ADSB data on now viewable on the OGN

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Davis Chappins

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Apr 7, 2022, 7:40:49 PMApr 7
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With the discussion about OGN data happening in another thread, now is a good time to say that I have been forwarding ADSB locations to the OGN.

It's running on my raspberry pi at home alongside the SPOT/Inreach to OGN scripts.
I have been running it since Feb and seems to be working well.

Why did I do this? I got bored last year and wanted to do a project in python to learn the language more and this sounded like fun.

How will you know if the position is from ADSB or FLARM? Some OGN websites will show the receiver detecting the aircraft (or source of the data), "ADSBExch" is visible in that field when the position is coming from ADSB data.

How does it work?
This script connects to an ADSB API (for ADSB positions) and the OGN (for FLARM positions). The script listens to both sources and manages a traffic list composed of each unique aircraft's position, speed, altitude, etc from both sources.

If a glider position exists from ADSB and not from FLARM, that glider's position is pushed to the OGN from the ADSB source.
If a glider position exists from both ADSB and FLARM, that glider's ADSB position will only be pushed to the OGN when the FLARM source is 120 seconds older than the ADSB source. Thereby seamlessly transitioning between the high refresh rate FLARM position and a lower refresh rate but larger ranged ADSB position.

To be seen, you will need to have a Mode S (non ADSB and be within MLAT range) or a Mode S (with ADSB) transponder. The script is set up to run on my pi from 9a to 8p MST, 7 days a week. And at the moment it is only set up to scan the North American lat/lon range.

The API is queried at 10 second intervals then the valid positions are sent to the OGN. For tracking, the signal has a refresh rate of somewhere between 5 and 15 seconds. A much lower resolution than the OGN's 1-2 second position intervals but ADSB has a much larger range.

John Godfrey

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Apr 8, 2022, 8:34:19 AMApr 8
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Outstanding!

Charles Gillespie

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Apr 8, 2022, 10:43:50 AMApr 8
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Hi Davis, cool project. Do you know if the pushed ADSB targets create duplication with existing FLARM targets on OGN displays?

Charlie

Bruce

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Apr 8, 2022, 11:55:05 AMApr 8
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Quoted from Davis's original message

Charles Gillespie

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Apr 8, 2022, 2:27:00 PMApr 8
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I can see that to be true. I was watching a couple of gliders doing airwork at Boulder on GlideandSeek and GliderRadar. One of our club gliders which has ADSB and a FLARM registered on OGN, toggles between OGN and ADSBExch as its receiver source while in the air (within line of sight to OGN receiver) and exclusively ADSBExch while on the ground (when it drops below line of sight to OGN receiver). The other glider from the nearby commercial operation shows ADSBExch both on the ground and in the air, suggesting that it has ADSB and and no FLARM equipped, or has a FLARM which is not registered to OGN. Good stuff!

Davis Chappins

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May 18, 2022, 1:19:12 PMMay 18
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https://i.imgur.com/808hJkM.png

Last Saturday had about 50 ADSB gliders being forwarded to the OGN, which is cool.
This python script continues to run on my pi at home. If anyone knows of a more professional hosting, feel free to reach out.

Philip Lee

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May 19, 2022, 9:38:21 PMMay 19
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I moved some of my OGN/python scripts to AWS without issue couple of years ago. Costs about $10/mo.
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