Alpha values for EPP
In accordance with modernizing the National Spatial Reference System (NSRS), Euler Pole Parameters (EPP) are needed to define the relationship between the ITRF2020 and models on the North America, Caribbean, Pacific and Mariana plates as discussed in Blueprint Part 1. The values in this table serve as an Alpha version for software and model testing.
These values were derived using coordinates in IGb14, which are essentially the same as ITRF2014. The expectation is that ITRF2014 will be very similar to ITRF2020, so these values should provide adequate control for software development purposes.
Once the Multi-Year CORS Solution 3 (MYCS3) is complete in late Spring to early Summer 2024, ITRF2020 coordinates and coordinate functions will have propagated to the entire NOAA CORS Network (NCN). EPP values will then be determined in ITRF2020 to provide exact mathematical relationships between ITRF2020 and the four new NSRS models: NATRF, CATRF, PATRF, and MATRF.
The reference epoch, to which these EPPs refer (t0) is 2020.00.
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| # | NATRF2022 | PATRF2022 | CATRF2022 | MATRF2022 |
|---|---|---|---|---|
 X,I→N,P,C,M |
0.051 | -0.409 | -0.189 | -8.089 |
| Y,I→N,P,C,M |
-0.736 | 1.047 | -4.722 | 5.937 |
| Z,I→N,P,C,M |
-0.024 | -2.169 | 2.962 | 2.159 |
| Total Rotation | 0.738 | 2.443 | 5.577 | 10.264 |
All values in milliarcseconds/year and rotation sense is consistent with a positive rotation in the counterclockwise direction of a right-handed coordinate system, when viewed down the axis from the viewpoint of its positive end (Leick and van Gelder, 1975).
