E○ P variations If analysis is near real-time, variations in polar motion and ut1 will need to be estimated After a few weeks these are available from IERS (+0. 2 mas of pole position, 0.05 ms UT1) in the ITRF2000 no-net-rotation system For large networks, normally these parameters are re-estimated. Partials are formed by differentiating the arguments of the rotation matrices for the inertial to terrestrial transformation 04/17/02 12.540Lec1804/17/02 12.540 Lec 18 7 EOP variations • If analysis is near real-time, variations in polar motion and UT1 will need to be estimated. • After a few weeks, these are available from IERS (±0.2 mas of pole position, 0.05 ms UT1) in the ITRF2000 no-net-rotation system. • For large networks, normally these parameters are re-estimated. Partials are formed by differentiating the arguments of the rotation matrices for the inertial to terrestrial transformation