[ntp:questions] Start of new GPS 1024 week epoch

Magnus Danielson magnus at rubidium.dyndns.org
Fri Aug 16 07:12:19 UTC 2013


On 08/16/2013 05:44 AM, David Taylor wrote:
> On 15/08/2013 21:33, Magnus Danielson wrote:
> []
>> They completely avoid it by not numbering it that way. They have their
>> own numbering scheme that fit's the system, and the conversion over to
>> UTC is an added feature. It's all in ICD-GPS-200 for the current set of
>> details, and in the ION red book series for the early stages.
>>
>> GPS and GPS problems is best understood if you realize that everything
>> is counted in the GPS clock machinery with it's own set of gears.
>> Conversion isn't that hard and it is done every second in the GPS
>> receiver.
>>
>> Cheers,
>> Magnus
>
> Thanks, Magnus.  I've not heard of ICD-GPS-2000 or ION red book
> before.  Perhaps one day I will look them up.
If you go here:
http://www.gps.gov/technical/icwg/

you will find IS-GPS-200G (which is the new name since 2006, I have
failed to adapt) on this link here:
http://www.gps.gov/technical/icwg/IS-GPS-200G.pdf

Using ICD-GPS-200D gives a fair idea of what the older GPS receivers was
designed to meet.

In these documents, the "gears" of GPS is explained such that you should
be able to implement a correctly working receiver (in principle). There
are a handful of technical details outside of this spec you need to
figure out too, but there are good books for that.
> GPS continues to impress me - I counted and on holiday recently we
> took (at least) 7 GPS receivers - his and hers smart-phones, 2 iPads,
> Garmin GPS 60 CSx, Ventus 750, and one built into my Sony HX200V
> camera!  The Garmin spent much of its time with a puck antenna stuck
> on the cabin porthole plotting our course.
They have gone small now, but you still have L1 C/A only receivers. Many
of them probably does not use carrier phase in any way.

Cheers,
Magnus


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