Resolution Of Measurement

In addition to conductivity accuracy, spatial resolution must be finer than the features of interest. The functions of depth sensitivity for the HCP and PRP arrays indicate the depth resolution of an LIN instrument. For depth expressed in terms of p, the cumulative depth sensitivity of the HCP array is

FIGURE 21.2 The 1 m horizontal coplanar/perpendicular (HCP/PRP) depth sensitivities.

FIGURE 21.2 The 1 m horizontal coplanar/perpendicular (HCP/PRP) depth sensitivities.

and the cumulative depth sensitivity of the PRP array is

Figure 21.2 graphs these functions for arrays with p of 1 m.

Note that there is an appreciable difference in the functions. For example, about half the sensitivity of the PRP array accumulates within a depth of about 0.3 m, and half the sensitivity of the HCP array accumulates within a depth of about 0.9 m. As these depths are similar to the depths of golf-course features, an H/P-1 at ground level appears to be suitable for mapping such features. The difference in cumulative sensitivity is the basis for resolving changes in conductivity with depth, as the 1 m PRP array is relatively sensitive to material to a depth of about 0.5 m, and the 1 m HCP array is relatively sensitive to material between the depths of about 0.3 and 1.5 m.

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