On 5/26/21 4:45 PM, Ronald Held wrote:
What is the main reference time on the ISS? Is it a primary frequency standard? How is it updated?
Others may weigh in with better info, but as of a few years ago, there wasn't anything like a "house 10 MHz" - most things were timed off the MIL-STD-1553B bus if they needed timing. There is Ethernet, but I don't know if there's an NTP server, or whether they've implemented anything like PTP. For the most part, if you need good timing for your experiment, you fly your own reference (a GPSDO or a Rb or something).
Typically, you don't even know where you are in 3D space that accurately - there's a Broadcast Ancillary Data (BAD) stream with XYZ and rates, but it's generated as a predict by Goddard's Flight Dynamics Facility. For that matter, the entire structure (which is as large as a football stadium) flexes quite a bit (meters), so if you're looking for meter or nanosecond accuracy, you would need to ask "relative to where".
https://www.nasa.gov/mission_pages/station/research/quick-start-guide https://www.nasa.gov/pdf/190373main_TP-2007-214768.pdf http://large.stanford.edu/courses/2014/ph240/clark1/docs/np-2010-09-682-hq.pdf _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
