A method for determining performance information for an object located within an athletic field area, wherein the object comprises a piece of athletic equipment, the method comprising: obtaining magnetic field map data for the athletic field area; measuring first magnetic field data when the object is located at a first position within the athletic field area at a first time, wherein the first magnetic field data comprises magnetic field intensity data and magnetic field direction data, wherein the first magnetic field data is measured using a magnetometer coupled to the object, wherein the magnetometer is adapted to measure the intensity and direction of the earth's magnetic field in the vicinity of a sensor module comprising the magnetometer ; comparing the first magnetic field data with the magnetic field map data for the athletic field area; determining a set of possible locations of the first position of the object at the first time within the athletic field area; measuring second magnetic field data when the object is located at a second position within the athletic field area at a second time; comparing the second magnetic field data with the magnetic field map data for the athletic field area; filtering the measured magnetic field data, wherein filtering the measured magnetic field data comprises factoring in motion dynamics constraints of the object; and determining performance information for the object within the athletic field area based on the magnetic field map data for the athletic field area and the filtered measured magnetic field data, wherein the performance information determined for the object comprises a location of the first position of the object in the athletic field area. obtaining magnetic field map data for the athletic field area; measuring first magnetic field data when the object is located at a first position within the athletic field area at a first time, wherein the first magnetic field data comprises magnetic field intensity data and magnetic field direction data, wherein the first magnetic field data is measured using a magnetometer coupled to the object, wherein the magnetometer is adapted to measure the intensity and direction of the earth's magnetic field in the vicinity of a sensor module comprising the magnetometer ; comparing the first magnetic field data with the magnetic field map data for the athletic field area; determining a set of possible locations of the first position of the object at the first time within the athletic field area; measuring second magnetic field data when the object is located at a second position within the athletic field area at a second time; comparing the second magnetic field data with the magnetic field map data for the athletic field area; filtering the measured magnetic field data, wherein filtering the measured magnetic field data comprises factoring in motion dynamics constraints of the object; and determining performance information for the object within the athletic field area based on the magnetic field map data for the athletic field area and the filtered measured magnetic field data, wherein the performance information determined for the object comprises a location of the first position of the object in the athletic field area. <EOS>