Antenna system

• US 4,994,812 A
• Filed: 12/12/1989
• Issued: 02/19/1991
• Est. Priority Date: 12/13/1988
• Status: Expired due to Fees

• Current Assignee: Nippon Steel Corporation, Systems Uniques Corporation A-Shi
• Original Assignee: Nippon Steel Corporation, United Systems, Inc.
• Inventors: Kato, Kazuro, Uematsu, Masahiro, Hiratsuka, Ryuichi
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US07/449,671
• Time in Patent Office: 434 Days
• Field of Search: 343/765, 342/75, 342/359, 342/442
• US Class Current: 342/359
• CPC Class Codes: G01S 3/42 the desired condition being maintained automatically
• CPC Class Codes: G01S 3/46 using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: H01Q 1/3275 mounted on a horizontal surface of the vehicle, e.g. on roof, hood, trunk

Abstract

A satellite tracking antenna system comprises three or four plane antennas juxtaposed on a single plane. A first and a second antenna are juxtaposed in an azimuth direction, and a phase difference between signals received by these antennas is detected in order to determine a declination of an antenna unit with respect to the satellite as viewed in the azimuth direction. The first and a third antenna are juxtaposed in an elevation direction, and a phase difference between signals received by these antennas is detected to determine a declination of the antenna unit with respect to the satellite as viewed in the elevation direction. The antenna unit is driven so as to reduce these declinations to zero. Stated differently, values of a sine and a cosine function are extracted which have a phase difference between signals received by a pair of antennas as a parameter, and a tangent value representing the ratio therebetween is calculated and is then inversely converted to provide phase difference information.

Claims

1. An antenna system comprising

an antenna support;

drive means for driving the antenna support for rotation about a single axis;

a first and a second antenna mounted on the antenna support and spaced apart from each other in the direction of rotation, the first and the second antenna having respective directivities which are oriented parallel to each other;

functional value detecting means for detecting a value of a first function and a value of a second function which is orthogonal to the first function, each of the functions including a phase difference of the signal received by the second antenna with respect to the signal received by the first antenna as a parameter;

and control means for detecting the phase difference in terms of a ratio of a value of the first function to a value of the second function, and for determining a quadrant in which the phase difference is located from the positive or negative polarity of the values of the first and the second function, the control means energizing the drive means in the direction to reduce the detected phase difference and a declination of the directivity of the first antenna with respect to the travelling direction of the wave in the associated quadrant substantially zero.

2. An antenna system according to claim 1 in which the first antenna comprises a plane antenna and the second antenna comprises a plane antenna having a surface for receiving an electromagnetic wave on an extension of the surface of the first antenna on which an electromagnetic wave is received.

3. An antenna system comprising

an antenna support;

drive means for driving the antenna support for rotation about a single axis;

a first and a second antenna disposed on the antenna support and spaced apart in the direction of rotation, the both antennas having directivities which are oriented parallel to each other;

functional value detecting means for detecting a value of a first function and a value of a second function which is orthogonal to the first function, each of the functions having a phase difference of a signal received by the second antenna with respect to a signal received by the first antenna as a parameter;

and control means for deriving a mean square of the values of the first and the second function, the control means energizing the drive means in a direction to maximize the mean square, the drive means subsequently detecting the phase difference on the basis of a ratio of the value of the first function to the value of the second function, the control means determining a quadrant in which the phase difference is located from the positive or negative polarity of the values of the first and the second function, the control means energizing the drive means in a direction to reduce the detected phase difference and the declination of the directivity of the first antenna with respect to the travelling direction of the wave as occurring in the quadrant substantially zero.

