Question about source of corrections

Reach Module / M+ / M2 Getting started
1

Hello all!
I need an RTK GNNS system on my autonomous rover. Firstly I wanted to use a receiver from trimble but then I discovered your project and it seems really interesing, good job! I read your manuals and technical data but still don’t understand some concepts. I don’t know too much about RTK GNSS but I know for sure that in Poland land surveyors always use GPS receiver for example from trimble (as rover) and get corrections from paid system called ASG-EUPOS ( see: ASG-EUPOS, Opis systemu, Stacje referencyjne ). You propose REACH to be gps receiver rover which get’s corrections from second REACH which act’s like a base station. In RTK measurement base station must be excatly known, that’s why people buy subscrption from ASG-EUPOS and get corrections from closest base station to their rover’s. My question is how your system works, how base station created with REACH knows excactly it’s position so it could send corrections to the rover?

Cheers

2

Hi, did you read this?

And this
https://docs.emlid.com/reach/common/reachview/base-mode/

3

How you determine that base station coordinate is up to you. So, do you:

  • place your base station over a known point with published coordinates and manually enter them into the base
  • subscribe to a correction service (ASG-EUPOS) and be automatically using their base coordinate
  • upload your log files to a (free) PPP service and get a base coordinate sent back to you
  • let Reach take an average of its position for a period of time and use that as a base coordinate

Each of those options has a certain amount of accuracy.

After, you have determined a base coordinate, then you can use a rover to perform RTK and get approx 2cm accuracy relative to the base station.

4

Thank you TB_RTK and bide for you answers, now I understand it but still have one question. If I will buy subscription to a ASG-EUPOS correction service which sends correction via NTRIP in RTCM 3.1 format then will I need my own base station? I think that if will buy a rover and a correction service then it will be enough for me. Am I right?

5

Yes, you only need one for ntrip.