Which coordinate system do my points end up in?

Q&A forumCategory: QuestionsWhich coordinate system do my points end up in?
GIS Ingenj├Âr asked 1 month ago

I am using the Ardusimple Surveyor Kit, and am using NTRIP with connection to a local swedish RTK correction service. They state that their NTRIP service provides positions in our local coordinate reference system (SWEREF 99).
My question is, can I be sure that when I export my data from SWmaps, it will end up in my local CRS without me needing to reproject it? Or does the GNSS-receiver collect my coordinates in a different coordinate system such as WGS84?

I guess I am just asking for an explanation as to how it works ­čÖé
Thanks a lot!

Ardusimple Staff replied 1 month ago

Hi GIS Ingenj├Âr,
The position output by the surveyor kit uses the same coordinate system as the correction service you are using.

If you use the receiver in standalone mode or uses another ardusimple zed-f9p board as a base station, then it’s when positions are in WGS84.

As far as we know the swedish ntrip service is free for sub-meter accuracy, and is premium (you have to pay) if you want centimeter-level correction data.

GIS Ingenj├Âr replied 1 month ago


So how does it work, does the RTCM messages from the correction service carry information about the coordinate reference system, and then the application board transforms coordinates accordingly before output?

Thanks for helping me out here ­čÖé

Ardusimple Staff replied 1 month ago


Best is the explanation in zed-f9p integration manual:

“When operating as a rover, the ZED-F9P can receive RTCM 3.3 corrections from another ZED-F9P operating as a base, or via NTRIP from a virtual reference service provider operating a network of base receivers. In this mode, the receiver coordinates will be expressed in the datum used by the RTCM correction provider. For more information on this topic please refer to the RTCM ITRF Geodetic models section in the Appendix.”

1 Answers
13vadimka13 answered 3 weeks ago

GIS Ingenj├Âr, hi!
You can use Android free app Landstar 7 (https://play.google.com/store/apps/details?id=com.huace.landstar7&hl=ru) + Xbee buetooth (or simple HC-05 module)+ simpleRTK2b board and end up it in your local coordinate system (for example screenshot from Landstar 7 app with range of types SWEREF 99: https://drive.google.com/file/d/12TMLKkWqgvLizfddOD_5Wir-HzdTTW7e/view?usp=sharing). You will survey in WGS84 and automaticaly convert it in local