Hi there,
What a nightmare yesterday. Yes, Im a newbie and I thought the home location is saved at where i took off.
Story goes: I decided to try the RTH function. The reason I tried to use was purely experimental, I could see the craft easily within my eyesight.
As expected, it began to reach the RTH altitude. I was hoping it to come towards me, BUT, it began to fly away from me in another direction.
After 2 hrs of searching the bush nearby. Using the aircraft's remaining power of GPS location and my phone's GPS. I finally retrieved the craft after nightfall. The craft apparently suffered only minimal damage. My prayer worked! I don't dare to test it again.
Then I came home to download the video clip and most inportantly he flight telemetry. The video still haunts me. As for telemetry, I discovered the home location suddenly changed while in mid air to another absolutely different location. (almost 1km away where I took off from and I had never flew there before)
Would any DJI expert please tell me what happened?  Did I wrongly input any new home location accidentally into the app during the flight? I thought home location cannot be changed after took off.
I wish I can send you the flight telemetry log. Please tell me how and I will. I had uploaded into my DJI cloud account.
Any comment is very much welcome.
Kind Regards,
Kenneth

This happened recently to another guy with a P3S. Don't think dji ever responded. It must be some sort of glitch or something. Heres a tip for when you lose control of the aircraft: Switch to atti mode, increase your altitude to avoid things you don't know about, open up your map, and fly home in the direction that is pointing towards the blue dot (not your home location, your location). Did you try to cancel the RTH?

At that critical moment, my cellphone lost signal with the craft. I remember clearly that my screen turned black and white. Thus, the craft would inevitably GO home as it lost connection with me. The question is this home is not REAL home anymore as it drifted. I wonder if that was simply interference? I have proof that the HOME changed as the flight record shows. Yes, it was horrible. OK, I will practice more ATTI mode and use this when it misbehave again. Thanks.

How many GPS signals did you have?
Did the number of GPS signals suddenly drop?

http://healthydrones.com

One theory I have is that possibly the bird lost all GPS signals and then regained them but the software app got confused and reset a new home point.
Why so far away?  Well say the bird was facing you and the app tried to put the home point back on, but instead of using past known longitude and latitude it might have just popped in the home based on the distance the controller and bird but not factoring in the rotation angle thus placed it in a completely different location.

This is just a theory, but only logical answer I can think of.

TJ10 Posted at 2016-4-21 21:45
This happened recently to another guy with a P3S. Don't think dji ever responded. It must be some so ...

Yes, no response so far. I think this is something they probably know but can't help. As this might have to do with surrounding interference or their RTH is not perfect yet. First of all, I will practice more in A mode. Secondly, as I saw from other members, RTH is the last resort option. Do it if no other choice, always rely on visual flight if possible. Thirdly, if RTH is to be used, open up the map and verify the home point first.
After viewing the footage, I got a better idea. First home point was relocated, so it drifted after RTH button pushed. Then, signal losts (as I remember my phone picture turned black and white), the craft stationed 1-2 seconds. Lastly, signal regained, the craft yawed towards new home point, directly crashed into the tree. That's what I saw and to share.

microcyb Posted at 2016-4-21 23:43
How many GPS signals did you have?
Did the number of GPS signals suddenly drop?

When I took off, think there were about 10?? Not quite sure. But it says safe to fly all the time before it happened. So, I guess its safe?
Yes, I guess your theory is possible. The location where I first took off, less than 50m is huge sea water pump house. 100m away, there is a 30m high abandoned power station. So, there is lots of metal/buried cable I supposed. As a result, after the craft climbed to higher altitude, the GPS signal could be a lot different from where I took off.
I will search for another safer location to fly from now on. Thanks for your reply.

hihi_shrek Posted at 2016-4-22 14:46
When I took off, think there were about 10?? Not quite sure. But it says safe to fly all the time  ...

The power station and pumping station would not have had any effect on either the compass or the GPS reception. Something else altogether happened, and until you put up the logs, it will not be known.

hihi_shrek Posted at 2016-4-22 14:46
When I took off, think there were about 10?? Not quite sure. But it says safe to fly all the time  ...

"or their RTH is not perfect yet.  ... Secondly, as I saw from other members, RTH is the last resort option. Do it if no other choice"

On the contrary, RTH is very reliableand a useful tool, not just a last resort.
The biggest problem with RTH is flyers that don't know how it works.
The day you need RTH is not the day to start learning how to use it.

