[IGSMAIL-1803] Joint CSTG/IERS Call for Participation in ILRS

John John
Thu Feb 12 07:45:12 PST 1998

IGS Electronic Mail      Thu Feb 12  7:45:12 PST 1998      Message Number 1803

Author: John J. Degnan
Subject: Joint CSTG/IERS Call for Participation in ILRS

The following is a Joint CSTG/IERS Call for Participation in the establishment
of an International Laser Ranging Service (ILRS) modelled in part after the
successful International GPS Service (IGS). Full details regarding the new
organization can be found at the following CSTG SLR/LLR Subcommission Web Site.

Standard forms to assist you in responding to the call by the March 31, 1998
proposal deadline can also be downloaded from the Web site.

Since at least three overlapping email server lists are being used to
announce this new organization, you may receive this notice more than once
and we apologize in advance. 


John J. Degnan
Chairperson, CSTG SLR/LLR Subcommission

Bob. E. Schutz
SLR Representative to IERS Directing Board  



Laser ranging  to  the  Moon  and  artificial  satellites  was  initiated
in  the  1960s  and, during the  1970s  and  1980s, matured  into  an
operational  space  geodetic  technique supporting a  variety  of
scientific  applications.  Satellite  laser  ranging  (SLR)  was  a
significant  source  of  tracking  information  for  early  altimeter
satellites,  such  as GEOS-3  and  SEASAT,  and  has  provided  a  long
time series  of  data  from  the  Starlette and  LAGEOS  satellites  since
their  launch  in  the  mid-1970s. 
In  the  early  1980s, the SLR  and  Lunar  Laser  Ranging  (LLR)
communities  participated  in MERIT (Monitoring Earth Rotation and
Intercomparison of Techniques)   to  demonstrate  the  utility  of  modern
space techniques in determining Earth  rotation  parameters. Earth  rotation
solutions, based on laser  ranging  to  LAGEOS, have  been  delivered weekly
since  1981, and represent the  longest,  continuous  Earth rotation series
obtained using modern  space  techniques.  

In  1987,  the  newly formed International  Earth  Rotation  Service  (IERS)
issued  a  call requesting  commitments  from  the  geodetic community  to
participate  in  the new IERS program. Since the inception of  the  IERS  on
January  1,  1988,  SLR,  LLR  and  Very  Long  Baseline  Interferometry
have been embraced  by  the  IERS.  Since  1988,  the  laser  techniques
have  not  only  contributed  to  the  determination  of  Earth  rotation
parameters  but  have  become  a  significant  component  of  the  IERS
Terrestrial  Reference  Frame  (ITRF)  as  well, especially in the
determination of Earth Center of Mass and scale, and contribute
significantly to precision  orbit  determination  for  current  satellite
altimetry  (TOPEX/POSEIDON  AND  ERS-2).  Furthermore,  SLR  data,
collected  from  a  variety  of  satellites,  is  the  dominant  contributor
to  modern  gravity  field models,  such  as  JGM-3,  EGM96  and  GRIM4. In
addition, LLR  has  been  an  important  factor  in  the  evaluation  of
characteristics  of  Earth-Moon  dynamics,  including  effects  associated
with  general  relativity.  


The CSTG Satellite and Lunar Laser Ranging (SLR/LLR) Subcommission Steering
Committee and the IERS  Directing  Board jointly believe it  is now
appropriate for supporting institutions  to  reaffirm  their future
participation in the SLR/LLR effort and to cooperate in a more formal
structure designed to improve the operational efficiency of  the  laser
ranging  community and to foster data product standardization and new
developments.  In  an  era  of  diminishing  resources, an equitable and
international distribution  of  responsibilities meeting the needs  of  the
global scientific  community  is  needed.  Toward  this  goal,  the  CSTG
SLR/LLR Subcommission has  developed  a  "Terms  of  Reference" document
which describes  the  needs and vision  for this new organization, the
International Laser Ranging Service (ILRS). The CSTG SLR/LLR Subcommission
and IERS  Directing  Board have agreed to issue this joint "Call  for
Participation" as a first step in establishing the new ILRS to  conduct  the
operational  support  and  analyses  required  by  the  scientific
community,  including  the  results  contributed  to  the  IERS in support
of the International Terrestrial Reference Frame (ITRF).  

