Hi all , just got a DJI refurbished Phantom 3 Advance from DJI and having RTH accuracy Problems.

Issue: In all test RTH is 15 to 18 feet off on RTH. Aircraft does not reorient to takeoff direction and lands 15 to 18 feet from RTH location. As I have owned a Phantom 3 Advance before I am aware that this is not normal behavior and it is capable of greater accuracy. My other P3A was generally less than 3 feet, and almost always landed back on the landing pad shown in video.

Info: The is a DJI factory refurbished Drone received on 8-11-2017. All item were charged and updates done (aircraft firmware and controller were required). Calibrated compass, controller, and IMU. Mainland China setting set to off. Took out for first flight today 8-12-2017 and ran through test.

Constants: The is not my first DJI, I actually got this to replace a drowned P3A I had for over a year and I am familiar with the aircraft. Flight location is the usual location with no know magnatic or GPS hazards. KP was a 1 so no notable solar activity. A Phanton 3 standard and Mavic flying had no issues and we tested their RTH to use as control to elelimnate environmental variables. Theirs was fine and with in normal range

Attemped resolutions: repeated test and calibration of compas and IMU several times, verified satelite locks and sufficient GPS prior to take off as well as Manually settring home point.

I am posting here first just in case there is a setting or something I can fix without it having it go back to DJI. Below is video of the issus as well as some flight logs. Excuse the blurry video. DJI please advise of possible solutions or if this may need to be returned.



AirData UAV Flight Link 1
AirData UAV Flight Link 2
AirData UAV Flight Link 3
AirData UAV Flight Link 4

This is primarily a user forum, there is no guarantee that DJI support would even see this. One of the mods probably will, and they will tell you to send it back for repair. But before doing any of that, I would take that gimbal guard off and try the experiment agian.

You don't say how many test flights you have run to see if it si consistent or juat a one-time thing.
RTH accuracy is only as good as consumer GPS accuracy which is usually better than 10 feet but can occasionally be more.
But it shouldn't be a cause for concern anyway.
You don't need to let RTH land your Phantom.
You can cancel RTH and take control and you can probably choose a better landing spot yourself.

Yes, once the drone begins to descend, take back control and land it nearer to your take off point. It's easy. ;-)




RedHotPoker

The drone will land on average around a 10ft radius from home point.

Geebax Posted at 2017-8-12 16:25
This is primarily a user forum, there is no guarantee that DJI support would even see this. One of the mods probably will, and they will tell you to send it back for repair. But before doing any of that, I would take that gimbal guard off and try the experiment agian.

Ok on the DJI, and I will try today without the guard.

Labroides Posted at 2017-8-12 16:52
You don't say how many test flights you have run to see if it si consistent or juat a one-time thing.
RTH accuracy is only as good as consumer GPS accuracy which is usually better than 10 feet but can occasionally be more.
But it shouldn't be a cause for concern anyway.

I did 6 test flights and posted log links for 4 of them

RedHotPoker Posted at 2017-8-12 17:16
Yes, once the drone begins to descend, take back control and land it nearer to your take off point. It's easy. ;-)

I generally don't remain at take off site and are usually not in a spot to land. RTH is used often to return and land the aircraft where it took of from and I am not. I.E. take off from land by river and go out on river with no ability to land at my location. RTH back to bank for landing (usually one of other guys there fishing). There are a lot of other instances where I use this a lot. Basically around water a lot, why previous P3A drowned in river. But I get what you are saying about take back control. It is mostly that the craft does not reorient to take off direction and that I know from my other it could/should be more accurate and does the fact it does not reorient and so off indicate some other issue. Thank you for all responses.

I have a lot of experience using handheld GPS units.  I have been using Garmin units since about 1998 while doing aircraft crash research in the mountains and deserts.  In general, I have found all units to be off by sometimes as much as 15 feet.  They have improved considerably in the last few decades.  But still, 6 or 7 feet off is a norm for me.

As far as the Phantoms are concerned, I expected it to be off by about that much and was never concerned about it.  I never really paid much attention to the distance discrepancy. Whether some Phantoms do better than others, I really don't know.  I just know my P3S and my P3 Pro, and I have never been able to RTH and land within 6 feet of the landing pad.  It does vary somewhat with conditions.

djordan2 Posted at 2017-8-13 09:36
I have a lot of experience using handheld GPS units.  I have been using Garmin units since about 1998 while doing aircraft crash research in the mountains and deserts.  In general, I have found all units to be off by sometimes as much as 15 feet.  They have improved considerably in the last few decades.  But still, 6 or 7 feet off is a norm for me.

As far as the Phantoms are concerned, I expected it to be off by about that much and was never concerned about it.  I never really paid much attention to the distance discrepancy. Whether some Phantoms do better than others, I really don't know.  I just know my P3S and my P3 Pro, and I have never been able to RTH and land within 6 feet of the landing pad.  It does vary somewhat with conditions.

With your P3S and P3Pro when they RTH are they turning back to face the take direction. Trying to figure if maybe this is some sort of change as my drowned P3A was over 1.5 years old but did do this.

