$100 ADS-B receiver for Dynon/Garmin

[kevinh]

Hi ya'll,

So lately I've been recreationally making some software for hobbyist drones. In the process I found a really cool software based ADS-B decoder. Someone has made a really cool open-source project that uses a $30 USB radio to decode ADS-B data. I've tried it out at home and it works great.

My desire is to use a Rasberry-Pi to convert this data into a form acceptable for aircraft avionics. Does anyone know of a document that specifies the protocol garmin or dynon expects for aircraft and/or weather data? With such a document I can easily make this project go.

I suspect the total cost to add ADS-B in to your RV with this project would be about $100.

[kevinh]

alas - this is still cool but I just realized it is only supporting the 1090MHz stuff - so no weather and probably only traffic from 'big' airplanes. Bummer.

[comfortcat]

Would the serial USB from the rPI be fast enough? what OS are you experimenting with?

12V, low cost solid state SD chip. Easy to update and next gen will be WiFi.

Cool!

Dkb

[kevinh]

Yep - the USB on a low end ARM I have here for other purposes (approximately rPI class) had no problems.

Originally Posted by comfortcat

Would the serial USB from the rPI be fast enough? what OS are you experimenting with?

12V, low cost solid state SD chip. Easy to update and next gen will be WiFi.

Cool!

Dkb

[roee]

Originally Posted by kevinh

alas - this is still cool but I just realized it is only supporting the 1090MHz stuff - so no weather and probably only traffic from 'big' airplanes. Bummer.

Kevin, I'm not sure that's entirely true.

It is my understanding that the FAA's ADS-B ground based transceivers (GBT's) are supposed to re-broadcast traffic target information (TIS-B) between the 1090ES and UAT interfaces, essentially acting as a bridge. GBT's might even broadcast traffic information of non-ADS-B broadcasting targets as well that were acquired by radar (though I'm not certain about that capability being implemented). In any case, a 1090ES receiver should not be limited to knowing only about targets that are broadcasting on 1090ES (typically "big" airplanes), due to the bridging role played by the GBT's.

About weather (FIS-B), true, it is not supported on 1090ES. Only on UAT.

P.S. I think your idea is waaay cool, and when I get some time (after I get my airplane flying), I could definitely see picking it up and helping make it work (if you haven't already)!

[roee]

P.S. I don't know what your technical background is, but if you have the right skills and are so inclined, you could implement a UAT receiver using the same approach these guys took to implement the 1090ES receiver. UAT uses a different band (978MHz), different modulation scheme, and different data protocol. But it sounds from the cursory description of this piece of hardware that it gives you all you need for the RF front end to support UAT as well. And beyond that, it's a soft decoder that you have to implement for the UAT standard.

[Aiki_Aviator]

In Oz that is all we are getting. I would think that there are a lot of people down under that would like this project... me included :-)

Originally Posted by kevinh

alas - this is still cool but I just realized it is only supporting the 1090MHz stuff - so no weather and probably only traffic from 'big' airplanes. Bummer.

[kevinh]

Good to know. Okay, I'd happily do this then. Anyone know of docs on the protocol Garmin or Dynon wants their traffic data in? (So I can have my widget emit data in the form they will display)

Originally Posted by roee

Kevin, I'm not sure that's entirely true.

It is my understanding that the FAA's ADS-B ground based transceivers (GBT's) are supposed to re-broadcast traffic target information (TIS-B) between the 1090ES and UAT interfaces, essentially acting as a bridge. GBT's might even broadcast traffic information of non-ADS-B broadcasting targets as well that were acquired by radar (though I'm not certain about that capability being implemented). In any case, a 1090ES receiver should not be limited to knowing only about targets that are broadcasting on 1090ES (typically "big" airplanes), due to the bridging role played by the GBT's.

About weather (FIS-B), true, it is not supported on 1090ES. Only on UAT.

P.S. I think your idea is waaay cool, and when I get some time (after I get my airplane flying), I could definitely see picking it up and helping make it work (if you haven't already)!

[rocketbob]

I still really like the 396/496. It would be really cool if one could reverse-engineer the GXM30 antenna protocol so that a Pi receiving ADS/B weather could be used instead. I suspect its no more than a USB-to-serial connection.

[Kahuna]

I too am happy to help.
Been working on my Pi aprs iGate. This would be more fun.
I think I have some gld39 data captures laying around.