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- Location: Langley Research Center
The GMT is determined by first computing the number of seconds in the day since midnight:
if JFract > 0.5,then Seconds = 86400.0 * (JFract-0.5)
if JFract <= 0.5, then Seconds = 86400.0 * (JFract+0.5)
Then compute HH, MM, and SS where:
HH = Int(Seconds/3600)
MM = Int(Seconds-(HH*3600.0)/60)
SS = Seconds-(HH*60.0 + MM)*60.0
In your note, the fraction is 0.500080335. Since it is greater the 0.5, we subtract 0.5 to get 0.000080335. Multiply it by 86400 and get 6.93792 seconds.
Therefore HH = 0, MM = 0, SS = 6.93792 or 00:00:06.93792.
The nonfraction part of the time is related to the day, since the day on the CCCM is related to noon, 2454648 runs from noon on June 30, 2008 until just before noon on July 1, 2008. After noon, the Julian day becomes 2454649 or July 1, 2008.
If you subtract the first time of observation from the last, it will be approximately 1 meaning the file contains a days worth of data.
Since this is a day file, it will have 14 equatorial crossings at 1:30 Local Time and cross a pole approximately 50 minutes before or after each one.
The SSF and CCCM documentation is helpful in explaining variables on the CCCM. The core of the product is an SSF. Deviations from the SSF and additional variables are explained in the c3m document.
https://ceres.larc.nasa.gov/documents/c ... G_R2V1.pdf
https://asdc.larc.nasa.gov/documents/ce ... _B1_v2.pdf