Wed May 12, 2021 4:45 pm
#1846506
If the mods think this should be tacked on to one of the other existing EC threads, please feel free to move it.
I have a query about the GPS altitude shown on my ipad (using Skydemon) using the Sky Echo 2as my location source.
Before I had my Sky echo 2 device I noticed that the GPS altitude on my ipad mini 3 (using its own GPS), my Garmin 295, the altimeter and the Displayed Flight Level on my transponder screen (with an appropriate mental arithmetic calculation for the difference between QNH and 1013) tended to agree most of the time.
Now I use Sky Echo 2 as my external GPS for the ipad, I find that GPS altitude sometimes varies significantly in level flight from minute to minute (and by several hundred feet) and is usually the odd one, in that the Garmin 295, the altimeter and the Transponder displayed FL agree with each other.
So I have 3 related questions,
1) Could the GPS module in my Sky Echo 2 be faulty in altitude only (seems unlikely) or does it just have a lousy view of the sky.
2) Does the altitude output in my Sky Echo's ADSB broadcast come from the Sky Echo's GPS, or from its built in altitude encoder.
3) Is the traffic vertical separation against other traffic as shown on my ipad in flight based on my GPS altitudes, (which may be wrong if my GPS is returning the wrong altitude) or from the built in altitude encoder derived altitude.
and one more question. Has anyone else noticed this?
I have a query about the GPS altitude shown on my ipad (using Skydemon) using the Sky Echo 2as my location source.
Before I had my Sky echo 2 device I noticed that the GPS altitude on my ipad mini 3 (using its own GPS), my Garmin 295, the altimeter and the Displayed Flight Level on my transponder screen (with an appropriate mental arithmetic calculation for the difference between QNH and 1013) tended to agree most of the time.
Now I use Sky Echo 2 as my external GPS for the ipad, I find that GPS altitude sometimes varies significantly in level flight from minute to minute (and by several hundred feet) and is usually the odd one, in that the Garmin 295, the altimeter and the Transponder displayed FL agree with each other.
So I have 3 related questions,
1) Could the GPS module in my Sky Echo 2 be faulty in altitude only (seems unlikely) or does it just have a lousy view of the sky.
2) Does the altitude output in my Sky Echo's ADSB broadcast come from the Sky Echo's GPS, or from its built in altitude encoder.
3) Is the traffic vertical separation against other traffic as shown on my ipad in flight based on my GPS altitudes, (which may be wrong if my GPS is returning the wrong altitude) or from the built in altitude encoder derived altitude.
and one more question. Has anyone else noticed this?
Last edited by Dodo on Wed May 12, 2021 5:55 pm, edited 1 time in total.