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Goeff, Mark ,
others.
OzFLARM, which uses the
core FLARM micro has a different way of presenting the information ( see OzFLARM
news ) If a glider is behind you, further than 1 km , a green LED will light up
in that direction. If he is less than 1 km , a RED led will light up. If he is a
potential threat , the red will blink and the audio will go
off.
The core collision
algorithms are the same.
I should have the manual
ready in a few weeks, around the time 66 OzFLARMS are going to be flying around
in close formation at Lake Keepit!
Cheers
Nigel
Nigel Andrews
Managing Director
RF Developments Pty Ltd
"A Queensland Company devoted to Research and Development in
aviation electronics"
Email [EMAIL PROTECTED]
Web www.rf-developments.com
Ph: (61) 7 54635670 Fax: (61) 7 54635695
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Thanks for that Mark. It assists understanding a
lot.
I found it interesting that based on the latter
part of that video, it would be possible to be at the same height and flying
towards (but a tad behind) that other glider ... and not get any warning
unless the tracks intersect or converge ................ and if the
other remains unseen it would be possible to tighten the turn and
converge to get a warning just as they collide.
For some reason I assumed that if you are
constantly getting closer to, but not intersecting with, another Flarm
equipped aircraft, then you would get some type of "heads-up" (poor pun)
warning.
I'm not complaining, mind you, I just want to
understand the way that it operates. It just proves that Flarm is certainly
useful but it is an aid to the "see" of see-and-avoid, but there can never be
any guarantees even if all aircraft are equipped.
On looking at that video again, the LEDs were unlit
during the turn to port and early in the approach to the other aircraft. How
does it indicate proximity as per your 2nd last para?
Regards & thanks for your response
Geoff
----- Original Message -----
Sent: Tuesday, October 25, 2005 2:34
PM
Subject: Re: [Aus-soaring] Zaon Flight
Systems collision avoidance
Geoff Kidd wrote:
> In
trying to understand your explanation, and wanting to fully grasp
>
the way these things work, I looked again at the Flarm video on DG's
> website http://www.dg-download.de/Videos/flarm-rennes.wmv.
>
In that case the display alarms initially at the 12.30/01.00 LED,
>
which is about where the other glider is, when the tracks of the 2
>
aircraft appear to be intersecting but when there also appears to be a
> reasonable height separation ..... and it looks to me like there
was not
> a "risk of collision".
They were on a converging
heading. The FLARM was essentially saying,
"Even though the
separation is high, if you continue the way you
are at the moment you
will probably hit each other."
Note that the alarm tone was different
to what it was later on when
they were
closer.
> The pilot then bears away to
starboard and turns back to port to fly
> directly at or towards the
other aircraft.
Obviously not directly at it, because they didn't hit
each other.
Unless it's directly in front of you, flying directly at the
position
another aircraft is in *right now* will cause you to miss it,
because
by the time you reach that position the other aircraft won't
be
there anymore.
They were on diverging headings during that
phase of the demo, when
the alarm was silent. They were in close
proximity to each other,
but there was no collision risk, so there was no
alarm.
> It looks to me that there is a
greater risk of collision after he
> turns back to port towards the
other ship when it is visible in his
> screen ........... yet the
alarm doesn't sound again until he is
> reasonably
close.
Reasonably close *and converging*.
There is no mystery
to this, Geoff. You can fly as close to another
glider as you
want; but if you're not converging with it, FLARM won't
bother to
sound an alert (it'll still indicate proximity on its visual
display, but
it won't sound an alarm to indicate an imminent collision)
That's the
right answer, isn't it? Nobody wants a "collision avoidance"
system
which chirps continuously just because you happen to be sharing
a thermal
with someone else, do they? What we really want is a
collision
avoidance system which is silent when you're sharing a thermal
with
someone else *unless you're about to hit each
other*.
-
mark
--------------------------------------------------------------------
I
tried an internal
modem,
[EMAIL PROTECTED]
but it hurt when I
walked.
Mark Newton
----- Voice: +61-4-1620-2223 ------------- Fax:
+61-8-82231777
-----
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