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Re: PAW Multilateration and 360 Radar

PostPosted:Tue Jun 11, 2019 3:56 pm
by johnm
I have to say I'm in awe of the expertise displayed by some on this thread :thumright: Moreover I think I may be approaching the point where I suggest to the group that we acquire something :-)

Re: PAW Multilateration and 360 Radar

PostPosted:Thu Jun 13, 2019 8:24 pm
by dublinpilot
I (think) the long and the short of that discussion is that there are some odd combinations out their in “SIL=0 land” that are giving out some low NACp that generate mahoosive circles.


But what I don't get is why this requires any changes by PilotAware. As far as I can see, they are already sending the data to the nav apps. So surely EasyVFR and SD can simply show the traffics with the circles. When the circles get too big (in the eye of the nav app developer) they can simply choose not to draw that piece of traffic nor it's circle, and simply treat it as bearingless traffic.

That way the user get's the benefit of accurate traffic, and the map isn't cluttered by pessimistic traffic. No change would be required by Pilot aware for this to happen. It would be us in EasyVFR and Tim in SD that would need to make the changes to our apps. And it would seem like a relatively easy change to make.

Re: PAW Multilateration and 360 Radar

PostPosted:Fri Jun 14, 2019 8:11 am
by leemoore1966
@dublinpilot
Its a bit of a no win situation for the EFB I think
A sizeable number of ADSB contacts in GA land, have such poor emitted accuracy (NACp), it would mean displaying nearly all those contacts with 2nm circles
In an ideal world you would say fix the source of the problem - which is the ADSB transponders, but it seems there is little appetite for doing that, so the solution is to ignore what they are saying.
This seems a strange solution given the debate here regarding accuracy of reported positions, but probably the most expedient when you don’t like the data you are given
I did ask @cub how he would propose displaying the NACp - but no suggestions given

Thx
Lee

Re: PAW Multilateration and 360 Radar

PostPosted:Fri Jun 14, 2019 2:58 pm
by riverrock
Perhaps as bearingless (with height) or on a map as greyed out or dotted? Or bearingless when close, dotted when far away (as its close up when accuracy matters / is dangerous).
I think SD currently ignore the accuracy value, just plotting / alerting where it says, as for ADS-B sources it’s generally the accuracy value that is wrong rather than the position.

Re: PAW Multilateration and 360 Radar

PostPosted:Fri Jun 14, 2019 4:53 pm
by Straight Level
I'd like to be able to quickly distinguish between a target who's position was MLAT or "GPS" based (i.e Flarm, PAW or ADSB etc).
For MLAT targets, then I'd initially look in the direction as indicated on the EFB, if not visually acquired, then extend the scan laterally.
The EFB could simply indicate MLATs by placing a small circle, square etc over the MLAT target, which would be sufficient for quick determination that the position accuracy could be not 'exactly as indicated.
The MLAT 'circle' size would not need to be related to the NACp accuracy value.
SL

Re: PAW Multilateration and 360 Radar

PostPosted:Fri Jun 14, 2019 5:12 pm
by neilmurg
Straight Level wrote:The MLAT 'circle' size would not need to be related to the NACp accuracy value.
SL
That's what I hoped they'd do last time. As for the the FLARM/GPS/MLAT differentiation, probably best to try it first and go from there. If you're receiving a 'Target, 5km, 2 o'clock, 200ft above' (I'm paraphrasing) and you spot it, it's job done, no circle required.
If you're also listening on a busy LARS channel, the question then is, which one is more useful?

Or, with a choice of -say- SD voice, PAw voice and/or LARS - which works best for you?
[edit]PM'd you[/edit]