A system for tracking the position of an instrument relative to an area of interest includes a first fixator configured to carry first and second localizing devices. A second fixator is configured to carry the first localizing device. A third localizing device communicates with the first localizing device and the second localizing device communicates with the first localizing device such that the position of the second localizing device can be determined relative to the position of the third localizing device. The second localizing device is attachable to the instrument and the first localizing device is attachable to the first fixator such that the first localizing device communicates with the second localizing device on the instrument in order that the position of the second localizing device on the instrument can be determined relative to the third localizing device.