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Old Apr 05, 2012, 10:02 PM
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AP_OZ's Avatar
Joined May 2010
1,393 Posts
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Warning.. DJI wookong-m - gps problems!!

Just thought I'd start a thread for those who are having problems with the gps return to home and position hold.

It appears that while the gps works well in the northern hemisphere, those of us who live in the southern hemisphere experience gps drop outs and general unreliability. I also hear ace1 users are having the same problems.

Hopefully by starting this thread DJI will take notice and adjust the code to make it work. Otherwise we can all have a whinge about spending $$$ on something that doesn't work as advertised.

Cheers,

John
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Old Apr 05, 2012, 11:42 PM
AlouetteIII's Avatar
near the Beach
Joined Sep 2007
649 Posts
@AP_OZ - As the AU distributor for DJI Wookong we are the ones who have invited DJI out to work on the software on the ground in AU with us and find the bug which currently causes drop outs on some flight. Bearing in mind that the number of Sats in the sky changes minute by minute from 6-10 - We dont always see this bug on a well set up Multicopter but we do experience random drop outs of GPS (red flashes) in AU - by this I mean it will go from Zero red flashes - to three red flashes while hovering smoothly in the take off zone - in clear vision of 8 sats and on other flights (new battery but same day) it will complete the flight with no red flashes - So we pretty well know there is a bug, most likely in code related to Southern Hemisphere.

The feedback we need from Users please (or anybody else) is Cause or causal factors which either reduce or increase drop outs - this will help engineers zero in on the location of the bug in their code. They dont see this issue in CN and rely on user feedback to isolate it.

We at MultiWiiCopter.com recommend the following to minimise these drop outs from GPS Nav -> ATTi mode
a) optimal GPS antena height is ≥120mm - this keeps the GPS antenna out of the ESC EMI zone - Use Opto or heatsink shielded ESC to reduce EMI in the first instance
b) re-calibration of MAG before every flight
c) placing a ferrite ring on any gimbal servo and any FPV lines - 4-5 turns
d) allow extra 60 secs before take off - after red flashes extinguish
e) balance all props both statically and also check each one dynamically - do a hover-power vibration check - for Ace one tail rotor and main rotor balancing is required.
f) Using a rigid 12mm CF GPS antenna/post using silicon - to prevent resonance/vibration of the MAG in the GPS pod.

For AceOne users the Ace device has a full data log which can be saved out to PC and send it to us - this .dat file contains a lot of engineering data about the cause of the drop out - ie only 6 sats in view due to obstacles or CPU overflow or calibration issue etc...

Please post on-topic data/details of your Wookong or AceOne system ESC/MotorKv/Props/Airframe and what you know a)increases or b)decreases the Red flashes GPS drop out issue.

Quinton
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Last edited by AlouetteIII; Apr 07, 2012 at 08:42 PM. Reason: added item f)
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Old Apr 06, 2012, 12:18 AM
Registered User
Australia, ACT, Canberra
Joined Apr 2011
104 Posts
Quote:
Originally Posted by AP_OZ View Post
Just thought I'd start a thread for those who are having problems with the gps return to home and position hold.

It appears that while the gps works well in the northern hemisphere, those of us who live in the southern hemisphere experience gps drop outs and general unreliability. I also hear ace1 users are having the same problems.

Hopefully by starting this thread DJI will take notice and adjust the code to make it work. Otherwise we can all have a whinge about spending $$$ on something that doesn't work as advertised.

Cheers,

John
John

I just put a pack thru mine out in the front yard surrounded by houses and trees with GPS on and didn't touch the sticks, and it's gusty out there now! I'm out at Jerra if you want to see for yourself. It took a while to find the ideal location for all the electronics and GPS but once you find it - perfect!
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Old Apr 06, 2012, 01:55 AM
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sydney, downunder
Joined Jan 2011
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Well my WKM sometimes fly very nice but other times got the toilet bowl effect. A friend of mine also got the same issue.
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Old Apr 06, 2012, 02:21 AM
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Australia, ACT, Canberra
Joined Apr 2011
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Originally Posted by fajar View Post
Well my WKM sometimes fly very nice but other times got the toilet bowl effect. A friend of mine also got the same issue.
Are you getting any red flashes at all during flights?
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Old Apr 06, 2012, 02:37 AM
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sydney, downunder
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Originally Posted by Yammysho View Post
Are you getting any red flashes at all during flights?
most of the time full sat locks so no red flashes. Only in few occasions I got red flashes.
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Old Apr 06, 2012, 03:09 AM
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Australia, ACT, Canberra
Joined Apr 2011
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Originally Posted by fajar View Post
most of the time full sat locks so no red flashes. Only in few occasions I got red flashes.
Even 1 red flash and mine will toilet bowl a little, it's taken a while (trying different layouts) but I can go flight after flight with no red flashes a real good PH even better PH when there is lots of wind. Most flights are in the front yard with lots of surrounding houses etc. Having said all that there is one local park I cannot get sat lock, think it's due to an aircraft radar beacon a 100 meters away? I check available sats with a bluetooth GPS connected to a laptop running OZIExplorer and have noticed somedays that sat reception is very poor but thats pretty rare.
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Old Apr 06, 2012, 06:41 PM
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Australia, Lord Howe Island
Joined Jan 2010
834 Posts
I am reposting this as this is intended to be a repository for people in Australia only who are having issues with gps lock.


