I am using Beta firmware 700 on my drone. It works great for me.  I do have a little probem though and that's accrucy  of the Rth program. It misses the RTH target by about 3 meters. I have one of the folding circle orange/black landing pads.  When I use my Mavik in the same spot its dead on for returning.

I believe I just need to make a calibration on the P4.  I have done the compass  and IMU but thats all.  Could it still be the IMU cal?  Whenever I first start up it seems to always have the "IMU warming up" for a few seconds and thats when the temp is around 70F.  Thanks for any suggestions.

I have had a Phantom 4 for over a year now and it has never RTH at the exact same spot, its always a few feet off.

That's just the precision you can expect with consumer GPS.
Try 10 RTH landings and you'll see you get a range of points.
Most will be within 3 metres, many even closer and occasionally you could get some even further out.
I believe I just need to make a calibration on the P4.
No .. the calibrations you mention won't make any difference - it's all down to GPS.

Later models have a Precision Landing feature that uses optical technology to return ti within inches.
But there's no need to let RTH do the landing for you.  It's more of a gimmick than an important feature.
You can cancel RTH and land for yourself wherever you choose.

I'm no expert and maybe my P4A is an exception but I have been amazed by the precision of the RTH landings relative to takeoff point in the 10 or so times I've tried it and allowed it to land.

Phantom 4 is using precision landing most of the time. When you takeoff within 7 meters altitude you should wait a while to "see" the environment and then you can fly, after that try to land with RTH and see the precision landing corrects the aircraft position.  

Labroides Posted at 2018-1-23 17:11
That's just the precision you can expect with consumer GPS.
Try 10 RTH landings and you'll see you get a range of points.
Most will be within 3 metres, many even closer and occasionally you could get some even further out.

Before last years FW update that caused all the trouble my Phantom 4 Always was spot on when landing. Also my Mavic  has never missed the circle target when RTH.   My son's  Mavic also is spot on every time when using the circle target. Now granted, the target cicle is  about 1 1/2 meter so there is a little leway but I would always expect it to return to the circle and so far, with the Mavics at least  that's what happens.

My P4 which I have now flown 8 times has always RTH within 11/2 M most times within1M it may just be down to the satellite fix.