Orientation system

A relative azimuth indication system, comprising:

• a front and a back plate adapted to form a hollow indicator disc defining an image area;
• an optically responsive medium contained in said hollow disc;
• a gyroscope;
• a means to support said gyroscope in a plane essentially parallel to a plane tangent to the surface of the earth and permit 360.degree. of rotation about an axis perpendicular to said plane;
• coupling means adapted to rotate said indicator as a function of the relative rotation between said gyroscope and said support means about said perpendicular axis;
• a directional radio receiver;
• a band pass filter means responsive to signals detected by said radio receiver and adapted to pass signals representing lightning generated static signals;
• a first analog-to-digital converter adapted to convert said signals passed by said band pass filter into range pulses representing the distance between the origin of said lightning generated static signals and said radio receiver;
• a plurality of transparent, concentric conductors of increasing diameter starting from a point essentially at the center of said image area and positioned at a first side of said indicator;
• means to couple said range pulses to said concentric conductors;
• a second analog-to-digital converter adapted to convert the analog azimuth data representing signals received by said directional radio receiver into azimuth pulses representing the relative bearing of the source of said signals;
• a plurality of equally spaced conductors positioned on a second side of said indicator opposite said transparent concentric conductors, said equally spaced conductors electrically isolated from each other and radiating outward from the center of said image area;
• and means to couple said azimuth pulses to said equally spaced conductors.