That is clear to me, Jan, at first sight I am thinking that the time
table info could be easily modulated on the GPS signal.
I could not find detailed specification of the system and signals.
Greetz, Jos
On 28-Mar-17 14:42, Jan van Wijk wrote:
Hallo Jos,
On Tue, 28 Mar 2017 11:19:56 +0200 Jos de Fotograaf wrote:
_Is DST in the GPS info itself?_
No
Some members suggested that the camera needs look-up tables to see DST data of
specific countries.
I am not so sure about that.
You need either DST tables (combined with timezone info), OR manual setting of
DST yes/no
I did not get a clear answer from Google.
But, GPS was designed for military purposes, it contains time information, so
why not also DST data?
The GPS sattelite(s) don't know where YOU are, they only send an encoded very
exact TIME signal which can be received everywhere the sattelite is 'visible'
Your GPS device can then calculate its position by comparing time-differences
as received from multiple sattelites (closest sattelite is received first :)
The decoded time will be available to the GPS device this way, but it is UTC
time.
The device needs to convert that to local time using timezone + DST information.
For military on the ground it can be crucial to know the exact local time.
Even when all other systems fail.
Yes, but the GPS only supplies UTC times.
BTW: In large scale military operations, they often use UTC times directly,
it used to be called ZULU time, for ZERO deviation from the ZERO-meridian time
:)
_Well, all together it took me a lot more time, than simply adapting the clock
manually! But I gained knowledge!
Indeed, I checked my K3, it did not have DST checked either (fixed now).
It is important to set that correctly, otherwise the 'Sync' done by the GPS
unit will set
the time wrong (since the conversion from UTC to local-time will be off by 1
hour)
I have had that happening a few times, setting it manually, then seeing it
change
automatically as soon as the GPS unit gets a proper connection :)
Regards, JvW
------------------------------------------------------------------
Jan van Wijk; http://www.dfsee.com
Flickr : jvw_pentax
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