"As a result, after the craft climbed to higher altitude, the GPS signal could be a lot different from where I took off".

Steelwork on the ground and at a distance will not affect your Phantom in flight.
Your GPS satellite coverage should only improve as you fly higher.

Without flight data, everything is just a guess and quite likely to ve very wrong.

ok, how to share flight record? i did sync it to cloud in the Dji App.

Geebax Posted at 2016-4-22 13:08
The power station and pumping station would not have had any effect on either the compass or the GP ...

can you teach me how to share flight record ? i already sync it in the app.

hihi_shrek Posted at 2016-4-22 18:42
can you teach me how to share flight record ? i already sync it in the app.

Sure. go to: http://www.phantomhelp.com/LogViewer/Upload/

you will find instruction there on how to upload your flight record. Ppost a link back to to the results.

got it thanks.

Here is the flight record link.

http://www.phantomhelp.com/LogViewer/U3WARW5VPEQZQLPMBBDE/#

Pay attention to 18m25s.1, That's when my craft still up in the air and NEW home point recorded. Any idea why this happened?

Geebax Posted at 2016-4-22 17:02
Sure. go to: http://www.phantomhelp.com/LogViewer/Upload/

you will find instruction there on how  ...

Thanks for the help. The link is pasted as below.

http://www.phantomhelp.com/LogViewer/U3WARW5VPEQZQLPMBBDE/#

labroides@yahoo Posted at 2016-4-22 14:14
"or their RTH is not perfect yet.  ... Secondly, as I saw from other members, RTH is the last reso ...

Thanks for your advise. Hey, if you have some spare moments, would you mind to have a look of the flight record I just uploaded. Note, the new home point suddenly set when the craft still up in the air at 18m.25s.1. Hope you have some idea whats happened and I can avoid it in future.

TJ10 Posted at 2016-4-21 21:45
This happened recently to another guy with a P3S. Don't think dji ever responded. It must be some so ...

Hey, guys, flight record uploaded. Appreciated if you can take a look and comment. Thanks. Note 18m25s.1 when NEW home point recorded.

microcyb Posted at 2016-4-21 23:43
How many GPS signals did you have?
Did the number of GPS signals suddenly drop?

Hey, guys, flight record uploaded. Appreciated you can comment after viewing. Thanks. Note 18m25s.1 when NEW home point recorded (the craft still up in the air)!

hihi_shrek Posted at 2016-4-23 17:16
Thanks for your advise. Hey, if you have some spare moments, would you mind to have a look of the  ...

Yes ... looked at the data and it's as you described.
It reset home at 18:25 - and again at 22:22

This should not be happening and it's something that I haven't heard of until just the last couple of weeks and now three times and I think each time it was a P3 Standard.

If you noticed it as you were flying, it would show the new home point on your screen.
Right then the best option (if you see it) would be to reset home to the location of your controller.
But it appears to be a definite DJI issue that's just come in recently.
Phantoms should not be resetting their own home point at random.
In your case and at least one other, the owner had a max distance set.  
This may or may not be a factor?
It would probably make things worse because even though the reset location is not far away, it is more than the  max distance set, so the Phantom immediately tries to get back closer to its new home point.

Definitely something that DJI need to sort out and it does not appear to be user error.

I'd recommend practising with RTH and making sure you can reset it to your location if you need to.
And turning off the max distance in case that's a factor.
But more importantly notify DJI so they can investigate and find a remedy.

hihi_shrek Posted at 2016-4-21 11:35
At that critical moment, my cellphone lost signal with the craft. I remember clearly that my screen  ...

keep in mind you have 2 concurrent connections with the Phantom from your RC/phone.

just because video link goes out does not mean you have  lost control connection via rc.

video and control are 2 different freq and have different ranges especially in crowded wifi areas.

so while you did not see video you probable were still flying , just blindly...

my guess anyhow

labroides@yahoo Posted at 2016-4-23 21:50
Yes ... looked at the data and it's as you described.
It reset home at 18:25 - and again at 22:22
...

I don't even know how to manually reset home location. I will try some experiments with simulator.
The case is sent to DJI. Lets see how they reply. I will post updates in that. Cheers mate.

kirk2579@aol.co Posted at 2016-4-24 00:36
keep in mind you have 2 concurrent connections with the Phantom from your RC/phone.

just because  ...

