Skydemon SoftRF compatibility

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Skydemon SoftRF compatibility

Author	Message
buzz53	buzz53 posted 12/16/2020 10:17:03 AM Topic Details Share Topic
Group: Forum Members Posts: 23, Visits: 52	Skydemon and SoftRF (an open source EC device) are no longer fully compatible. The issue arises when SoftRF is operated in Pilotaware mode, and with Airconnect/FLARM protocol. After some experimenting it seems this is because SoftRF emits an IDtype parameter of ‘3’ in the $PFLAA sentence, and Skydemon rejects this with the dialogue “Unexpected GPS data”. Values 0/1/2 are accepted. I’m pretty sure SoftRF has not changed since December 2019 (when this worked OK). I think this needs fixing at the SoftRF end but just be 100% sure, I'd be grateful if you could tell me: 1) Please confirm IDtype values > 2 in $PFLAA are rejected by Skydemon ? 2) Has this changed at the Skydemon end since Dec 2019? 3) The only public version of the FLARM dataport spec shows ‘3’ as a valid value (“Anonymous mode”) but I think this mode was abandoned by FLARM. Can you confirm it is no longer a valid value in the latest spec (which I guess you must have)? TIA, Alan Edited 12/16/2020 10:20:47 AM by buzz53
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Tim Dawson	Tim Dawson posted 12/16/2020 4:03:35 PM Post Details Share Post
Group: Forum Members Posts: 8K, Visits: 9.1K	It looks like SkyDemon has never supported anything other than 0, 1 or 2 for that field. If we encountered a 3 we would indeed abort the connection.
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pilot-byom	p pilot-byom posted 12/16/2020 4:44:34 PM Post Details Share Post
p Group: Forum Members Posts: 323, Visits: 388	I am confused, isn't ID = 3 mode <reserved>/<only used> for the anonymous GDPDR-compliant mode of OGN and not even part of FLARM? After all, SoftRF is a OGN tracker, not a FLARM device, and the Legacy mode is derived from the reverse engineered interface from OGN to FLARM - I feel this is definitely no question for Skydemon at all, but better addressed directly to Linar Yusupov elsewhere? Edited 12/16/2020 4:56:41 PM by pilot-byom
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buzz53	buzz53 posted 12/18/2020 2:38:12 PM Post Details Share Post
Group: Forum Members Posts: 23, Visits: 52	Tim: thanks for confirming, I don't know how I persuaded myself it was working last year! By forcing IDtype = 1 (ICAO addressing), SoftRF now works in Pilotaware RF mode with Skydemon using Airconnect, GDL90, and Pilotware interface modes. My motivation for this BTW is that otherwise only GDL90 can be used and this results in incorrect altitude display due to the way you handle geoid correction (I haven't investigated in any detail but the story from SoftRF is that you do it "correctly" but all the other EFBs don't and SoftRF have gone with them)! I have raised this mod this with SoftRF to see if it can be adopted by them, as I assume you are not keen to change your end? pilot_byom: it is incorrect to say SoftRF is an OGN tracker. Yes, it can function in that mode but also emulates FLARM or Pilotaware, very successfully in my experience. Clearly this is not something for everyone, for various reasons, but we should be factually accurate. I've got a lot of notes on SoftRF/Skydemon compatibitity which I'll add once this is concluded, in case other confused SoftRF users pass this way.. Alan Edited 12/18/2020 2:39:56 PM by buzz53
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Tim Dawson	Tim Dawson posted 12/18/2020 2:44:22 PM Post Details Share Post
Group: Forum Members Posts: 8K, Visits: 9.1K	Please make sure that the addresses being sent by SoftRF actually ARE ICAO addresses in that case. If they're not, there is a risk of address collisions with another aircraft. The Flarm protocol ONLY supports ICAO addresses and Flarm addresses.
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pilot-byom	p pilot-byom posted 12/18/2020 5:50:31 PM Post Details Share Post
p Group: Forum Members Posts: 323, Visits: 388	+x Tim Dawson - 12/18/2020 2:44:22 PM Please make sure that the addresses being sent by SoftRF actually ARE ICAO addresses in that case. If they're not, there is a risk of address collisions with another aircraft. The Flarm protocol ONLY supports ICAO addresses and Flarm addresses. Just to add to the plea, please make absolutely sure HEX data from SoftRF devices is never fed backwards into one of the other traffic networks or merged with other sources without an explicit flag that this is a SoftRF address. Keep in mind, there are only 16,777,214 distinct aircraft addresses possible in the whole world and the assignment of ICAO address to aircraft call sign is regulatory set in ICAO Annex 10. Edited 12/18/2020 7:20:57 PM by pilot-byom
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