A phantom to determine navigational error in a surgical navigation system that tracks the location of an elongate tool having a tip and a shaft based on a plurality of fiducials attached to the elongate tool. The phantom includes a base portion that models a lower portion of a mammalian head and having a top surface with a plurality of touch points, each of the touch points being a respective indentation, and a frame detachably securable to the base portion and having an upper portion spaced apart from the top surface, the upper portion having defined therein a plurality of apertures. A tip of the elongate tool is to be inserted through said one of the apertures and in one of the touch points, and the surgical navigation system determines positional and angular error.