I've got a P4P

Today I noticed that once I took off, after switching from VPS the app said the total distance was 11k foot, it was about 30ft away and the vps said 30ft, I calibrated the compass and now it says 26k foot after it switches from the vps mode.


Please help

I think you might have taken off too soon when VPS was active, but didn't wait for GPS lock and home point reset at your new location.

This is a classic fly away situation. Always wait for GPS Lock and RTH home location to be set before taking off.

I think you need to understand the function of VPS as compared to GPS. VPS measures height above ground, and is used to hold position when GPS is not available such as indoors. It does not give location information or set RTH. GPS will hold position but also give altitude and location information as well as set a home point. When you start up, VPS is active first, and you can take off, but should only do so when GPS is not available. The P4P will then give a 'cannot take off' message while it is trying to lock onto enough satellites to set a home point. Once that is done, it will go green and allow you to take off again. At that point your distance information should be accurate.

Thanks for the reply however I can confirm I've been flying since the p2 and know to wait for the lock and home point conform before taking off.

I've done some more tests and it seems when my GPS of my phone is turned on, it works perfectly, however the issue above is only when the GPS on my phone if off, is that how the P4P is designed?

Also capo, the home point on the map on all flights without GPS today were 100% accurate

fans8f6a669a Posted at 2017-5-10 11:01
Thanks for the reply however I can confirm I've been flying since the p2 and know to wait for the lock and home point conform before taking off.

I've done some more tests and it seems when my GPS of my phone is turned on, it works perfectly, however the issue above is only when the GPS on my phone if off, is that how the P4P is designed?

It's not with the aircraft itself, but a combination of the RC and the Go app. The Phantom RCs do not have bult in GPS modules like the Inspire series does, so it uses the GPS module in the mobile device to accurately provide the distance between you and the aircraft.

But the distance and height reading are both correct, only the combined figure is wrong

I just can't understand why the values circled in green are correct but the one in red that should add both together is miles off.


Also the P4P does have GPS inside.

fans8f6a669a Posted at 2017-5-10 13:00
I just can't understand why the values circled in green are correct but the one in red that should add both together is miles off.

The number highlighted in red is not a "combined" distance and has nothing to do with altitude + distance.
It is the distance from the controller (as opposed to distance from home).
Normally this is a very similar number to distance from home.
But if you were on a moving car or boat you would see big differences.
The number uses your phone's GPS location to calculate the distance between the Phantom and the phone.
It would appear that your phone is giving a very inaccurate location, probably derived from wifi or cell tower triangulation..

Right, on the p3p the same figure was a combination of height plus vertical distance, my biggest concern is that should I have  RTH emergency, it tries to fly 26k away?

To confirm, the independent height and distance are correct and the homepoint on the map are correct.

fans8f6a669a Posted at 2017-5-10 22:16
Right, on the p3p the same figure was a combination of height plus vertical distance, my biggest concern is that should I have  RTH emergency, it tries to fly 26k away?

To confirm, the independent height and distance are correct and the homepoint on the map are correct.

On the P3, that number was not a combined anything.
It was just as I explained above.
You can test to see how it works by setting the Phantom up and powering everything on.
Then walk 20 metres away with the controller and see how that changes the numbers.
It should show the Phantom about 0 metres from home but the distance from the controller should be about 20 metres.

Since RTH only relies on the GPS location your Phantom records at launch, the position shown by your phone will not have any effect.

I've spoke to DJI today, the number circled in red is I need distance, it's the total distance away from home, and the way the number is arrived is adding the height from home and the distance.

fans8f6a669a Posted at 2017-5-10 11:01
Thanks for the reply however I can confirm I've been flying since the p2 and know to wait for the lock and home point conform before taking off.

I've done some more tests and it seems when my GPS of my phone is turned on, it works perfectly, however the issue above is only when the GPS on my phone if off, is that how the P4P is designed?

My apologies. If you read your first post it was not very clear what the issue was and was easy to come to this conclusion.

fans8f6a669a Posted at 2017-5-11 10:57
I've spoke to DJI today, the number circled in red is I need distance, it's the total distance away from home, and the way the number is arrived is adding the height from home and the distance.

Unfortunately whoever told you this has no idea what they are talking about.
This is completely wrong.
How could a number that is combined height + distance be of any use to anyone?
Particularly when you already have the distance from home and relative altitude clearly displayed?

If you want to know what the number is, I have explained it thoroughly above.
If you doubt me, just try the experiment I gave in my last post.
Or try flying 10 metres out and 20 metres up and see what your "combined" number shows.

Thanks again for the reply, the problem is, undid fly 20m and 10m up (approx) and the number showed in the 3rd box was 11km

fans8f6a669a Posted at 2017-5-11 21:46
Thanks again for the reply, the problem is, undid fly 20m and 10m up (approx) and the number showed in the 3rd box was 11km

I'm unsure what you are saying but as explained earlier, that number is the distance your Phantom is from the controller.
But your phone is giving a false location so the distance is wrong.
Look at maps on your phone and you'll see the location it's giving.

When I checked the map on 3 test flights, the map and home point are 100% accurate.

Any idea how to fix this, Issue?

fans8f6a669a Posted at 2017-5-12 07:08
When I checked the map on 3 test flights, the map and home point are 100% accurate.

Any idea how to fix this, Issue?

If you mean the home point for the Phantom, it's not the problem.
I meant use the maps app in your phone to see where the phone thinks it is.
The Phantom has its own GPS receiver but the "problem" you have is your phone gives a false location when you have its GPS turned off.

The GPS in your phone is only used for two things in flying:
1.  Follow-me flying - the Phantom has to have location data for what it is following
2. Resetting home point to the current location of the controller - useful if you fly from a moving car or boat.
That's it, there's nothing else that the GPS in your Phone will have any effect on.
So if you want to do follow-me flying or to reset home to the current location of the controller, make sure you have the GPS in your phone turned on.
For all other flight, you can ignore that number since you know it is likely to be false but doesn't affect anything.

Thanks for all the replies, DJI asked me to return it to fix the fault LOL

one thing that has me stumped is why some vids on YT show up as "N/A" but mine will give off a false location (Happens with my s8 on android 7 and my K1 tablet on Android 6)

fans8f6a669a Posted at 2017-5-20 03:53
Thanks for all the replies, DJI asked me to return it to fix the fault LOL

one thing that has me stumped is why some vids on YT show up as "N/A" but mine will give off a false location (Happens with my s8 on android 7 and my K1 tablet on Android 6)

Return what to fix?
It's got nothing to do with your Phantom or controller.
It's between your phone/tablet and the app.

Labroides Posted at 2017-5-11 14:53
Unfortunately whoever told you this has no idea what they are talking about.
This is completely wrong.
How could a number that is combined height + distance be of any use to anyone?

Psst, Labroides, are you saying that a hypotenuse is of no use?  (of course the measurements need to be squared first, and a square root of their sum must be extracted... )