[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: 20.3.3.3.3.1 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.

--lou

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         |
>> | Geodetic Research Laboratory                  Web: https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fgge.unb.ca%2F&data=01%7C01%7Cgblewitt%40unr.edu%7C774951b84d5e4a6cb0a008d585f74283%7C523b4bfc0ebd4c03b2b96f6a17fd31d8%7C1&sdata=%2BTwS2iSLv490Bgaijk13IuFR3zwmVnd%2FBnM3FITsOSc%3D&reserved=0     |
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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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