[time-nuts] Frequency Ensemble

[Anders Wallin]

If you search for "GNSS time transfer" you will find a lot of papers etc.
For example these might get you started:
https://www.bipm.org/ws/CCTF/TAI_TRAINING/Allowed/Fundamentals/Training-2012-GNSS-Defraigne.pdf
https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7909843

I tried to collect some tools for PPP post-processing on github:
https://github.com/aewallin/ppp-tools
I am not sure what (open) software exists for common-view analysis...
PPP uses satellite clock-corrections and orbit-corrections from an IGS
data-centre. They have "ultra rapid" and "rapid" products (=downloadable
files) that are available with some days or hours of delay.
The "final" products can have up to two weeks (?) of delay.
With a dual-frequency receiver the ionosphere delay can be removed
('ionosphere-free L1/L2 linear combination') and my understanding is the
troposphere-delay (water content) is one of the larger remaining
uncertainties.

AW


On Mon, Mar 18, 2019 at 5:03 PM Rodger via time-nuts <
time-nuts at lists.febo.com> wrote:

>
> Regarding your comments on collecting raw time data from GPS and post
> processing it.  Can you provide any reference info, links, etc. with more
> detail on that topic?
> Clearly I'd need a GPS that outputs the proper raw messaging and the
> software for processing it.  I'm somewhat familiar with the techniques
> involved to improve GPS position data, but hadn't thought about it as much
> for timing.
>
> Thanks,
>
> Rodger
>
>