You are here: Home USNO Earth Orientation Software Earth Orientation Matrix Calculator
The USNO websites,,,,,, and are undergoing modernization efforts. The expected completion of the work and the estimated return of service is Fall 2020, subject to change due to potential impacts of COVID-19.

Earth Orientation Matrix Calculator


IERS Rapid Service Prediction Center (IERS RS/PC)

Earth Orientation Parameters Division, US Naval Observatory

*****This interface to the calculator is a work in progress. ******

A working version of the calculator can be found at:


The Earth Orientation Matrix Calculator requires a start date and time (UTC) and a stop date and time (UTC).  For example, for February 10, 2009 at 14:25:10.1234567890 one would enter: 2009, 2, 10, 14, 25, 10.1234567890.

Choose any of the desired input variations:

Enter the MJD on which the finals2000A.daily file was created.  If no MJD is entered, then the most recent file will be used.

Choose any of the desired output quantities:

Do you wish quaternion output instead of matrices for the above quantities? (check box if yes):

Note to users:  This form is a work in progress.  Please check back later.

USNO Master Clock Time
Javascript must be Enabled