The principle of what's been referred to here as "filtering" is based on
the fact that if a glider is, say 2km from you (as per a flarm
transmission) and if a flarm message is transmitted once per second, then
if the receiving flarm fails to receive a transmission a second later with
an updated position, this obviously does not mean that the glider just
vanished, it is obviously still there somewhere probably still close by.
So the question is: what to display in that case? One possibility is to
predict it's position based on the last vector or series of vectors
received. This is not trivial!
I am assuming that Butterfly would consider their implementation a
value-added competitive advantage and wonder how will they respond if
asked.....
There are other displays in the market that seems to be of the "smart"
kind, such as the LXNAV flarmview
http://www.lxnav.com/products/flarmview.html From V7 discussions, my
understanding is that the LXNAV folks are very responsive and they may be
more open to discussing what, if anything, they are doing in their display.
On Tue, Sep 11, 2012 at 9:45 AM, Ramy Yanetz <[email protected]> wrote:
> Just to clarify, I did not notice slower response on the butterfly. If
> there is, it is very short and not significant. So the current
> implementation in XCSoar does not really provide a more instantaneous
> advantage. As other pointed out, XCSoar Flarm radar is more for situational
> awareness while the butterfly display is the real collision avoidance
> device. As such, it will be much better for situational awareness to
> implement the same filtering as butterfly implements, so you can actually
> monitor the traffic around you instead of trying to catch a blinking target.
> It would be great if we could get clarification from butterfly. I hope
> XCSoar developers can get this information from butterfly or from Flarm
> developers.
>
> Ramy
>
> On Sep 11, 2012, at 2:04 AM, Henrik Bieler <[email protected]> wrote:
>
> > Hey,
> >
> > I think both approaches (filtered output vs. instantaneous) have their
> > advantages and disadvatages.
> >
> > What makes a filtered output appealing to me is:
> >
> > -Extended usable range:
> > A circling glider at the outer limit of the reception range will
> > appear and disappear as target depending on the momentary antenna
> > geometry. Such a target coming on and off just to show me the
> > limitations of my FLARM does not seem reasonable to me. I might be
> > interested in the climb rate of the other glider and it would be an
> > improvement to see the last received data. So you can spend the time
> > looking outside instead of waiting for the target to come back on.
> >
> > -An average climb rate feature would give information which is probably
> > more useful for decision making.
> >
> > The advantages of instantaneous display are:
> >
> > - No wrong or outdated information
> > -Faster response
> >
> >
> > How about combining some of the advantages?
> >
> > Wouldn't it be possible to keep the instantaneous display and whenever a
> > target is not received anymore, the last position data received is still
> > displayed with the average climb rate.
> > Maybe the Glider Symbol could change color when reception is lost or the
> > Callsign could be prefixed by an Asterisk or such.
> >
> > What do you think?
> >
> > Greets Henrik
> >
> > Am 11.09.2012 09:38, schrieb Michael Huber:
> >> Von: Ramy Yanetz [mailto:[email protected]]
> >> Gesendet: Dienstag, 11. September 2012 01:59
> >>
> >>> Now perhaps the butterfly display has indeed a built in filter which
> continuously
> >>> interpolate the other target position based on changes in my position
> and heading,
> >>> I cant tell.
> >> The significant delay of the Butterfly display reported by Sascha might
> be a hint that some kind of filtering is implemented.
> >>
> >>> But whatever it is doing is better than blinking traffic/blinking
> radar in XCSoar. I
> >>> recommend implementing the same logic in XCSoar.
> >> Sorry, I have to disagree. Bad or no reception in some relative
> positions is an issue of the original FLARM implementation (single antenna)
> in a carbon fuselage, and not something that can be solved by software.
> There simply is no FLARM data available at this time, and any display
> showing a target is simply guessing its position. This guessing may work
> for centered thermalling, but will definitely be wrong when someone leaves
> a thermal. If I have to choose between correct and convenient (but
> incorrect) data, I choose the correct one.
> >>
> >>> But if this is not a problem with my implementation, am I the only one
> noticing it?
> >> A possible reason: In Europe pilots started to use FLARM with lower
> expectations. We used the very simple LED display, and just to get a hint
> that there is some other glider in an approximate direction was considered
> useful (there even wasn´t any relative altitude info available in the
> beginning!) . FLARM was considered as an additional chance to find traffic
> you might have missed, not as a tool to get situation awareness. And we got
> used to FLARM limitations, that are clearly stated in the manual by the
> way. Today we have radar like displays that are great, but may create a
> false impression and wrong expectations, if people don´t consider the
> limitations underneath.
> >>
> >>> I am pretty sure it is not a problem with my powerflarm installation
> since I already
> >>> tried couple of antenna locations and I can see traffic more than 5
> miles away.
> >> Unfortunately, this proves exactly nothing. You may have a range of
> 5miles in some directions, and not half of a mile in a different direction
> or to a different aircraft. Even if FLARM range analysis (
> http://www.flarm.com/support/analyze/index_en.html) shows good range in
> all directions, it does not mean that you will see any target in that range.
> >>
> >> Michael
> >> PS: Your pictures at soaringcafe are great!
> >>
> >>
> >>
> ------------------------------------------------------------------------------
> >> Live Security Virtual Conference
> >> Exclusive live event will cover all the ways today's security and
> >> threat landscape has changed and how IT managers can respond.
> Discussions
> >> will include endpoint security, mobile security and the latest in
> malware
> >> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> >> _______________________________________________
> >> Xcsoar-user mailing list
> >> [email protected]
> >> https://lists.sourceforge.net/lists/listinfo/xcsoar-user
> >
> >
> >
> ------------------------------------------------------------------------------
> > Live Security Virtual Conference
> > Exclusive live event will cover all the ways today's security and
> > threat landscape has changed and how IT managers can respond. Discussions
> > will include endpoint security, mobile security and the latest in malware
> > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> > _______________________________________________
> > Xcsoar-user mailing list
> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/xcsoar-user
>
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Xcsoar-user mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/xcsoar-user
>
------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and
threat landscape has changed and how IT managers can respond. Discussions
will include endpoint security, mobile security and the latest in malware
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
_______________________________________________
Xcsoar-user mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/xcsoar-user
