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Mavic 2 Height Inaccurate

Aquaman1414

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My problem is when it 1st takes off the height is accurate but after flying a lil if the screen says I'm at 3ft I'm really about 17 ft high. I have calibrated it and it still does it. Anyone have an idea what the problem could be?
 

Meta4

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My problem is when it 1st takes off the height is accurate but after flying a lil if the screen says I'm at 3ft I'm really about 17 ft high. I have calibrated it and it still does it. Anyone have an idea what the problem could be?
What have you calibrated?
Only the IMU would have any effect.
 

Meta4

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I just did the reg calibration. Is there another one? Still new to this
I have no idea what you calibrated, there is no "reg calibration".
Perhaps you mean you recalibrated the compass, which would not do anything for heights or anything else that isn't compass related.
You need to calibrate the IMU (if that's possible in the Mini).
 
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Aquaman1414

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Ok, I just watched a video on IMU calibration. You are correct, I only did a compass calibration. I will do a IMU calibration in the morning and I will let you know know if it fixed it. I have a Mav 2 Pro by the way, I've only had it about a week so still learning.
 

Shivers

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Ok, I just watched a video on IMU calibration. You are correct, I only did a compass calibration. I will do a IMU calibration in the morning and I will let you know know if it fixed it. I have a Mav 2 Pro by the way, I've only had it about a week so still learning.
Take your time and go through all the Ins and outs. Watch the videos... go through all the steps and know the AC before takeoff. Download DJI assistant, this will help with other calibrations, as well recal the visions sensors, or updates! You can do updates Via Wi-Fi as well. Each battery you have and the AC plus controller will prob need updates. Up to you if you wish to do them. Personally I don’t update the fly safe data anymore... cause DJI in China has no clue about no fly in USA. So, I use other apps to aid in my safe areas of flights.
So, I would take a battery that’s charged... calibrate that IMU, and the rest... See what you can do in settings before takeoff. Then enjoy your flights. Be safe! No buzzing the tower, or fly bys! Lolol.
 
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My problem is when it 1st takes off the height is accurate but after flying a lil if the screen says I'm at 3ft I'm really about 17 ft high. I have calibrated it and it still does it. Anyone have an idea what the problem could be?
I find I have the same issue the altitude reading is seldom accurate after one or two minutes of flight. Don’t know how to fix it
 

DanMan32

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Same here, but only up to about 5ft or so, and usually reporting lower than actual.
VPS height is quite accurate though.
 

Dave Maine

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Make sure you understand what is being reported. Altitude reported is the height above ground at the takeoff point. It has nothing to to with the height above ground away from the takeoff point. If the terrain slopes up, you will shortly be tunneling if you fly at a constant altitude.
 

DanMan32

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Yes but my terrain is relatively flat, and as I approach landing pad where I took off from, it is in the negative.

My P3 was that way too.
 

sar104

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While relative up and down movement is primarily detected by the IMU accelerometers, absolute height over the course of a flight is tracked by barometric pressure. That should be accurate to a couple of meters if ambient atmospheric pressure is steady, but it often isn't. A few meters of drift over the course of a flight is perfectly normal.
 

DanMan32

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A couple of meters is around 6ft, so that makes sense. The drifts can be seen sometimes within a minute or two from takeoff.
 

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Following your thread. Wonder how I would deal with launching a Pro 2 from a mountain or cliff and flying below the takeoff point altitude and how to set the RTH altitude relative to the takeoff point.
 

sar104

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Following your thread. Wonder how I would deal with launching a Pro 2 from a mountain or cliff and flying below the takeoff point altitude and how to set the RTH altitude relative to the takeoff point.

You answered your own question. The RTH height is relative to the take off point.
 
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Agree that would make sense. Based on your previous post, is it advisable to add another couple of meters to the RTH setting to allow for the drift you mentioned? And based on your experience, how does aircraft handle RTH if you fly down a valley, say 400’ below take-off point, when Low Batt or Emergency RTH takes over? Thanks for any replies. There’s lots to learn from experience but trying to avoid learning the hard way!
 

sar104

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Agree that would make sense. Based on your previous post, is it advisable to add another couple of meters to the RTH setting to allow for the drift you mentioned? And based on your experience, how does aircraft handle RTH if you fly down a valley, say 400’ below take-off point, when Low Batt or Emergency RTH takes over? Thanks for any replies. There’s lots to learn from experience but trying to avoid learning the hard way!

I'd never set any automated flight with a vertical or horizontal margin for error of less than 10 meters. The FC handles RTH exactly the same way independent of height - it rises to the set height above the takeoff point. Of course if it is now out over a valley that is 400 ft lower, then climbing to the RTH height will put it in excess of 400 ft AGL, but there isn't much you can do about that if you want it to RTH.
 

Aquaman1414

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UPDATE: Sorry it took so long to get back, its been raining here in Cali (can you believe it). I did the IMU calibration and it did "help". It's only off by 3 ft or less now. Which is a lot better than it was. The measurements are always taken from my back yard on level concrete. My Mav Air is never more than a 1/2 a foot off.
 

Aquaman1414

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Take your time and go through all the Ins and outs. Watch the videos... go through all the steps and know the AC before takeoff. Download DJI assistant, this will help with other calibrations, as well recal the visions sensors, or updates! You can do updates Via Wi-Fi as well. Each battery you have and the AC plus controller will prob need updates. Up to you if you wish to do them. Personally I don’t update the fly safe data anymore... cause DJI in China has no clue about no fly in USA. So, I use other apps to aid in my safe areas of flights.
So, I would take a battery that’s charged... calibrate that IMU, and the rest... See what you can do in settings before takeoff. Then enjoy your flights. Be safe! No buzzing the tower, or fly bys! Lolol.
Hey Shivers, what do you mean when you say calibrate each battery? Are you saying to do a IMU calibration with each individual battery? Sorry for the questions but with my Mav Air I just messed around and took a couple of pics/videos and learned how to fly it, but with the Mav Pro I've gotten a lot more serious about the Ins & outs so I've been trying to learn as much as I can about. Been doing a lot of reading and watching videos and the more I learn the more I realize I don"t know a **** thingo_O
 

DanMan32

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No, he means with a full battery do all calibrations.

In the beginning he was referring to firmware updates, making sure all your batteries have the update.
 
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Shivers

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Thanks Dan for that! Yes... At your house connected to Wi-Fi before flights. You should turn the unit on, with each battery. Make sure the firmware is up to date! You can do this with the assistant, or by Wi-Fi and turning on. You’ll see a firmware does not match... if the batteries have not been done. As well, make sure the Remote control and Aircraft are also up to date.. I’m sure you have. Then, with a full battery... no standing around anything metal... no cars, no dumpsters, nothing like so... And do your imu and compass calibrations. This should be a quick process. Couple spins and stuff. If your not sure, watch a You Tube video at the proper circle to perform. (Heck, I also watched the video first time, rather then trying to spin it, just walk in a circle) If you don’t do this correctly, it will toss off errors, and cause issues. After you calibrated your IMU and your compass... Set it back down, and make sure you have a clear line of sight to the sky.. take off in GPS mode only! Do not take off till ATTI mode disappears. Once you see GPS and your landing zone has been updated on the map (it will state this) try taking off.
Let us know what ya get.
Thanks Dan! Always got my back somehow!
 
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