Recent Posts

Pages: [1] 2 3 ... 10
Lasers / Laser Profiling paper
« Last post by pywang on June 10, 2022, 11:38:15 AM »

Former time it was very common to use a kind of special paper (e.g. Kodak Linograph 1895) to check the dye laser profile.
Does anybody know how/where to order such paper now?
Or any alternatives?
Is Baryta coated paper applicable?


Peiyuan Wang
Data and Software Questions / Re: - New Release 1.2
« Last post by Matt Wilkinson on June 01, 2022, 10:06:36 AM »
An update is now available on the ILRS website

The update includes the following changes:
Version 1.2.1
    --    CPF interpolation replaced with high order polynomial fit. This is to provide better prediciton values and to remove some actifacts in range residuals.
    --    Update matplotlib subplot axis referencing method to work with the latest versions.
Data and Software Questions / Re: - New Release 1.2
« Last post by DanielK on April 28, 2022, 12:05:17 AM »
Awesome, thank you so much!
Open a Discussion / Re: How does an SLR station affect the local bird population?
« Last post by sandmann on March 08, 2022, 04:43:42 PM »
Hi there Ole,
No real studies from my time at Yarragadee, but anecdotally, they seem to enjoy flying through the beam. I would notice around sunset time, some increase in bird activity around the telescope. It may have had nothing to do with the laser at all...
The best was when they would use the all-sky camera as a perch, and we could get a very wide angle view of the underneath of a bird. :)
Data and Software Questions / Re: - New Release 1.2
« Last post by Matt Wilkinson on January 25, 2022, 12:57:28 PM »
Graham pointed me to these proceedings:

And the document:

which contains the paper "Formation of on-site Normal Points" that details the original mathematical method used.
Data and Software Questions / Re: - New Release 1.2
« Last post by DanielK on January 22, 2022, 02:26:17 AM »
I hope it is a simple question to some - where can I find the basic orbit fit theory that is implemented here? In math terms. Something what I could code myself as a parallelized algorithm. Thanks for any references on this.
Data and Software Questions / - New Release 1.2
« Last post by Matt Wilkinson on January 04, 2022, 10:22:57 AM »
A new version of the orbit adjustment and normal point formation software,, is now available through the ILRS software webpage

This software is designed to work for all SLR stations to compute range residuals and form ILRS normal points. It can be installed and used for comparisons at stations.

ILRS full-rate data files can also be used to inspect the SLR measurements for any satellite pass for any station and repeat the normal point calculation. 

The update contains many refinements and new features and these are listed below. 

Please update to this version and also consult the README file. If you have a questions, issues or suggestions you can post them in the comments below. 

With regards

# Update History

Version 1.1
    --    Added import of warnings Python3 module
    --    New method for cal2mjd() and mjd2cal()
    --    Include option for full CRD normal point output file.
    --    Include 1st iteration quick-pass option to prevent high density segments dominating pass fit.
    --    Include input of 'System Configuration ID'.
    --    Adjusted method for gauss fit to front of residual distribution.
    --    Allow for disagreement in first epoch and H4 record.
    --    Station coordinates and velocities taken from an ILRS SINEX solution file
    --    Peak-Mean calculated using a tangent fit to a smoothed profile.
    --    Option to include unfiltered range measurements

Version 1.2
    --    Gauss fit filter added.
    --    Peak-Mean default as 1*sigma iterative mean.
    --    Option to calculate a '50' record if not included in full-rate CRD file.
    --    Include option to output final ranges in CRD format with met and calibration values.
    --    Filtering at two levels. The first is to form the normal points and the second is to include in the full-rate output
    --    Include option to input satellite centre of mass offset to improve the orbit solution and flatten range residuals.
    --    Indicate if individual normal point residual bins have slopes.
    --    Select SLR station data in full-rate data file from list.
    --    Matplotlib figure window now kept open to allow for much faster plotting of a series of passes.
Data and Software Questions / Re: COSPAR ID to ILRS format
« Last post by kalvis on November 23, 2021, 09:20:28 AM »
Any success? I have found COSPAR international designation origins -  IGY Bulletin: No. 61, No. 62, No. 63. Trans AGU 43:345. (In case the number of components or objects of a satellite launching is large, the following convention will be used: the letters I and 0 will always be skipped; the 25th object or component will be designated AA, the 26th AB, etc., the 49th BA, etc., etc)
The question is how the ILRS Cospar id is calculated. For Tubin(2021-059X, 2105922) and Elsa-D(2021-022N, 2102213) seems that its just a conversation  according to the rule above, but there are a few examples  in the past (Lightsail 2 and GFZ-1) which doesn't follow this convention.

