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I'm new to CN, but isn't the only reason that we try to keep the AP within
30 NM of the intercept for convenience in plotting?  In theory we don't even
need an AP: with the right tools (electronic would be the only practical
way) we just need the GP of the Body, Azimuth to the GP, and co-altitude
(distance to the LOP from the GP).  In that special case, the intercept is
the co-altitude, which of course tends to be many hundreds or even thousands
of miles away from where we are on the celestial LOP.  All a computer would
have to do is produce data that we need to plot a short segment of the LOP
and the intercept on a large-scale plotting sheet; specificaly a reference
point on the plotting sheet, a bearing line to draw toward or away from that
point, and the distance from that point to the LOP along the bearing line.

I know -- that "reference point" is the same concept as an AP.  But is there
any other reason why we need to select an AP relatively close to our real
position?

Jim Thompson
jim2@jimthompson.net
www.jimthompson.net
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-----------------------------------------

> -----Original Message-----
> From: Navigation Mailing List
> [mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM]On Behalf Of Aubrey
> O'Callaghan
>
> I then placed my initial position nowhere near where I was. After about 3
> iterations it converged to my actual position. I was quite surprised as I
> had thought that one's initial guess should be approximately where one is
> (at least within a few degrees).

   

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