[teqc] upcoming improvements to teqc's qc antenna position calculation

Lou Estey lou at unavco.org
Fri Mar 9 13:25:50 MST 2018

Richard, Geoff,

Yes, the Sagnac effect, as you know, is a relativistic correction due to the Earth's rotation
and is proportional to "r dot v" of the SV's position and velocity at the time of signal
transmission: in the IS-GPS-200, or Section III in Neil Ashby's 2006 summary paper
https://www.aapt.org/doorway/TGRU/articles/Ashbyarticle.pdf on relativistic effects.

Time correction for signal propagation time (on the order of 0.1 second) during the Earth's
rotation is, e.g., covered here: http://www.navipedia.net/index.php/Satellite_Coordinates_Computation

I can send either of you two trial executables: one with the Sagnac effect off and the
other ignoring the Earth's rotation during the signal travel time to the antenna.


On 09-Mar-18 01:03 PM, Geoffrey Blewitt wrote:
> Lou
> I agree with Richard, accounting for Earth rotation in the ECEF frame IS the Sagnac effect.  Its is also equivalent to computing in the ECI frame (like GIPSY does).
> Just hope you are not counting this twice.
> Thanks,
> - Geoff
>> On Mar 9, 2018, at 11:52 AM, Richard Langley <lang at unb.ca> wrote:
>> Lou:
>> Aren't these the same thing? That is, in the Earth's rotating frame of reference (e.g. WGS 84), the Earth rotation correction IS the Sagnac effect.
>> -- Richard
>> -----------------------------------------------------------------------------
>> | Richard B. Langley                            E-mail: lang at unb.ca         |
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>> -----------------------------------------------------------------------------
>>> On Mar 9, 2018, at 2:41 PM, Lou Estey <lou at unavco.org> wrote:
>>> - the relativistic Sagnac correction to each SV position calculation,
>>> - accounting for the rotation of the Earth during the travel-time of signals
>>>   from each SV to the antenna

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