A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Linear regression and other tools
From: Brad Morris
Date: 2018 Oct 10, 15:48 -0400
When the era of common CN ended, along came the birth of the electronic calculator. Computers were giant stationary mainframes at the time. While regression can obviously be used in CN now, I do not believe it was generally used then. The computational tools simply didn't exist for the mariner or aviator.
There may be other reasons, of course. For example, personal error, abnormal refraction and horizon error all will contribute to uncertainty in CN. Some errors will be constructive, others destructive. With multiple sources of error, using linear regression may be unsatisfactory as this best fits a line to one error term.
But, for example, if you hold all other variables as perfect, you can indeed utilize your data to determine the dip.
Elsewhere I was pointed to an on-line calculator that provides the regression/approximation functionality. One enters his data values, for example times of sights and their relevant HCs - then the approximating function is being searched for (automagically).
Having obtained such function the navigator can determine perfectly simultaneous HCs for the direct fix calculation SR.
Now I try to do this on a TI-83+ for off-line usage.
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