TRACKING DEVICE, SURGICAL INSTRUMENT COMPRISING SAME, AND SURGICAL NAVIGATION SYSTEM WITH THE SURGICAL INSTRUMENT

A tracking device for use in a surgical navigation system is disclosed. The device comprises an electromagnetic sensor configured to generate a sensor signal that depends on an external electromagnetic field. The device also comprises at least one line element electrically connected to the sensor, wherein the line element comprises a first line section, a second line section, and a third line section arranged between the first line section and the second line section. The device further comprises a strain relieve unit comprising a core, wherein the core comprises a longitudinal axis, an outer surface and at least one recess which extends in the outer surface circumferentially around the longitudinal axis, wherein the first line section extends into the strain relieve unit on a first side of the strain relieve unit, the second line section extends into the strain relieve unit on a second side of the strain relieve unit opposite the first side, and the third line section extends within the recess.