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- NTPClockOffset, NTPFreqOffset: These values are computed by the NTP software on the DSM, and written to the NTP "loopstats" file. See http://www.eecis.udel.edu/~mills/ntp/html/monopt.html
for information on the NTP monitoring options. NTP ClockOffset is the estimated offset of the GPS time from the data system time. A positive value indicates the GPS clock is showing a later time than the system clock. NTPFreqOffset is the correction applied to the system clock frequency in parts-per-million, a positive value indicates that NTP has determined that the system clock oscillator is slow and the frequency offset is being added to the system clock values. These
The NTP values have not been recorded consistently since the beginning of the project. Only data from May 3 to August 12, 2010, Oct 14 to November 9, 2010, and April 9, 2011 onward have been archived.
On April 12, 2011 the old Garmin GPS 25-HVS at the tower was replaced with a much newer Garmin 18x-LVC model. The model numbers are shown in the $PGRMT messages, where the time is UTC:
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