Hello Fellow Yuneec Pilot!
Join our free Yuneec community and remove this annoying banner!
Sign up

Altimeter Error Accuracy Improvement?

Joined
May 20, 2017
Messages
74
Reaction score
8
Age
44
Location
San Antonio
When I turn on my TP H after it locks on GPS and I start to preflight, the ST 16 shows +.5 ft +- .2' or so. The moment I take off, the altimeter jumps to -21', causing the drone to lurch upwards and become very/very slow to descend at a higher altitude than usual... This happened repeatedly after 4 land reboots, and 2 attempts at calibrating both GPS and Accelerators. The sponges and foams are all in place on the Mainboard and over the sensors. I know the baro's are pretty basic, but seems odd that there would be such great variation, especially right after takeoff, always negative as well.

Winds were only about 4-5 mph max gust and it was a nominal 89 degrees, any ideas on improving this altimeter error? I know some have siad in the thread that+- 30' ins normal, I never had that kind of variability in several other controllers, the way this acts it is almost like the drone is causing the pressure changes...

Maybe a result of the magnetic storms? *joking*
 

Steve Carr

Missed Approach
Staff member
Premium Pilot
Joined
Dec 15, 2015
Messages
7,870
Reaction score
4,318
Location
Bessemer, MI
he moment I take off, the altimeter jumps to -21',
That is odd behavior. Perhaps the barometer is faulty. Each time the motors are started the altimeter reading resets to zero. Next time you fly take off a few feet, then land and restart the motors and see what it reads. If you are taking the H from an air conditioned car and setting it outside on a hot day the temp is not stabilized inside the aircraft. That can cause the altimeter to give strange readings.
 
  • Like
Reactions: GRH
Joined
May 20, 2017
Messages
74
Reaction score
8
Age
44
Location
San Antonio
Question, altimeter is on the fc side of the boards correct? I had thought perhaps sitting in the sun with the black ty h case stationary maybe getting hot and then when airflow started in flight maybe it was cooling to give a misread. Cooler air more density agl making it go negative?
 
R

Rayray

Guest
Curious indeed if it is repeating.

Is this a new TH? If not, is this a new behavior? Normal for the height to vary when close to ground, especially with a rising or falling barometric pressure, but what you describe is not normal.
 
Joined
Aug 6, 2016
Messages
362
Reaction score
205
Age
34
Location
Mexico
When I turn on my TP H after it locks on GPS and I start to preflight, the ST 16 shows +.5 ft +- .2' or so. The moment I take off, the altimeter jumps to -21', causing the drone to lurch upwards and become very/very slow to descend at a higher altitude than usual... This happened repeatedly after 4 land reboots, and 2 attempts at calibrating both GPS and Accelerators. The sponges and foams are all in place on the Mainboard and over the sensors. I know the baro's are pretty basic, but seems odd that there would be such great variation, especially right after takeoff, always negative as well.

Winds were only about 4-5 mph max gust and it was a nominal 89 degrees, any ideas on improving this altimeter error? I know some have siad in the thread that+- 30' ins normal, I never had that kind of variability in several other controllers, the way this acts it is almost like the drone is causing the pressure changes...

Maybe a result of the magnetic storms? *joking*

I am currently experiencing this issue with one of my aircrafts.

Not every flight, but some times I have this, unusual, aparently altimeter related problem. Reviewing the telemetry data I can see that shortly after taking off the altimeter logs are far on the negative side after take-off when this has happened. I check hardware monitor and stick output regularly, before every flight session, so this is not (in my case) a ground station hardware issue.

Flight behavior can be described as: a tendency to slowly keep ascending immediately after take off and a slow descent rate, although at full negative throttle (hare rate) the aircraft lands without issues. In my experience, after a few seconds it normalizes and everything continues normally.

I have only seen this immediately after take off. After I first experienced this a compass calibration seemed to fix the issue, however on later flights accel/compass calibrations don't seem to do much.

It can be very uneasing the first time this shows up, but up to now it has been just a nusiance, but definitely something I am keeping an eye open for.

I still haven't seen a pattern to when this happens: I have flown 4 batteries one right after another without this issue showing up. And other times I've experienced this on the very first flight and nothing on the rest. However this only happens to one of my aircrafts, so I'm leaning towards the faulty altimeter hypothesis.

Here are the altimeter graphs for my last 5 flights (all on the same session)

- Flight #1 and #2 went completely normal

- Flight #3 and #4 I immediately noticed the odd behaviour and decided to abort flights and run accel/compass calibrations.

- Flight #5 Issue was significantly reduced, after a few seconds hovering normalized and the rest of the flight went normally and uneventful.


Here is the actual footage of aborted flights #3 and #4:


Good to know I'm not the only one experiencing this.

Greetings!
 
  • Like
Reactions: Steve Carr
Joined
May 20, 2017
Messages
74
Reaction score
8
Age
44
Location
San Antonio
very nice graphs, This was a new TH I got back in may, but had a hard bump landing after trimming a tree, and she flew away...

Did not have this issue with the old FC, but for some reason the old FC had no pan and tilt when connected to the new mainboard...I will laugh if I have a bad baro sensor after all the stuff I have been through getting this bird to work right...
I will try to upload logs tonight and ask if anyone will help take a look.

JullesTEo, what are you using to get those good looking graphs? I am not very strong on the analysis side of the drone, more a hardware side, smash and rebuild guy :) Usually I know pretty well why they smashed :)
 

New Threads

Members online

Forum statistics

Threads
18,947
Messages
220,276
Members
22,094
Latest member
Midaswells