Thanks for your information.
Yes, I do know video and RC functions are using 2 different channels.
I can assure you that there was no input whatsoever from my remote during the "NEW" homing process. From the video I retrieved, there was brief control, then lost. The craft then yaw towards home, then flew hard out towards it. I can see my inputs from the flight record.
So back to the ground zero question again, why did the home reset to new location at the first place? I had sent flight records, video, fault report form to DJI. I do hope they do reply to this, as seems I am not the only one encountered such drama.

labroides@yahoo Posted at 2016-4-23 21:50
Yes ... looked at the data and it's as you described.
It reset home at 18:25 - and again at 22:22
...

DJI replied but I am very surprised of their investigation result. I attached below is their reply and my response. Please comment on this and I wish DJI Hong Kong can involve in this.

Dear Kenneth,

As our data analysis team has conducted the reasons to cause this accident are;

The main reason caused this crash is the home point was changed during the aircraft return to home therefore, the aircraft was punched a tree.
Can someone comment on how this could be done? How could I change the home location, when the craft was in the air, and the new home location I had never travel to, land on it, and take off from?


You can definitely to press the ‘H’ button to cancel the return to home while control the aircraft but you did not do.
I did push the home button again when I spotted the craft was drifting away from me. But if the drone had already recorded a new home position, that means I had probably accelerated the crash as well. Right? So I do know how to cancel the homing process if necessary.

Solution;

Operational errors.
15% off to replace new drone.
Im not here to begging for a replacement drone. My drone still flyable albeit the props and guards are damaged.  I do not need this sympathetic 15% off.


If you have any questions please feel free to contact me.

Thanks for choosing DJI.

Best regards,

vivi.liu

Question again, why new home location was set?

I am surprised of their response assumed I manually changed the home location when I don't even know how to. Unless DJI can tell me how to amend home location to a new location while drone is still in the air, the assumption of my human error is unfounded.

Is it possible to manually dot a new location on the map and tell the drone this is the new home?

hihi_shrek Posted at 2016-4-26 23:02
DJI replied but I am very surprised of their investigation result. I attached below is their reply ...

G'day hihi ... It appears that whoever "investigated" did a pretty poor job and missed the point entirely.
As you say, the mystery homepoint resetting is the critical factor and a real mystery.

In the app you have the option of resetting Home to either the current location of the Phantom or the current location of the controller.
But you can't point to the map and designate a new homepoint just anywhere.
It's pretty clear that neither you nor the Phantom was anywhere near the mysteriously reset home point.
So ... how did it happen?

Perhaps DJI-Ken can assist?

hihi_shrek Posted at 2016-4-26 15:02
DJI replied but I am very surprised of their investigation result. I attached below is their reply ...

Hi! I'm sorry for your accident, just for curious which firmware and DJI GO App version did you used when it happened?

hihi_shrek Posted at 2016-4-24 05:11
Thanks for your information.
Yes, I do know video and RC functions are using 2 different channels ...

I'm sorry I misunderstood what you had said, I thought you were saying since you lost the video your quad would RTH
"...that critical moment, my cellphone lost signal with the craft. I remember clearly that my screen turned black and white. Thus, the craft would inevitably GO home as it lost connection with me..."

Did you ever get any answer to what and why it reset the HP?


Good luck and have fun flying!

Nicola90s Posted at 2016-4-26 22:17
Hi! I'm sorry for your accident, just for curious which firmware and DJI GO App version did you us ...

I will check and reply you when I home. Thanks.

kirk2579@aol.co Posted at 2016-4-26 22:29
I'm sorry I misunderstood what you had said, I thought you were saying since you lost the video yo ...

Nothing yet. The reply from DJI China is posted as above and I am not very happy about it.

labroides@yahoo Posted at 2016-4-26 22:15
G'day hihi ... It appears that whoever "investigated" did a pretty poor job and missed the point e ...

Labroides, Thank You for reaffirming me that I can't simply point to the map and reset the new home point. That's what I thought too.
As you can see from the flight record, the Phantom was nowhere near the new home point, but at 18m25s it reset the home location to the north of craft. I was standing at the west of the craft . Just to give everybody a picture about it.
I do hope DJI HK (where I purchased it) can step in and investigate. As you said before, recently there had been a few cases relating to P3S homing issue.
FYI to those new to the thread, flight log again.
http://www.phantomhelp.com/LogViewer/U3WARW5VPEQZQLPMBBDE/#

hihi_shrek Posted at 2016-4-23 02:20
Hey, guys, flight record uploaded. Appreciated you can comment after viewing. Thanks. Note 18m25s. ...

