RTH got confused.

[Rogerlin]

I arrived in Spain from UK, recalibrated the compass and flew a few times, RTH was very accurate, then I changed location, from ground level, to the roof terrace, again RTH accurate.

However on returning to the ground level position again RTH on three occasions attempted to land on the roof, luckily I got it back down safely manually. Each new location I set the home position so I am a little concerned as to what may have caused this to happen and would appreciate any advice.

 

[Simmo]

Its not you that sets the HP.
It will be set by the AC every time you spool up the motors. (should conditions allow)
Any prior HP recorded is forgotten.

 

[Rogerlin]

Its not you that sets the HP.
It will be set by the AC every time you spool up the motors. (should conditions allow)
Any prior HP recorded is forgotten.

I realise that, it was just a double precaution, but it still landed, or tried to land at the previous HP, andI can’t understand why...

 

[Simmo]

To my knowledge, that cant happen.
If you were close by (to the original flight), maybe a normal GPS anomoly made it look like it was going to another HP?
Bigger, better Brains than mine required to comment further!!! @sar104

 

[msinger]

Check out your TXT flight log to see if it explains what happened. You can upload and view it online here. If you'd like other people to review and comment on your flight log, then please post a link back here after you upload it.

 

[Rogerlin]

I will attempt that when I return home, it occurred to me the HPs were close in a lateral sense but obviously not vertically, but it definitely picked up on the wrong one.

 

[Meta4]

I will attempt that when I return home, it occurred to me the HPs were close in a lateral sense but obviously not vertically, but it definitely picked up on the wrong one.

A home point is recorded as lat and long but it has no altitude data.
When the drone auto-lands, it descends until it can descend no further at whatever altitude that occurs.
How far apart were the home points from the different flights?

If you post flight data, that will show exactly what happened and help to give accurate answers to your questions.

 

[Rogerlin]

Horizontally I suppose around 4 meters,
I also sent it up by the coast, quite windy, and most times RTH was good but, a few times it was out by several meters so reverted to landing manually, which is all good practice.

At the risk of sounding a bit dim, in simple terms how do I go about uploading the post flight data,
I had turned recording off prior to my original near miss, and I use the rather brilliant smart controller btw.

 

[Meta4]

At the risk of sounding a bit dim, in simple terms how do I go about uploading the post flight data,

With homepoints about 4 metres apart and the accuracy of GPS being approx +/- 2 metres it could be that there was nothing malfunctioning in what you observed.

To post flight data, go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report of the flight.
Come back and post a link to the report it gives you.

It's a little different for the plus controller for the Phantoms and I'd suspect the Smart Controller would be the same as those too.
The link gives additional instructions for the Plus controllers.