I have been wondering where the camera in my V+ gets its time stamps from.
Then it occurred to me, it probably comes from the GPS data.
Would this be true?
Then it occurred to me, it probably comes from the GPS data.
Would this be true?
It is certainly availble in the GPS data - so I assume so.Narrator said:I have been wondering where the camera in my V+ gets its time stamps from.
Then it occurred to me, it probably comes from the GPS data.
Would this be true?
Huh? He's asking how the file's creation time is generated on the filesystem when the images/videos are saved.Prylar Bek said:What do yo mean? Like recording time? Mine doesn't 'stamp' as much as just shows recording time, until I xfer it to the comp, then it stamps it> Is that what you mean?
It's quite interesting how a GPS receiver calculates the time from the various satellite info.Hughie said:It is certainly availble in the GPS data - so I assume so.
https://en.wikipedia.org/wiki/Global_Po ... imekeeping
Yep.. I'm sure.N017RW said:First let me say I don't have a V+.
But are you sure you're not talking about the file's time/date/etc when you up load to your PC?
That has nothing to do with GPS data from your a/c.
I read Wikipedia regarding GPS. It said something like this: The receiver must get 4 GPS signals, from which it calculates the actual time, based on angles and time stamps from the satellite telemetry. (Something like that anyway.)N017RW said:The GPS clock is UTC I beleive thus requiring some addtional input (offset) to convert to your local time.
My guess is it (the Naza) is sync'ed with your PC clock during upgrades, calibrations, etc.
Curious to see what others may think.
In typical GPS operation as a navigator, four or more satellites must be visible to obtain an accurate result. The solution of the navigation equations gives the position of the receiver along with the difference between the time kept by the receiver's on-board clock and the true time-of-day, thereby eliminating the need for a more precise and possibly impractical receiver based clock. Applications for GPS such as time transfer, traffic signal timing, and synchronization of cell phone base stations, make use of this cheap and highly accurate timing. Some GPS applications use this time for display, or, other than for the basic position calculations, do not use it at all.
PhantomFanatic said:Yes, it is included with GPS data, as was stated earlier.
ianwood said:PhantomFanatic said:Yes, it is included with GPS data, as was stated earlier.
Local time is not included with GPS data.
The GPS navigation message includes the difference between GPS time and UTC. As of July 2012, GPS time is 16 seconds ahead of UTC because of the leap second added to UTC June 30, 2012.[109] Receivers subtract this offset from GPS time to calculate UTC and specific timezone values. New GPS units may not show the correct UTC time until after receiving the UTC offset message. The GPS-UTC offset field can accommodate 255 leap seconds (eight bits).
Narrator said:ianwood said:PhantomFanatic said:Yes, it is included with GPS data, as was stated earlier.
Local time is not included with GPS data.
From the same page I linked earlier:
The GPS navigation message includes the difference between GPS time and UTC. As of July 2012, GPS time is 16 seconds ahead of UTC because of the leap second added to UTC June 30, 2012.[109] Receivers subtract this offset from GPS time to calculate UTC and specific timezone values. New GPS units may not show the correct UTC time until after receiving the UTC offset message. The GPS-UTC offset field can accommodate 255 leap seconds (eight bits).
GPS to UTC offset is different than the offset for UTC to local time.
Hughie said:I assume that the UTC time is derived from GPS. What other options are there.
This really is a question about where does the Phantom get its timezone info from. This could be done as has been suggested based on the PC clock that the assistant is on. I would be interested to see if in addition to timezone, the daylight savings time (DST) profile is taken account of. These can be fiddly to apply on an international product. Even where DST is defined it can still have exceptions. For example Arizona I believe has regions which do their own thing.
Great question - not silly.
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