Powerflarm

[edwalker]

I'm hoping that there are a few motorglider pilots out there who can help me think this through.

I have a Phoenix motorglider with SV and ADSB. Some of my operations are in the usual traffic environment where the TIS and ADSB signals are the norm; however, I need to be able to see other gliders which are using Powerflarm (PF). My understanding is that at least some of you have added the PF core to your aircraft and have worked out the connections.

1) What do the PF signals look like when displayed on SV? PF has a different detection algorithm than ADSB and TIS, so I'm wondering if a PF glider looks any different on SV from power traffic?

2) The PF has two outputs and it seems that one can be dedicated to SV while the other can go to a PF display ( I already have a LXNAV V7 variometer which doubles as a Flarm display.)

Has anyone hooked up a PF to Skyview with reliable results?

 

[Dynon]

On the traffic depiction question - SkyView doesn't show different traffic sources differently. Also, only one traffic source can provide traffic at any one instance. In other words, multiple devices aren't composited by SkyView. If you have multiple devices, which is only really seen here in the US, they're used in a priority order that's defined in our manual.

 

[edwalker]

If you have multiple devices, which is only really seen here in the US, they're used in a priority order that's defined in our manual

Actually, this is what I was trying to clarify, but it would be helpful to know exactly how this prioritization occurs. It sounds like in the absence of an ADSB UAT the SV will drop down the list looking for alternatives. In the presence of a transponder with no UAT it will display TIS data. In the absence of both the UAT and transponder the Flarm might be the next unit available. How this happens is what interests me. If I have a UAT, transponder and Flarm I can't understand the circumstances in which the Flarm data would ever make it to the display.

For example, given all three devices, would the devices higher in the list have to be off to activate the Flarm targets on the SV display, or do they just have to have no active targets? If the latter, would the presence of a new ADSB or xpder TIS target kill the Flarm targets in the display?

This problem arises from the fact that GA and glider traffic are using different traffic avoidance systems in the same airspace, so it would be nice to integrate the displays. I may just need to have two separate systems running in parallel.

 

[Dynon]

So, before we get into the general answer, what are all the capable traffic devices that are connected to SkyView, what serial ports on SV are they each connected to, and what format are they configured to use?

 

[edwalker]

I currently have SV with standard Dynon transponder and Dynon ADSB. I would like to purchase a Powerflarm core unit and connect it serially. I do not have the PF core yet - trying to decide if it can be connected and used in a compatible manner.

 

[dynonsupport]

We don't support two traffic devices at the same time. De-conflicting from both sources is very difficult, and will end up with multiples of the same target.

If you are in an area with ADS-B FULL coverage, it will use that. If you are not, it will drop to TIS-A from the transponder if TIS is active. If not, it will use the powerflarm, and if the powerflarm is off it will go to ADS-B PARTIAL coverage.

If you are in an area with both TIS and ADS-B, why can't you see the gliders via those services? If they have a transponder, you can see them already.

 

[edwalker]

Okay, thanks for sticking with this thread - I think I see the disconnect.

Because of battery issues gliders do not generally carry transponders. The European soaring community devised an alternative, low-power collision avoidance system for gliders called Flarm (Flight Alarm). It uses a low power VHF transceiver connected to a GPS computer to determine flight paths for targets within a 4 km radius with emphasis on display of potential collisions. It focuses on collision avoidance for participating gliders but it  does not always give a complete picture of the traffic environment.

The FAA would not allow Flarm in the US given our commitments to the TIS/ADSB, so an alternative was developed called PowerFlarm (PF) which combines Flarm with ability to RECEIVE BUT NOT TRANSMIT 1090-ES, TIS and ADSB signals. So a PF can show on its own display a mixed GA and glider traffic picture, but it does not contribute information to the 1090/TIS/ADSB environment.

My question was about whether PF could be integrated into SV. It sounds like if it is the only device it can, but if a XPDR or ADSB unit is connected and operating then the PF will likely be prioritized out of the mix. Motorgliders are a very small segment of your market, so I don't expect this to be a development priority for Dynon.  It's possible to just have a separate PF display and turn off the SV while soaring. In that case I can see the 1090/ADSB GA traffic on the PF display but the GA traffic will not see me because I have turned off my XPDR and ADSB. Just wanted to see if there was any way to integrate the displays.

I appreciate your help.

 

[edwalker]

Having reflected on this for a few days, I have a suggestion for the Dynon design team. I can appreciate the challenge of parsing a multiple-device stream for NMEA messages with the potential for duplicate targets, so I understand your approach of letting the software choose the device with the highest quality data from your rank list and ignoring other devices. Nevertheless, it might be nice to have this be a software default that could be configurable. For example, what if I had a software option to choose to listen only to my Powerflarm and disregard XPDR and ADS-B device data? In the soaring environment that would give me the most complete picture of what I need. I think your original ranked default strategy is the right one for the GA marketplace, but this change might open up more opportunities to the growing LSA motorglider market.