Electronic analogue compass

An analogue compass comprising:

• sensing means for sensing first and second components of a magnetic field and for producing first and second outputs proportional to said first and second components;
• an integrating means in communication with said sensing means for performing an integrate on said first output, and for performing an integrate on said second output, each of said integration operations continuing until a first pre-determined voltage is reached and then reversing in direction of integration until a second pre-determined voltage is reached and then reversing in direction, the time of changing from said first to said second pre-determined voltage being inversely proportional to said first and second outputs, respectively, so as to generate a first and a second triangle form integration signal, having a first and a second frequency, respectively, dependent on said first and second outputs, respectively;
• microprocessor means in communication with said integrating means for determining true north based on said first and second triangle form integration signals;
• a gauge motor having a rotary output shaft;
• a disk coaxial mounted on said output shaft for rotation therewith, said disk including at least one reference marking;
• a gauge controller for controlling said gauge motor to vary the orientation of said reference marking on said disk with respect to said magnetic field;
• said microprocessor means communicating with said gauge controller to cause said reference marking on said disk to point toward true north.