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At 18:54 21/04/02 -0500, you wrote:
>
>On Sun, 21 Apr 2002 11:30:34 +0100, Dr. Geoffrey Kolbe wrote:
>
>>
>>Since each of these scenarios is equally likely, the chances are one in
>>four that the cocked hat due to the intersection of the bearings taken from
>>three land marks will include your actual position.
>>
>This is the fallacy in the argument. It assumes that the bearing
>measurement contains no information. If you assume that the error in
>the bearing is equally likely to be anywhere away from the measured
>bearing, you have eliminated the reason for taking the bearing.

Rodney, I have made no assumptions regarding the actual error distribution.
For the purposes of my arguments it can be anything you like.

What I _have_ assumed is that the error in measuring the bearing on a
particular landmark is equally likely to be to one side of the landmark as
to the other. Do you have a problem with this?

There is only one angle of bearing for which this statement is true (an
error to either side is equally likely) and that is the true bearing. It is
this that gives the measurement of that bearing meaning.

Geoffrey Kolbe.


Border Barrels Ltd., Newcastleton, Roxburghshire, TD9 0SN, Scotland.
Tel. +44 (0)13873 76253 Fax. +44 (0)13873 76214.

   

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