The supporting operational elements  of  the  new  ILRS  organization,  for
which proposals are being sought, are:

Central  Bureau  -  provides  overall  coordination  of  global laser
ranging  activities; maintains documentation and electronic databases;
organizes meetings and workshops

Laser Tracking Stations and Subnetworks -  acquire and transmit lunar  and
satellite  data to an Operations Center and/or Data Center.  Individual
stations may submit their proposals separately or as part of a Subnetwork 

Operations Centers -provide for  the collection and merging of data from the
subnetwork, initial data quality checks, data reformatting into a uniform
format, compression of data files if requested, maintenance of a local
archive of the tracking data, electronic transmission of data to a
designated ILRS Data Center; provide sustaining engineering, communications
links, and other technical support to a subnetwork.

Regional and Global Data Centers - collect,  archive  and  distribute  the
data  acquired  by  the  stations on behalf of  the user community. Global
centers archive and provide electronic access to the entire SLR/LLR dataset
often in cooperation with Regional or other Global Centers. 

Analysis  and Associate Analysis Centers  -  Analysis Centers generate
precision  ephemerides  for the approved satellite constellation and
regularly submit Earth  rotation  results and station  coordinates  and
velocities for ITRF in strict accordance with IERS standards and delivery
schedules. Associate Analysis Centers generate products of a specific or
specialized nature, provide  quality  control  of  the  products  generated
by  the  various Analysis  Centers,  and/or  generate  combination
products.  Analysis Centers (or Associates) are asked to indicate in their
proposal their interest in routinely performing intercomparisons and quality
checks of different Center solutions, prior to submission to the IERS, and
perhaps even providing "combined solutions" to the IERS.

The duties and functions of the various supporting organizations are
described in more detail in the ILRS Terms of Reference which can be
accessed via the CSTG SLR/LLR Subcommission Home Page at the following address:


It is highly recommended that all organizations responding to this call
review the Terms of Reference document before submitting their proposal.

Policy guidelines for the new ILRS will be set by the ILRS Governing Board,
an international elective body which is expected to supplant the current
CSTG Satellite and Lunar Laser Ranging Subcommission but retain its CSTG
affilliation. The ILRS Governing Board will elect from among its members an
Analysis Coordinator who will also serve as the ILRS representative  to  the
IERS  Directing  Board  and, as part of a reciprocal arrangement,   the
IERS  will  appoint  a  representative  to  the  ILRS  Governing  Board.


The  CSTG Satellite and Lunar Laser Ranging Subcommission and the IERS
requests  proposals  for  participation  in  the  new International Laser
Ranging  Service (ILRS).  Qualified  institutions, or collaborating groups
of institutions,   are  encouraged  to  submit  proposals  to  serve  in
one  or  more  of  the  following  areas:  

o  Central  Bureau  
o  Laser Ranging Station or Subnetwork
o  Operations Center  
o  Regional or Global Data Center  
o  Analysis or Associate Analysis Center

Participants must  provide  their  own  financial  resources in carrying out
their proposed duties . The proposal should clearly address the services and
capabilities being offered by the institution (or institutions), its (their)
financial ability to carry them out, and appropriate points of contact.
Proposal lengths of one to four  pages should be adequate for all
organization types. Further suggestions on proposal  format and content for
each type of organization will be placed on our CSTG SLR/LLR Subcommission
website by January 30, 1998.


Detailed proposals must be submitted in writing by March 31, 1998, to:  

Dr. John J. Degnan  
Chairperson,  CSTG Satellite and Lunar Laser  Ranging  Subcommission
Code 920.3
NASA Goddard Space Flight Center
Greenbelt, MD 20771 USA  

The proposals will be jointly reviewed by a special session of the CSTG
SLR/LLR Subcommission Steering Committee to be held in advance of the 23rd
General Assembly of the European Geophysical Society (EGS) in Nice, France
during the week of April 20-24, 1998.and by the IERS Directing Board at its
19 April 1998 meeting.  Successful proposers will be notified by early June
with a goal of fully implementing the new ILRS organization by November 1, 1998.

_________________________________			__________________________________
John J. Degnan, Chairperson				Bob E. Schutz, SLR Representative
CSTG Satellite and Lunar Laser Ranging Subcommission	IERS Directing Board
Dr. John J. Degnan                       Phone: (301) 286-8470

Head, Geoscience Technology Office       Fax: (301) 286-0213
Code 920.3                               Email: jjd at ltpmail.gsfc.nasa.gov
NASA Goddard Space Flight Center
Greenbelt, MD 20771 USA

"The great thing about senseless, sadistic policies is that they don't 
require a lot of explanation." - Catbert :-(

[Mailed From: jjd at ltpmail.gsfc.nasa.gov (John Degnan)]

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