Apparatus for determining positional coordinates utilizing the terrestrial magnetism as a directional reference

Apparatus for determining the positional coordinates of a moving object comprising:

• a plurality of magnetic field vector detecting devices each having a rotary magnetic piece and a fixed coil, said detecting devices being disposed in spaced apart fixed relationships to each other;
• an inclination detecting device for detecting the inclination of said magnetic field vector detecting devices relative to a vertical direction;
• a distance detecting device for detecting the distance that the moving object has travelled during a particular period of time;
• and
• arithmetic means which receives output from said magnetic field vector detecting devices as well as from said inclination detecting device, calculates the horizontal component force vector of the geomagnetic field by using said output from said magnetic field vector detecting devices and from said inclination detecting device, further calculates the vector in the progress direction of the moving object referring to said horizontal component force vector, and integrates the product of said vector in the progress direction and the output from said distance detecting device, whereby the positional coordinates are obtained as the output of said arithmetic means, and coordinates which have initially been set at an arbitrary point are replaced by the newly determined coordinates when turning to the right or left is carried out at said arbitrary point correctly as ordered.