Configuring for high-accuracy GNSS data collection.
Hello, over the past couple of weeks we have been having trouble correctly configuring ArcGIS Field Maps for use with a high-accuracy (centimetre) GNSS receiver. The GNSS receiver itself is a Septentrio Altus nr3, and it is configured to use GDA1994. We are collecting data using Field Maps into a hosted feature layer in GDA2020 MGA Zone 55 (7855). We are using ESRI basemaps for use in Field Maps thus the map coordinate system is WGS 84 Web Mercator (3857).
There seem to be so many pieces to this puzzle and we are quite a loss trying to find out how best to collect centimetre accurate data with the greatest level of simplicity within ArcGIS Field Maps.
Points of configuration where issues may be arising are the coordinate system defined in the RTK, coordinate system of the hosted feature layer where data is being collected, the Collection Settings Profile defined in Field Maps, the transformations configured in the web map when published from ArcGIS Pro or other possibilities.
In the below images we are having collected points moving when viewing on tablet in WGS84 Web Mercator (3857). Blue crosses are our surveyed points for a pipe and line up correctly.
When viewing in ArcGIS Pro with the map coordinate system set to GDA 2020 Zone 55 (7855), the points move relative to the pipes.
Strangely both layers are in the same coordinate system (7855), but changing the map coordinate system makes them move relative to each other. Is there something else behind the individual layer configuration that could be causing this change of relative location when moving between 7855 and 3857?
If anyone can offer some advice for troubleshooting, or provide a guide for technical configuration on the ArcGIS side for data collection it would be greatly appreciated.
