An example method includes measuring, with a sensor tool, an electromagnetic field generated by an excitation source in order to determine an azimuth angle from the sensor tool to the source. An initial calibration of the sensor tool is performed to generate a library of sensor tool constant coefficients. Each sensor tool coefficient in the library is associated with a different range of azimuth angles. A sensor tool constant coefficient is selected from the library of sensor tool constant coefficients in response to the azimuth angle from the sensor tool to the source. The gradient field component of down hole measurements provided by the sensor tool are then calibrated based on the selected sensor tool constant coefficient.