An apparatus for determining the position of a wireless catheter probe being used during a surgical procedure. Magnetic fields are projected into an anatomical body to induce voltage signals in a sensing coil that are sufficient to describe the position of a wireless sensor/transmitter. The voltage signals are wirelessly re-transmitted by the sensor/transmitter as positional signals indicative of a current location of the sensor/transmitter in the anatomical body. In a preferred embodiment, the wireless catheter probe is self-powered using the induced voltage signals on a sensing coil. In another embodiment, induced voltage signals of a separate coil are used to power the device.