[MOIMS-NAV-EXEC] CCSDS: Green Book glossary update

[Berry, David S (3920)]

Cheryl:

Here are my further comments, restricted to Column H.

1. Good work!
2. There is a very minor typo on "Doppler":  change "tye" to "type" (last word).
3. On "GPS": I wonder if "global satellite navigation system" should be "global navigation satellite system", or even "GNSS", to be consistent with the immediately preceding definition.
4. On "Orbital elements":  change "describe" to "describes" (subject/verb agreement with "set").
5. On "Nutation" and "Precession": I recall that Alain, Dan, and Juergen Fertig (ESA) were the principal participants in the discussion that led to the corrigendum in the ADM (Spring 2015). I won't presume to weigh in on this discussion... I appreciate the fact that you are digging in to this. Clearly there's a range of technical opinion.
6. On "Range": I like your simple, alternate version.

Thanks!
David






From: MOIMS-NAV-EXEC <moims-nav-exec-bounces at mailman.ccsds.org> on behalf of "moims-nav-exec at mailman.ccsds.org" <moims-nav-exec at mailman.ccsds.org>
Reply-To: "Gramling, Cheryl J. (GSFC-5950)" <cheryl.j.gramling at nasa.gov>
Date: Monday, December 10, 2018 at 12:10 PM
To: "moims-nav-exec at mailman.ccsds.org" <moims-nav-exec at mailman.ccsds.org>
Subject: [MOIMS-NAV-EXEC] CCSDS: Green Book glossary update

Hello Everyone,

The attached spreadsheet has the glossary terms vetted against the existing SANA glossary terms.  The terms from the Green books are in Columns B & C.  If SANA has an existing definition that is different from those definition in the Green Book(s), it can be found in Column G.  Based on these two sources as well as comments received, Column H hosts suggested updates to SANA, either for new terms to be added or to existing terms.

ACTION to ALL:  Please provide your comments or concurrence on these terms on Column H.



I request your thoughts on two terms: Nutation, Precession.
Based on several references (Kaplan (pp 53-54), Wertz (493-498), Markley, Julie’s inputs to SANA for Attitude/Spacecraft Conventions, etc), nutation is the angular momentum vector offset from spin/principle axis introduced by geometric offsets (not external torques); precession is the change in the angular momentum vector due to external torques.

In the ADM, the distinction between nutation and precession is not clear:
From ADM Corrigendum:
As in some attitude dynamics references, in this document the term ‘nutation’ is used to mean the motion of the spin axis of a body about an inertial axis. In many other references this motion is called ‘precession’.

The definitions in the Green Book Glossary(ies) are inconsistent with the cited references or unclear.

ACTION:  I’d like your inputs – particularly from Alain! – on a resolution to add these terms correctly to SANA, and whether the ADM corrigendum text needs to be updated to be consistent with the definitions.


Thank you all!

Kind Regards,
Cheryl


---
Cheryl Gramling
GSFC/Sr. Navigation Systems Engineer
cheryl.j.gramling at nasa.gov
[O] 301-286-8002
[C] 240-328-5517

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