<span style=" font-size:10pt;font-family:sans-serif">Hi Erik,</span>
<br><span style=" font-size:10pt;font-family:sans-serif">
In principle I have no problem
adding altitude, but perhaps as an optional parameter as altitude may not
make sense in all cases, e.g. smaller celestial bodies ?</span>
<br>
<br><span style=" font-size:10pt;font-family:sans-serif">Cheers for now,</span>
<br>
<br><span style=" font-size:10pt;font-family:sans-serif">Colin</span>
<br><span style=" font-size:10pt;font-family:sans-serif"><br>
<br>
---------------------------------------------------------------------------------------------------------<br>
Dr. Colin R. Haddow,<br>
HSO-GI, European Space Agency,<br>
European Space Operations Centre,<br>
Robert-Bosch-Str 5,<br>
64293 Darmstadt,<br>
Germany.<br>
<br>
Phone; +49 6151 90 2896<br>
Fax; +49 6151 90 3010<br>
E-Mail; colin.haddow@esa.int<br>
---------------------------------------------------------------------------------------------------------<br>
</span>
<br>
<br>
<br>
<br><span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">From:
</span><span style=" font-size:9pt;font-family:sans-serif">"Barkley,
Erik J (3970)" <Erik.J.Barkley@jpl.nasa.gov></span>
<br><span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">To:
</span><span style=" font-size:9pt;font-family:sans-serif">"Colin.Haddow@esa.int"
<Colin.Haddow@esa.int>, "Anthony Crowson (anthony.crowson@telespazio-vega.de)"
<anthony.crowson@telespazio-vega.de></span>
<br><span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Cc:
</span><span style=" font-size:9pt;font-family:sans-serif">"Bui,
Tung (397G)" <Tung.Bui@jpl.nasa.gov>, CCSDS Service Mgmt WG
<smwg@mailman.ccsds.org></span>
<br><span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Date:
</span><span style=" font-size:9pt;font-family:sans-serif">06/10/2018
03:27</span>
<br><span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Subject:
</span><span style=" font-size:9pt;font-family:sans-serif">PIF
question -- off earth aperture coordinates</span>
<br>
<hr noshade>
<br>
<br>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Georgia">Colin,
Anthony,</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Georgia"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Georgia"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Georgia">As
you may recall, the PIF has an accommodation for specifying the coordinates
for apertures on celestial bodies other than earth. You may also
recall that we (NASA/JPL) are supporting one of the prototypes for the
PIF exchange. In working through this, we have found out that indeed the
Mars relative Lat/Long coordinates are used for determining the communication
geometry for the overflight orbiters. But the PIF appears to be a
tad bit deficient in that it only specifies Lat/Long whereas the current
local implementation used in coordinating all of this also supplies altitude
as part of the coordinate information. Given that Mars definitely has variations
in local terrain altitude, I think this is in fact important to include
in the PIF. In fact in poking around with the internal services I made
a query that returned location information indicating over 3,300 m in elevation
-- I suspect that if we are to be accurate etc. this has some bearing on
the communication geometry in terms of properly reporting range and/or
light time. However, somewhat interesting to me is that the altitude is
from the center of the planet. It seems a bit odd but it also makes
sense in that there really is no definition of “sea level” for Mars.
So my suggestion is to add an altitude parameter as indicated below.
Perhaps we can further discuss this at the Berlin meetings.</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Georgia"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Georgia">Best
regards,</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Georgia">-Erik
</span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Georgia"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><span style=" font-size:12pt;font-family:Georgia"> </span></p>
<p style="margin-top:0px;margin-Bottom:0px"><img src=cid:_2_129CC6EC129CC2DC00332EE1C1258321 style="border:0px solid;"></p>
<p style="margin-top:0px;margin-Bottom:0px"></p>
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