How much "Drift" is considered accecptable
1944 20 2015-4-8
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markkinley
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Hello Good People.. I recently upgraded my P2v+ to the latest firmware and preformed all calibations and upgrades....
Aquired 11 sats and lift off. At 15 feet AGL, (no wind)  I let it hover and I noticed that the unit hovered but drifted slowly away from it's location.
Thinking it was ground effect causing it, I hovered again at 30 feet and the same thing happened.
I corrected it and then slowly it went back again to drifting..

any clues?





2015-4-8
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nrgwise
Second Officer

United States
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Does it keep drifting always in one direction?  Does it ever stop and try and correct itself?  It will drift around a bit, but should try and recover location.  If you are constantly having a drift, I would perform an advanced IMU cal.  Make sure your bird is level, not near metal, and if it says too hot, click okay and let it continue.  It is done when you see a green check.

Being LEVEL is important.
2015-4-8
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jtrjr
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nrgwise Posted at 2015-4-8 21:02
Does it keep drifting always in one direction?  Does it ever stop and try and correct itself?  It wi ...

+1. "Ditto"

Carefully! if not right, do it again and again...

Jerry
2015-4-8
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markkinley
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nrgwise  - Yes it continues to drift slightly i.e. it's facing north but drifts to the east and i can see it attempting to stop but doesn't completely. I always calibrate before each flight. and I'm flying in an open park away from all interference...

jtrjr - i dont recall having this issue with the 3.08 firmware version..

Thanks


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DJIP2plus513
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I had this same problem on Saturday and realized that the S1 switch was in the middle (non GPS) position. Switched back to the up position and the drift stopped. So, you might check that and your satellite count.
2015-4-8
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jtrjr
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markkinley@yaho Posted at 2015-4-8 22:19
nrgwise  - Yes it continues to drift slightly i.e. it's facing north but drifts to the east and i ca ...

Mark,

I was never on 3.08 so I couldn't say. All I can say is I had to do the advanced calibration four times before it felt right. It's certainly much better than it was out of the box but I'm not convinced that it's "perfect" yet. I won't be able to tell for sure until the weather stabilizes here. I'm just throwing out my opinion. I know Nrg and others never had this issue but many others have.

Jerry
2015-4-8
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Raybro
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jtrjr@yahoo.com Posted at 2015-4-8 22:48
Mark,

I was never on 3.08 so I couldn't say. All I can say is I had to do the advanced calibratio ...

Mine has some drift as well. I notice it when it's hovering close by and also during landing. If I try to put it in a particular spot I am constantly pulling back on the right stick to get it where I want it. I know the closer you get to the ground, ground effect will occur but not 10 feet in the air.

Straight from the Spec sheet of the Phantom 2:
Hover Accuracy (Ready to Fly)
Vertical: 0.8m;
Horizontal: 2.5m


Spec sheet from P3
Hover Accuracy
  • Vertical: +/- 10cm
  • Horizontal: +/- 1m

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nrgwise
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markkinley@yaho Posted at 2015-4-8 22:19
nrgwise  - Yes it continues to drift slightly i.e. it's facing north but drifts to the east and i ca ...

Perform an advanced IMU cal.  Not the same as 'always calibrating before you fly' unless you do an advanced IMU cal before each flight.  The advanced IMU cal is the fix for drifting.
2015-4-8
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markkinley
lvl.4

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I will do the "advanced IMU calibration again", it seems redundant to repeat this step.
But I like this hobby and  I will update you as soon as the DERN RAIN leaves!
Thanks
2015-4-9
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jtrjr
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Mark,

If you continue to experience the "drift" issue And you have a little time on your hands you may want to read through the thread I'm going to link in this note. You are correct, you'd think doing the cal once should suffice but some of us (not all) have had some real issues with the advanced cal process. If you do take the time to read it, read through the whole thing before you start doing things. It appears that different processes could get you back to where you need to be. I was able to do mine without taking my bird apart as some had to do.

http://forum.dji.com/forum.php?m ... ra=page%3D2&lang=en

Jerry
2015-4-9
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Raybro
lvl.4
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Speaking of drift......good example of a P2 holding it's own in high wind.


