EMlid Reach RS+ Workflow for conversion of manual coordinates / lat long AHD to ellipsoid to achieve fix solutions?

Hi Guys,

i am wondering if someone has a work flow that provides a workflow to successfully enable the use of 2 Reach RS’ as a base and a rover, with the base being set up over known coordinates with height in AHD?

The situation i have is that the known coordinates and heights are provided by various clients but using the Reach in manual base mode on various attempts i am unable to obtain a fix solution when using the rover and base? What conversions are required to enable this to achieve fix?

Thanks for any help and suggestions.



What number formatting are you using for input?

Easting/northing AHD

Hi James,

You may be unable to obtain fix solution because the manually entered coordinates differ a lot from the real Reach position. You need to reproject AHD coordinates in the WGS84 first. I’d recommend trying QGIS or other tools for this workflow.

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Thanks. Have managed to sort the horizontal locations, just struggling with the elevation differences now?

Hi James,

Would you mind describing the issue with the elevation differences in more detail?

What is AHD? Is it a projected coordinate system? Is it based off MSL elevations? If so, check the geoid undulation for your area. If it matches the elevation offsets, you found your problem: all GNSS measurements are based off ellipsoid height and need to be converted to geoid/MSL height.

(Conversely, to find your LLH manual position for the base, you need to transform your projected point to WGS84, including the vertical component).

Thanks Gabriel.

Mean sea level on the Australian Height Datum (AHD)

Have sorted the LLH its just the height thats causing me grief…

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