A system for determining a location of a structure within a patients vasculature includes three or more pads adhered to the patients torso in a predetermined pad pattern. Each pad generates a pad electrical signal. A stylet has longitudinally spaced proximal and distal stylet ends, with at least one stylet electrode located proximate the distal stylet end. The stylet electrode receives the pad electrical signals and responsively generates a stylet electrical signal. A signal processor is operatively coupled for signal exchange with the stylet and to each of the pads via a selective electrical coupling. The signal processor compares the stylet electrical signal and at least two pad electrical signals to triangulate a position of the stylet electrode relative to each of the pads and responsively produce a triangulated position. The triangulated position is indicative of a position of the stylet electrode within the patients vasculature.