Differential magnetic proximity sensor

A distance measuring device comprising:

• a first sensing module having a first zero angle measurement axis point, a second sensing module having a second zero angle measurement axis point,
• a reference device,
• an evaluating module,
• a horizontal base line connecting the first zero angle measurement axis point and the second zero angle measurement axis point,
• wherein each one of the first and second sensing module is configured to detect the strength of a magnetic field in a first sensing direction and a second sensing direction,
• wherein the reference device is movable with respect to the first sensing module and the second sensing module along a movement trajectory,
• wherein the reference device emits a magnetic field detectable by the first and second sensing module,
• wherein the first sensing module is configured to detect the magnetic field and to determine a first opening angle between the second sensing direction and the position of the reference device as a result of the detected magnetic field strength,
• wherein the second sensing module is configured to detect the magnetic field and to determine a second opening angle between the second sensing direction and the position of the reference device,
• wherein the evaluating module is configured to determine the distance between the base line and the reference device based on the first opening angle and the second opening angle.