The position-circle transfer in the celestial sight-run-sight case

Abstract

Reviewed are the theoretical assumptions underlying two transfer techniques known from celestial navigation. The objective of both techniques is to correctly transfer the GP of an earlier sight for the run. One is the running fix technique (RFT) known from coastal navigation and applied to celestial configurations, here called celestial RFT. An application of celestial RFT is the iterative least-squares (LSQ) program, which incorporates celestial RFT and is then denoted as LSQ*. The other transfer technique, called GD-UT, refers to the transfer of the position circle of an earlier sight by transferring its GP for the run data. With GD-UT, the motion of the observer relative to the GP of the original sight only depends on the run data and is therefore divorced from the assumed initial and final coordinates of the run. It is this latter assumed position, which in applying celestial RFT introduces various anomalies in respect of the properties of the transferred position circle. Only in ‘limiting’ configurations such as the presence of small Zd will the position solution with RFT converge on the one obtainable with GD-UT.