting to discuss FLARM in the USA
We should be able to attend the SSA convention in February.
If you wish we can make a presentation about FLARM. We have no reservation whatsoever to sell FLARM in the US, legal questions can be solved, but we would like to get positive feedback from the US soaring community before doing so. Some comments about the recent r.a.s. posts: The frequency in all FLARM units can be set by software, therefore all units work worldwide. The transceiver is designed to meet FCC rules, but we have not yet fully verified this. It transmits at less than 1% duty cycle and (currently) 10mW. "Nuisance alarms" versus "real alarms" will always be a hot topic for any collision warning device in soaring. 1) We can and will further reduce "nuisance alarms" based on pilot feedback and our own continuing research. 2) If the pilot "behaves well" in a gaggle he is much less likely to suffer from "nuisance alarms" as the predicted trajectory will not cross someone else's. 3) One of the unique features of FLARM is that each aircraft performs and transmits its own trajectory prediction based on aircraft type, flight path history and other parameters. This results in superior system performance, especially in high density or heterogeneous traffic environments. It also safes a lot of processing power as each unit only needs to do one sophisticated prediction and then just compares all received trajectories to it. Position and velocity vector is not sufficient information for a smart collision alert, and don't get me started on the cheap "transponder sniffer" devices... ;-) Urs --- FLARM |
#27
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Meeting to discuss FLARM in the USA
danlj wrote:
Aviation Consumer's current issue has an article on traffic-detection systems. It points out that mode S is already going away and ADS-B in only just beginning to be installed. and that a defect of ADS-B is that several seconds may elapse between the time aircraft A replies to the radar facility, the facility processes the signal and calculates vector information, and then broadcasts this. So this isn't going to help as much as we'd like in gaggles, never mind that it won't be available everywhere for a long time. I haven't read the article, but the above is only partially correct. This only refers to the case of an ADS-B equipped aircraft detecting a nearby Mode C or S equipped aircraft. When two ADS-B (more correctly, UAT) equipped aircraft are in proximity, they communicate directly with minimal delay, the ground network and radar facilities are not involved. It sounds as though FLARM is available and functional. It might be possible for pilots to cooperatively use it without an FAA imprimateur, though the FTC will have jurisdiction over the use of frequency. If a FLARM-like device using an FCC approved frequency was available, we could use it without FAA approval. But, our glider population density is much lower than Europe, except in a few areas, and other aircraft are a hazard these days in many areas. ADS-B UAT is a FLARM-like device with regulatory issues that make it difficult to develop a low cost device. It seems to me that the best thing to do is attack the regulatory problem, so that gliders, balloons, light sport aircraft, etc. can all participate in the system at a lower cost... Marc |
#28
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Meeting to discuss FLARM in the USA
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#29
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Meeting to discuss FLARM in the USA
On 26 Oct, 18:18, Ramy wrote:
On Oct 26, 9:07 am, Ian wrote: SNIP [1] and have no intention of doing so: I'm profoundly sceptical about a further increase in the number of things to fiddle with and focus on inside the glider. Why not just look out? Because your human eyes can't detect most threats on time to avoid it, especially gliders and especially if they are comming from behind or the side. The pilots of these gliders should be able to see me - if they are not busy concentrating on yet another electronic gadget in the cockpit. Anyway, my human eyes have successfully detected /all/ threats in time to avoid them so far. How common are midair glider collisions? Ian |
#30
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Meeting to discuss FLARM in the USA
On 27 Oct, 17:08, pascal wrote:
It's always a shock when you pass a glider coming from the front without having the warning (because it is not equipped with flarm); and despite looking out you surprise yourself not having noticed that particular glider. I wonder how well you look (ie one looks) out when a little part of the brain assumes that flarm would have reacted to anything that mattered? Ian |
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