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

David Taylor david-taylor at blueyonder.co.uk.invalid
Fri Aug 16 08:36:28 UTC 2013

On 16/08/2013 08:12, Magnus Danielson wrote:
> 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

Yes, all my receivers are very simple, consumer-level ones.  Sometimes I 
see as low as 2m "location accuracy" on the GPS 60 CSx, more likely 3m 
when walking.

Thanks for the pointers to the documents.  A pity that they haven't been 
able to find two or three spare bits to reduce the 1024 week ambiguity 
to nearer a half-century or even 100 years.  Oh, well!

Web: http://www.satsignal.eu

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