A scaling system and technique which employs an analog-to-digital converter having at least 10-bit accuracy and a ranging circuit to compensate for abnormally large vehicle magnetic fields. The ranging circuit employs variable resistance negative feedback, which enables an electronic compass system to reduce the output voltage of an integrator to within the fixed output voltage range of the integrator. An analog-to-digital converter of at least 10-bit accuracy makes resolution of heading information possible and enhances the accuracy of subsequently performed calibrations.