Fixing DJI's Compass Problem

slapface · Mar 25, 2014

I have the exact issue.
The P2V worked perfectly out of the box in December.
Updated the firmware and whammo, it now is doing the j-curve -- identical to the video.
I sent it to dronefly because I thought I tweaked a motor when I hit a branch -- not thinking the firmware update would cause the copter to fly WORSE than before the update.
They replaced a motor and said it was perfect. They sent it back.
First flight it did the same thing. So I sent it back.
They "fixed" it and sent it back.
First flight and it did the same thing.
Sent it to DJI (still not seeing all the chatter online about the problem), they replaced the flight controller and gave me new props and said they tested it and it flew perfectly (they tested it on a tether, not outside to re-create the problem I was describing).
Guess what, first flight yesterday and it did the j-turn again.
YIKES!!! after 10-12 minutes it fixes itself.
So, count me on the list of people with the problem!!!!

MarkMooney · Mar 26, 2014

Can the current firmware be de-compiled?

I live in Petaluma, northern cal...

I have yet to see the J turn on my phantom 2 vision.

EyeUpHigh · Mar 26, 2014

Northern California, 38.5N -122.7W, +14 degrees declination

Have had this problem out of the box; participated in previous threads about the issue. Returned the P2V to DroneFly for repair (figuring it was a mis-alignment of some sort) but they returned it in the exact same condition.

Flight also tracks left about 20 degrees from straight, I believe this is a related flight control issue with confusion between GPS and compass heading - documented the problem for DroneFly here:

[youtube]http://www.youtube.com/watch?v=cWlB91E9xC8[/youtube]

As a software engineer who's written some motion control code, I'm astounded that they can't add in rudimentary declination correction (considering they know the GPS position down to ten feet!)

[edit] after reading your document (very thorough - great job!) I see you've come to the same conclusion: a small lookup table with declination fixes and the issue is solved. When the programmers have left something that simple out you have to wonder what else may be lurking in the code...

sahair1 · Mar 26, 2014

Add me to the list, I live in Utah and experience both the hook to the left at the end of straight flight and the toilet bowl effect when I go in to a hover. I did have a little confrontation with a tree when I first got mine in December and thought that was what was causing it. I hope you can get DJI's attention on this issue and we can get an update.

iResq · Mar 26, 2014

I wonder if this was what was addressed in the latest firmware?

Sent from my DROID RAZR using Tapatalk

Quadro · Mar 26, 2014

First, a word of heartfelt thanks for sharing your 8FG Phantom 2 (V4) profile. It's a beautiful thing. Works perfectly on the P1 and P2.

I live about 15 miles East of NYC.

I have a P1.1.1 and p2 -- both with current firmware (at least as of the last time I checked a couple of days ago).

The P1 is rock steady with no hook or wander or wobble -- and flies reasonably well in winds of 15 to 20 mph.

The P2, however, has been ornery from the git go. It weaves and wobbles and bobbles and sounds like an angry hornets nest even in a gentle breeze of 6 or 7 mph. In stronger winds it pitches violently when hit by gusts.

More to the point, I use the dual-rate switch that you programmed for the 8FG, because if I were to let it fly at anything like the speeds in your video at the top of this thread, it would J hook for 20 feet or more when I release the right stick in GPS mode.

The thing is, I just took it to LA and tried flying in Malibu Creek Park (in near calm conditions) and hooked there as well. I also tried it on the H.S. football field in Ojai -- and had to shut down because even at slow speeds it was drifting so badly that I was afraid it it would land in the bleachers.

My frustration has reached the point where I have ordered a bunch of Mad Dog 2700 mah batteries and am switching the Zenmuse gimbal over to the P1.

In mid April I'm driving to Santa Fe and plan to stop and fly along the way as often as possible. It will be interesting to see if the J hook persists across the Midwest. I'll let you know.

Thanks again for all your efforts!

John Shaw · Mar 26, 2014

I am located in the Pacific Northwest at about 17 degrees east and fly a stock P2V. I have noticed both the hook and especially the offset angle when flying in Course Lock. I have learned much from this thread - Thanks. On the next dry day I will run more specific tests.

