Attitude control system for mobile antenna

• US 5,061,936 A
• Filed: 09/14/1990
• Issued: 10/29/1991
• Est. Priority Date: 09/14/1989
• Status: Expired due to Term

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Kabushiki Kaisha Shinsangyokaihatsu
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), K.K. Shinsangyo
• Inventors: Suzuki, Katsuo
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US07/582,734
• Time in Patent Office: 410 Days
• Field of Search: 342/75, 342/359, 343/713, 318/649
• US Class Current: 342/359
• CPC Class Codes: H01Q 1/1257 using the received signal strength
• CPC Class Codes: H01Q 1/3275 mounted on a horizontal surface of the vehicle, e.g. on roof, hood, trunk
• CPC Class Codes: H01Q 3/10 to produce a conical or spiral scan

Abstract

The attitude of an antenna which is used with an artificial satellite emitting a radio wave is controlled by a combination of the establishment of an antenna attitude in accordance with gyro data, a small range conical scan which is conducted when a reception level is less than a first reference and at or above a second reference and is relatively high for altering the antenna attitude to a direction which provides a higher reception level, and a broader range search scan which is conducted when the reception level is less than the second reference and is relatively low for altering the antenna attitude to a direction which provides a higher reception level. In one manner, in order to reduce an antenna driving time, an antenna attitude is regarded as an optimum if a fluctuation which occurs in the reception level during the small range conical scan is small, and the first reference is updated to a value which is slightly less than a maximum value in the reception levels which are obtained during the conical scan. In second manner, the first reference is a fixed value, and as long as the reception level continuously remains at or above a given value, which may be the first reference, for example, gyro data is initialized at a given time interval in order to prevent an accumulated error in gyro data from increasing. In other words, data representing a start point and a variance from the start point are cleared.

Claims

1. An attitude control system for mobile antenna comprising

an antenna supported on a moving vehicle so as to be capable of changing its attitude;

a drive mechanism for altering the attitude of the antenna;

reception level detecting means for detecting a reception level from the antenna;

and electronic control means responsive to a reception level detected by the reception level detecting means for performing a small range scan control which is conducted when the reception level is less than a first reference and at or above a second reference for scanning the antenna over a small range through the drive mechanism and for altering the attitude of the antenna in a direction which is found during the scan to provide a higher reception level, for performing a search control which is conducted when the reception level is less than the second reference for scanning the antenna over a broader range than that of the small range scan through the drive mechanism, and for detecting a fluctuation of the reception level during the small range scan and for updating the first reference to a value which is slightly less than a high value obtained during the small range scan when the fluctuation is less than a third reference.

2. An attitude control system for a mobile antenna comprising

an antenna mounted on a moving vehicle so as to be capable of changing its attitude;

a drive mechanism for altering the attitude of the antenna;

reception level detecting means for detecting a reception level from the antenna;

attitude detecting means for detecting a variance in the attitude of the moving vehicle from a start point thereof;

and electronic control means responsive to a change detected by the attitude detecting means for altering the attitude of the antenna through the drive mechanism so as to compensate for an offset in the directivity of the antenna which is caused by the detected change in the attitude of the moving vehicle,

the electronic control means being responsive to a reception level detected by the reception level detecting means for performing a small range scan control which is conducted when the reception level is less than a first reference and at or above a second reference for scanning the antenna over a small range through the drive mechanism and for altering the attitude of the antenna to a direction which is found during the scan to provide a higher reception level, for performing a search control which is conducted when the reception level is less than the second reference for scanning the antenna through the drive mechanism over a broader range than that of the small range scan, and for detecting a fluctuation in the reception level which occurs during the small range scan and for updating the first reference to a value which is slightly less than a high value obtained during the small range scan when the fluctuation is less than a third reference.

3. An attitude control system for mobile antenna comprising

an antenna mounted on a moving vehicle so as to be capable of changing its attitude;

a drive mechanism for altering the attitude of the antenna;

reception level detecting means for detecting a reception level from the antenna;

attitude detecting means for detecting a variance in the attitude of the moving vehicle from a start point thereof;

and electronic control means for performing a first control in which the attitude of the antenna is altered by the drive mechanism so as to compensate for an offset in the directivity of the antenna which is caused by a change detected by the attitude detecting means, a second control which is responsive to a reception level detected by the reception level detecting means for scanning the antenna over a small range through the drive mechanism and for altering the attitude of the antenna to a direction which is found during the scan to provide a higher reception level when the reception level is less than a first reference and at or above a second reference, a third control responsive to a reception level detected by the reception level detecting means for scanning the antenna through the drive mechanism over a broader range than that of the small range scan when the reception level is less than the second reference, and a fourth control responsive to a reception level detected by the reception level detecting means for initializing a start point and a variance from the start point for the attitude detecting means to compensate for any accumulated error in the variance at a given time interval as long as the reception level is at or above a given value.