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<p class="MsoNormal"><span style="color:#1F497D">Just one comment : <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Having more than one (absolute or relative) time is associated with an event may cause confusion :
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">The time associated with an event enables defining an “order”.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">But if there are 2 different time references, you may have :
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="FR" style="color:#1F497D">T1(event a) < T1(event b)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="FR" style="color:#1F497D">T2(event a) > T2(event b)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="FR" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">This would be not consistent. <o:p>
</o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">(to avoid this, T1 and T2 would have to be guaranteed equivalent, which is difficult to achieved).
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">But I suppose there are other ways :
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">It should (and this could be a new requirement) to add information (that is to say data) to an event.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">This could for instance allow adding timing information or anything else that may be useful to the user of the event
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">(in some particular context). <o:p>
</o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">PS: I’ll answer the 1<sup>st</sup> message from Dan later<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Alain<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="FR" style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="FR" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">De :</span></b><span lang="FR" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> MOIMS-NAV-EXEC [mailto:moims-nav-exec-bounces@mailman.ccsds.org]
<b>De la part de</b> Gramling, Cheryl J. (GSFC-5950)<br>
<b>Envoyé :</b> jeudi 20 octobre 2016 14:05<br>
<b>À :</b> Oltrogge, Daniel; moims-nav-exec@mailman.ccsds.org<br>
<b>Objet :</b> Re: [MOIMS-NAV-EXEC] Notional Events requirements from NAV WG<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="FR"><o:p> </o:p></span></p>
<p class="MsoNormal">Ah, well, now you raise a good point. <o:p></o:p></p>
<p class="MsoNormal">I wasn’t thinking of 2 different absolute time scales or even 2 different absolute time epochs, associated w 2 (or more) relative times; merely 2 different relative time scales referenced to the same absolute scale/epoch. In my case [1@ABS:2@REL],
you could identify RELTIME_1,….RELTIME_n.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">If we try to address your point, it seems you’d need a way to define cross-strapping of the systems. ABSTIME_1,…ABSTIME_n to each of RELTIME_1,…RELTIME_n :<o:p></o:p></p>
<p class="MsoNormal"> RELTIME_1_1<o:p></o:p></p>
<p class="MsoNormal"> RELTIME_1_2<o:p></o:p></p>
<p class="MsoNormal"> :<o:p></o:p></p>
<p class="MsoNormal"> RELTIME_1_n<o:p></o:p></p>
<p class="MsoNormal"> RELTIME_2_1<o:p></o:p></p>
<p class="MsoNormal"> RELTIME_2_2<o:p></o:p></p>
<p class="MsoNormal"> :<o:p></o:p></p>
<p class="MsoNormal"> RELTIME_2_n<o:p></o:p></p>
<p class="MsoNormal"> :<o:p></o:p></p>
<p class="MsoNormal">where the second number refers to the ABSTIME.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">How often would more than one ABSTIME [SYS or SCAL] be used? I can’t think of any examples. However, I do think at least 2 different RELTIME [SYS] would be used somewhat frequently.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Cheryl<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b><span style="color:black">From: </span></b><span style="color:black">"Oltrogge, Daniel" <<a href="mailto:doltrogge@agi.com">doltrogge@agi.com</a>><br>
<b>Date: </b>Thursday, October 20, 2016 at 1:46 PM<br>
<b>To: </b>"Gramling, Cheryl J. (GSFC-5950)" <<a href="mailto:cheryl.j.gramling@nasa.gov">cheryl.j.gramling@nasa.gov</a>>, "<a href="mailto:moims-nav-exec@mailman.ccsds.org">moims-nav-exec@mailman.ccsds.org</a>" <<a href="mailto:moims-nav-exec@mailman.ccsds.org">moims-nav-exec@mailman.ccsds.org</a>><br>
<b>Subject: </b>RE: [MOIMS-NAV-EXEC] Notional Events requirements from NAV WG</span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Times New Roman","serif""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:#1F497D">You raise a very good point. And that’s fundamentally different that what I’d assembled below.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Any suggestions on how we could potentially reference the different relative times to their respective absolute times in a non-confusing, rigorous way ?</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D">Thanks,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"><br>
Dan</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Daniel L. Oltrogge</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">SDC Program Manager & Senior Research Astrodynamicist</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Center for Space Standards and Innovation</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Analytical Graphics Incorporated</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="FR" style="color:#1F497D">Voice: 719-482-4552; E-mail:
</span><span style="color:#1F497D"><a href="mailto:oltrogge@agi.com"><span lang="FR">oltrogge@agi.com</span></a></span><span lang="FR"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="FR" style="color:#1F497D"> </span><span lang="FR"><o:p></o:p></span></p>
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<p class="MsoNormal"><b>From:</b> Gramling, Cheryl J. (GSFC-5950) [<a href="mailto:cheryl.j.gramling@nasa.gov">mailto:cheryl.j.gramling@nasa.gov</a>]
<br>
<b>Sent:</b> Thursday, October 20, 2016 5:07 AM<br>
