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    Re: 3 sights SR example
    From: Andrés Ruiz
    Date: 2017 Jun 28, 10:34 +0200
    In the summer of 2014, while sailing in the Mediterranean Sea, anchored off the Formentera coast, I took to sights with the plastic Mark 15 sextant that the charter sloop had onboard, (depending on the navigation area is mandatory in the EU to have one as a safety equipment). I plotted the two LoPs on the nautical chart, and.... the crossing was far from the GPS fix. I checked the index error, too hot nearly 40ºC, and great humidity. I suspected that a systematic error was took place.

    And Leafing through Bowditch 2017 edition, page 302 reminded me this situation.

    So, I took an example from a book, and did the inverse calculating; the true altitudes from the position, and then, I introduced a systematic error in altitudes.

    With this clue, ¿what is the fix?

    With this example I want to show that the most robust methods have their weaknesses.

    Andrés Ruiz
    Navigational Algorithms
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