GPS reception, SafeSky and SkyDemon

Hi everyone. Just trying to get to the bottom of what exactly is going on with GPS reception, where it’s coming from and how it’s being transferred between Apps etc. Specifically SafeSky and SkyDemon.

I go flying in SkyDemon using the GDL90 protocol. I see no GPS data and my aircraft isn’t shown on the moving SD map. SD says “waiting for device”. I have no external devices connected to my iPad.

I start SafeSky with traffic sharing disabled and “fly” in SafeSky. Still no GPS reception on Sky demon it still says “waiting for device”.

As soon as I share traffic data on SafeSky with Sky Demon i see a GPS reception on SD. This means SS must be passing GPS data to SD through the GDL90 protocol, correct?

I can only assume that GPS data is coming from the internal GPS receivers on my iPad (because no other way of getting that GPS data)? And if so, does this mean that if i connect a bluetooth GPS receiver the data from that external receiver is transmitted to SD instead of the devices internal reception data? Maybe the techs at SafeSky can answer that so we have a clear answer?

Given that GPS data is being passed between the apps what is the function of the “Force to use SafeSky as a GPS source” Button in this context? Again maybe a tech from SafeSky can answer?

If i connect my SkyEcho2 unit to SafeSky and use it for extra traffic data. Does the SafeSky app then use the GPS data from the SkyEcho2 unit or does it still use the internal devices reception (or perhaps a bluetooth connected GPS device reception) ? What’s the pecking order in this scenario?

Just trying to work out exactly what is going on. Clear answer from the developers would be great.

Hi Andy, this rings a bell somewhere. Are you sure that Safesky continues to run in the background when SD is in the foreground ? I don’t know iPads as I only use Android, but there may be some setting to allow background apps to continue to operate. If that is not enabled, then as soon as you switch focus to SD then maybe SS stops sending GDL90 data ??

I found this article from Apple that may be useful. Refresh content in apps you’re not actively using on Apple Vision Pro – Apple Support (MY).

Perhaps one of the technical folks at SS can answer the questions? That would make it clear to everyone how it all works.

Hi,

We invite you to take a look on the manual of SafeSky.

And more specific…

Thanks xtof for your reply but the manual doesn’t answer the specific questions in my post! Could I ask you to read the post above and answer the questions it poses. Kind regards, Andy

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Just to put my hat in the ring here - I too am interested in the answer to this question. The manual doesn’t answer it. I have also found that if my phone, while running SS and feeding into SD, drops out, SD on my tablet then stops tracking (although there is an option I have seen which tells the built-in tablet GPS to pick things up). I think what we are interested in/want here is to know if we can send just traffic data to SD and have SD use it’s own GPS.
Thanks

I’ve posted a similar question on the Sky Demon forum. Tim has stated it isn’t possible to add the safe Sky traffic to SD whilst using your Bluetooth GPS for GPS position in SD. You have to use GDL90 which gives SD traffic AND GPS.

What I want to know is where does Safe Sky get the GPS location it’s sending SD? Is it only ever from the internal iPad receiver? Does it get it from Sky Echo 2 if connected? Is it Bluetooth GPS if connected? Does it use the mobile network for GPS positioning?

None of this is discussed in the manual.

Thanks Andy, that’s answered the question I had about whether we can use the GPS independently of the phone app. Cheers!

Hello,

Thanks a lot for all the detailed questions.

In short, SD requires 3 GDL90 messages:

  • Ownship Report
  • Ownship Geometric Altitude
  • Traffic Report (optional)

All other known EFB only requires the “Traffic Report” message. They then use their own GPS position as normal if no other messages are provided.

The first two messages are used to carry GPS and altitude information.

We made some efforts to simplify the complexity for pilots so that you don’t have to ‘understand’ how this is working. As a pilot, when I set SafeSky with a configuration, everything automagically adapts. Still, here are some explanations:

  • When you are configuring “SkyDemon” as a EFB in SafeSky, we are providing all the messages to SD so that it just works. The iPad is the source for the GPS information.
  • If you are also combining a SkyEcho2 in your setup, and have it configured from SafeSky, we are only providing the “Traffic Report” message. SkyEcho2 become the source for the GPS information for both SafeSky and SkyDemon.
  • In you want to fine tune for other EFBs which all only requires “Traffic report” message, the option to “Force to use SafeSky as a GPS source” can be chosen to use your iPad GPS position - this can be useful when using an iPad with no GPS connected to an iPhone with “Internet sharing”

If you are using an external bluetooth GPS in IOS, the Location Service from IOS will provide it’s position globally to all apps running in a seamless manner to SafeSky.

I hope this clarifies the behaviours.

Fly Safe everyone,

Tristan

That’s really helpful Tristan. I can understand why you would want to simplify these things. But also helpful to understand exactly what’s going on.

Based on your answer I have one last question ……

If I’m running safe Sky with SkyEcho2 connected with “Force to use SafeSky as GPS source” SWITCHED ON. And I’m also running Sky Demon in GDL90 mode so I can see traffic on SD. Will the GPS reception being sent to SD be internal iOS and not from SkyEcho2? And hence if I’ve also got a Bluetooth GPS connected to my iPad, SD in GDL90 mode via SafeSky with be getting GPS from the Bluetooth receiver?