ZED-F9P - Integration manual
needs to do the transformation for use in a mapping application if it does not use the same reference
frame. An offset can occur if this is not done.
The ITRF reference frame years are listed below:
• ITRF94
• ITRF96
• ITRF97
• ITRF2000
• ITRF2005
• ITRF2008
• ITRF2014
There are other similar reference systems used by GNSS correction services, such as the ETRS89.
For example, the EUREF network uses the ETRS89 reference frame. For information, see their
homepage:
.
See the ITRF website for more information and an online transform calculator:
.
Another online tool is available on the EUREF network page:
.
Figure 52: Transforming between two datums
The user needs to transform the frame of the reference receiver (or base) into the required system
being used by their application and mapping system. If comparing the rover position with a reference
system, the same RTCM stream should be used to ensure that the reference and the rover output
the same position. If the reference system is post-processed, its output must be transformed to the
same ITRF and datum being used by the rover.
For example, when viewing RTK-accurate positions that could be in any ITRF transform reference
frame (based on reference receiver (or base) reference frame) on Google Earth: The heights on
Google Earth refer to EGM96 and are, therefore, Geoidal heights.
The lat/long are referred to the WGS 84 (ITRF2008) ellipsoid. The result is a visible inaccuracy, and
the RTK receivers' position output must be transformed to the Google Earth transform system
before it can be used. This ignores any local map tile inaccuracies.
Geodetic coordinate systems and ellipsoids
UBX-18010802 - R08
Appendix
Page 95 of 110
Early production information