Aussie here on the gold coast.

I have all but given up on my wkm. It has never ever worked as described. I was until now thinking it was my relative newbie ness to the hobby, ie its all my fault..... I must have something wrong in the setup...... Because from day 1 it has never held gps lock constantly under any conditions at all. The best I got was a hot start after leaving it in the garden for 35 mins on the ground until all sat lock red flashes were gone and then it held for about 3 mins before it lost all sats again and started to fly off.

Things I have done :

Extended the pole
Reduced the pole to zero
Mounted the gps antenna on a copper plate
Soldered a wire from the battery negative from the copper plate
Moved the gps around
Recalibrated the compass on every flight
Changed frame
Changed frame AGAIN ( I thought it must be the vibrations on the frames)
Tried long periods of ground acquisition time ( up to 1 hour )
Changed escs to firmware flashed ones
Changed props balanced props
Changed reciever ( I thought it must be emf from the reciever)

I cannot do anything else . I had probs with my unit not starting after CSC and I too sent it back to cn and it checked out ok. I know use it only in ATT mode and it is really good but hey so is my naza and that costs 200 bucks and NOT 1300.

I will be selling it soon if they don't fix this issue. It is useless as a gps hold and I'm buggered if I'm putting thousands of dollars of camera gear under it when it seems to have a mind of its own. Please Dji will you fix your current product line BEFORE you release new products ? You are looking more and more like xaircraft every day, and they are scammers.

Thanks
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Old Apr 06, 2012, 06:59 PM
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Australia, NSW, Sydney
Joined Apr 2006
2,074 Posts
I was so close to buying the Wookong but now I'll hold off after hearing all of these reports.

Any timeframe on the engineers visiting Australia?

Cheers

Matt
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Old Apr 06, 2012, 07:06 PM
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Joined Nov 2010
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Quote:
Originally Posted by jetbootz View Post
I am reposting this as this is intended to be a repository for people in Australia only who are having issues with gps lock.


Aussie here on the gold coast.

I have all but given up on my wkm. It has never ever worked as described. I was until now thinking it was my relative newbie ness to the hobby, ie its all my fault..... I must have something wrong in the setup...... Because from day 1 it has never held gps lock constantly under any conditions at all. The best I got was a hot start after leaving it in the garden for 35 mins on the ground until all sat lock red flashes were gone and then it held for about 3 mins before it lost all sats again and started to fly off.

Things I have done :

Extended the pole
Reduced the pole to zero
Mounted the gps antenna on a copper plate
Soldered a wire from the battery negative from the copper plate
Moved the gps around
Recalibrated the compass on every flight
Changed frame
Changed frame AGAIN ( I thought it must be the vibrations on the frames)
Tried long periods of ground acquisition time ( up to 1 hour )
Changed escs to firmware flashed ones
Changed props balanced props
Changed reciever ( I thought it must be emf from the reciever)

I cannot do anything else . I had probs with my unit not starting after CSC and I too sent it back to cn and it checked out ok. I know use it only in ATT mode and it is really good but hey so is my naza and that costs 200 bucks and NOT 1300.

I will be selling it soon if they don't fix this issue. It is useless as a gps hold and I'm buggered if I'm putting thousands of dollars of camera gear under it when it seems to have a mind of its own. Please Dji will you fix your current product line BEFORE you release new products ? You are looking more and more like xaircraft every day, and they are scammers.

Thanks
Hi Jetbootz,
I think it's a little unfair to compair xaircraft to DJI ,
At least we know other people are not having problems
Outside Australia,so it does work ,just not for us.
Let's just see what's going to be done?
I agree though I now have a very expensive Naza???

Also everything you mentioned ,is pretty much actually what I did
And still same problems as you,and I'm not far away from you,
North Brissy.


Regards
Jubbee
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Old Apr 06, 2012, 07:52 PM
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Australia, QLD, Brisbane
Joined Oct 2011
140 Posts
Some people are having problems with GPS in here in Brazil either. I almost bought, but I decided to wait some fix for this problem!
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Old Apr 06, 2012, 08:10 PM
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Lake Zurich, IL
Joined Jan 2008
5,653 Posts
The engineer is getting visa. Takes a little more time to get visa from any country for mainland Chinese. I'd say this month he should be able to head for the land down under.
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Old Apr 06, 2012, 08:17 PM
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Australia, QLD, Brisbane
Joined Oct 2011
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Originally Posted by sidneyw View Post
The engineer is getting visa. Takes a little more time to get visa from any country for mainland Chinese. I'd say this month he should be able to head for the land down under.
The engineer is going from where to where??
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Old Apr 06, 2012, 08:56 PM
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AP_OZ's Avatar
Joined May 2010
1,393 Posts
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Originally Posted by marcelog View Post
The engineer is going from where to where??
He's coming to Australia.

As it appears to be a southern hemisphere thing it's probably the easiest place to get to from china.

Hopefully they get here soon as I personally know about 10 people who are waiting for the problems to be fixed prior to buying dji gear. That's a lot of $$ they are losing out on. even more when you think some would buy the ace1.
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Old Apr 06, 2012, 09:02 PM
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Just had a look and Qantas are doing flights from beijing to sydney for around $500usd each way. Not a big outlay considering the sale of a single wookong would pay for the whole trip.
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