A surgical system comprises a surgical instrument having distal and proximal portions. The surgical system also comprises a reference fixture positioned in a first reference frame and a shape sensor extending from the distal portion through the proximal portion to the reference fixture. The surgical system also comprises a processor configured to perform a registration step to register the first reference frame to a fixed world reference frame. The registration step includes receiving a set of shape information of the shape sensor with a distal point of the surgical instrument located at a patient reference point. A first portion of the shape sensor is in a known geometrical shape at a fixed location along a length of the shape sensor. The registration step also includes computing a location of the patient reference point and computing a pose of the first reference frame relative to the fixed world reference frame.