2015-4-9
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PanamonCreel
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Mexico
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markkinley@yaho Posted at 2015-4-8 22:19
nrgwise  - Yes it continues to drift slightly i.e. it's facing north but drifts to the east and i ca ...

Does it always drift in the same direction in relation to the Phantom orientation?
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markkinley
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OK the rain and storms had passed for the moment...
I have tested the phantom and yes PanamonCreel it  does always drift in the same direction in relation to the Phantoms orientation and it also lowers itself as much as 1 foot in each direction the rises back up to the assigned altitude.  I purchased new props (Carbon Fiber & Plastic) and tested them after a full calibration was performed. I got the same same results.
I take mt laptop with me and re calibrated the P2V+ between battery changes and still get the same results...  
2015-4-14
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kirk2579
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markkinley@yaho Posted at 2015-4-14 20:41
OK the rain and storms had passed for the moment...
I have tested the phantom and yes PanamonCreel i ...


it would be hard to get a good IMU calibration in the field if that what you are doing with the laptop.

it needs to be be absolutely level on solid surface. Then even run a level across the motor posts to see if they are level. shim as needed to level the motor tops then run the advanced imu cal.

do when quad has been off a bit so you don't get the MC hot error. have it ready in assistant then power up the phantom and immediately calibrate


http://www.phantompilots.com/thr ... -yaw-problem.38596/
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Raybro
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Good thread here as well and extensive work done regarding yaw drift.... could solve your issue.

http://forum.dji.com/forum.php?m ... age%3D2&lang=en
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jtrjr
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markkinley@yaho Posted at 2015-4-14 20:41
OK the rain and storms had passed for the moment...
I have tested the phantom and yes PanamonCreel i ...

Mark,

Raybro sent a link to the whole fiasco. It has a number of ways to do the advanced IMU calibration. I suggest you try this first. This is what I did and it worked perfectly for me. I don't know if it will work for you but I think it's an easy way to start before you go opening up the shell. I'll just paste the way I did it in this post. If it doesn't work than you should thoroughly read what the others have done in the link Ray sent and try some of their methods.

"Okay Fella's here's what I did. A hybrid of what you guys have done. I was hoping I wouldn't have to open the shell again. I want to avoid removing the screws over and over again. Wasn't sure whether it would work without leveling the IMU itself but thought I'd give it a shot.

Found the most level surface I could find to put the Phantom on.
Got 4 plastic spacers from an old flat screen TV mount kit that fit perfectly over the motor studs
Took apart a picture frame that had a 10" x 13" pane of glass in it. (Standard size, I think)
Put the spacers over the studs
Laid the glass across the 4 spacers
Took a 2' straight level and leveled from front to back, side to side and then across all posts
I used standard business cards and started shimming
It took (looking from the rear at the battery: RR-5, RF-5, LR-1, LF-3 to get level in every position
Ran the advanced IMU calibration"

Worked great for me. Hope it helps!

Jerry
2015-4-14
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PQ2V+
lvl.1

Germany
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I don't understand how do the motors need to be level? What is shimming?
2015-4-14
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jtrjr
Second Officer
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PQ2V+ Posted at 2015-4-15 03:29
I don't understand how do the motors need to be level? What is shimming?

PQ,
Have you read through the threads we've suggested? It explains the whole problem and process with pictures. I'd suggest once again that you go take a read. I don't want to keep posting redundant responses.

Jerry
2015-4-14
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PQ2V+
lvl.1

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I'm sorry, I didn't see this was about IMU. Shame on me
2015-4-14
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PanamonCreel
lvl.4

Mexico
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markkinley@yaho Posted at 2015-4-14 20:41
OK the rain and storms had passed for the moment...
I have tested the phantom and yes PanamonCreel i ...

Take a close look at the stick calibration firstly on the TX and after directly on the Phantom.
2015-4-14
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kirk2579
Second Officer
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PQ2V+ Posted at 2015-4-15 03:29
I don't understand how do the motors need to be level? What is shimming?


slightly adjust the level by adding small increments, example sheets of paper, playing cards.

to fly level the imu needs to be level. if the top of motor post are all level to each other then the imu is calibrated it should LEVEL out your flight

props equally level means little variation in balance

as others keeps saying start reading the links posted and look at some of the videos and ALL will be answered

google is your friend, use it,
2015-4-14
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