I tested RTH with my new Platinum tonight and was amazed at the accuracy.
Landed about 18 inches from take off spot.

I think it is a great one, for the precision landing, a small deviation is permitted. Thank you for sharing your flight.

When my Mavic was new, out of the box, I could count on the RTH spot being within 6 to 12 inches. After a month or two of flying, now the accuracy is about four or five feet. I've had to intercede occasionally to keep my Mavic from landing in a problem area.

Any ideas why this might be happening?

I have owned the MP and now own the Platinum and always an exceptional RTH.  I think it helps when you let it take of precisely and let it hover for about 10 secs.

LSessions Posted at 2017-12-26 22:28
When my Mavic was new, out of the box, I could count on the RTH spot being within 6 to 12 inches. After a month or two of flying, now the accuracy is about four or five feet. I've had to intercede occasionally to keep my Mavic from landing in a problem area.

Any ideas why this might be happening?

I see this as well. It is now far enough away that I need to override and do a manual landing. As much as a few yards.

I don't fully understand home point identification. I have heard many talk about the drone taking a downward image of some sort as the home point is updated. Yet that doesn't seem to matter at all. If this happens, how exactly is this home point snapshot utilized in guiding the MA2 to it's original take off point?

I wonder if the drift in accuracy could point to the need to re-calibrate the compass?

LeeG Posted at 10-5 13:55
I see this as well. It is now far enough away that I need to override and do a manual landing. As much as a few yards.

I don't fully understand home point identification. I have heard many talk about the drone taking a downward image of some sort as the home point is updated. Yet that doesn't seem to matter at all. If this happens, how exactly is this home point snapshot utilized in guiding the MA2 to it's original take off point?

Yes it does take a photo of the ground below. But I have found that it is necessary to hover the MA2, not at a specific height as suggested, but above most of the surrounding objects, like trees and bushes and walls. If I don't do that, it comes back out of place and I have to correct on the way down. And by the way, use of a landing pad makes a lot of difference.

https://forum.dji.com/forum.php?mod=viewthread&tid=218580

LeeG Posted at 10-5 13:55
I see this as well. It is now far enough away that I need to override and do a manual landing. As much as a few yards.

I don't fully understand home point identification. I have heard many talk about the drone taking a downward image of some sort as the home point is updated. Yet that doesn't seem to matter at all. If this happens, how exactly is this home point snapshot utilized in guiding the MA2 to it's original take off point?

No, because the compass has absolutely nothing to do with where it lands.

LeeG Posted at 10-5 13:55
I see this as well. It is now far enough away that I need to override and do a manual landing. As much as a few yards.

I don't fully understand home point identification. I have heard many talk about the drone taking a downward image of some sort as the home point is updated. Yet that doesn't seem to matter at all. If this happens, how exactly is this home point snapshot utilized in guiding the MA2 to it's original take off point?

Your drone can use the Precision Landing feature or it can just use GPS for RTH guidance.
If your RTH isn't landing within a couple of inches, it's not using Precision Landing.
GPS alone might place your drone within a couple of feet or sometimes a couple of yards.
That's the nature of GPS technology.

Check your manual for details of the Precision Landing feature.

LeeG Posted at 10-5 13:55
I see this as well. It is now far enough away that I need to override and do a manual landing. As much as a few yards.

I don't fully understand home point identification. I have heard many talk about the drone taking a downward image of some sort as the home point is updated. Yet that doesn't seem to matter at all. If this happens, how exactly is this home point snapshot utilized in guiding the MA2 to it's original take off point?

Hi Lee,

Precision Landing (PL) is activated when a craft does a only vertical take-off and craft is stopped at approx 7 meter height ** and stopped for a while.   
A scan is made of the terrain and stored.  [ ** MA2 value ]
RTH uses compass and GPS to fly back above the HomePoint coordinates, PL activated or PL not activated.
Due to the sometimes not very accurate GPS data craft is not always exact above the take-off spot, but in my flights (always good GPS data and reception) never really far form the take-off spot (few inches to max 10 inches)

With PL activated it will scan the terrain during landing and if it matches to the stored scan than, if nessesary, craft will adjust its position to perform a precision landing.
A message on the screen does inform the user that craft is making a precision landing correction.Message in the log =  "Precision Landing__Correcting Landing Position", cannot find a screenshot (yet) how this message is seen in the app.

EDIT just checked in the flyapp on my MA2, it does perform a precision landing but no messages on the screen and no correction messages in the log

Note
- When during flight HP is set to a new postion, PL will not work as the stored image will not match the terrain of the new HP.
- Important is that the terrain must have sufficiently distinctive features.

2 examples, MA and P4prof (using GoApp not FlyApp)


cheers
JJB