Hy
I tested the 3DR GPS uBlox LEA-6 for high altitude however I discovered something strange.
In the datasheet of the uBlox LEA-6 it’s written that the altitude limitation is at 50'000m so you could use it for ballooning. However I tested it with an APM 2.5. At an altitude of 12'200m the GPS stopped sending valid data so in the Mission Planer there was no more Ground Speed, no altitude, and the GPS coordinates were wrong.
After it reached back 11'000m it started to send valid data again.
So I'm asking myself where the problem is.
Is this a problem in the code of the ArduPlane not able to store big numbers or might it be the GPS?
Can someone pls help me. thx Andy
Replies
Hi Andy,
I think the altitude limit of 12000m for your uBlox is because of a bug we had in our uBlox initialization code, which I fixed last week. The uBlox LEA-6 has different maximum altitudes depending on what "dynamic model" you initialize it with.
The APM uBlox driver for ArduPlane tries to initialize it with a dynamic model of Airborne-4G, which has a maximum altitude of 50km. Unfortunately we had a race condition in the initialisation of the GPS that meant it sometimes initialized to a dynamic model of "Portable", which is the default for uBlox. That has a maximum altitude of 12km, which I suspect is what you hit.
The bug is fixed in the APM tree now, and will be in the next release of ArduPlane and ArduCopter.
Cheers, Tridge
Andy,
i guess you don't have any log files or anything do you?