NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Still on LOP's
From: Jared Sherman
Date: 2002 May 1, 13:36 -0400
From: Jared Sherman
Date: 2002 May 1, 13:36 -0400
Dov-I would argue that the problem, as stated, is both solved and trivial. Given the absence of specific measurements and data, one can only assume the gun can be fired freely in all positions throughout a spherical space. Since the target, even a target of infinite size, can only intercept the shots fired "toward" it, and bullets have a finite limited travel distance, the size of the circle containing all bullet holes on the target is limited to the smaller of two cases: One being a circle that contains the entire target, if the bullets ARE capable of being fired beyond the target's boundaries. The other being a circle equal in size to the range of the bullets, i.e. if the bullets can reach the target 3 miles from dead center (but fall to ground and stop traveling at + miles) then the size of the circle is limited to the area the bullets can reach. The only question left is the mathematically trivial one of whether the target chosen will be smaller than the range the bullets can reach. That is really not a math problem but more in line [pun intended] with topology. The sextant/cocked hat/LOP problem really devolves down to more complex questions as to what the multiple error factors are and might be, and probably is equally trivial aside from the number crunching and research needed to determine the error factors and quantify them. Theories are all well and fine, but theories as to errors are often put to the lie by simple field experiments. Someone needs to go out, fudge up their readings to accomodate the entire range of potential bumbling errors, and then see how that affects the plot versus the real location. And I'm betting that the most reliable answer will still be "The center of the cocked hat, overlaid with a suitable circle of uncertainty". Most of the navigational skill lies not in plotting the cocked hat, but in accurately sizing the circle of error.