Comments (12)
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.
from stratux.
GDL90 in general supports bearingless targets. See this in the GDL90 spec on FAA:
"A target with no valid position has Latitude, Longitude, and NIC all set to zero. "
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 ...
from stratux.
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.
In this case, I would also say that there is no point in implementing this for now.
@TomBric: Anyway, Stratux does not report bearingless targets via GDL90, that's why you will not see them in SD.
from stratux.
Reponeing this. I have investigated some more:
While it is possible to send GDL90 Targets without position, it is impossible to state the distance to that target in GDL90. Therefore, this information is useless for the EFB.
Interestingly, some EFBs seem to interpret the NACp value for bearingless targets and use that to draw a distance ring. That, however, is non-standard and not widely supported.
In the flarm-nmea branch, I have done some experiemnts for analyzing correlation between signal strength and traffic distance, with a self-adjusting tuning parameter that is learnt from ADS-B signals and then used to predict Mode-S signals. Flarm NMEA output works aswell (however, to make this connect to your EFB, you might have to change your Stratux IP to 192.168.1.1).
The value in the braces show the estimate, the one outside show the real value from the ADS-B Positions. At least for close traffic (< 15 nm), it seems to work rather well.
Some more things to consider:
- FLARM can only transmit one Mode-S target (the closest one). I think that is enough.
- Right now, one parameter is tuned via ADS-B to predict the distance of non-ADS-B traffic. This does not consider the fact that usually large aircraft have a higher transmit power than smaller ones.
This means, that with this one tuning parameter, we will usually show small aircraft too far away and large aircraft too close. - If this is merged at some point, we need a way to set the IP address of the stratux, so EFBs can actually connect
- If this is merged, we can update the web-radar to use the server-generated estimate instead of doing computation on the client side, so that we have the same estimates everywhere.
- Right now, this is only tested with SkyDemon
from stratux.
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 ...
from stratux.
Yes, that is what I am proposing. Don't worry, I don't want to replace GDL90, just offer another option.
I.e. transmit GDL90 via UDP 4000 as always, and await connections on TCP 2000 that can receive Flarm-nmea if they want.
With Flarm-nmea, it is possible to transmit bearingless targets with a distance (which will be drawn as a circle in SkyDemon). With GDL90, it is not. I can transmit targets without a position, but there is no way for the EFB to know its distance (or is there any way that works for Foreflight?) I'm happy to provide the same distance info via GDL90, if there is a way to make EFBs display it.
from stratux.
Attached an example how ForeFlight shows Mode-S targets, no idea whether any distance is displayed:
from stratux.
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 ...
from stratux.
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..
See cyoung#489 for how many EFBs show the bearingless targets WITH distance estimate - but that's Flarm-NMEA stuff, not GDL90.
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..
According to https://forums.flyer.co.uk/viewtopic.php?t=112166:
Bearingless targets are a feature provided by Flarm and PilotAware. Those devices pass us the aircraft id, altitude, vertical speed, estimated range (guesswork but based on signal strength; the user can learn to interpret the ring size changes over time) and even callsign.
SkyEcho doesnโt have anything like that. Its only offering is to send us the altitude of a mode C/S return as it comes in. No vertical speed, no range (estimated or otherwise), or even an aircraft id. I declined that offering.
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.
from stratux.
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 ...
from stratux.
If you have a contact there, it would be great to know how they encode this in GDL90
from stratux.
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.
@VirusPilot Would you mind testing this with ForeFlight?
EDIT: Note: There is also a settings switch. You might need to enable that first.
from stratux.
Related Issues (20)
- no FLARM traffic on ForeFlight HOT 4
- No network on LAN when using AP+Client settings HOT 4
- Feature Request - ICARUS protocol HOT 6
- Support of BMP390 pressure sensor HOT 7
- dump1090 not using dev branch
- uAvionix Ping USB support HOT 2
- Unable to find documentation for AHRS Report (4c:45:01) message HOT 1
- configuring serial ( /dev/ttyAMA0 ) gps device HOT 5
- Customizing raspberry to output audio
- Run SoftRf on the raspi as a stratux child process (feature proposal) HOT 4
- Serial interfaces not recognized
- Feature Add: Set ADSB Antenna Gain HOT 1
- Add u-blox M7 Power mode setting UBX_CFG_PMS HOT 4
- Support for OGN-Tracker on T-BEAM with AXP2101 PMC HOT 2
- Change OGN Tracker settings not possible HOT 20
- Major problem with T-Motion and GDL90 HOT 3
- No USB devices recognized on Rasberry Pi 3B HOT 3
- No WLAN when setting a secure (password protected) WLAN network in AP+Client mode HOT 2
- Cannot get BMP388 / ICM20948 sensors to work HOT 4
- Incomplete RF spectrogram
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
๐ Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. ๐๐๐
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google โค๏ธ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from stratux.