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Leap Second
Posted by MitchPTD on December 5, 2016 at 3:03 pmjohn-hamilton replied 7 years, 7 months ago 8 Members · 8 Replies -
8 Replies
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“Receivers that are not on the list will not be affected be the leap second event…”
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Jim Frame, post: 402436, member: 10 wrote: “Receivers that are not on the list will not be affected be the leap second event…”
Pointing out the misuse of effected is an affectation 😉
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Wow, there have been 17 leap seconds since GPS time started (01/05/1980). Hard to believe that a firmware update is needed to deal with another one that was clearly coming. Besides, GPS time is NOT affected by leap seconds, it has been continuous since 0s GPS and each time a leap second is introduced, it “steps”.
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I look at it this way: That list includes mostly their current receivers. Wonder if anyone even looks at the older stuff.
We have 4 different types of older Topcon receivers but they are relegated strictly to static use now. Curious if we will have any issues. -
John Hamilton, post: 402460, member: 640 wrote: Wow, there have been 17 leap seconds since GPS time started (01/05/1980).
The suspicious side of me is wondering if the leap second variable is coded as an unsigned nibble or semioctet in their software (4 bits) and can only express the integers 0-15. Remarkable parsimonious use of storage if true.
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John Hamilton, post: 402460, member: 640 wrote: Wow, there have been 17 leap seconds since GPS time started (01/05/1980). Hard to believe that a firmware update is needed to deal with another one that was clearly coming. Besides, GPS time is NOT affected by leap seconds, it has been continuous since 0s GPS and each time a leap second is introduced, it “steps”.
From ICD-GPS-200C at http://www.navcen.uscg.gov/pubs/gps/icd200/ICD200Cw1234.pdf
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The way Trimble data files work is that there is a single record that contains the GPS week number. Then, each data record contains the seconds of the week that the observation was made. So leap second should not matter in a basic sense if it is GPS only. But, receivers often display UTC time, so it is necessary to know the leap second. AND, GLONASS uses UTC, so it is necessary to know the offset for mixed observations. I don’t know if it is a required value, but rinex files usually contain the UTC-GPS offset (integer number of seconds)
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