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Re: Formula for calculating a position fix
From: Bela Kovacs
Date: 2025 Mar 28, 10:43 -0700
From: Bela Kovacs
Date: 2025 Mar 28, 10:43 -0700
Hello Huub,
I have attached some pages from the book "John Karl: Celestial Navigation in the GPS Age". Also available on Kinde.
You can see that you can calculate the intersection of two position circles using only the Hc/Az formulas. (and using the trigonometric identities cos(90-x)=sin(x) and sin(90-x)=cos(x).) The first line is the sin(Hc) formula. If the distance between the two celestial bodies is greater than 90°, we get a negative value. But it doesn't matter because the cosine of this value is used in the next two formulas, etc.
Once the Hc/Az formula is programmed, the (two possible) positions can be calculated with a few lines of code.
Bela
File:
