| Term: | GEI2000 |
| Definition: |
Spacecraft orbits and locations are often made available in geocentric equatorial inertial coordinates for a fixed epoch, e.g. the standard astronomical epoch known as J2000.0, which is 12:00 UT on 1 January 2000. We treat this as a separate coordinate system (with the qualified acronym GEI2000) and specify how to transform from this to other systems. |