New Channel: "Open Glider Network" / "GliderNet"

[TwinFan]

Current Situation / Problem
Limited GA, no glider coverage in LiveTraffic. GliderNet is not supported as a tracking data channel.

Suggested Solution
Support GliderNet, an open solution.

Benefits
A little increase in GA traffic, adding glide traffic.
Would make LiveTraffic interesting also for sailplane / glider sim pilots.

Additional context
While there are high-level APIs available they require pretty fat libraries to include, which I'm reluctant to do. However, there seem to be just standard request/reply possibilities, which would fit into the LiveTraffic design.

E.g. http://live.glidernet.org/lxml.php?a=1&b=51.7568&c=47.3490&d=15.0239&e=1.0054&z=2 returns something like

<markers>
<m a="48.517132,1.640970,_7a,a90b107a,149,16:41:23,31002,0,0,-0.1,1,LFFL,0,a90b107a"/>
<m a="47.448650,8.209450,SGI,HB-SGI,792,16:41:09,31016,120,178,-3.6,8,Bohlhof,4B302C,991d079d"/>
<m a="49.984921,11.642450,ZG,D-EFZG,476,17:05:53,29532,0,0,0.7,8,EDQD,3D146C,25200416"/>
<m a="50.352421,8.905480,_7e,82b8df7e,349,17:16:03,28922,170,185,-0.2,1,Nidda,0,82b8df7e"/>
<m a="49.602821,7.160050,_af,697429af,508,17:23:29,28476,155,93,-2.7,8,EDRG,0,697429af"/>
<m a="50.061871,11.287950,_00,e5f39900,1107,16:31:33,31592,6,178,1.2,1,EDER,0,e5f39900"/>
<m a="49.601021,8.351350,_59,70bac159,174,17:06:58,29467,63,94,-3.1,2,LuDaN,0,70bac159"/>
...
</markers>

Todos

• Understand the format and how request/reply works
• Design how the data fits into the LTFlightData model. This is not ICAO defined, we need to map and match it somehow to integrate with the existing LT world.
  • Allow other FD a/c keys than ICAO, e.g. FLARM id
  • Provide mapping from FLARM acft type to CSL models like we did for cars already.
• Might need some adjustments to the flight model...gliders aren't Airbusses
• Last but not least we need one or two reasonable CSL models to represent the found gliders.

[TwinFan]

172MC has a glider, downloaded from X-Plane: ASK21

[TwinFan]

Documentation for request/reply is rather thin. The following I consolidated from various sources:

A valid request is as stated here:

http://live.glidernet.org/lxml.php?a=1&b=51.7568&c=47.3490&d=15.0239&e=1.0054&z=2

The Python source code of an alternative OGN backend (the server answering the requests) gives away details of the request and reply format.

• Request Format

show_offline = request.args.get('a', 0, type=int) == 1
    lat_max = request.args.get('b', 90, type=int)
    lat_min = request.args.get('c', -90, type=int)
    lon_max = request.args.get('d', 180, type=int)
    lon_min = request.args.get('e', -180, type=int)

And by trial and error I assume that z is a timezone to which the timestamps are to be converted. As LiveTraffic prefers ZULU/GMT anyway we just leave it out.

• Reply Format

lines.append('<m a="{0:.7f},{1:.7f},{2},{3},{4},{5},{6},{7},{8},{9},{10},{11},{12},{13}"/>'
                     .format(aircraft_beacon.location.latitude,
                             aircraft_beacon.location.longitude,
                             competition,
                             registration,
                             aircraft_beacon.altitude,
                             utc_to_local(aircraft_beacon.timestamp).strftime("%H:%M:%S"),
                             elapsed_seconds,
                             int(aircraft_beacon.track),
                             int(aircraft_beacon.ground_speed),
                             int(aircraft_beacon.climb_rate*10)/10,
                             aircraft_beacon.aircraft_type,
                             aircraft_beacon.receiver_name,
                             address,
                             code))

Aircraft type is likely the FLARM type, field ACFT as in the FLARM specs.

[TwinFan]

Sent a mail to contact [at] glidernet.org, asking permission to use the data.