A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding
From: Andrés Ruiz
Date: 2012 Oct 3, 08:32 +0200
t is used for running fix.
See at my website in the "papers" section the article: Celestial Fix - n LoPs NA Sight Reduction algorithm. Paper & Excel
Also in NavList archive there are a lot of information about this method, originally: by DeWit.
Optimal Estimation of a Multi-Star Fix, C. De Wit. NAVIGATION, Vol.21 , No. 4, Winter 1974-75, pp 320-325.