hi i have a new p3s do i need to calibrate the compass every time i fly thanks for any advice

Aloha Mitch,

     A fairly broad consensus is that once you get a good calibration (without metallic or magnetic interference), you do not need to calibrate again unless your Phantom is stored for an extended period or in a metallic / magnetic location (next to a CMU wall with lots of rebar inside?) or you fly the Phantom again in a location far away (200 miles or so).  

     If you do experience some odd behavior when flying your Phantom, you may want to calibrate the compass again (since it is easy) to see if you had accidentally put your Phantom in a questionable location.  Also be sure to not fly close to concrete and iron/steel and magnetic areas.  This can distort your compass with interference.  I almost hit a tree once because I was flying way too close to a piece of heavy equipment.

     Be really sure the location where you calibrate is free from interference.  Over a concrete driveway, or on a concrete building rooftop, can cause distortion.  

     Hope this helps!

Aloha and Drone On!

Once you have a good calibration - LEAVE IT ALONE !!

Seriously - there is no need to re-calibrate unless something significant has changed ... location (100 miles or more)  ..... or you've updated FW.

DO NOT recalibrate if you get a warning .... this is a mistake unless its due to a change IN THE MODEL .... What you should do is shut-down, move a reasonable distance away from that spot ... maybe 20 - 30m or so ... power up again and see what you have then. Most likely it was something in the ground like an old 'bed-spring' or something farmer / builder lost !!  But the trick is to power down all, move and power up again. Its no good just moving as often the warning does not resolve itself.

Most certainly do not re-calibrate because of a questionable location .... reason is that once you take off and move out of that influence - you will now have Compass error because the interference has now reduced. The only good solution to questionable location is MOVE to another position.

Nigel

thanks for the advice

Its worth noting that the DJI manual gets mis-reported quite often by people .... it does not say to re-calibrate every flight ... but does mention if new location. I think it time for DJI to rewrite their manual and correct or at least better detail some of the items so people are more clear on points.

I think also that people tend to forget that DJI models travel a lot and DJI is an international based Chinese Co. with expectation of their models to travel a lot. To many in US / UK etc. - people don't travel as much as some - so new location means a different thing. But to a traveller ... lets take myself - I travel all over the world and a new location to me is thousands of miles not just round the corner to next town !!

A little bit of background to change of location and magnetics .....

There are three basic influences on a magnetic compass :
a) Variation - This is the offset angle based on the magnetic north being to the 'west' of the real North Pole. This magnetic pole is actually moving further away from the real pole slowly. But we can take it as stationary for our purposes. Depending on where you are in the world - the offset will be different and this is tabulated into electronic navigation where required. The navigator who travels oceans will have variation charts for applying the values to on-board compass readings. Error East - Compass Least, Error West - Compass Best ...
b) Deviation - This is based on surrounding structures or effects such as a boats engine / electronics / etc. They are basically constant unless modifications made. The 'flux' effect changes with direction of the structure with relation to magnetic pole of the earth so Deviation curves are drawn up by navigators to apply to compass readings based on heading.
c) Magnetic anomaly which is usually a localised effect due to items around during passage or over a small area ... ites you may have in your pocket etc. !

It is a) that indicates you should re-calibrate after moving significant distance from usual location.
b) should not normally affect you because the deviation of the model should be reasonably constant.
It is c) that is the culprit when you are in a field and Compass goes 'nuts' ..... there is an anomaly affecting you at that point. Move away and the anomaly effect is reduced.

Hope this helps people appreciate the magnetics affecting your compass.

Nigel
(I was a trained Professional navigator. My Father was also Govt Inspector for the first Commercial UK TransPolar passenger flight and Chief Navigation and Safety Inspector for UK CAA)