Analysis on the Uncertainty of the Coil Sensitivity based on the Principle of Scalar Calibration Method

Scalar calibration method is quite convenient and widely used in the coil sensitivity calibration for certain coil system. The uncertainties of the results are critical in evaluating the accuracy of the coil sensitivity. Based on the calibration principle, a mathematical description of the coil sensitivity uncertainty is given, which shows that the current, the environmental magnetic field and their uncertainties are the main factors attributing to the coil sensitivity uncertainty. Series of tests were conducted under different currents and stable environmental magnetic fields. The results show a very good accordance with the analytical description. With the increase of the current, the coil sensitivity uncertainty becomes smaller and goes to a limit decided by the current uncertainty while the influence of the environmental magnetic field is comparatively insignificant.