****
Do we know if the recently announced software update effects this issue? It doesn't look like it's listed.

ianwood · Mar 27, 2014

We are up to 52 people after only 8 days. The new firmware is confirmed to not have any influence on the problem one way or the other. So, it is a good time to reach out to DJI and make sure they are addressing this issue. I am going to start working the channels. If anyone has any high-level contacts at DJI or one of their main dealers, please PM me. I am open to ideas as to how best to get their attention. My only request is that we keep our efforts coordinated. I have a couple ideas already but I want to try the direct route and see if DJI will address it.

DesertFlyer53 · Mar 27, 2014

ianwood said:
We are up to 52 people after only 8 days. The new firmware is confirmed to not have any influence on the problem one way or the other. So, it is a good time to reach out to DJI and make sure they are addressing this issue. I am going to start working the channels. If anyone has any high-level contacts at DJI or one of their main dealers, please PM me. I am open to ideas as to how best to get their attention. My only request is that we keep our efforts coordinated. I have a couple ideas already but I want to try the direct route and see if DJI will address it.

I posted the link to this thread on DJI's facebook page a last week but so far... no response.

Byroman · Mar 27, 2014

Right on!
I have had this problem since I purchased my Vision back in November. I live in Northwest Montana around 17° E. declination. Mine does EXACTLY what you have described...left in forward flight and hunting for position after I put the brakes on. After maybe 5 to 10 minutes of flight, it mostly straightens out.
Sure hope a resolution comes soon.

Thanks!

wkf94025 · Mar 28, 2014

Count me in. My P2 hooks left in GPS mode, flies straight in ATTI mode, given same right stick forward input. When I send it straight away in GPS mode, after the hook left, if I pull right stick strait back, Phantom eventually hooks the other way, completing the "circuit".

Location upper Napa Valley.

Kelly

riblit · Mar 28, 2014

My tests today with a Phantom 2 Vision in Eastern Australia conform that I am getting the same left hook on forward flight and right hook on reverse in GPS mode. Phantom was upgraded to latest firmware today before the test.

BLACKTOWN NEW SOUTH WALES
Latitude: 33° 46' 0" S
Longitude: 150° 55' 0" E
Magnetic declination: 12° 22' EAST
Declination is POSITIVE
Inclination: -64° 12'
Magnetic field strength: 57050.5 nT

John

xybe · Mar 28, 2014

I have experienced erratic compass behaviour since the get go, hard to calibrate, even though the values show as normal on the Assistant software I still circled the magnetometer with a magnet to try to get better values, which had very little effect. Many failed (compass dance) calibrations and the P2V seems to track to the right on GPS mode.

There may be additional factors at play.

Easter South America

Montevideo
Latitude: 34° 51' 29" S
Longitude: 56° 10' 15" W
Magnetic declination: -10° 7' WEST
Declination is NEGATIVE
Inclination: -40° 9'
Magnetic field strength: 22997.9 nT

arnonel · Mar 28, 2014

Anyone aware of Android or IOS apps to measure magnetic interference?

Sent from my Nexus 5 using Tapatalk

EyeUpHigh · Mar 30, 2014

Geert said:
I flew with my P2V in Greece and in Thailand.

No compass problems here.

That would make sense - your magnetic declination is only 4 degrees East of North. (I'm envious of those Brits who are at 2 degrees West of North - no real declination to speak of!

GMANNZ · Mar 30, 2014

arnonel said:
Anyone aware of Android or IOS apps to measure magnetic interference?

Sent from my Nexus 5 using Tapatalk

Seems to be plenty just google - Magnetic declination apps ??

cliveg · Mar 30, 2014

I am new here. Got a phantom Vision about 2 weeks ago. Yes I seem to have this problem, have not been able to get it fly straight yet. But I am enjoying it anyway. I am in Hamilton New Zealand.

jimre · Mar 30, 2014

I thought the point of doing the compass calibration "dance" was to adjust for local declination. Is that not the case?

BigBadFun · Mar 30, 2014

jimre said:
I thought the point of doing the compass calibration "dance" was to adjust for local declination. Is that not the case?

You need to read the very first post.

GMANNZ · Mar 30, 2014

cliveg said:
I am new here. Got a phantom Vision about 2 weeks ago. Yes I seem to have this problem, have not been able to get it fly straight yet. But I am enjoying it anyway. I am in Hamilton New Zealand.

hope you dont get in trouble like your fellow Hamilton flyers