Antenna apparatus and attitude control method

• US 5,089,824 A
• Filed: 04/11/1989
• Issued: 02/18/1992
• Est. Priority Date: 04/12/1988
• Status: Expired due to Fees

• Current Assignee: Nemoto Project Industry Co., Ltd., Nippon Hoso Kyokai, Nippon Steel Corporation
• Original Assignee: Nemoto Project Industry Co., Ltd., Nippon Steel Corporation, Nippoon Hoso Kyokai
• Inventors: Nemoto, Isao, Uematsu, Masahiro, Harakawa, Tetsumi, Kato, Kazuro, Hiratsuka, Ryuichi, Ito, Yasuhiro, Yamazaki, Shigeru, Ohmaru, Kenji
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US07/336,991
• Time in Patent Office: 1,043 Days
• Field of Search: 343/765, 342/75, 342/359, 342/442
• US Class Current: 342/359
• CPC Class Codes: H01Q 1/18 Means for stabilising antennas on an unstable platform
• CPC Class Codes: H01Q 1/185 by electronic means
• CPC Class Codes: H01Q 3/08 for varying two co-ordinates of the orientation

Abstract

Attitude control is implemented by detecting the phase difference between signals received by at least two antennas and detecting the angle of deflection between the direction of arrival of radio signals and the antenna beams. By using antennas that are separately driven, within the plane of rotation in which the deflection angle is to be detected, the phase of the received signals can be shifted equivalently to when the antennas are driven as a consolidated unit. Also, when at least three antennas are used in an orthogonal arrangement for detecting the deflection angle in two directions, the antennas are divided into two groups which are individually driven. This reduces the inertia of the moving parts and enables the size and weight of the drive mechanisms to be reduced.

In addition, two orthogonal functions are used to represent the phase of the deflection angle of the direction of arrival of the radio wave and the antenna beam as a multiplicity of quadrants, and by storing these, when there is a change in the deflection angle, the sequence of change can be traced back and the control effected accordingly. This enables error to be eliminated.

Claims

1. An antenna apparatus comprising:

first, second and third receiving antennas;

support means for supporting the first, second and third receiving antennas so that the antennas are movable in a first direction and in a second direction that is orthogonal to the first direction while the radiation lobes of the antennas are maintained parallel, and a plane that includes the radiation lobes of the first and second receiving antennas is maintained perpendicular to a plane that includes the radiation lobes of the first and third receiving antennas;

first drive means for driving the first, second and third receiving antennas in the first direction;

second drive means for driving the first, second and third receiving antennas in the second direction;

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.

2. An antenna apparatus according to claim 1 provided with in-phase combining means for in-phase combining of signals received by at least two receiving antennas selected from among the first, second and third receiving antennas.

3. 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.

4. An antenna apparatus according to claim 3 provided with in-phase combining means for in-phase combining of signals received by at least two receiving antennas selected from among the first, second and third receiving antennas.

5. A method of controlling receiving antenna attitude comprising

rotating a first receiving antenna about a first axis and a second receiving antenna about a second axis which is parallel to the first axis while maintaining the beams of the first and second receiving antennas parallel;

and

shifting the phase of the signal received by the first receiving antenna by a phase corresponding to 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, obtaining the direction of the radio wave source and setting the attitude of the first and second receiving antennas on the basis of 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.

6. 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.

7. 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.

8. 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.

9. An attitude control method in which drive means are linked to a control object the prescribed attitude of which can be changed and data indicating the target attitude are applied, and the drive means are energized by energizing data based on the provided data, comprising:

detecting first attitude data that indicate the attitude to be induced in the control object when the drive means are energized and second attitude data indicating the actual attitude of the control object, obtaining disturbance data indicating disturbance from the differential between the first attitude data and the second attitude data, and compensating the energizing data used to energize the drive means on the basis of the disturbance data.

10. An attitude control method according to claim 9 wherein intensity data indicating the intensity of the energizing force actually applied to the drive means are detected and the energizing data compensated accordingly.

11. An attitude control method in which drive means are linked to a control object the prescribed attitude of which can be changed and data indicating the target attitude are applied, and the drive means are energized by energizing data based on the provided data, comprising:

when the drive means are energized, detecting first update rate data that indicate the attitude update rate for the energization to produce the intended attitude in the control object and second update rate data indicating the actual attitude update rate, and compensating the energizing data used to energize the drive means on the basis of first disturbance data obtained from the differential between the first and second update rate data obtained from the differential between the first update rate data and the second update rate data.

12. An attitude control method according to claim 11 wherein intensity data indicating the intensity of the energization actually applied to the drive means are detected and the energizing data are compensated accordingly.

13. An attitude control method in which drive means are linked to a control object the prescribed attitude of which can be changed and data indicating the target attitude are applied, and the drive means are energized by energizing data based on the provided data, comprising:

detecting first attitude data that indicate the attitude to be induced in the control object when the drive means are energized, first update rate data that indicate the attitude update rate, second attitude data indicating the actual attitude of the control object, and second update rate data indicating the [actual] attitude update rate, obtaining first disturbance data from the differential between the first attitude data and the second attitude data and second disturbance data from the differential between the first update rate data and the second update rate data, and compensating the energizing data used to energize the drive means on the basis of the first and second disturbance data.

14. An attitude control method according to claim 13 wherein intensity data indicating the intensity of the energization actually applied to the drive means are detected and the energizing data are compensated accordingly.