The first technique estimates a set of values for the magnetic intensity at each flight-line/tie-line intersection point. These are obtained after an intersection-moving procedure to reduce loop closures and are subject to the constraint that the datums calculated from the differences between the raw data and the corrected data have minimum along-line variation. This least-squares method is equivalent to the older manual loop closure methods used for magnetic, gravimetric, and geodetic surveying. The second method involves the fitting of polynomials to the observed flight-line/tie-line intersection errors along each line in the survey. These are then subtracted from the raw data and intersection locations are adjusted to give minimum intersection errors. The least-squares method was found to be superior as a leveling procedure. It produced datums which were similar in amplitude and had a high correlation with the base station magnetometer recordings. The polynomial method produced datums which had greater amplitudes and showed a tendency to fluctuate at the ends of lines.--Modified journal abstract.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.