4. An antenna system comprising

an antenna support;

first drive means for driving the antenna support for rotation in an azimuth direction about an axis;

second drive means for driving the antenna support for rotation in an elevation direction about another axis which is perpendicular to the first mentioned axis;

a first and a second antenna disposed on the antenna support and spaced apart in the azimuth direction, the both antennas having directivities which are oriented parallel to each other;

a third and a fourth antenna disposed on the antenna support and spaced apart from each other in the azimuth direction and are also spaced from the first and the second antenna in the elevation direction, the third and the fourth antenna having directivities which are oriented parallel to the directivity of the first antenna;

first detection means for detecting a value of a first function and a value of a second function which is orthogonal to the first function, each of the first and the second functions having a phase difference of a signal received by the second antenna with respect to a signal received by the first antenna as viewed in the azimuth direction as a parameter;

second detection means for detecting a value of a third function and a value of a fourth function which is orthogonal to the third function, each of the third and the fourth function having a phase difference of a signal received by the third antenna with respect to a signal received by the fourth antenna as viewed in the elevation direction as a parameter;

and control means for deriving a ratio of the value of the first function to the value of the second function to detect a phase difference in the azimuth direction, and for determining a quadrant in which the phase difference in the azimuth direction is located from positive or negative polarity of the values of the first and the second function, the control means energizing the first drive means so as to reduce the phase difference detected in the azimuth direction and a declination in the azimuth direction of the directivity of the first antenna with respect to a travelling direction of a radio wave which corresponds to such quadrant substantially zero, the control means also deriving a ratio of the value of the third function to the value of the fourth function to detect a phase difference in the elevation direction, and for determining a quadrant in which the phase difference in the elevation direction is located from positive or negative polarity of the values of the third and the fourth function, the control means energizing the second drive means for reducing the phase difference detected in the elevation direction and a declination in the elevation direction of the directivity of the first antenna with respect to a travelling direction of a radio wave which corresponds to such quadrant substantially zero.

5. An antenna system according to claim 4 in which the first antenna comprises a plane antenna and the second antenna comprises another plane antenna having a surface which receives an electromagnetic wave and which is disposed on an extension of a surface of the first antenna which receives an electromagnetic wave.

6. An antenna system comprising

an antenna support;

first drive means for driving the antenna support for rotation in an azimuth direction about an axis;

second drive means for driving the antenna support for rotation in an elevation direction about another axis which is perpendicular to the first mentioned axis;

a first and a second antenna disposed on the antenna support and spaced apart from each other in the azimuth direction, the both antennas having directivities which are oriented parallel to each other;

a third and a fourth antenna disposed on the antenna support and spaced apart from each other in the azimuth direction and also spaced from the first and the second antenna in the elevation direction, the third and the fourth antenna having directivities which are oriented parallel to the directivity of the first antenna;

first detecting means for detecting a value of a first function and a value of a second function which is orthogonal to the first function, both the first and the second function having a phase difference of a signal received by the second antenna with respect to a signal received by the first antenna as viewed in the azimuth direction as a parameter;

second detecting means for detecting a value of a third and a value of a fourth function which is orthogonal to the third function, both the third and the fourth function having a phase difference of a signal received by the third antenna with respect to a signal received by the first antenna as viewed in the elevation direction as a parameter;

and control means for deriving a mean square of the values of the first and the second function and for energizing the first drive means in order to maximize the mean square, the control means also deriving a mean square of values of the third and the fourth function and for energizing the second drive means to maximize the mean square thereof, the control means subsequently detecting a phase difference in the azimuth direction on the basis of the ratio of the value of the first function to the value of the second function and determining a quadrant in which the phase difference in the azimuth direction is located from positive or negative polarity of values of the first and the second function, the control means energizing the first drive means in order to reduce the phase difference detected in the azimuth direction and a declination of the directivity of the first antenna with respect to the travelling direction of a radio wave as viewed in the azimuth direction which corresponds to such quadrant substantially zero, the control means also detecting a phase difference in the elevation direction on the basis of a ratio of the value of the third function to the value of the fourth function and for determining a quadrant in which the phase difference in the elevation direction is located from positive or negative polarity of values of the third and the fourth function, the control means energizing the second drive means in order to reduce the phase difference detected in the elevation direction and a declination of the directivity of the first antenna with respect to the travelling direction of a radio wave as viewed in the elevation direction substantially zero.

