Ulysses HISCALE Data Analysis Handbook
Appendix 7. LAN EDR Interface Specification
A7.6 Binary Epoch Standard Time
Binary Epoch Standard Time is a self-specifying binary time code based on a cumulative count of seconds and binary fractional subseconds since a known epoch used as a point of reference. A diagram illustrating the specific fields in the time format follows. It specifies values and contents of three fields: timecode identifier, coarse time, and fine time.
The chosen epoch is 00:00:00 hours UTC on January 1, 1950. This allows unambiguous identification of data from the epoch to 2086 A.D. Four bytes of coarse time represents approximately 136 years while the two bytes of fine time allow a resolution of approximately 15 microseconds.
TIMECODE FORMAT
OCTET (BYTE)
P = Timecode Identifier (8
bits)
CT = Coarse Time: elapsed seconds since epoch (32 bits)
FT = Binary sub-multiples of coarse time (16 bits): contains
the fractional portion of a second with an assumed binary
point to the left of byte 6.
TIMECODE IDENTIFIER
Figure A7-5 EDR/MDR Format Layout
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Updated 8/8/19, Cameron Crane
QUICK FACTS
Mission End Date: June 30, 2009
Destination: The inner heliosphere of the sun away from the ecliptic plane
Orbit: Elliptical orbit transversing the polar regions of the sun outside of the ecliptic plane