Turns out that this standard already exists. UT1 (and its close cousin UT1R) track Earth's rotation using radio astronomy techniques. The basis for adding lea

Turns out that this standard already exists. UT1 (and its close cousin UT1R) track Earth's rotation using radio astronomy techniques. The basis for adding leap seconds is the wind up between UTC and UT1. I agree, we ought to align UTC to UT1 instead of TAI. Doing so is not trivial on a technical level, though. At the very least, the GNSS broadcast time parameters wouldn't support such a revision for decades.