Systems and associated methods for tracking and/or guiding an underground boring tool are disclosed. Each system or arrangement uses one or more detectors to measure the intensity of an electromagnetic field which is transmitted from an underground boring tool. The measured intensities may then be used to determine the location of the boring tool. In a dead reckoning embodiment of the invention, one detector may be employed while, in a position determination embodiment, two or more detectors may be employed. In any embodiment, physically measurable parameters may be used in addition to measured magnetic intensities. A highly advantageous mapping tool instrument and a cubic antenna are disclosed. The former for use in the position determination embodiment and the latter for use in any magnetic field detector employed herein. A highly advantageous apparatus and associated method for determining the movement of the boring tool underground by monitoring the motion of a drill string, which is attached to the boring tool and extends to a drill rig, are also disclosed wherein measurements are performed relating to movement of the drill string at the drill rig.