In my previous post I explained how our problems using the orbit state vectors transmitted in the telemetry of Tianwen-1 were caused by an incorrect interpretation of the timestamps attached to these vectors. The timestamp is a 32 bit counter with a 100us resolution, but the difficulty is that the epoch of this counter is not known. It seems that the epoch is around 2020-07-23 00:00 UTC, which is the day of launch, but not quite because approximately 57 minutes need to be subtracted from the epoch.
In my post I used some sort of experimental procedure to determine the correction that needs to be subtracted from the timestamp, and I obtained 3400.2 seconds, which I believe should be accurate to within a few seconds.
However, I found this correction somewhat unsatisfactory, as I wasn’t able to explain where it comes from. Now I think I have found a reasonable explanation.