2015-025L     | 1502511  |40661|   Lightsail 1   
2019-036AC   | 1903629  |44420|   Lightsail 2   
1986-017JE   | 8601795  |23558|  GFZ-1
Open a Discussion / How does an SLR station affect the local bird population?
« Last post by Ole Klingan on September 27, 2021, 12:33:44 PM »
Hi everyone!

For the SLR station in Ny-Ålesund, Svalbard, we are trying to find out how an SLR station will affect the local bird polulation. The station is located nearby a bird nesting area.
So my question to the community is if anyone has ever put any attention into what happens to the local bird population over time, and if you ever have seen birds taking damage from the laser?

Best Regards

Data and Software Questions / COSPAR ID to ILRS format
« Last post by pywang on February 04, 2021, 03:14:50 PM »
Hello everybody,

Now I have a problem regarding converting COSPAR Int'l Code to ILRS format.
For a normal case it is easy, eg. "2009-005A" to “0900501”
But when having "2020-061AX", how then?
Second, is it correct that only 'O', ‘L’ and ‘I’ are omitted in COSPAR#, not more?

I put the discussing with Randy (I hope that is Okay for him) below, and there are some hits but not 100% solve my problem.

thanks in advance and best regards,
Wang Peiyuan

Hi Wang,

It's good to hear from you!

As you may know, the COSPAR ID to ILRS ID conversion algorithm is in the CRD and CPF manuals. I include it below. That explains the conversion, although there have been some exceptions over the years. The "i" is not used, as I understand it, because of its similar appearance to lower case "L" and the number "1". The letter "o" is apparently also not used because it looks like zero. Unfortunately, I don't have any source documentation on the COSPAR ID. I am cc-ing this message to Carey Noll and Julie Horvath, who have worked with the COSPAR ID more than I have.

As far as the debris data is concerned,  i.e., data that the ILRS analysts will never see, the ILRS ID could be set to "na" and the COSPAR ID could be included in a "00" comment record. You would still have the NORAD ID to identify the target, which should exist for all debris. (How much of the debris actually has a COSPAR ID? If stations are tracking rocket upper stages, farings, etc., do they have anything but a NORAD number?)

I am reluctant to say "use the COSPAR ID", because the ILRS ID is all numbers and the COSPAR-ID is numbers+letters+ "-". That could break current reading routines. The all-numeric solution you suggest might be a better idea, although that would have to be documented in the manual, too, and it is a bit clumsy. We could have a broader discussion in the DFPSG or the CB about changing the CRD manual so that the COSPAR ID could replace the ILRS ID for debris data only. You are right that this discussion would have been easier a year ago.  :-)

Take care,

COSPAR ID to ILRS Satellite Identification Algorithm:
YYYY is the four-digit year of when the launch vehicle was put in orbit
XXX is the sequential launch vehicle number for that year
A is the alpha numeric sequence number within a launch
Example: LAGEOS-1 COSPAR ID is 1976-039A
Explanation: LAGEOS-1 launch vehicle was placed in orbit in 1976; was the 39th launch in that year; and LAGEOS-1
was the first object injected into orbit from this launch.
ILRS Satellite Identification Format: (YYXXXAA), based on the COSPAR ID
YY is the two-digit year of when the launch vehicle was put in orbit
XXX is the sequential launch vehicle number for that year
AA is the numeric sequence number within a launch
Example: LAGEOS-1 ILRS Satellite ID is 7603901
-----------------------    Randy Ricklefs    ------------------------
      Center for Space Research,  The University of Texas at Austin
                            Austin TX 78712

Sent: Friday, February 14, 2020 2:32 AM
To: Ricklefs, Randall L <>
Subject: COSPAR ID convert to ILRS
Hello Randy,
Some question about COSPAR ID.
As you know LAGEOS-1 ILRS Satellite ID is 7603901 relating to COSPAR ID 1976-039A.
But how to convert targets ID like a decaded debris 1993-036ASU to ILRS ID, 93036011820 or something else?
,there A-01, S-18, U-20
Why S-18 not S-19? Because I found the letter “I” is not used in COSPAR ID
And I don’t know if any other letter also not used. :)
A example of S-NET serial, no “I” used.
43186 S-NET D  2018-014G
43187 S-NET B  2018-014H
43188 S-NET A  2018-014J
43189 S-NET C  2018-014K
I could not find the specification of COSPAR ID, and do you have it?
Do you see any chance that in CRD ver2, we just use COSPAR ID instead of ILRS format?  -- sorry a little too late.
Thanks in advance!!
Pages: [1] 2 3 ... 10