On Tue, 28 Jan 2003, Mathew McBride wrote:
> I have some more info on this in a seperate thread:
> http://seneca.me.umn.edu/pipermail/flightgear-devel/2003-January/014707.html
My message is probably fully off-topic here, but then again; maybe
not...
I'm a rookie here. Don't want to know the virtual damage I've done to
the virtual planes I flew. I'd like to throw in a few observations based
on comments you made, and some of my own.
> 1) IVAO. This is more of a european network, but with much better
> connections in other parts of the world (Australia). I belive they use their
> own server, and you can download it from
> http://www.ivao.org/network/default.htm. I use this network
They've got a nice assortment of info in addition to the virtual live
world. But it once again struck me that there is no open (as in, at
least GPL/LGPL, or BSD styled) repository of aviation related data. I've
pieced together some databases myself (country registration prefixes,
airline data, aircraft data, ACARS codes), but I rate this collection
Personal Use because of unclear licensing of the base data gleaned from
web sites (and the way data is presented, such as on the IVAO web site,
makes it pretty obvious that you're not supposed to feed that data into
your personal database).
Is there any web site that has a meta-database of available info, that
specifies license restrictions? Am I overlooking any sources of data?
Would a Sourceforge project dedicated just to avdata make sense to
anyone?
It's all window dressing as far as I'm concerned, but it is nice to be
able to augment
PH-HZF HV0992 H1 #M1BPRG/FNHV0992/DTEHAM,19R,77,014711,29C98F
with
B737-8K2 delivered 06/11/99
Flight: Transavia 992
Destination: Schiphol Apt, Amsterdam, The Netherlands
Runway: 19R
ETA: 01:47:11
without having to perform a gazillion of web lookups, followed by
parsing the HTML response.
> Some other FG comms stuff on my long term radar:
> 1) ACARS. Hey, aircfaft don't communicate over voice completely. They do use
> Text comms some times.
In my copious spare time, I've been playing the sorcerors apprentice at
DSP coding and come up with a Unix tool to decode ACARS from a radio
receiver with a sound card. It sort of works (I'm not really impressed
with the number of packets I decode successfully, but when working from
recorded chirps my code seems to beat SkySweeper, and it certainly beats
WACARS and KRACARS that I never got to work properly :-)
Given how sparse ACARS info is, I think that free-text is the only
viable part of ACARS to emulate. Even something as simple as a position
report comes with many options to represent the data (some conflicting
with observed practice; possibly as a result of comms error on board,
but not showing up through parity error or CRC failure).
As an illustration of just how perilous parsing ACARS data is without
access to the airline specs, I've seen WACARS decode a weather report
for traffic enroute to EGLL into "Wanxian - China" simply because "WXN"
was in the string.
The biggest brick wall I run into is lack of redistributable reference
data; and, of course, lack of documentation on the data that travels
ACARS.
My personal impression is that most people collecting and publishing
such data got bitten by con artists taking off with the fruits of their
labor; a practice that seems common in the MSFS and MSTS communities; in
that sense (as well as many others), FlightGear is a breath of fresh
air.
Anyway, I'm looking for guidance on how to approach this ACARS toy
project of mine. It's easy enough to register the thing on SourceForge
and put some code out, but it's a different thing altogether to bundle
it with enough data to make sense of the packets, and not run afoul of
licensing issues. The DSP bits probably make more sense in the HAM
community, but the ACARS data components drag if firmly back into the
realm of the aviation emulators (how's about the AI Tower Controller
warning you about conflicting traffic that actually is overhead of where
you're playing FlightGear, or even warning that TransAvia flight that
there is a rogue Cessna in the pattern and would the Cessna turn left
_now_?).
Cheers,
-- Bert
--
Bert Driehuis -- [EMAIL PROTECTED] -- +31-20-3116119
If the only tool you've got is an axe, every problem looks like fun!
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