I've been doing some testing at client with an outdoor site. I've placed markers and a 3D model via GPS coordinates, but I'm seeing big differences between the positioning between iOS and Android. Typically iOS behaves as I would expect, however on Android the position of markers seems to be by as much as 16° in some cases. I know there is some room for error in regards calibration of sensors, but I'm seeing this result consistently.
Does the Android code take in to account Declination? So the difference between magnetic north and true north. According to this site https://maptools.com/declination the Declination where I'm testing is 13° so that might explain for the big difference.
There's nothing in the documentation about Declination.
Accuracy of the Geo experience highly depends on the Location Service that operates in the back.
Please have a look at the Google Location Service Implementation. Ideally, this solves the issue. If you already use it, please investigate on multiple devices and post a summary if you encounter any unexpected behaviours.
Do you, or anyone else for that matter, have any examples of apps where their location service has been implemented successfully? As taking this next step will require me bringing in developers, and unless I can be sure it will improve the situation, it's a gamble that will cost money.