Error in the conversion in ReachView 3 MGI GK M31 Austria

Norbert · February 16, 2021, 9:03pm

I am using 2 RS+ units. When I measure my RS + with RV, I get the same measurement result as on the RV3 with WGS84.
If I switch to MGI / Austria GK Central EPSG:31255 in the RV3, I get a wrong result.

Data from my RS +
13.74914758969
48.394227850770015

Measured value from ReachView 3
30853.03 m E (Error 0,45 m)
361867.94 m N (Error 0,13 m)

WGS84 with http://www.edv-knoll.at/dab/Hoehlenkunde/PHP/Koord_menue1.htm converted to MGI GK M31.
30852.58 m E
361867.81 m N

How do I get a different calculation in my RV3 version 5.5?

kseniia.suzdaltseva · February 18, 2021, 2:09pm

Hi Norbert,

May I ask you to provide me with the following details on your tests:

Do I understand it right that all the coordinates were collected in Fix?
Is your base in ETRS89 when you work in MGI / Austria GK Central?

Norbert · February 19, 2021, 7:37am

Hi Kseniia,

Yes, it is measured in fixed terms.
I don’t know and where you can change the correction format between the base and the rover on the RS +.

kseniia.suzdaltseva · February 19, 2021, 2:36pm

Hi Norbert,

Base coordinates should be saved in ETRS89 in the Base mode tab on a base unit. It will allow the rover to apply base correction in the right way.

May I ask you to try ETRS89 base coordinates and check if it helps?

Norbert · February 19, 2021, 3:44pm

Please tell me where?

This is how the authority converts it.

The survey CSV.

Name,Easting,Northing,Elevation,Description,Longitude,Latitude,Ellipsoidal height,Easting RMS,Northing RMS,Elevation RMS,Lateral RMS,Antenna height,Solution status,Averaging start,Averaging end,Samples,Base easting,Base northing,Base elevation,Baseline
2,30850.707,361868.979,432.657,13.74911638,48.39423733,432.657,0.010,0.010,0.011,0.014,2.086,FIX,2021-02-19 17:38:54.2 UTC+01:00,2021-02-19 17:39:14.1 UTC+01:00,100,30851.328,361858.253,437.337,11.054

kseniia.suzdaltseva · February 20, 2021, 2:16pm

Hi Norbert,

Please enter the Latitude, Longitude, and Height in ETRS89 in the Base coordinates window.

WGS84 and ETRS89 coordinate systems are quite close to each other. However, they are not the same. If the base transmits corrections in WGS84, and the rover transforms the result to MGI / Austria GK Central considering the corrections are in ETRS89, the shift may appear. That’s why it’s important to enter the base coordinates in ETRS89.

Norbert · February 22, 2021, 9:52pm

Hello Kseniia,

I had a displacement of about 47cm in my base.
Now I have re-measured my base with a survey point from the surveying office in RV3.
Thanks for your support, I’ve solved the problem.

system · June 4, 2021, 7:46am

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