How accurately are the UT times determined?
GSOC tracks the real spacecraft time in the following manner: A time signal is uplinked, which starts a counter. At the next time signal interrupt, the spacecraft time and the counter total are transmitted to GSOC. This occurs about once a week. The time signal counter is used to correct the error between spacecraft time and UT, usually about 10 msec, to about 1 msec.
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