Networks and Engineering Standing Committee Forum

General Topics => Station Performance => Topic started by: Toshimichi Otsubo on September 16, 2017, 03:42:40 PM

Title: Station Performance 2016-2017 (Riga Workshop Spoiler)
Post by: Toshimichi Otsubo on September 16, 2017, 03:42:40 PM

Dear Worldwide Laser Ranging Colleagues,

Hello from Tokyo.

In preparation for 2017 ILRS Technical Workshop in Riga http://www.ilrstw2017.lu.lv (http://www.ilrstw2017.lu.lv), I have just generated and uploaded a number of charts on station performance from various aspects.

• LAGEOS-1 & 2 "precision" charts:
  Single-shot RMS, NP RMS, Pass Range Bias (RB) RMS and Pass Time Bias (TB) RMS
  http://geo.science.hit-u.ac.jp/slr/bias/2017sp/variousrms.pdf (http://geo.science.hit-u.ac.jp/slr/bias/2017sp/variousrms.pdf)
  (Single-shot RMS taken from CRD, NP RMS smoothed by a simple function (RB only, RB + TB, or RB + RB-dot + TB) per pass, RB/TB RMS taken from pass-by-pass biases)
  
• LAGEOS-1+2: Pass RB RMS vs Session-by-session system delay RMS
  (Page 1 >> ZOOM >> Page 2 >> ZOOM >> Page 3)
  http://geo.science.hit-u.ac.jp/slr/bias/2017sp/DelayVsLag7.pdf (http://geo.science.hit-u.ac.jp/slr/bias/2017sp/DelayVsLag7.pdf)
  (Good performing stations are mostly stable in calibration too.)
  
• 6-Sat: POD residuals vs Applied system delay
  http://geo.science.hit-u.ac.jp/slr/bias/2017sp/SortDelay7.pdf (http://geo.science.hit-u.ac.jp/slr/bias/2017sp/SortDelay7.pdf)
  (Negative 1:1 trend indicates untrue variation in calibration.)
  
• 6-Sat: POD residuals vs Intensity (returns per NP bin)
  http://geo.science.hit-u.ac.jp/slr/bias/2017sp/SortIntensity7.pdf (http://geo.science.hit-u.ac.jp/slr/bias/2017sp/SortIntensity7.pdf)
  (Negative trend indicates intensity dependence.)
  
• 6-Sat: POD residuals vs Single shot RMS
  http://geo.science.hit-u.ac.jp/slr/bias/2017sp/SortRms7.pdf (http://geo.science.hit-u.ac.jp/slr/bias/2017sp/SortRms7.pdf)
  (Positive trend indicates the mean being affected by the tail clipping.)
  
• 6-Sat: POD residuals vs Local time
  http://geo.science.hit-u.ac.jp/slr/bias/2017sp/SortHour7.pdf (http://geo.science.hit-u.ac.jp/slr/bias/2017sp/SortHour7.pdf)
  (Day-night observability and stability.)
  

Period: July 2016 to June 2017.
Satellites: LAGEOS-1, LAGEOS-2, AJISAI, STARLETTE, STELLA and LARES.
POD Software: c5++.  Station positions are solved for.  Atm + hyd loading displacements are applied.  Grav coeffs 5x5 are solved for with some empirical acceleration params.

I will be able to only present only a small part of them in my presentation (Session 2),
but I am willing to discuss these results with everyone. 

See you soon in Latvia,
Toshi
---
Toshimichi Otsubo (t.otsubo@r.hit-u.ac.jp)
Hitotsubashi University

Title: Re: Station Performance 2016-2017 (Riga Workshop Spoiler)
Post by: Yarragadee on September 20, 2017, 01:22:17 AM

Nice work again Toshi!

Thanks for these great charts - they really help us to know how we are going and if our tracking practices have improved.
It looks like we have tightened things up a bit from last year  8) and it will be cool to see how the new event timer looks when you get enough data.

Cheers,
Randall.

Title: Re: Station Performance 2016-2017 (Riga Workshop Spoiler)
Post by: Matt Wilkinson on September 21, 2017, 10:28:07 AM

Hi Toshi

These are really useful and i guess every station has something to think about. The SGF, Herstmonceux has been addressing its residual vs RMS plot by looking at our data reduction procedure.

It would be great if all stations could post here on the forum what they are doing to address the trends seen in these charts.

The pdf http://geo.science.hit-u.ac.jp/slr/bias/2017sp/SortDelay7.pdf has multiple entries for Potsdam, Greenbelt, Wettzell and others, is this correct?

Matt

Title: Re: Station Performance 2016-2017 (Riga Workshop Spoiler)
Post by: ArttuR-H on September 21, 2017, 11:11:14 AM

Hi Toshi,
Maybe this is a trivial question as I'm not so familiar with the analysis process. But for curiosity, what atmospheric and hydrological (oceans and land water?) loading models did you use? Did these include any non-tidal corrections? I'm just wondering, cause for example in Metsahovi the non-tidal loading caused by mass variations in the small Baltic Sea can cause even 1cm vertical displacement. Which is something we see in our GNSS and gravimeter time series, and maybe in the future also in our SLR and VLBI results.
BR,
Arttu @ Metsähovi

Title: Re: Station Performance 2016-2017 (Riga Workshop Spoiler)
Post by: jsteinborn on September 21, 2017, 02:42:10 PM

Quote from: Matt Wilkinson on September 21, 2017, 10:28:07 AM

Hi Toshi

These are really useful and i guess every station has something to think about. The SGF, Herstmonceux has been addressing its residual vs RMS plot by looking at our data reduction procedure.

It would be great if all stations could post here on the forum what they are doing to address the trends seen in these charts.

The pdf http://geo.science.hit-u.ac.jp/slr/bias/2017sp/SortDelay7.pdf has multiple entries for Potsdam, Greenbelt, Wettzell and others, is this correct?

Matt

Hi Matt,

I think its due to the fact that we are using different detector/laser setups.

Best
Jens

Title: Re: Station Performance 2016-2017 (Riga Workshop Spoiler)
Post by: Toshimichi Otsubo on September 22, 2017, 05:35:53 AM

Thanks for the quick responses.  Great to hear from you.

Arttu,
I used Strasbourg EOT Loading available at http://loading.u-strasbg.fr/,
and I took ATMIB and MERRA_hyd data.  Not many models cover latest periods.

Matt and Jens,
Jens gave the right answer - thanks. 

Toshi