-
-
Notifications
You must be signed in to change notification settings - Fork 62
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Worth implementing Flarm-compatible output for bearingless targets? #4
Comments
I believe GDL90 supports bearingless targets, in my case I saw such targets in ForeFlight, connected to my Air Avionics Air Traffic device. The display method in FF though is not perfect - a number of dots that connect to a virtual circle. I haven't tested this with SD but using FLARM-NMEA with SD is much nicer - SD actually draws a complete circle. Still I believe that implementing FLARM-NMEA should not be #1 priority. |
GDL90 in general supports bearingless targets. See this in the GDL90 spec on FAA: Skydemon should also display GDL90 bearingless targets if enabled (that says the documentation, but I have not experienced that yet, when connecting SD to my Stratux) For me FLARM-NMEA as well has no priority ... |
You are absolutely right. I read in some random forum post that GDL90 wouldn't support it, but checking the spec myself confirmed what you say. |
Are you proposing to use the FLARM-NMEA protocol for transmitting Mode-S targets to the EFB? If so, keep in mind that some popular EFBs only support GDL90, e.g. ForeFlight ... |
Yes, that is what I am proposing. Don't worry, I don't want to replace GDL90, just offer another option. |
A related observation: ForeFlight is now promoting uAvionix SkyEcho 2 with FLARM support and for a short period of time SkyEcho 2 had even implemented Mode-S targets but they removed this feature recently. I wonder how FF would have displayed such targets ... |
That is.. interesting. What is this foreflight connected to? Because for now, Stratux does completely drop any bearingless targets from its GDL90 stream. Only aircraft with a valid position are sent via GDL90 - and I don't see any useful way to change that - There are always mode-S targets around - without any information about their estimated distance, the EFB really can't do anything useful with it.. No idea what protocol SkyEcho2 is using, but since they removed this again, I would not bet on many EFBs supporting their implementation in the future..
EDIT: the only GDL90 conforming way would be to transmit these Mode-S Aircraft with my OWN position, but a NACp value that indicates that the precision of this transmission is only, say, 10 miles, if the aircraft is estimated to be 10 miles away. The problem is, that probably no EFB understands that, so it will show the Aircraft at my own position and indicate a collision. |
I had FF connected to AT-1 from Air Avionics. They have implemented GDL90 recently together with Mode-S display. I could simply ask them how they did this implementation ... |
If you have a contact there, it would be great to know how they encode this in GDL90 |
I just implemented something like AirAvionics in GDL90, by simulating 8 targets in a circle, which indicates the distance. Will look something like this: Limits for traffic to be displayed are the same as for NMEA output: +-2000ft, 15km (8nm) distance. EDIT: Note: There is also a settings switch. You might need to enable that first. |
In the original Stratux repository, there is a lengthy discussion from 2017 regarding Flarm-NMEA output:
cyoung#489
aswell as initial work done:
cyoung#560
While this seems not entirely needed these days, since most EFBs now support GDL90, I want to discuss if bringing these patches to a usable level in modern Stratux would still be worth it?
From the discussion, I take that Flarm-NMEA supports bearingless targets (which GDL90 does not) and this actually seems to be implemented in many EFBs.
Feel free to discuss...
The text was updated successfully, but these errors were encountered: