IMU and Barometer Errors after First Flight. Please Help!

[Dacon Productions]

Didn't know that???
Air pressure is based on temperature, humidity, elevation.
If you calibrate IMU inside (barometer takes a reading) in a AC room without humidity and go outside where is hot and humid, do you think you get the same altitude readings?
You start your drone on the ground, outside, right? Why calibrate IMU inside and at a different height than you fly from? Just make sure the "ground" is very leveled.

 

[Phantom751874]

So what do you do then?

An IMU calibration in the cool morning before flight then an IMU calibration in the hotter afternoon before flight? Then maybe one when humidity levels are low before flight and one when humidity levels are high before flight? Maybe one before flight for every 100ft change in elevation?

 

[Phantom751874]

I suspect the barometer isn't calibrated when an IMU calibration is done at least not in the sense of setting whatever current reading it gets during the IMU calibration until the next IMU calibration.

I wouldn't be surprised if the barometer sets a value or does a calibration itself every time the P3/4 is turned on so that it has a current "nominal" value to use as a baseline and from there determine height based on a difference from that baseline. This would make the most sense as it would account for the varying temperatures and humidity levels that people fly in day to day inbetween IMU calibrations.

 

[With The Birds]

Barometer.

No. I suspect this do be of no practical relavence. Barometer resets to zero reference at home point at take off. Even if you were to take off from the same location as calibrated every flight small variations in atm pressure would still make calibrating at that point of no benefit.

 

[Dacon Productions]

It doesn't matter of when, where, how, the barometer concept is stupid since the GPS is a lot more accurate and not influenced by weather. Main readings should be based on GPS and back up on barometer.
You trust the GPS to hold horizontal position on a windy day, why not hold altitude???
Modern planes auto pilot, ICBMs, rockets all hold altitude on GPS and not on barometer...but its a DJI concept and live with it.

 

[With The Birds]

It doesn't matter of when, where, how, the barometer concept is stupid since the GPS is a lot more accurate and not influenced by weather. Main readings should be based on GPS and back up on barometer.
You trust the GPS to hold horizontal position on a windy day, why not hold altitude???
Modern planes auto pilot, ICBMs, rockets all hold altitude on GPS and not on barometer...but its a DJI concept and live with it.

The discussion here was about IMU calibration. I was, and remain, interested to learn the basis (if any) of your assertion that IMU calibration cannot be reliably performed indoors.

With respect to altimeters, or at least your suggestion that reading barometric pressure to determine altitude is stupid- aircraft rely on pressute altimeters in preference to trilateration (deriving altitude from GPS) because it is more accurate.

 

[Phantom751874]

It doesn't matter of when, where, how, the barometer concept is stupid since the GPS is a lot more accurate and not influenced by weather. Main readings should be based on GPS and back up on barometer.
You trust the GPS to hold horizontal position on a windy day, why not hold altitude???
Modern planes auto pilot, ICBMs, rockets all hold altitude on GPS and not on barometer...but its a DJI concept and live with it.

GPS can't determine altitude.

 

[N017RW]

It doesn't matter of when, where, how, the barometer concept is stupid since the GPS is a lot more accurate and not influenced by weather. Main readings should be based on GPS and back up on barometer.
You trust the GPS to hold horizontal position on a windy day, why not hold altitude???
Modern planes auto pilot, ICBMs, rockets all hold altitude on GPS and not on barometer...but its a DJI concept and live with it.

Can you link to these assertions?
According to this GPS is not reliable for altitude due to many factors:
Altitude Accuracy

This info may be 'stale' so can you help us to understand it as you do?

 

[Oso]

It doesn't matter of when, where, how, the barometer concept is stupid since the GPS is a lot more accurate and not influenced by weather. Main readings should be based on GPS and back up on barometer.
You trust the GPS to hold horizontal position on a windy day, why not hold altitude???
Modern planes auto pilot, ICBMs, rockets all hold altitude on GPS and not on barometer...but its a DJI concept and live with it.

As noted by others here, in many other threads, as well as in the real world, GPS is not a good source of altitude data.
Waypoint accuracy?

 

[Fat City]

In the past I've helped develop GPS-based navigation instruments, including an avionics IFR device. GPS (including with WAAS) is not very good for altitude measurements and AFAIK ia never used that way in aircraft. (If the receiver is known to be stationary, as in surveying, I think it can do a lot better.) A barometer is much more accurate, at least over a flight's duration.

 

[Erised]

I had a barometer error in flight at 350 feet elevation (posted this) after all the flashing red screens the P4 had maintained the exact altitude I was at. Go was showing my max altitude at 5331 feet and displayed my present altitude correctly. A weather front was comming in and decided to fly before it got to me, I think at 15000 feet out I got to it. To go from my take off point at 850' elev. to go to 5331' you need a pressure drop of 2.17 psi. As you know fluid velocity over a surface causes a pressure drop, this is what I believe happend here, atm drop and air velocity around the bird. Got home did a stop and go and all was normal, I pretty shure the bird knows better to fly with that type of error and used gps to hold and reset (did a good job too) because I would have slamed in the ground. We all have some elevation variances and that's could be caused by pressure variations and temperature. Same pressure at 850' elevation at 60F will show 884' at 80F. I don't understand why some would want to calibrate cold, you just made it worse. Like Phantom751874 says the bird probably recalibrates on start up. That would be the right way to do it.

 

[Adam Squibb]

Did you solve this problem as I am getting the exact same problem

 

[GrammatonxXXxCleric]

You also need to point at it while doing a MUI calibration. The drone will learn who it's master is during this process and will hard code the control image in it's EPROM chip.