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Re: Submarine celestial through periscope
From: Andrés Ruiz
Date: 2023 Mar 8, 11:10 +0100

A sense of the goodness of the distribution of the sigths is given by the EoC, Ellipse of Confidence, and by the Azimuth Factor

/*
THE ACCURACY OF CELESTIAL FIXES AS COMPARED TO NAVSAT POSITIONS BY LEAST SQUARES ADJUSTMENT
H. F. Van Der Grinten
NAVIGATION, Journal of The Institute of Navigation
Vol. 22, No. 2, Summer 1975
pp. 128-134.
*/

public double AzimuthFactor(double[] z)
{
// Observations perfectly balanced 0 <= fabs <= 1 Observations totally imbalanced
    int n = z.Length;

    double sZn = 0;
    double cZn = 0;

    for (int i = 0; i < n; i++)
    {
        sZn += SIN(z[i]);

cZn += COS(z[i]);

  }
    double f = sqrt(SQ(sZn) + SQ(cZn)) / (double)(n);

    return (f);
}

Re: Submarine celestial through periscope
From: David Pike
Date: 2023 Mar 7, 13:03 -0800
Andrés
Please explain what you mean by ‘azimuth factor’ in this context. Also, are you suggesting that if you work in three dimensions rather than two, fixes are still practical even if the differences in plan-view azimuth between stars is less than 30 degrees (the RAF limit). DaveP

3D, 2D, ..., Sorry Dave, I don't understand what you mean

Andrés Ruiz
Navigational Algorithms
http://sites.google.com/site/navigationalalgorithms/

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