NavList:

   

Reply

Well the least squares point (MPP) of two lines is where they cross.

But the elliptical probability contour is still defined, and the
ellipse is not a circle if the LOPs do  not meet at 90 degrees
See for example
Stansfield, R. G. "Statistical theory of DF fixing." Journal of the
Institution of Electrical Engineers-Part IIIA: Radiocommunication
94.15 (1947): 762-770.
which includes the case n=2 lines
Bill Lionheart
On Tue, 6 Nov 2018 at 03:03, Gary LaPook  wrote:
>
> I made the sugestion several times in the past that the way to avoid all the 
discussion and desention about finding the proper point to represent the 
"fix" in a three-star "cocked hat" was simply to only observe two stars. It 
appears that this is the method used by the Air Force in its automated 
star-tracker systems, only using two stars at a time. And it acheives better 
than a 1,000 foot CEP. This means that 50% of the fixes will be within 1,000 
feet, 93,7% will be within 2,000 feet, and only 0.2% will fall outside of 
3,000 feet. The automatic star tracker is sugested for surface Navy ships 
but, for surface navigation, the same old problem of clouds raises its ugly 
head. At 25,000 feet the probability of a clear line of sight anywhere on 
earth and at any time is 68% and becomes 100% at higher altitudes. Would it 
were it this good on the surface!
>
>  http://www.dtic.mil/dtic/tr/fulltext/u2/a090649.pdf
>
> 
https://www.sr-71.org/blackbird/manual/4/4-161.php?fbclid=IwAR0NWtsAhGXlRyghSFgK-8BPpS7oA5Z_pUWjwLSCxlDV4B7sepDLvIfQUoE
>
> 
https://www.maritime-executive.com/blog/automated-celestial-navigation-for-the-navy?fbclid=IwAR32JyfjX4GJHYsr8KvQg-AdWaLJEpSK-md8BQr1_N59bhPU39ggetNMar0
>
> gl
>
> 

   

Reply