#$%^&*AU2018282479A120190718.pdf#####ABSTRACT An apparatus includes a memory and a processor. The memory is configured to hold values indicative of known relative positions of multiple position sensors of a 5 position tracking system that are coupled to a medical device. The processor is configured to receive one or more signals indicative of estimated positions of the position sensors, as measured by the position tracking system, and to initiate a responsive action in response to detecting a 10 discrepancy between the known relative positions and the estimated positions.1/3 Q)' 04 0)0
