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Joe, The easy part is telling whether the target is approaching or
departing. The hard part is getting a converging solution as to which
side of the lobe the target is on. By remaining motionless you will not
be able to do this. Using Target Motion Analysis (TMA), it is possible to
determine which side of the lobe the target is on over a ten minute period if
the target maintains a constant heading. To complete TMA and arrive at a
solution (with a range), you have to run a straight course while taking
bearings (and plotting the azimuths) to the target and then alter your course
again plotting bearings to the target. If you have a solid sound contact,
the solution should become evident. I don’t picture this being done
in a K-350 sized submersible. None of this holds true for sailboats
or other slow moving electric boats…insufficient sound signature. Aboard today’s modern subs with conformal sonar arrays
down their sides, a long towed array, and fast computers the solution is
rapidly arrived at without having to run much of a course and no heading
changes. R/Jay Respectfully, Jay K. Jeffries Andros Is., Bahamas A skimmer afloat is but a submarine, so poorly built it will not
plunge. From:
owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org]
On Behalf Of Joseph Perkel Jay, Interesting,...explains what I see mounted on the old fleet boats with that
funny shaped array. In that scenario regarding the lobes, if I understand you correctly, the
problematic determination of direction is for a sound source that is
maintaining a fixed bearing, is this correct??...which would be bad news if
it's getting louder! So if you have a prop sound that is in fact changing bearings, could you
reasonably determine if it were P or S, converging or not? Joe
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