When a sub-section of a predefined path temporarily cannot be traversed by an autonomous mobile unit, an extended path is found for subsequently traversing the temporarily blocked sub-section. The SAP can be applied on many levels of circuit components including transistor devices, logic gate devices, and System-on-Chip or chip designs. In one embodiment, a first multiplicand is determined by multiplying a first display time difference between a first video picture and a second video picture by a power of two scale value. A severity of the at least one drilling hazard is estimated.