[MOIMS-NAV-EXEC] "Navigation & Timing"

[Berry, David S (US 3920)]

Dan:

Good points, but what you describe seems to me to reflect a dependence on accurate measurement of time, but not the responsibility for determining UTC-UT1, TDT, leap seconds, etc. attributes of the time scales. Pages 12 and 13 at the following link (source = CCSDS Time Management WG) define the relevant terms:

https://cwe.ccsds.org/sea/docs/SEA-TIME/Meeting%20Materials/2020/2020-01-09%20teleconference/TimeDef_v2.3.pptx?Web=1

I guess part of my question about lumping these timing functions with navigation in CCSDS relates to the following questions: If timing (i.e., time transfer, time correlation, time synchronization/distribution) is within the responsibility of navigation, why has no one in the Navigation Working Group or the CESG ever argued that we are professionally derelict by neglecting to ever propose standards for these functions? Why is a working group in the System Engineering Area assigned to create standards in these areas?

To me the answer is that these timing functions are fundamental for all areas of space missions, not just navigation. The "Rationale" on the definition of "Time Correlation" on p.12 of the link reflects this.

David




From: "Oltrogge, Daniel" <doltrogge at agi.com>
Date: Sunday, January 12, 2020 at 4:17 AM
To: "Berry, David S (US 3920)" <david.s.berry at jpl.nasa.gov>
Subject: [EXTERNAL] RE: "Navigation & Timing"

David –

For AGI, if you mean distribution of timing such as UTC-UT1, TDT, leap seconds, etc., then yes absolutely we deal with that.  The AGI product line needs those to run properly.

__________________________
Dan Oltrogge
Director, Center for Space Standards and Innovation
Analytical Graphics, Incorporated
Voice: 719-482-4552   ҉   E-mail: oltrogge at agi.com<mailto:oltrogge at agi.com>

From: MOIMS-NAV-EXEC <moims-nav-exec-bounces at mailman.ccsds.org> On Behalf Of Berry, David S (US 3920) via MOIMS-NAV-EXEC
Sent: Saturday, January 11, 2020 6:45 PM
To: moims-nav-exec at mailman.ccsds.org
Subject: [MOIMS-NAV-EXEC] "Navigation & Timing"


All:



I've been assigned to review a document produced by the CCSDS System Engineering Area called the "Application Support Layer Architectural Description Document" (hereafter, ASL/ADD). This book abstracts at a high level functions of the MOIMS (Mission Operations & Information Management Services) and SOIS (Spacecraft Onboard Interface Services). Recall that the Navigation Working Group is organized under MOIMS.



Within the ASL/ADD, there is a MOIMS function labelled "Navigation and Timing". In my limited experience, the "timing" function is not within the purview of the navigation function; while navigation is obviously concerned with timing and depends upon its accurate measurement, so is nearly every other space mission function (I can't really think of one that doesn't depend at some level on accurate measurement of time).



So my question to the members of the Navigation WG:  Is "Navigation and Timing" a function in your navigation organization, i.e., is your organization responsible for time correlation, time distribution, time synchronization, etc.



Thanks

David




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