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    Re: Navigation without dead reckoning
    From: Gary LaPook
    Date: 2007 Dec 23, 13:54 -0800
    Gary LaPook writes:

    You can pick any spot on earth as the initial assumed position and calculate a fix from there. Then using that first fix as a new AP calculate a second fix. Repeat the process one or maybe two more time and you have your accurate fix. If you have three LOPs you get a unique fix. If you only have two LOP you will get two fixes which are usually far enough apart so there is no ambiguity as to which one is the correct one.

    Thomas Kleemann wrote:
    Sara and Dan schrieb:
      
    I am new to this navlist and any help would be appreciated.
    
        
    Welcome at NavList.
      
    My problem is that since I am not traveling in a straight line at a
    constant speed it is not possable to calculate a
    dead reckoning point.
    
        
    
    St Hillaire is an iterative algorithm.
    So if you use any coordinates at just the right hemisphere you will get
    a fix nearer to your true position. Using this as your corrected D.R.
    and computing another iteration gives you again a better fix.
    
      
    My thought is that there ought to be a way to get accurate enough
    coorinates by taking several noon sightings of the sun, graphing them
    and picking the highest point and using this time as local apparent noon
    to get longitude and using
    the observed altitude to get latitude.  If  I take these coordinates and
    use them as my dead reckoning position for later
    readings I think that this would yeald fairly accurate results.
    
        
    You are right here.
    Even tough it is not possible to get the exact time of the culmination
    by observation, it will provide you with coordinates accurate enough for
    a fairly precise D.R.
    
    Merry Chrismas,
        Thomas.
    
    
    
    
    
      


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