Known point datum transformation

Output from PPP using NRCan, AusPos, OPUS gives a point in various datums like ITRF2014, NAD83(PA11) etc. I’ve been told the RS2 in base mode only uses WGS84.

My question is, do I need to run my PPP point through a transformation from NAD83(P11) to WGS84 and use the results from that transformation for my manual point LLH?

I’m also confused about how RV3 works with setting up different coordinate systems for new projects. I can start a new project and set the CRS to NAD83 (PA11) / UTM zone 5 N, for example. Does that mean, even if my base is using WGS84 the corrections being sent to my rover have this transformation between datums already done? And what about the vertical datum? In my area I commonly see NAVD88 being used as the vertical datum. I need some good reading material on how to best work with vertical datums. Any suggestions?

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Answered my own question about vertical datums. Anyone interested can find it here: https://vdatum.noaa.gov/docs/datums.html

Still need help with how Emlid Base/Rover talk to each other when set up on different datums though.

Hi @sweet.scott,

The main requirement is that the base station’s coordinates should be in LLH format.

These coordinates are related to a datum. NAD83(PA11) is a datum, so its coordinates can be used for the base station.

If you set up the base in NAD83(PA11), it’s also possible to set NAD83 (PA11) / UTM zone 5 N in your project in ReachView 3. So this way, you’ll get points in this coordinate system in your project.

  • And what about the vertical datum? In my area I commonly see NAVD88 being used as the vertical datum.

NAVD88 provides you with orthometric heights. It’s a vertical datum that contains a geoid model. Orthometric height is the height related to the mean sea level. Geoid models allow you to move from ellipsoid heights to orthometric heights.

To work with NAVD88 heights on the rover, you need to set the ellipsoid height related to NAD83(PA11) for your base station.

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