4 ms·
GPS, UTC and TAI Clocks (2001)
- idlephysicist 3y agoI'd not heard of TAI before, the page doesn't explain how it differs from Loran-C, though perhaps some of the reference links will. I'll have to check them out.
- duskwuff 3y agoDifferent offsets. That's about it; they both tick at the same rate and ignore leap seconds. The mention of LORAN-C kind of dates the page, actually. The last remaining LORAN transmitters were shut down at the end of 2015.
- jcrawfordor 3y agoTAI, UTC, and GPS and LORAN-C time are all the same time scale but at offsets resulting from having stopped adopting leap seconds at different points. The only confusing thing is that we tend to talk about TAI's variation from UTC rather than the variation of each system from TAI, which is fixed for everything but UTC (until 2035). We can thus sort of discuss them like time zones: UTC: TAI-37s GPS: TAI-19s LORAN-C: TAI-10s UTC will stop applying leap seconds but hasn't yet, so the offset for UTC could potentially change. Once UTC stops applying leap seconds, they will all be fixed and these offsets will just be technical details. Of course the whole thing has actually become obsolete in the case of LORAN-C which was shut down, but it seems less likely that TAI will fall out of use.
- dang 3y agoRelated: GPS does not account for leap seconds (2002) - https://news.ycombinator.com/item?id=33620933 https://news.ycombinator.com/item?id=33620933 - Nov 2022 (53 comments)
- ggm 3y agoThe UTC time scale which currently serves as the basis for all civil time is defined to be calculated from UT1. If civilization continues to desire the use of mean solar time then UT1 will eventually fail to serve that need. Within the next millennium the IAU will have to consider defining and naming a new version of UT to serve as the quantity which is measured by analemmatic sundials. A name for that time scale might perhaps be Analemmatic Universal Time (UTA). ok. We better form a committee. We don't have much time.