A system for determining a configuration and a position of an instrument, comprising: an instrument having a distal end and a proximal end and an inflatable shape-changing portion between the distal end and the proximal end; wherein the inflatable shape-changing portion is configured to change from a first configuration to a second configuration; at least one flexible coil positioned adjacent to or on the surface of the inflatable shape-changing portion and configured to change configuration with the inflatable shape-changing portion; a distal tracking device integral to said distal end and a proximal tracking device integral to said proximal end; a tracking system configured to track said distal tracking device and said proximal tracking device and said at least one flexible coil; wherein the tracking system comprises a localizer configured to generate an electromagnetic field; wherein the at least one flexible coil is configured to sense the electromagnetic field from the localizer or generate an electromagnetic field to be sensed by the localizer; and wherein said distal tracking device and said proximal tracking device are configured to sense the electromagnetic field generated with the localizer or generate an electromagnetic field to be sensed by the localizer; a tracking processor configured to execute instructions to determine: - a position of the instrument based on a first signal generated upon fields emitted by the distal tracking device and proximal tracking device and sensed by the localizer or emitted by the localizer and sensed by the distal tracking device and proximal tracking device, and - a configuration of the instrument according to a configuration of the at least one flexible coil as determined based on a second signal generated upon a field sensed by the localizer and emitted by the at least one flexible coil, or emitted by the localizer and sensed by the at least one flexible coil. an instrument having a distal end and a proximal end and an inflatable shape-changing portion between the distal end and the proximal end; wherein the inflatable shape-changing portion is configured to change from a first configuration to a second configuration; at least one flexible coil positioned adjacent to or on the surface of the inflatable shape-changing portion and configured to change configuration with the inflatable shape-changing portion; a distal tracking device integral to said distal end and a proximal tracking device integral to said proximal end; a tracking system configured to track said distal tracking device and said proximal tracking device and said at least one flexible coil; wherein the tracking system comprises a localizer configured to generate an electromagnetic field; wherein the at least one flexible coil is configured to sense the electromagnetic field from the localizer or generate an electromagnetic field to be sensed by the localizer; and wherein said distal tracking device and said proximal tracking device are configured to sense the electromagnetic field generated with the localizer or generate an electromagnetic field to be sensed by the localizer; a tracking processor configured to execute instructions to determine: - a position of the instrument based on a first signal generated upon fields emitted by the distal tracking device and proximal tracking device and sensed by the localizer or emitted by the localizer and sensed by the distal tracking device and proximal tracking device, and - a configuration of the instrument according to a configuration of the at least one flexible coil as determined based on a second signal generated upon a field sensed by the localizer and emitted by the at least one flexible coil, or emitted by the localizer and sensed by the at least one flexible coil. - a position of the instrument based on a first signal generated upon fields emitted by the distal tracking device and proximal tracking device and sensed by the localizer or emitted by the localizer and sensed by the distal tracking device and proximal tracking device, and - a configuration of the instrument according to a configuration of the at least one flexible coil as determined based on a second signal generated upon a field sensed by the localizer and emitted by the at least one flexible coil, or emitted by the localizer and sensed by the at least one flexible coil.