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Re: Are we most likely not where we are?
From: Rodney Myrvaagnes
Date: 2002 Apr 15, 10:45 -0500
From: Rodney Myrvaagnes
Date: 2002 Apr 15, 10:45 -0500
For the very concept of MPP to make sense, it seems to me necessary to treat unknown errors as random. There is a concomitant necessity to eliminate systematic errors as far as possible. That is what is meant by measurement.
An incorrect value for height of eye could produce an effect of the kind Bill cites, but it would have to be really gross to get 5 miles off.
My sextant came with a graph of arc errors measured by the maker. I suppose they all do?? These are very small, and to get them big enough to be significant on a small boat would take a severe drop. It probably wouldn't even turn
On Mon, 15 Apr 2002 09:27:15 EDT, WSMurdoch@AOL.COM wrote:
--Original Message Text---
I am not so sure about that. think it may be true if the errors are random, but not if they are not. ??s say I have three bodies at 300, 000, and 060 degrees (the horizon is dirty to the south), and a sextant with an (unknown to me) 5 arcminute error. reduce my sights, get a nice small cocked hat and am actually 5 miles to the same side of all three LOPs. seems to me that my most probable position is outside the cocked hat. these are non-random errors, but those are the pretty normal (at least for me).
Rodney Myrvaagnes J36 Gjo/a
"Curse thee, thou quadrant. No longer will I guide my earthly way by thee." Capt. Ahab
An incorrect value for height of eye could produce an effect of the kind Bill cites, but it would have to be really gross to get 5 miles off.
My sextant came with a graph of arc errors measured by the maker. I suppose they all do?? These are very small, and to get them big enough to be significant on a small boat would take a severe drop. It probably wouldn't even turn
On Mon, 15 Apr 2002 09:27:15 EDT, WSMurdoch@AOL.COM wrote:
--Original Message Text---
I am not so sure about that. think it may be true if the errors are random, but not if they are not. ??s say I have three bodies at 300, 000, and 060 degrees (the horizon is dirty to the south), and a sextant with an (unknown to me) 5 arcminute error. reduce my sights, get a nice small cocked hat and am actually 5 miles to the same side of all three LOPs. seems to me that my most probable position is outside the cocked hat. these are non-random errors, but those are the pretty normal (at least for me).
Rodney Myrvaagnes J36 Gjo/a
"Curse thee, thou quadrant. No longer will I guide my earthly way by thee." Capt. Ahab
