[aprssig] Another kind of SmartBeaconing?
Scott Miller
scott at opentrac.org
Tue Aug 21 18:00:47 EDT 2007
I considered adding some geofencing-based profile switching options to
the OpenTracker, but so far I haven't gotten around to it. I can
probably manage it on the Tracker2. It'd most likely take the form of a
series of conditions (inside box, outside box, etc) that'd trigger
configuration commands (e.g, INTERVAL 10).
The trackers don't need to be certified by the FAI, do they? I know
they have some requirements for loggers. The hardware that ran the
first OpenTracker (and its NMEA parsing code) were originally built as
part of a paraglider datalogger project.
Scott
N1VG
Rikard Sohlberg wrote:
> I would like to throw out a question.
>
> I use APRS for tracking gliders (sailplanes). From humble beginnings
> here in Sweden, it has grown into a big success, almost turning a niche
> sport/event into a spectator sport. Watching a sport where the track is
> anywhere from 150 to 500 km (when will you boys go metric… ;.) used to
> be a problem. Now we have some 25 trackers active in Swedish gliders,
> and everybody loves it. And, yes, it is perfectly legal, even when there
> is no ham onboard. Of course I can’t speak for all jurisdictions, but at
> least in Sweden, we are OK.
>
>
>
> Now to my problem or question. We have tried SmartBeaconing and fixed
> interval beacons. Neither one serves a glider particularly well. A
> glider (when it leaves to vicinity of the airfield), typically circles
> in a thermal to gain altitude and then flies in a straight line to get
> around the track. Tests of SmartBeaconing has shown that it is not well
> suited to this kind of motion. In fact, it gives the exact opposite of
> what we want, se below. Also, to have an exact fix when the glider is
> 200 km away is not needed. What is needed, though is fast updating at
> the end of the track. Incredible as it may seem, many competitions end
> up with the gliders chasing each other within a few meters (ehh… feet
> any one…;-) apart in the race to the finish line. And that is often the
> case after flying a track of, say 300 km and 3-4 hours. Speeds are
> typically up to 250 km/h (mph..?) at the race for the finish line.
>
>
>
> So after this wordy preamble… What I see needed is some kind of
> Geofence/box-type beaconing.
>
> The algorithm being something like:
>
>
>
> If (tracker.lat<N60.5 and tracker.lat >59.8 and tracker.long<E16.5 and
> tracker.long>15.9) then beacon every 10 secs
>
> If (tracker.distance-to-goal-line < 5 km) beacon every 2 secs
>
> Else
>
> Beacon every 3 minutes
>
>
>
> I’m not a programmer (any more), but you are clever guys, you get my
> idea. When inside the box (including the starting gate and finish line)
> beacon often, outside the box fall back to once every 3 min or so not to
> clutter up the QRG.
>
>
>
> Does anyone know of some tracker code/application for this?
>
>
>
> Of course, what would also be handy would be a Glider specific mode:
>
>
>
> If(course .changes. more than 15 seconds) stop beaconing ./ When
> entering a thermal and starting to circle /.
>
> When (course .eq. last.course(15 sec))) beacon ./
> When leaving the thermal and flying in a straight line /.
>
>
>
> Any one out there doing something like this?
>
>
>
> Thanks for any thoughts and ideas.
>
>
>
> 73 de SM0JWX/Rikard
>
>
>
> (Go metric before Burma, please…)
>
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