1. Field of the Invention
The present invention relates in general to communication systems and components, and related methods. More particularly the present invention is directed to antenna systems for wireless communication networks.
2. Related Background Information
The coverage area offered by an antenna in a wireless communication network is dependent on the installation facilities, for example antenna tower, or other suitable support structure. In less than ideal circumstances such antenna support structure may have a mounting surface which is not vertical—i.e. having a compound angle deviation from vertical z-axis. When a two-way antenna is installed on a non-vertical support the effective coverage area offered by such antenna is no longer uniform, depending on azimuth and down tilt settings as commanded by network operator. This causes a difficulty in providing the desired coverage in a consistent manner due to unpredictable installation variations.
In a first aspect the present invent the provides an antenna system comprising an antenna support structure, an antenna including one or more radiating elements, and an antenna mounting structure coupling the antenna to the antenna support structure, the antenna mounting structure including a movable mount allowing change of the antenna orientation. The antenna system further includes an antenna position sensor module mounted on the antenna for detecting at least one of vertical and azimuth orientation relative to the earth, wherein the antenna orientation is adjustable in response to the detected orientation relative to the earth.
In a preferred embodiment of the antenna system the antenna position sensor module comprises an earth gravitational field sensor detecting inclination of the module from vertical. The antenna tilt may be adjusted in response to the detected inclination from vertical and/or the antenna azimuth orientation may be adjusted in response to the detected inclination from vertical. The adjusting may be responsive to a remotely provided tilt control signal. Alternatively, the antenna position sensor module may further comprise a microprocessor for determining a tilt adjustment from the detected inclination and controlling the adjusting. Similarly, the azimuth adjusting may be responsive to a remotely provided azimuth control signal or the antenna position sensor module may further comprise a microprocessor for determining an azimuth adjustment from the detected inclination and controlling the adjusting. Alternatively, or in combination, the antenna position sensor module may comprise an earth magnetic field sensor. The antenna position sensor may further comprise a microprocessor for converting the detected magnetic field into a horizontal component which is used for deriving an azimuth orientation of the antenna. The antenna support structure may for example comprise a pole. The antenna system may further comprise a radome and the radiating elements and antenna position sensor module are mounted in the radome. The antenna system may further comprise an electromechanical actuator coupled to move the radome about the movable mount in response to a control signal. For example, the electromechanical actuator may comprise a motor and gear coupled to the radome.
In another aspect the present invention provides an antenna orientation control system. The antenna orientation control system comprises an orientation sensor for detecting orientation relative to the gravitational or magnetic field of the earth and an antenna orientation controller for providing control signals to control adjusting antenna orientation.
In a preferred embodiment of the antenna orientation control system the antenna orientation controller provides antenna tilt control signals. The antenna actuator controller may also, or alternatively, provide antenna azimuth pointing direction control signals. The antenna orientation control system may further comprise a microprocessor unit for receiving sensor output signals from the orientation sensor and converting them to the control signals. Alternatively the antenna orientation control system may comprise a microprocessor unit for receiving sensor output signals from the orientation sensor and providing the signals to an external base station, wherein external control signals are received from the base station and provided to the antenna orientation controller.
In another aspect the present invention provides a method for controlling the orientation of an antenna. The method comprises receiving sensor information corresponding to detected orientation relative to the earth's gravitational or magnetic field and adjusting the orientation of an antenna in response to the detected orientation relative to the earth.
Further features and advantages of the present invention will be appreciated from the following detailed description of the invention.
The present invention provides an antenna system and method with uniform or compensated sector coverage by monitoring tri-vector gravitational inclinometer and earth magnetic field, determining correction factors for antenna tilt and azimuth beam adjustments. Optionally, azimuth antenna beamwidth can be compensated in addition to antenna down tilt angle and azimuth direction of antenna beam. The latter can be used with a three-way antenna. In preferred embodiments of the present invention, tri-vector gravitational inclinometer and earth magnetic field sensors are provided together with a microprocessor for calculating correction factors for the two-way antenna control parameters.
In
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It is well known that the earth's magnetic field is globally non-uniform and has both vertical and horizontal vector components. APS (12) preferably utilizes the horizontal component of the magnetic field after being transposed into true horizontal plane. Thereafter, the transposed magnetic field vector can be used to determine relative azimuth antenna orientation. An MPU (120) performs magnetic field vector transform into a horizontal coordinate system as determined by tri-vector gravitational (122) sensor.
Antenna azimuth orientation relies on the earth magnetic field which is subject to local disturbances, such as strong electro magnetic fields and or nearby ferrous materials. However, above the mentioned magnetic field variations can be readily compensated during initial installation by referencing out their effects against known nearby landmarks.
In view of the above it will be appreciated that the present invention provides a number of features and aspects. The foregoing description should not be viewed as limiting in nature as various additional implementations and modifications will be apparent to those skilled in the art.
The present application claims the benefit under 35 USC 119(e) of U.S. provisional patent application Ser. No. 61/063,215 filed Feb. 1, 2008, the disclosure of which is incorporated herein by reference in its entirety.
Number | Name | Date | Kind |
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5517205 | van Heyningen et al. | May 1996 | A |
20080258971 | Nichols et al. | Oct 2008 | A1 |
Number | Date | Country | |
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20090195467 A1 | Aug 2009 | US |
Number | Date | Country | |
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61063215 | Feb 2008 | US |