[CESG] RE: CCSDS 131.4-R-0 bis, TM Channel Coding Profiles for CCSDS Agency review

[Hooke, Adrian J (9000)]

Gian Paolo: could you please clarify the status of this proposed document in terms of whether or not it reflects consensus? You used the word twice:


1.      "It is also worth mentioning that a careful analysis of all comments produced during the previous CESG e-poll have been discussed with the Book Editor and the approach taken in the book with complete WG consensus has been compared against other approaches to confirm its validity"

2.      "Despite sometimes the debate was very active, comments were lively discussed finding convergence versus full WG consensus."

Does Item 2 imply that you used some process called "convergence" rather than the required process of consensus? As a reminder, the CCSDS procedure manual is quite clear on this point:

5.1.2 CONSENSUS
The decisions of all CCSDS organizational units shall reached through consensus. In this context, consensus does not necessarily mean that unanimous agreement has been reached, but that the result incorporates the best set of compromises to which all parties can agree
5.2.5 WORKING GROUP MEETINGS
5.2.5.1 Purpose
Working Group meetings are convened to enable face-to-face technical discussions leading to consensus.

Please clarify whether or not the revised document does in fact represent full Working Group consensus.

Best regards
Adrian

Adrian J. Hooke
Chairman, CCSDS Engineering Steering Group (CESG)
Space Communications and Navigation Office (SCaN)
Suite 7L70
Space Operations Mission Directorate
NASA Headquarters
Washington DC  20024-3210

From: Gian.Paolo.Calzolari at esa.int [mailto:Gian.Paolo.Calzolari at esa.int]
Sent: Friday, January 28, 2011 2:58 AM
To: Hooke, Adrian J (9000); Nestor.Peccia at esa.int
Cc: CCSDS Secretariat; cesg at mailman.ccsds.org
Subject: CCSDS 131.4-R-0 bis, TM Channel Coding Profiles for CCSDS Agency review


Dear Adrian and Nestor,
        I am asking you - CESG Chair and Deputy CESG Chair - to poll the CESG as soon as possible to authorize the CCSDS Agency review for the attached revised version of the  TM Channel Coding Profiles proposed Draft Magenta Book.
The document includes improvements according to the comments gathered during the previous CESG e-poll.

It is also worth mentioning that a careful analysis of all comments produced during the previous CESG e-poll have been discussed with the Book Editor and the approach taken in the book with complete WG consensus has been compared against other approaches to confirm its validity. As an example, the Report of the Space Internetworking Strategy Group (originally produced on 15 November 2008 and revised July 2010) was checked keeping in mind that the purpose of the two documents (SISG Report vs. TM Coding Profiles) is very different with the proposed Magenta Book focusing on actual recommendations limited to Telemetry while the SISG Report addresses (in "Appendix G: The Scenario Template Table") a much wider scenario (e.g. the accent on TC and space-to-link is not minor) with a reporting and forecast  approach.

The SISG report takes into accounts different "Mission Types" but finally for Direct To Earth (DTE) links identifies always the same frequency bands (S, X, Ka) with no granularity while the approach used in the Magenta is just more accurate according to expectation, focus, pertinence and expertise of the Space Link services Area.
The SISG Table is "lumping together S-Band, X-band and Ka-band frequencies"  in the row Frequency Band DTE, for both Mission Type "Earth Exploration Missions" and "DTE/DFE Science Missions"while the related "Coding DTE" rows are different. Therefore is NOT a surprise (as criticized)  that the Magenta book proposes different types of codes.

The (criticized) overlapping of the scenarios in a few cases is natural since missions belonging to different categories can have the same type of orbit. If the categorization would start from orbit types, the overlapping would just fall into the frequency ranges. Validity if of the Magenta book is also confirmed by an analysis of the four Mission types identified in the SISG Report  (i.e. Earth Observation Missions, excluding geostationary satellites; Lunar Missions;  DTE/DFE Science Missions and Mars Missions): the Magenta Book identifies 2 types (Earth Exploration and Space Research with the latter split in 2 sub-types depending on the distance from Earth) but the correspondence is obvious and the higher SISG granularity was important to the target of that group but not those of the Magenta Book. In fact the  "Coding DTE" rows related to the last 3 SISG types are identical stating only the high level types of codes with a level of detail clearly not sufficient for the Magenta Book target (i.e. taking the SISG approach the Magenta Book would just fail).

Therefore I consider that the Coding and Synchronization Working Group did an excellent job in producing this draft Magenta Book that represents a  very focused exercise with very effective results.
Despite sometimes the debate was very active, comments were lively discussed finding convergence versus full WG consensus.
It is also IMPORTANT to remember that, as per CESG agreement in London,  the Earth Exploration column of Table 3-1 (i.e. clauses 3.2.3 and 3.2.5) is not going to be subject  to Agency Review (i.e. no RID on those two clauses will be acceptable).

Thank you for your collaboration and best regards

Gian Paolo Calzolari
SLS-C&S Chair




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