Jamesjts Posted at 2017-8-13 09:09
I generally don't remain at take off site and are usually not in a spot to land. RTH is used often to return and land the aircraft where it took of from and I am not. I.E. take off from land by river and go out on river with no ability to land at my location. RTH back to bank for landing (usually one of other guys there fishing). There are a lot of other instances where I use this a lot. Basically around water a lot, why previous P3A drowned in river. But I get what you are saying about take back control. It is mostly that the craft does not reorient to take off direction and that I know from my other it could/should be more accurate and does the fact it does not reorient and so off indicate some other issue. Thank you for all responses.

If you have a device with built in GPS, you can change that dynamic home point, to where ever the RC in your hand is.  That was part of the reasoning by my purchasing the iPad Air2 Cellular. The Celluar iPad's have the GPS module installed.
What sort of device are you utilizing now?

RedHotPoker

Jamesjts Posted at 2017-8-13 10:14
With your P3S and P3Pro when they RTH are they turning back to face the take direction. Trying to figure if maybe this is some sort of change as my drowned P3A was over 1.5 years old but did do this.

You know, I never paid any attention as to which way it was facing upon landing.  I'll have to check.  But personally, I don't care as long as it comes home.

Edited:  Tested and answered in a later post.

Could you try another test.  This time don't reset the home point manually.  Let the drone do it.  Accept the one where the lady says, "Home point set, check it on the map."  See what that does.

As discussed above, the GPS discrepancy is in normal range, I do not think it is necessary to return it.

Well went out today to do some more test and had terminal failure, it dropped out of the sky on first flight this is with 1h12m42s of air time on the bird. 2 broken props, 1 bent prop, camera mount destroyed (broken at the neck). I am not knew to RC aircraft and my previous P3A had 69h+ air time. Next time I feel something is not right I guess I will listen to myself. It just did not perform on par with my previous P3A and did not feel right. Even when it did the auto landings they seemed a bit rough. I will be emailing support to try and see if I can get a warenty replacement, posting DJI log in case someone can see something I am not seeing or am not aware of as I don't usually bother with the DJI logs and use Healt Drone (airdata UAV).

Jamesjts Posted at 2017-8-15 21:22
[view_image][view_image]Well went out today to do some more test and had terminal failure, it dropped out of the sky on first flight this is with 1h12m42s of air time on the bird. 2 broken props, 1 bent prop, camera mount destroyed (broken at the neck). I am not knew to RC aircraft and my previous P3A had 69h+ air time. Next time I feel something is not right I guess I will listen to myself. It just did not perform on par with my previous P3A and did not feel right. Even when it did the auto landings they seemed a bit rough. I will be emailing support to try and see if I can get a warenty replacement, posting DJI log in case someone can see something I am not seeing or am not aware of as I don't usually bother with the DJI logs and use Healt Drone (airdata UAV).
[view_image]
[view_image]

Healthydrones does not reveal as good a set of data as Phantomhelp. If you upload to Phantomhelp and return here with a link to the resyults, some of the excperienced people here will look at your flight and give an opinion.

Jamesjts Posted at 2017-8-15 21:22
[view_image][view_image]Well went out today to do some more test and had terminal failure, it dropped out of the sky on first flight this is with 1h12m42s of air time on the bird. 2 broken props, 1 bent prop, camera mount destroyed (broken at the neck). I am not knew to RC aircraft and my previous P3A had 69h+ air time. Next time I feel something is not right I guess I will listen to myself. It just did not perform on par with my previous P3A and did not feel right. Even when it did the auto landings they seemed a bit rough. I will be emailing support to try and see if I can get a warenty replacement, posting DJI log in case someone can see something I am not seeing or am not aware of as I don't usually bother with the DJI logs and use Healt Drone (airdata UAV).
[view_image]
[view_image]

Whatever it is that you've attached is unreadable.

Anyone trying to help you needs to see actual flight data and the way to provide that is to go to http://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.
Come back and post a link to the report it provides .

The battery is what anyone is going to want to check first.
And the question they will ask is:
Was it fully charged at the start of the flight.

Sorry all that was the DJI file was trying to just attach the file vs a link to it but just drop boxed it instead and battery was 100%. Was flying out to try and RTH and it just dropped, no warnings or any indication of issue that I saw.
https://www.dropbox.com/s/846m4ckd0mav506/DJIFlightRecord_2017-08-15_%5B19-19-36%5D.csv?dl=0

Looking through the logs I also realize there were RTH's that were as mush as 25 feet off that I had not included in the discussion as they were not the average, these I actually took control as there were not good spots for the bird to land. Also all these fights took place at a AMA flight area with no known interference issues, was not trusting enough to take to normal water spots I would fly. I am actually copying off the DJI dat files from the bird a well to try and see if they show something and can post if anyone is interested.

Just for the heck of it, I did a test flight today on both my P3Standard and the P3 Pro.  I am using Android on my Samsung Tab A.  On the Pro, I went out 11,500 feet at 300 altitude.  I then activated the RTH.  The drone came back at altitude and landed normally on its own.  It did not face the same direction as when it took off.  It was facing in the final direction of travel.  And the landing spot was about 10 feet off from the take off point.  I've been flying this Pro since last summer and that has always been the norm for it.  The Standard did the exact same thing. Only I was able to go out just 1,600 feet before auto RTH kicked in.  I've been flying the Standard longer than the Pro.  I've never been able to go out much more than that with the Standard.  It also auto landed about 8 feet off the original point and was also facing in the return direction.  Other than that, both flights were what I consider perfectly normal...and fun.