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From: Alexandre Eremenko (no email)
Date: Sat Nov 06 2004 - 22:34:13 EST
Dear Chuck,
On your resume I have few little comments.
1. In all this long discussion on Averaging,
I never discussed the situation you describe
(except the very last message yesterday).
I was always talking of ONE body.
And my point was shortly speaking that you can
improve the precision and reliablity of ONE
position line obtained from ONE body.
2. On my opinion, the "fix" that is a pair of numbers
(your latitude
and longitude) is not the "ultimate goal" of Cel Nav.
On my opinion, the ultimate goal is to know where you are.
The information on your position that you can obtain
from your observations is NOT reduced to
these two
numbers. Any observations give you really a "spot" not a "point"
a spot where you probably are. The size and shape of this spot
are also RELEVANT.
3. What I would do with your data is this. I would average
each star observation. Obtain 3 position lines.
Draw them on the map (ALL three of them!) and write with a pencil
on each line from how many observations was it obtained.
(A line obtained from the average of several observations
is nore reliable than a line obtained from one observation).
For example, there could be a potential danger (a reef)
on the West from my DR position. Then I will take every
oppotrunity to observe a body whose azymuth is roughly West,
or East, to obtain a position line in the N-S direction.
4. Notice: I do not object the algorithm Herbert promotes.
Though it seems suitable only for computer navigation,
apparently he does not propose to do it by hands:-)
But the fact that his algorithm is feasible in some
circumetsnces for computer navigation does not
justify his sweeping statements that "averaging is the thing
of the past" that "aweraging is always wrong" etc.
It is only these strange statements that I strongly
object.
I call them "strange" because I have never heard or read anything
like this before (though I read much on the subject),
and I could not imagine a person familiar with the subject
making such statements.
A
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