[Scan-DC] Tracking system to better pinpoint planes' locations

[Jordan Hayes]

> I wonder how the new system compares to ACARS.  That can be 
> entertaining to monitor.

It has some of the same information, but it's different.  It's a very 
good companion to ACARS; in fact, I know people have asked for the 
ability to fuse the two data streams.  The future is bright :-)

The big deal is that it gives you, once-per-second, location 
information: Lat/Long, Altitude, Speed, Bearing, and climb/sink rate 
(in ft/sec).  So if you have software to plot the track, you get a very 
up-to-date picture of what the aispace looks like.  Each datapoint is 
identified by a unique code which can be translated into a specific 
airframe.  There's room in the data format for a flight number or 
callsign, and many of the systems going into airliners are hooked into 
the flight management system, so you get the flight number.  You also 
get the Mode C ("squawk") code, so that helps to tie things up if you 
are litening to ATC as well.

Here's an example: this is a British Airways 747-400 that has just 
taken off from SFO, crosses over the Golden Gate Bridge and is heading 
for London.  At the point where I took the screen shot, he was just 
going out of range for me and you can see where the data is dropping 
out, but the solid plot is once-per-second.  His code translates to the 
airframe G-BNLX and he was flying as BAW284 that day.  His heading, 
when I lost him, was about 50 degrees; he was doing 384.1 knots; and he 
was ascending through 12,200'.  He was about 8nm from where I was, and 
I was able to snap a digital picture of him a few seconds earlier, 
which I have superimposed into this screenshot.

http://infothecary.org/jordan/sbs/20050918-G-BNLX-BAW284.jpg

I did this shortly after getting the box and I hadn't had time to do 
things like get better maps.  I have a much better map of the Bay Area 
now that includes runway layouts, etc:

http://infothecary.org/jordan/sbs/SF-BayArea.jpg

When I zoom in, I can often catch data points of aircraft taxiing on 
the runways at SFO, and I can tell the difference between a 28L and 28R 
arrival/departure.

/jordan