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    Re: Do We Still Need to Use Sextants?
    From: Frank Reed
    Date: 2013 Mar 27, 11:34 -0700

    Hello Şems Aktuğ,

    I see that you are listed as an instructor in a course called "Celestial Navigation II" at Piri Reis University which is, as I understand it, a relatively young maritime academy in Istanbul. Welcome aboard.

    Tell me, if we get rid of sextants, will they have to update the logo for the university? There are two stylized sextants there! I am attaching a copy for other NavList readers. :)

    The idea that you have of using MEMS sensors to determine orientation and replace sextant functionality is certainly possible, and there are systems that do this already to some limited extent, but what is the angular accuracy of off-the-shelf MEMS sensors today? Hundreds of millions of smartphones include such sensors which can be used for a sort of celestial navigation with an accuracy of a degree or so in altitudes. That's not good enough for live navigation, but it's wonderful for star identification, and it certainly makes any other method of star finding look downright medieval. Could we ever do celestial navigation with such systems and actually replace a sextant? If we can get minute of arc accuracy, that might start to get interesting. With any system like this, the big problem is keeping the vertical reliably. This is possible, but it's relatively complicated. And then there's always the issue of fitting the product to a real market. Who needs it? If we like electronics, there's GPS. If we want a non-electronic backup, then this wouldn't fill that role. There are some military applications where there's an assumption that they might have to operate under war conditions where GPS is being actively, severely jammed (and there are strong rumors of systems just like you describe already in the field, but they are very high-tech and presumably quite expensive). Are there commercial customers who would worry about such wartime conditions, and what would they pay for such a system?

    -FER

    PS: Clearly you did receive your NavList posting code by email since your message was sent from the NavList message boards, but just so you know, your mail server sent us a message saying that the email with your posting code bounced. Here's part of the message ('at' sign in actual email address masked but was originally present):
    "did not reach the following recipient(s): saktug*pirireis.edu.tr on Wed Mar 27 09:02:14 2013
    The e-mail account does not exist at the organization this message
    was sent to. Check the e-mail address, or contact the recipient
    directly to find out the correct address."
    You should contact your email IT staff and find out why this error message is being generated.


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