Patent ID: 7755353

Claim:
A three-axis fluxgate-type magnetism detection device, comprising: a three-axis fluxgate-type circuit having three fluxgate sensors for outputting three analog voltage values respectively; a controller operable to normalize three digital voltage values corresponding to said three analog voltage values, select a set of linear voltage values from the three normalized digital voltage values and calculate an azimuth based on the set of linear voltage values; and a memory operable to store a normalized reference magnitude value, wherein the controller calculates the azimuth based on a ratio of the reference magnitude value to the set of linear voltage values, and wherein the reference magnitude value is set at an initial stage through rotations of the three-axis fluxgate-type magnetism detection device when a geomagnetic field varies, wherein the three fluxgate sensors are a first fluxgate sensor in an X axis, a second fluxgate sensor in an axis counterclockwise rotated 120° from the X axis, and a third fluxgate sensor in an axis counterclockwise rotated 240° from the X axis, wherein if a magnitude of a normalized second digital voltage value corresponding to the second fluxgate sensor is greater than a normalized first digital voltage value corresponding to the first fluxgate sensor, and the magnitude of the normalized first digital voltage value is greater than a normalized third digital voltage value corresponding to the third fluxgate sensor, the azimuth is calculated by use of an equation as below: orientation ⁢ ⁢ angle = 120 ∘ - 60 ∘ ⨯ first ⁢ ⁢ voltage ⁢ ⁢ value reference ⁢ ⁢ voltage ⁢ ⁢ value wherein the first voltage value is a linear voltage value corresponding to the first fluxgate sensor.