Well, if a flarm-equiped glider 200m away cannot be detected, then I'd
assume someone's installation must be really really bad.....
To be clear, I am not advocating implementing this kind of filtering (yet).
I don't think we even know this is something the Butterfly display actually
does, do we? At this point, we are still speculating based on Ramy's
observations here. I personally have zero flight experience with Flarm of
any kind and with the XCSoar flarm display capabilities.
David
On Tue, Sep 11, 2012 at 11:48 AM, Michael Huber <[email protected]>wrote:
> 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?
>>
>
> The issue is not with a glider that is 2km away. Filter it or not, keep it
> on the last known position for a few seconds or try to predict its position
> from its last vectors, it doesn´t matter much as long as it is still 2km
> away.
> For a glider only 200m away or even in the same thermal it will make a
> difference. When no transmission is received some clever algorithm may
> predict that the other glider is still circling with a constant turn rate
> like a few seconds before, while in reality he decided to leave the thermal
> and dashes through the core right next to you.
>
> "After a short distraction, you realize that you have lost sight of the
> other glider thermalling with you. You immediately check on your [**
> superclevermotionpredictingbra**nd] FLARM radar and see he is now in your
> blind spot, but still circling nicely with a constant distance from you.
> You start to relax as you suddenly hear a loud bang..."
>
> If no FLARM transmission is received, then no data is available. Even the
> best motion prediction algorithm in the world can´t change that. If any
> predicted data was shown on the XCSoar FLARM radar, it should be
> immediately evident that this is predicted only, and not actual data.
>
> Michael
>
>
>
>
------------------------------------------------------------------------------
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
