I’ve been using an RS2 base/rover setup with great success recently on site that have a benchmark, but wanted to try and get familiar with using our state’s CORS system as well.
I am able to connect to the NTRIP service with the RS2 and can see all of the mountpoints available. The easting and northing values seem super accurate but I’m showing a little less than 100’ lower than I should be (showing 1311.xx and the actual site is 1406.xx). The mount points I’ve tried using are in the 14-25km range.
The documentation for Arizona is pretty minimal Link to AZ CORS Info but it does reference NAD83.
Looking at some of the MCDOT Survey Points it appears they use NAVD88 for the vertical datum. If I select that within a test project, I alway show a greyed out ‘Accept’ button when trying to set a point, with “No Solution” shown under it. This is despite having a FIX.
I’m hoping there is something painfully simple I’m missing that is right in front of me.
Yes, it sounds like you’re missing a geoid model in your projection settings. If you’re in Maricopa or Pima County, AZCORS offers a network solution called a Virtual Reference Station (VRS) which offers the best results over a single station. Look for the mountpoint named “VRS_MSM5”. This works well with the Emlid units. I use it all the time here in Tucson.
Yes, the geoid is important, took me a while to figure it out but the great thing about the current Emlid ‘survey’ package is…you can change it in your project, and it will convert all points to the new elevation.
hope this helps a little bit.
boston
It’s likely that Ellipsoid height was chosen during project setup. If so, you could change the coordinate system of your project by following this guide. After that, Flow will recalculate the coordinates for you.
In your case, please choose GEOID18 from the list.