Well I did a little test to check out my theory.
Set my home point on a very cloudy day to get 7 bars. home point was set.
Walked (not flown) the bird 100m away. Home point was still correct.
Used some copper and aluminium to block the GPS.  GPS bars drop, home point lost.
Walked 10 m. original home point found and set.
Blocked the GPS signal again. Home point lost
Removed the blocker. GPS bars back lost home point
Walked another 10 m. new home point set but not the original home point.

Well, I am not DJI, but does seem to be a app issue that should at least be looked over.  Not sure but maybe try to reach out to a 2nd level support or higher to really get a better look at your logs.

Better fly only on a clear sunny day with no interference.

hihi_shrek Posted at 2016-4-26 10:46
Labroides, Thank You for reaffirming me that I can't simply point to the map and reset the new home ...

hope you get this fixed man, please keep us posted (no matter the end result). I think its very odd it set the home point mid flight and flew away.  That doesnt seem 'by design' to me ..

microcyb Posted at 2016-4-27 02:11
Well I did a little test to check out my theory.
Set my home point on a very cloudy day to get 7 b ...

Much appreciate your experiment and investigation.
My craft is ok albeit damaged props and guards. But lost much confidence, at least, this HOME function. I will see how DJI response in the coming days.

digdat0@gmail.c Posted at 2016-4-27 02:25
hope you get this fixed man, please keep us posted (no matter the end result). I think its very od ...

Sure will do. I just cannot believe one of the big selling point of DJI drones is homing function. And yet this function nearly destroyed and lost by craft.

microcyb Posted at 2016-4-26 19:11
Well I did a little test to check out my theory.
Set my home point on a very cloudy day to get 7 b ...

That's an interesting experiment!

Pre-take off, it would be valid for the app/Phantom to reassess the home point according to signal changes and perhaps GPS signal loss is the main trigger to reposition the home point.

However, during actual flight that would obviously be highly undesirable in the event of GPS loss. That made me wonder if the piece of code that resets the home point after signal loss before flight is still getting called mid-flight  in error...

I wonder if a GPS jammer was pointed at a phantom mid flight, would it reset it's home point to its current position when the jammer is turned off.

Thinking on a bit, if all signals to the P3 were jammed (GPS and Remote Control) would the craft just auto land in place soon after the jamming stopped (loss of signal RTH to newly established home point)? Built-in drone take down feature?!

Having said all of that, I didn't see anything in the flight logs that suggested GPS signal was lost and surely the craft would have gone into P-ATTI mode if that had happened (I suppose there are thresholds and time delays before the mode changes automatically)

davidson_g Posted at 2016-4-26 14:18
That's an interesting experiment!

Pre-take off, it would be valid for the app/Phantom to reassess  ...

Not sure, but I sure am not willing to kill my bird for further research purposes.

microcyb Posted at 2016-4-26 20:39
Not sure, but I sure am not willing to kill my bird for further research purposes.

I certainly wasn't suggesting you try that - it was more of a thought experiment

davidson_g Posted at 2016-4-26 14:48
I certainly wasn't suggesting you try that - it was more of a thought experiment

But I have tried some crazy stuff.  
My other test was just to keep flying after purposely killing the app and see if the RTH works.
It does.

microcyb Posted at 2016-4-27 04:25
But I have tried some crazy stuff.  
My other test was just to keep flying after purposely killing ...

As your home point still remained the same.

hihi_shrek Posted at 2016-4-26 17:47
As your home point still remained the same.

Yes.  When the GPS signals is solid everything works awesome.
I have so many times flown passed the signal strength and the bird came back home.

hihi_shrek Posted at 2016-4-27 01:37
I will check and reply you when I home. Thanks.

dji go app 2.7.2

craft firmware 1.5.70?

I think the DJI response to this is appalling. Whoever vivi.liu is, they need to learn how to communicate with people properly. The inference in the reply is that it was the fault of the pilot, yet all the pilot can do is set a new home point according to where the aircraft is, or where the RC unit is. The person analysing this flight has completely ignored the fact that the new home point is nowhere near the RC unit, nor near where the aircraft was. As such, it is extremely unlikely the pilot did anything wrong.

DJI owe this owner a free repair.