Hi today I started my p3s and before flight made sure I had GPS(11 to be exact) so I took off and hovered for 30 seconds when I gained altitude about 10ft hovered all of a sudden p3s circled around then flew backwards as if it was trying to position itself at the same time error magnetic interference was noted GPS mode exited . I immediately landed and did a compass calibration , and started motors again said GPS ready, took off hovered and it happened again. Restarted process 2 more times finally it worked . Was wondering does this happen or is something malfunctioning

One more thing on the last restart up before it worked I switch to attitude mode hovered for a few second than switched back to GPS mode then it worked

Interferences depends in the zone you use to fly , city or out of city

DJI Phantom 3 Advanced lesson learned (electromagnetic interference)

DJI Tutorials - Phantom 3 Standard - Calibrating the Compass

Had you waited until the homepoint was set?

Blériot53 Posted at 2018-1-30 11:08
Had you waited until the homepoint was set?

Of course, for safety, it is also one of the first precautions to take into account, for me the main one after checking the device before flying

RTH position must be set correctly by AC,  is needed to not lose your bird

First .... Always check that opening data page before GO screen comes on ... telling you FW / Compass / etc. data. Don't just tap the X to get rid of it ..

Second ... if you had calibrated previously a good calibration - don't go and spoil it by calibrating again because you get a warning Mag Interference. MOVE position and power up again and see if that sorts it.

If you get Mag Interference and you then calibrate ......... UGH !! You've now spoilt your good calibration.

It is always better to move a few metres and try again ...

Nigel

Or choose a completely new location to fly from.
Some locations have naturaly occuring emi for example large deposits of iron in the ground.
First try moving a few meters if that doesnt work after a few tries then go to a new location far away from the last one.

At times I get Interference warning or AC drops to ATTI mode when I go over my yachts ... I have a lot of gear round there ... concrete with rebar + the boats of course. Its funny that if I am low height - I never see any error ... but if up about 25 - 30m I get it sometimes.

Doesn't seem to be any logic to it ... last time it happened - I started to fly back to land .. it corrected itself and I cautiously went out again .. no problem.

Nigel

The problem sometimes is not evident on the ground or at low level flight as the compass has compensated for the current magnetic field around it but once you fly out of the magnetic field ie by increasing altitude the compass then detects the change in the magnetic field and gives out an error

The same error occurs if you fly into a strong magnetic field

The most likely cause is that you launched from somewhere very close to a lot of iron or steel and launching from a magnetically clean area would avoid the problems.
Recalibrating the compass in a magnetically bad area is not recommended.
What can you say about where you launched from?