A system to detect and correct for magnetic distortion in a magnetic field for localizing a medical device positioned within the magnetic field, the system comprising: a magnetic field emitter including one or more emitter coils at known positions and orientations within the system, each of the emitter coils configured and arranged to emit a magnetic field; one or more sensor coils, each of the sensor coils configured and arranged to sense the magnetic field, and output a first electrical signal indicative of the sensed magnetic field at the medical device; an array of magnetic distortion sensors (111a-d) at known positions and orientations within the system, each of the magnetic distortion sensors (111a-d) in the array configured and arranged to sense the magnetic field, and output a second electrical signal indicative of the sensed magnetic field at the magnetic distortion sensor (111a-d); and processor circuitry communicatively coupled to each of the magnetic distortion sensors (111a-d) and the sensor coils, and configured and arranged to receive the first and second electrical signals, and determine a magnetic distortion corrected position of the medical device within the system based on the first and second electrical signals, and the known position and orientation of the magnetic distortion sensor (111a-d), wherein the processor circuitry is further configured and arranged to determine the magnetic distortion corrected position of the medical device, characterized by determining perceived locations of each of the magnetic distortion sensors (111a-d) in the array based on the sensed magnetic field at each magnetic distortion sensor (111a-d), determining a localized error between the perceived location and the known position of each of the magnetic distortion sensors, calculating a transform, based on the localized error determinations, that converts the perceived locations to the known locations for each of the magnetic distortion sensors, and using the calculated transform, determine the corrected position of the medical device within the system that compensates for the magnetic distortion. a magnetic field emitter including one or more emitter coils at known positions and orientations within the system, each of the emitter coils configured and arranged to emit a magnetic field; one or more sensor coils, each of the sensor coils configured and arranged to sense the magnetic field, and output a first electrical signal indicative of the sensed magnetic field at the medical device; an array of magnetic distortion sensors (111a-d) at known positions and orientations within the system, each of the magnetic distortion sensors (111a-d) in the array configured and arranged to sense the magnetic field, and output a second electrical signal indicative of the sensed magnetic field at the magnetic distortion sensor (111a-d); and processor circuitry communicatively coupled to each of the magnetic distortion sensors (111a-d) and the sensor coils, and configured and arranged to receive the first and second electrical signals, and determine a magnetic distortion corrected position of the medical device within the system based on the first and second electrical signals, and the known position and orientation of the magnetic distortion sensor (111a-d), wherein the processor circuitry is further configured and arranged to determine the magnetic distortion corrected position of the medical device, characterized by determining perceived locations of each of the magnetic distortion sensors (111a-d) in the array based on the sensed magnetic field at each magnetic distortion sensor (111a-d), determining a localized error between the perceived location and the known position of each of the magnetic distortion sensors, calculating a transform, based on the localized error determinations, that converts the perceived locations to the known locations for each of the magnetic distortion sensors, and using the calculated transform, determine the corrected position of the medical device within the system that compensates for the magnetic distortion.