<b>To:</b> Oltrogge, Daniel <<a href="mailto:doltrogge@agi.com">doltrogge@agi.com</a>>;
<a href="mailto:moims-nav-exec@mailman.ccsds.org">moims-nav-exec@mailman.ccsds.org</a><br>
<b>Subject:</b> Re: [MOIMS-NAV-EXEC] Notional Events requirements from NAV WG<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Dan,<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">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].<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">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?<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Thanks for putting this together.<o:p></o:p></p>
<p class="MsoNormal">Cheryl<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal"><b><span style="color:black">From: </span></b><span style="color:black">MOIMS-NAV-EXEC <<a href="mailto:moims-nav-exec-bounces@mailman.ccsds.org">moims-nav-exec-bounces@mailman.ccsds.org</a>> on behalf of "Oltrogge, Daniel" <<a href="mailto:doltrogge@agi.com">doltrogge@agi.com</a>><br>
<b>Date: </b>Wednesday, October 19, 2016 at 4:57 PM<br>
<b>To: </b>"<a href="mailto:moims-nav-exec@mailman.ccsds.org">moims-nav-exec@mailman.ccsds.org</a>" <<a href="mailto:moims-nav-exec@mailman.ccsds.org">moims-nav-exec@mailman.ccsds.org</a>><br>
<b>Subject: </b>[MOIMS-NAV-EXEC] Notional Events requirements from NAV WG</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Times New Roman","serif""> </span><o:p></o:p></p>
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<p class="MsoNormal">Particularly for Fran, Dale and Alain (but feedback from all welcomed):<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Here’s a rough draft of the NAV WG requirements for us to send to Colin regarding the events message…<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt">(1)<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>The elements of information that are *<b>not</b>* associated with timing systems that are in the current rough draft Events Message look okay;<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt">(2)<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>In a parent segment, a global absolute reference epoch <u>may</u> be specified.<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt">a.<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>For this reference epoch, the <b>optional</b> 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.<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt">(3)<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>Multiple events can be declared within a global object.<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt">a.<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>For each of these events, the event’s timing <b>may optionally</b> be specified as relative or absolute. If not specified, the event’s timing defaults to absolute.<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt">b.<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>When absolute timing is used:<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:108.0pt;text-indent:-9.0pt"><span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>i.<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>The timescale of that event-unique absolute time <b>may optionally</b> be set. If not specified, then the event-unique absolute reference epoch’s time scale shall default to UTC.<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-18.0pt">c.<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>When relative timing is used:<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:108.0pt;text-indent:-9.0pt"><span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>i.<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>An event-unique absolute reference epoch to which this relative timing is measured
<b>may optionally</b> be specified.<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:108.0pt;text-indent:-9.0pt"><span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>ii.<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>If an event-unique absolute reference epoch is specified, then the time scale upon which that event-unique absolute reference epoch is based
<b>may optionally</b> be specified. If not specified, then the event-unique absolute reference epoch’s time scale shall default to UTC.<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:108.0pt;text-indent:-9.0pt"><span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>iii.<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>If an event-unique absolute reference epoch is not specified, then it is <b>
mandatory</b> that a global absolute reference epoch is specified.<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:108.0pt;text-indent:-9.0pt"><span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>iv.<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>If both a global and an event-unique absolute reference epoch are specified, the event-unique absolute reference epoch shall
<b>override</b> the global absolute reference epoch for that event.<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:108.0pt;text-indent:-9.0pt"><span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>v.<span style="font-size:7.0pt;font-family:"Times New Roman","serif"">
</span>The timescale of the event relative time <b>may optionally</b> be set. If not specified, then the timescale shall default to UTC seconds.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal"><br>
Dan<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Daniel L. Oltrogge<o:p></o:p></p>
<p class="MsoNormal">SDC Program Manager & Senior Research Astrodynamicist<o:p></o:p></p>
<p class="MsoNormal">Center for Space Standards and Innovation<o:p></o:p></p>
<p class="MsoNormal">Analytical Graphics Incorporated<o:p></o:p></p>
<p class="MsoNormal">Voice: 719-482-4552; E-mail: <a href="mailto:oltrogge@agi.com">
oltrogge@agi.com</a><o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
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