NavList:

I tend to concur with JK that the issue is something to be taken with an open mind against the traditional concept of rFixes.
I have JK book "Celestial Navigation in GPS age" (pretty good one) and the subject is discussed between page 135 and 138. At the celestial navigation school I always been told that rFixes are as good as your DR is and to rely on them only till the next availability of proper sights; that is sometimes our DR accuracy can be better than our LOP accuracy. I have been told and retold to carefully register and cross check the data of DR in order to have always a good idea of my accuracy; it might well be that after a two days of overcast (extreme situation where I have to advance an LOP for 24 hrs or more), I discover that my rFix is less dependable than my DR position.
It doesn't take a PHD to understand that before taking a rFix as the absolute and uncontested position some thoughts are required even though it might be the only available information.
What JK is saying in his book is that because you have a rFix you cannot simply drop the DR information but you have to consider all the available data which includes a careful record of DR accuracy.
Paolo
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