Navigation aid system

A method for receiving carrier waves to impart a frequency modulation to the carrier waves for determining elevational and azimuthal angles of a source of the carrier waves, comprising the steps of:

• providing a receiving antenna having a first receiving position for receiving carrier waves from the source and a second receiving position for receiving carrier waves from the source;
• repetitively moving the first receiving position along a first line of motion fixed in the frame of reference of the receiving antenna;
• and
• repetitively moving the second receiving position along a second line of motion having a fixed orientation with respect to the first line of motion;
• at least a portion of the first line of motion being non-parallel to at least a portion of the second line of motion.

A method of radiating carrier waves from a known location on a reference coordinate system, said carrier waves having a frequency modulation dependent on an angle of propagation of the carrier waves from the location, comprising the steps of:

• providing a position from which carrier waves are radiated;
• and,
• moving the radiating position along a line of motion having a predetermined, fixed orientation on the reference coordinate system, so that at least one of the speed and direction of motion of the radiating position changes abruptly in a repetitive manner;
• whereby an angle of propagation of the carrier waves is determinable solely responsively to the amplitude of the frequency shift in the radiated carrier wave induced by the abrupt change in the motion of the radiating position, rather than being determinable from the phase of the frequency shifted waveform.

An apparatus for radiating carrier waves having directionally dependent frequency modulation for determining elevational and azimuthal angles comprising:

• first antenna means for radiating carrier waves from a first radiating position;
• second antenna means for radiating carrier waves from a second radiating position;
• first means for moving the first radiating position along a first line of motion, said first line of motion having a known, fixed location in a frame of reference so that at least one of the speed and direction of motion of the first radiating position changes abruptly thereby inducing an abrupt, directionally dependent Doppler shift in the frequency of the carrier waves;
• and,
• second means for moving the second radiating position along a second line of motion having a known, fixed location in the frame of reference so that at least one of the speed and direction of motion of the second radiating position changes abruptly, thereby inducing an abrupt, directionally dependent Doppler shift in the frequency of the carrier waves.

An apparatus for receiving carrier waves, said carrier waves having a frequency modulation dependent on the azimuthal and elevational angles of propagation of the carrier waves from at least one transmitter having a known location on a reference coordinate system comprising:

• first antenna means for receiving carrier waves at a first receiving position;
• second antenna means for receiving carrier waves at a second receiving position;
• first means for moving the first receiving position along a first line of motion;
• and,
• second means for moving the second receiving position along a second line of motion having a fixed orientation with respect to the first line of motion.

A method of radiating carrier waves from a location, said carrier waves having a frequency modulation dependent on an angle of propagation of the carrier waves from the location, comprising the steps of:

• providing a position from which carrier waves are radiated;
• and,
• moving the radiating position along a substantially straight line of motion, the radiating position being repetitively moved at a substantially uniform speed along the line of motion, and the direction of motion being reversed at the ends of the line of motion;
• whereby an angle of propagation of the carrier waves is determinable solely responsively to the amplitude of the frequency shift in the radiated carrier wave induced by the change in the direction of the motion of the radiating position.

A method of receiving carrier waves and frequency modulating the carrier waves dependent on the angle of reception of the carrier waves comprising the steps of:

• providing a position for receiving carrier waves from at least one transmitter of carrier waves;
• and,
• moving the receiving position along a substantially straight line of motion, the receiving position being repetitively moved at a substantially uniform speed along the line of motion, and the direction of motion being reversed at the ends of the line of motion;
• whereby the angle of reception of the carrier waves is determinable with respect to the orientation of the line of motion solely responsively to the amplitude of the frequency shift in the received carrier wave induced by the change in the direction of the motion of the radiating position.