Determining Target Depth by Triangulation

The receiver can be used for the traditional triangulation method to determine the approximate depthof a target as illustrated in the above figure. However, when using this method it is necessary to take into account the fact that the center of the cable-sensor is located 11 inches up the receiver tube from the black tip. When the position of the target has been determined by the null, mark the spot (#1) on the ground. Hold the receiver tip on the ground at this spot, slant the instrument at a 45-degree angle and slowly move directly back, to one side, from the target until a second null is obtained.

Now mark a spot (#2) on the ground that is directly below a point 11 inches up the receiver tube from the black tip. Measure the distance between spot #1 and spot #2. This measurement indicates the approximate depth of the target.

NOTE: You should always take a depth reading on both side of the line. IF the measured distances between #1 and #2 on both sides of the line are not the same, there is a good chance that a nearby line is causing the two measurements to be different. Move further along the line and repeat the depth reading procedure until the measurements are the same on both sides of the line.