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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:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">(1)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>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:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">(2)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>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:1.0in;text-indent:-.25in;mso-list:l0 level2 lfo1">
<![if !supportLists]><span style="mso-list:Ignore">a.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>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:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">(3)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Multiple events can be declared within a global object.<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-indent:-.25in;mso-list:l0 level2 lfo1">
<![if !supportLists]><span style="mso-list:Ignore">a.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>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:1.0in;text-indent:-.25in;mso-list:l0 level2 lfo1">
<![if !supportLists]><span style="mso-list:Ignore">b.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>When absolute timing is used:<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">
</span>i.<span style="font:7.0pt "Times New Roman""> </span></span><![endif]>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:1.0in;text-indent:-.25in;mso-list:l0 level2 lfo1">
<![if !supportLists]><span style="mso-list:Ignore">c.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>When relative timing is used:<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">
</span>i.<span style="font:7.0pt "Times New Roman""> </span></span><![endif]>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:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">
</span>ii.<span style="font:7.0pt "Times New Roman""> </span></span><![endif]>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:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">
</span>iii.<span style="font:7.0pt "Times New Roman""> </span></span><![endif]>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:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">
</span>iv.<span style="font:7.0pt "Times New Roman""> </span></span><![endif]>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:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">
</span>v.<span style="font:7.0pt "Times New Roman""> </span></span><![endif]>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: oltrogge@agi.com<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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