<DIV style="font-family:Arial, sans-serif; font-size:10pt;"><DIV>If you can get a compass far away from the sub with a pole of something you might be able to get a good reading. Also if there's enough light you could have a "sun compass" But you would need the ability to adjust it as the sun moves across the sky.</DIV><DIV> </DIV><DIV>Brian<BR><BR>--- personal_submersibles@psubs.org wrote:<BR><BR>From: via Personal_Submersibles <personal_submersibles@psubs.org><BR>To: personal_submersibles@psubs.org<BR>Subject: Re: [PSUBS-MAILIST] New Generation Inertial Sensors - Twice as Accurate<BR>Date: Thu, 23 Mar 2017 22:43:06 -0400<BR><BR>
</DIV><FONT color="#000000" face="Arial" size="2"><DIV>
</DIV><DIV><FONT size="3">Here's a link that gives quite a bit of information including
a reference to their Windows-based software. Once you open the link, the
more you scroll down the more you will see; it goes a long way! <A href="http://www.seismic.com.au/assets/pdf/SBG_Systems-Ellipse_Series_Brochure.pdf">http://www.seismic.com.au/assets/pdf/SBG_Systems-Ellipse_Series_Brochure.pdf</A></FONT></DIV>
<DIV><FONT size="3"></FONT> </DIV>
<DIV><FONT size="3">GPS is great as a starting point before you submerge and for
telling you where you are once you surface. Too bad radio signals don't
propagate so well under water. In the past we've discussed mounting a
GPS antenna on a Diver Below buoy with a cable running to the sub. I don't
recall what was said regarding theoretical depth limitations for such a setup as
well as the hydrodynamics of towing it.</FONT></DIV>
<DIV><FONT size="3"></FONT> </DIV>
<DIV><FONT size="3">It would be really interesting to see how well your INS
position matches up with your GPS when you resurface. I like the idea of
knowing just where you are with reasonable precision when submerged, being able
to return to a precise location on another day, being able to search or survey
methodically, navigating from A to B to C, etc.</FONT></DIV>
<DIV><FONT size="3"></FONT> </DIV>
<DIV><FONT size="3">Jim T.</FONT></DIV>
<DIV> </DIV>
<DIV>
<DIV>In a message dated 3/23/2017 7:55:50 P.M. Central Daylight Time,
personal_submersibles@psubs.org writes:</DIV>
<BLOCKQUOTE style="padding-left: 5px; margin-left: 5px; border-left-color: blue; border-left-width: 2px; border-left-style: solid;"><FONT color="#000000" face="Arial" size="2" style="background-color: transparent;">
<DIV>On 3/23/2017 6:40 PM, Brian Cox via
Personal_Submersibles wrote:<BR></DIV>
<BLOCKQUOTE>
<DIV style="font-family: Arial, sans-serif; font-size: 10pt;">
<DIV>There needs to be an underwater GPS
!!</DIV></DIV></BLOCKQUOTE><BR>I remember a discussion, long ago, about a GPS
antenna on a mast. I don't recall any
resolution.<BR><BR><BR>Mike<BR><BR>
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