Altitude references used by SafeSky

English
1

With reference to the latest SkySafe newsletter, it is good to see all these other EC systems integrating with SafeSky. This collaboration should offer all pilots the best possible EC solution available.

However, I do have a query regarding the reference use for altitude reporting by all these different EC systems.

My aircraft’s EC configuration is a Mode S-ES transponder (with ADS-B Out) for transmission and a SkyEcho 2 (SE2) for ADS-B and FLARM signal reception.

The SE2 is equipped with GPS receiver and a baro sensor so that my own aircraft’s altitude is always “reported” with reference to 1013.2 hPa.

The SE2 connects to my SkyDemon app which I use for navigation purposes .

As I am sure that you are aware, SkyDemon contains quite sophisticated EC conflict warning algorithms which will warn me of potential conflicts with ADS-B Out and FLARM equipped aircraft and gliders etc. For this to work accurately it is important that the altitude reported by potentially conflicting aircraft are always with reference to 1013.2 hPa.

If GPS derived altitude is used then the SkyDemon conflict warning algorithms may be less effective due to differences between GPS derived altitude and altitudes based upon the common 1013.2 hPa.

Can you please explain how SafeSky addresses this issue? I presume most of the “other” EC solutions that now integrate with SafeSky use GPS derived altitude?

2

For collision avoidance I believe it’s best to use GPS altitude , WGS 84. Also adsb does use that, in fact it sends both, Gps and barometric altitude…
That said, I am also very curious…

However, my biggest worry is at least where I fly, there are so many planes reported on the wrong locations, it’s not even funny… I did some tests and my own planes is reported a few miles away from the real location…

3

…mnmn

4

RVT,

I think 1013.2 should be the standard reference. After all, all transponder equipped aircraft (CAT, Military, some GA etc.) send their altitude referenced to that. Includes ADS-B Out and MLAT tracked aircraft.
Aircraft in wrong positions probably due to inaccurate MLAT tracking…

5

I connect to my SE2, from SkyDemon, using the SE2 connection (not the GDL 90 option).

6

I connect SE2 via SS via SD. Not sure how SS interpreds altitude reports from SE2