7. An antenna system comprising

an antenna support;

first drive means for driving the antenna support for rotation in an azimuth direction about an axis;

second drive means for driving the antenna support for rotation in an elevation direction about another axis which is perpendicular to the first mentioned axis;

a first and a second antenna disposed on the antenna support and spaced apart from each other in the azimuth direction, the both antennas having directivities which are oriented parallel to each other;

a third antenna disposed on the antenna support and spaced apart from the second antenna in the azimuth direction and also spaced from the first antenna in the elevation direction, the third antenna having a directivity which is oriented parallel to the directivity of the first antenna;

first detecting means for detecting a value of a first and a value of a second function which is orthogonal to the first function, each of the first and the second function having a phase difference of a signal received by the second antenna with respect to a signal received by the first antenna as viewed in the azimuth direction as a parameter;

second detecting means for detecting a value of a third function and a value of a fourth function which is orthogonal to the third function, both the third and the fourth function having a phase difference of a signal received by the third antenna with respect to a signal received by the first antenna as viewed in the elevation direction as a parameter;

and control means for deriving a ratio of a value of the first function to a value of the second function to detect a phase difference in the azimuth direction, and for determining a quadrant in which the phase difference in the azimuth direction is located from positive or negative polarity of values of the first and the second function, the control means energizing the first drive means in order to reduce the phase difference detected in the azimuth direction and a declination of the directivity of the first and the second antenna with respect to the travelling direction of a radio wave as viewed in the azimuth direction substantially zero, the control means also deriving a ratio of a value of the third function to a value of the fourth function to detect a phase difference in the elevation direction, and determining a quadrant in which the phase difference in the elevation direction is located from positive or negative polarity of values of the third and the fourth function, the control means energizing the second drive means in order to reduce the phase difference detected in the elevation direction and a declination of the directivity of the first and the third antenna with respect to the travelling direction of a radio wave as viewed in the elevation direction substantially zero.

8. An antenna system according to claim 7 in which the first antenna comprises a plane antenna, and the second antenna comprises another plane antenna having a surface which receives an electromagnetic wave and which is disposed on an extension of a wave of the first antenna which receives an electromagnetic wave.

9. An antenna system comprising

an antenna support;

first drive means for driving the antenna support for rotation in an azimuth direction about an axis;

second drive means for driving the antenna support for rotation in an elevation direction about another axis which is perpendicular to the first mentioned axis;

a first and a second antenna disposed on the antenna support and spaced apart from each other in the azimuth direction, the both antennas having directivities which are oriented parallel to each other;

a third antenna disposed on the antenna support and spaced from the second antenna in the azimuth direction and also spaced from the first antenna in the elevation direction, the third antenna having a directivity which is oriented parallel to the directivity of the first antenna;

first detecting means for detecting a value of a first function and a value of a second function which is orthogonal to the first function, each of the first and the second function having a phase difference of a signal received by the second antenna with respect to a signal received by the first antenna as viewed in the azimuth direction as a parameter;

second detecting means for detecting a value of a third function and a value of a fourth function which is orthogonal to the third function, each of the third and the fourth function having a phase difference of a signal received by the third antenna with respect to a signal received by the first antenna as viewed in the elevation direction as a parameter;

and control means for deriving a mean square of values of the first and the second function and for energizing the first drive means to maximize the mean square, the control means also for deriving a mean square of the values of the third and the fourth function and for energizing the second drive means in order to maximize the mean square thereof, the control means subsequently operating to detect a phase difference in the azimuth direction on the basis of a ratio of the value of the first function to the value of the second function and also determining a quadrant in which the phase difference in the azimuth direction is located from positive or negative polarity of values of the first and the second function, the control means energizing the first drive means in order in order to reduce the phase difference detected in the azimuth direction and a declination of the directivity of the first and the second antenna with respect to the travelling direction of a radio wave as viewed in the azimuth direction substantially zero, the control means also operating to detect a phase difference in the elevation direction on the basis of a ratio of the value of the third function to the value of the fourth function and also determining a quadrant in which the phase difference in the elevation direction is located from positive or negative polarity of values of the third and the fourth function, the control means energizing the second drive means in order to reduce the phase difference detected in the elevation direction and a declination of the directivity of the first and the third antenna with respect to the travelling direction of a radio wave as viewed in the elevation direction substantially zero.