Methods and systems for improved navigation

A system, comprising:

• at least one magnetoresistance sensor operatively coupled to a subject and configured to detect a magnetic field;
• and
• a processing subsystem operatively coupled to the subject via a cable and configured to:
• apply a bias signal having a desired bias frequency to shift a signal frequency of a response signal of the magnetoresistance sensor that includes common-mode noise;
• determine a useful portion of the response signal of the magnetoresistance sensor by measuring the response signal at a shifted frequency, the shifted frequency being a sum of the signal frequency and the bias frequency;
• and
• determine a position of the subject based on the useful portion of the response signal.

A method for navigation, comprising:

• measuring a first response signal received from at least one magnetic sensor in response to a magnetic field when the magnetic sensor has a reference sensitivity, wherein the magnetic sensor is operatively coupled to a target device;
• measuring a second response signal received from the magnetic sensor in response to the magnetic field when the magnetic sensor has a reversed sensitivity, wherein the reversed sensitivity is obtained by applying varying voltage configurations, frequency configurations, or a combination thereof to the magnetic sensor while an alignment of one or more magnetic domains corresponding to the magnetic sensor remains unchanged;
• determining a useful portion of the first response signal of the magnetic sensor by eliminating common-mode noise from the first response signal based on a difference between the first response signal and the second response signal;
• and
• determining a position of the target device based on the useful portion of the first response signal.

A method, comprising:

• shifting a signal frequency of a response signal that includes common-mode noise and is received from a magnetoresistance sensor in response to a magnetic field by applying a bias having a desired bias frequency, wherein the magnetoresistance sensor is operatively coupled to a subject and is configured to detect the magnetic field;
• determining a useful portion of the response signal by measuring the response signal at a shifted frequency, the shifted frequency being a sum of the signal frequency and the bias frequency;
• and
• determining a position of the subject based on the useful portion of the response signal.

A non-transitory computer readable medium that stores instructions executable by one or more processors to perform a method for surgical navigation, comprising:

• measuring a first response signal received from at least one magnetoresistance sensor in response to a magnetic field when the magnetoresistance sensor has a reference sensitivity, wherein the magnetoresistance sensor is operatively coupled to a target device;
• measuring a second response signal received from the magnetoresistance sensor in response to the magnetic field when the magnetoresistance sensor has a reversed sensitivity, wherein the reversed sensitivity is obtained by applying varying voltage configurations, frequency configurations, or a combination thereof to the magnetoresistance sensor while an alignment of one or more magnetic domains corresponding to the magnetoresistance sensor remains unchanged;
• determining a useful portion of the first response signal of the magnetoresistance sensor by eliminating common-mode noise from the first response signal based on a difference between the first response signal and the second response signal;
• and
• determining a position of the target device based on the useful portion of the first response signal.

A non-transitory computer readable medium that stores instructions executable by one or more processors to perform a method, comprising:

• shifting a signal frequency of a response signal that includes common-mode noise and is received from a magnetoresistance sensor in response to a magnetic field by applying a bias having a desired bias frequency, wherein the magnetoresistance sensor is operatively coupled to a subject and is configured to detect the magnetic field;
• determining a useful portion of the response signal by measuring the response signal at a shifted frequency, the shifted frequency being a sum of the signal frequency and the bias frequency;
• and
• determining a position of the subject based on the useful portion of the response signal.

A method, comprising:

• providing a magnetic sensor that is operatively coupled to a subject and is configured to measure a magnetic field;
• determining one or more magnetic field measurements corresponding to a desired position of the subject while operating the magnetic sensor in two or more different sensitivity settings, frequency configurations, or a combination thereof while an alignment of one or more magnetic domains corresponding to the magnetic sensor remains unchanged;
• determining one or more actual magnetic field measurements at the desired position by eliminating common mode noise based on a determined difference between the magnetic field measurements determined at the different sensitivity settings, frequency configurations, or a combination thereof;
• and
• determining an accurate position of the subject based on the actual magnetic field measurements.