Similarities between magnetic & North-Finding survey tools
In this technical article written for Coring Magazine, Duncan McLeod and Dag Billger from Inertial Sensing explore the surprising mathematical similarities between magnetic multishot tools and gyroscopic north-finders.
Although the systems rely on fundamentally different physical principles — Earth’s magnetic field vs. Earth’s rotation — the authors demonstrate that the equations behind azimuth calculation are nearly identical. This also means that several limitations traditionally associated with magnetic tools also apply to gyroscopic north-finders.
The article provides a clear breakdown of the three essential measurements needed for accurate borehole surveying and highlights why azimuth determination remains the most challenging aspect of survey science.