[MOIMS-NAV-EXEC] Notional Events requirements from NAV WG

[Gramling, Cheryl J. (GSFC-5950)]

Dan,

I think we need a requirement that more than one relative time may optionally be associated with an event [e.g. the case of UTC relative time and Spacecraft Clock relative time].

Should it explicitly be stated that both an absolute and a relative time may optionally be associated with an event, or does the “or” in Req 3.a adequately cover that?

Thanks for putting this together.
Cheryl

From: MOIMS-NAV-EXEC <moims-nav-exec-bounces at mailman.ccsds.org> on behalf of "Oltrogge, Daniel" <doltrogge at agi.com>
Date: Wednesday, October 19, 2016 at 4:57 PM
To: "moims-nav-exec at mailman.ccsds.org" <moims-nav-exec at mailman.ccsds.org>
Subject: [MOIMS-NAV-EXEC] Notional Events requirements from NAV WG

Particularly for Fran, Dale and Alain (but feedback from all welcomed):

Here’s a rough draft of the NAV WG requirements for us to send to Colin regarding the events message…


(1)     The elements of information that are *not* associated with timing systems that are in the current rough draft Events Message look okay;

(2)     In a parent segment, a global absolute reference epoch may be specified.

a.       For this reference epoch, the optional capability is required to specify the time scale upon which this absolute reference epoch is based.  If not specified, then the global absolute reference epoch’s time scale shall default to UTC.

(3)     Multiple events can be declared within a global object.

a.       For each of these events, the event’s timing may optionally be specified as relative or absolute.  If not specified, the event’s timing defaults to absolute.

b.       When absolute timing is used:

                                                               i.      The timescale of that event-unique absolute time may optionally be set.  If not specified, then the event-unique absolute reference epoch’s time scale shall default to UTC.

c.       When relative timing is used:

                                                               i.      An event-unique absolute reference epoch to which this relative timing is measured may optionally be specified.

                                                             ii.      If an event-unique absolute reference epoch is specified, then the time scale upon which that event-unique absolute reference epoch is based may optionally be specified.  If not specified, then the event-unique absolute reference epoch’s time scale shall default to UTC.

                                                            iii.      If an event-unique absolute reference epoch is not specified, then it is mandatory that a global absolute reference epoch is specified.

                                                            iv.      If both a global and an event-unique absolute reference epoch are specified, the event-unique absolute reference epoch shall override the global absolute reference epoch for that event.

                                                             v.      The timescale of the event relative time may optionally be set.  If not specified, then the timescale shall default to UTC seconds.

Thanks,

Dan

Daniel L. Oltrogge
SDC Program Manager & Senior Research Astrodynamicist
Center for Space Standards and Innovation
Analytical Graphics Incorporated
Voice: 719-482-4552; E-mail: oltrogge at agi.com

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