Skydemon with FLARM via Stratux

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Skydemon with FLARM via Stratux

Author	Message
efrenken	efrenken posted 7/24/2019 10:55:04 PM Post Details Share Post
Group: Forum Members Posts: 265, Visits: 3.5K	Tim, I use SD (newest Beta release) on an iPad Pro with the recent iOS. I‘ve experienced exactly what b3nn0 has written in his post above. Eric
	Reply Like 6
b3nn0	b b3nn0 posted 7/24/2019 6:03:32 PM Post Details Share Post
b Group: Forum Members Posts: 42, Visits: 3.4K	Hi Tim, this happens to many users on iOS and Android with the Stratux. I have debugged it thoroughly on the Stratux side and am fairly convinced that it is some wonkyness in SDs GDL90 implementation. I had a lengthy discussion about it with your support (Hannah, iirc), but it did not look like SD is willing to change something. On the Stratux side, I implemented a workaround by sending the GDL90 hearbeat message much more often, if enabled in the settings, which seems to reduce the gaps quite a bit to 2-3 per hour, instead of 20-30 per hour.. Feel free to check my communication with Hannah from support for more detail of my analysis. In short, it seemed like the UDP connection has some lags from time to time, especially when the phone is under load. The RaspberryPi/Stratux network stack then seems to try to correct that by multiple retransmissions that are received in a short time on Android/iOS. That seems to confuse SD, indicating a short connection drop of 2-3 seconds and drawing a gap in the log later. During flight, it can only be noticed by the vertical radar screen shortly dropping out and then being regenerated. Note that errors like this are to be expected for UDP connections, at least it's written in the RFC that applications should be tolerant to that. I have cross-checked this with a different GDL90 client implementation, which just checks the checksums and dumps the information in real-time. This way, it was easy to see the gaps and retransmissions at a similar rate that SD drops out. Also, I used two devices running SD, both connected to the same Stratux, and both show these gaps, but at different times. So the packet content is certainly correct - it's just the transmission which SD assumes is interrupted. Note: Feel free to contact me directly if you need more info - I'm the maintainer of Stratux Europe Edition. Edited 7/24/2019 6:04:16 PM by b3nn0
	Reply Like 7
Tim Dawson	Tim Dawson posted 7/24/2019 3:32:42 PM Post Details Share Post
Group: Forum Members Posts: 8.1K, Visits: 9.4K	It's just generally a more robust protocol, and it can receive UAT weather and encrypted FLARM messages too. This may not be applicable for you, of course. What sort of device are you using SkyDemon on where you're seeing gaps in recording?
	Reply Like 4
efrenken	efrenken posted 7/22/2019 4:31:43 PM Post Details Share Post
Group: Forum Members Posts: 265, Visits: 3.5K	Tim, Why do you recommend GDL90 as the best protocol? Since I‘ve been using the protocol b3nn0 has described above I don‘t have any gaps within my logs and I get the ring around my position for non-ADS-B traffic. By using the GDL90 protocol I get a gap every 3 mins in my logs and no ring. Eric
	Reply Like 5
Tim Dawson	Tim Dawson posted 7/22/2019 10:43:12 AM Post Details Share Post
Group: Forum Members Posts: 8.1K, Visits: 9.4K	Contrary to what is written above, we would recommend using GDL90 as the best protocol when a device supports it.
	Reply Like 5
Alf	Alf posted 7/22/2019 5:14:21 AM Post Details Share Post
Group: Forum Members Posts: 22, Visits: 20	Hi b3nno, I had several flights last weekend with Stratux Europe Edition 1.5b2-eu008 BETA, 868 antenna for FLARM, SD as software. I am really impressed, it works fantastic! Thank you for all your work on this! BR, Alf
	Reply Like 6
Biggles66	B Biggles66 posted 7/19/2019 4:25:20 PM Post Details Share Post
B Group: Forum Members Posts: 7, Visits: 1	+x b3nn0 - 7/19/2019 4:23:50 PM Then everything is perfect. You don't need an AirConnect. The Stratux implementation just pretends to be one. This is, IMO, the better option than GDL90, et least for SkyDemon, as SkyDemons GDL90 implementation seems to be a bit wonky from time to time. ok, got it... better go and try it out in the wild then, rather from my apartment... thx again!
	Reply Like 6
b3nn0	b b3nn0 posted 7/19/2019 4:23:50 PM Post Details Share Post
b Group: Forum Members Posts: 42, Visits: 3.4K	Then everything is perfect. You don't need an AirConnect. The Stratux implementation just pretends to be one. This is, IMO, the better option than GDL90, et least for SkyDemon, as SkyDemons GDL90 implementation seems to be a bit wonky from time to time.
	Reply Like 6
Biggles66	B Biggles66 posted 7/19/2019 4:12:11 PM Post Details Share Post
B Group: Forum Members Posts: 7, Visits: 1	+x b3nn0 - 7/19/2019 3:47:58 PM This is most likely what your settings should look like for SD: (If you want to use the Flarm-NMEA protocol, the IP Address additionally needs to be 192.168.1.1, but that's optional. Get the rest working first). Disable AHRS if you don't have one in your Stratux. If you have an ADS-B out equipped airplane, enter your transponders HEX in the top right. To get the Flarm-NMEA option in SkyDemon, you, of course, need to enable that in the Settings "FLARM via Air Connect". But as I said, that's optional. Yes, I recommend using an 868Mhz antenna instead of the 978. Reception range will be better. Cheers! Settings seem to be ok. I have already set the IP to 192.168.1.1 as otherwise the unit didnt seem to show any FLARM buttons or options. Apologies, obviously I am unclear what NMEA or Air Connect are exactly, only that you mention it is more stable. From what you state above, if I dont have an Air Connect module, should I just forget about it and continue with GDL90 connection? Although, I did now change the setting in Skydemon and selected connect via Air Connect (even though I dont have one) and it still seems to work the same way, this time with a large circle around my own position.
	Reply Like 5
b3nn0	b b3nn0 posted 7/19/2019 3:47:58 PM Post Details Share Post
b Group: Forum Members Posts: 42, Visits: 3.4K	This is most likely what your settings should look like for SD: (If you want to use the Flarm-NMEA protocol, the IP Address additionally needs to be 192.168.1.1, but that's optional. Get the rest working first). Disable AHRS if you don't have one in your Stratux. If you have an ADS-B out equipped airplane, enter your transponders HEX in the top right. To get the Flarm-NMEA option in SkyDemon, you, of course, need to enable that in the Settings "FLARM via Air Connect". But as I said, that's optional. Yes, I recommend using an 868Mhz antenna instead of the 978. Reception range will be better.
	Reply Like 5