NavList:

I am at a fixed point on the Earth. I shoot the Sun's altitude in the morning when it bears exactly due east. I shoot the Sun's altitude again at noon when it is due south. From those two sights, I get two LOPs which cross at 90 degrees at some point P. After sunset, I shoot the altitude of some star at azimuth z and, when I clear the sight, its LOP falls at a distance d from that earlier two-body fix P (d is the perpendicular distance from the LOP to P). Got it? Two LOPs crossing at right angles, another LOP dropped in at some distance at an arbitrary azimuth. So... where is the three-body fix (under the assumption that we are looking for a "least squares" best fix)? In particular, how far is the fix from point P?

I'm sure some of you will think this one is entirely obvious. But it may not be to everybody. Try drawing out the "cocked hat" for various orientations of the third LOP.

-FER

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