Antenna apparatus and attitude control method

An antenna apparatus comprising:

• a first antenna group that includes a first and second receiving antennas;
• a first support means for supporting the first antenna group so it can move in a first direction while the radiation lobes of the first and second receiving antennas are maintained parallel;
• a second antenna group that includes a third receiving antenna;
• a second support means for supporting the second antenna group so that it is movable in a first direction while maintaining the radiation lobes of the third receiving antenna parallel to the radiation lobes of the first and second receiving antennas, and maintaining the plane that includes the radiation lobes of the first and third receiving antennas perpendicular to a plane that includes the radiation lobes of the first and second receiving antennas;
• first drive means for driving the first and second antenna groups in the respective first direction;
• third support means for supporting the first and second antenna groups, the first and second support means and the first drive means so that said first and second antenna groups, first and second support means and first drive means are movable in a second direction that is orthogonal to the first direction;
• second drive means for driving the first and second antenna groups, the first and second support means and the first drive means in the second direction as a consolidated body;
• first phase detection means for detecting a first phase difference signal corresponding to a phase difference between a signal received by the first receiving antenna and a signal received by the second receiving antenna;
• second phase detection means for detecting a second phase difference signal corresponding to a phase difference between a signal received by the first receiving antenna and a signal received by the third receiving antenna;
• and
• control means for obtaining the direction of a radio wave source on the basis of the first and second phase difference signals and controlling the respective energization of the first and second drive means.

A receiving antenna attitude control apparatus comprising:

• first and second receiving antennas;
• a first support means for supporting the first receiving antenna so the attitude thereof can be changed in a first direction;
• a second support means for supporting the second receiving antenna separately from the first receiving antenna so the attitude of the second receiving antenna can be changed in a second direction that is similar to the first direction;
• drive means for driving the first receiving antenna in the first direction and the second receiving antenna in the second direction while the beams of the first and second receiving antennas are maintained parallel;
• a first detecting means for detecting the distance between projected points obtained when a point that is substantially the beam radiation point of the first receiving antenna and a point that is substantially the beam radiation point of the second receiving antenna are projected onto a single arbitrary line that is parallel to each beam;
• phase shifting means for shifting the phase of the signal received by the first receiving antenna by a phase corresponding to the said distance;
• second detection means for detecting the phase difference between the signal received by the first receiving antenna subsequent to the shift and the signal received by the second receiving antenna;
• and
• control means for obtaining the direction of the radio wave source on the basis of said phase difference and controlling the energization of the drive means.

A method of controlling receiving antenna attitude when the first and second receiving antennas whose attitude is changeable are driven to orient them toward a radio wave source while maintaining beams of the antennas parallel, comprising:

• multiplying together the signal received by the first receiving antenna and the signal received by the second receiving antenna and extracting the phase difference between the signals as a first function;
• multiplying together the signal received by the first receiving antenna and the signal received by the second receiving antenna phase-shifted 90 degrees and extracting the phase difference between the signals as a second function orthogonal to the first function;
• dividing the phase of the angle of deflection of the beams of the first and second receiving antennas with respect to the direction of the radio wave source into a multiplicity of quadrants based on the sign of the phase difference extracted as a first function and the sign of the phase difference extracted as a second function;
• while monitoring changes in the phase of the angle of deflection, correcting at least one of the phase difference extracted as a first function and the phase difference extracted as a second function on the basis of preceding phase quadrants and current phase quadrants, and setting the attitudes of the first and second receiving antennas on the basis of the corrected phase difference.

A receiving antenna attitude control apparatus comprising:

• support means for supporting first and second receiving antennas so the attitude thereof can be changed;
• drive means for driving the first and second receiving antennas while maintaining the beams thereof parallel;
• first phase difference extraction means for multiplying together the signal received by the first receiving antenna and the signal received by the second receiving antenna and extracting the phase difference between the signals as a first function;
• phase shifting means for shifting the phase of the signal received by the second receiving antenna 90 degrees;
• second phase difference extraction means for multiplying together the signal received by the first receiving antenna and the signal received by the second receiving antenna and extracting the phase difference between the signals as a second function orthogonal to the first function;
• control means for dividing the phase of the angle of deflection of the beams of the first and second receiving antennas with respect to the direction of the radio wave source into a multiplicity of quadrants based on the sign of the phase difference extracted as a first function and the sign of the phase difference extracted as a second function, storing each change of a prescribed extent in the deflection angle phase quadrant, correcting at least one of the phase difference extracted as a first function and the phase difference extracted as a second function on the basis of the stored preceding phase quadrants and current phase quadrants, and energizing the drive means in a direction in which the corrected phase difference approaches a prescribed value.