Abstract:
A system and method is for orientating and monitoring orientation of telecommunications antennas. The system includes an AISG compliant tilt sensor system mounted in-line between a telecommunications antenna enclosure and a communications cable, and positioned to measure the elevation tilt and slant of a telecommunications antenna enclosure relative to a reference axis. The tilt sensor system measures the angle of tilt and angle of slant of the enclosure with respect to a reference axis, and communicates the values through the communications cable using the AISG protocol for analysis by a telecommunications system operator. A printed circuit board with suitable microprocessor and circuitry receives and processes the tilt sensor data and reports directional alignment information to the user via a user interface.

Description:
[0001]    This application claims priority in U.S. Provisional Patent Application No. 61/160,641, filed Mar. 16, 2009, which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to antenna orientation, and in particular to a system and method for cellular telecommunications antenna orientation using tilt sensors. 
         [0004]    2. Description of the Related Art 
         [0005]    Antennas are commonly installed on structures, such as buildings and towers, at a height above the surface of the earth thereby permitting broadcast communication over a wide area. Some antennas are directional antennas requiring precise installation and orientation for optimal system performance. For example, the type of orientation that affects antenna broadcast communications include azimuth, elevation tilt, and slant. Therefore, depending upon the quantity and orientation of an array of antennas, each antenna will have an independent orientation in order to provide optimal performance. 
         [0006]    Telecommunication antennas are typically directional antennas housed within an elongated enclosure. Previously, telecommunication antenna orientation was accomplished manually by conducting a rough approximation from ground level, e.g., by surveyors, followed by an antenna-level fine adjustment consisting of reorientation of the antenna enclosure by skilled technicians using special equipment and techniques. Such manual antenna orientation and adjustment procedures had a number of disadvantages. For example, they tended to be relatively expensive because the technicians were relatively highly-trained, and the equipment was relatively sophisticated. Moreover, determining antenna orientation at any given point in time required technicians to ascend a structure, individually assess antenna orientation and adjust the antenna position, one-by-one, using iterative procedures, which tended to be time-consuming, particularly for installations consisting of a number of antennas. 
         [0007]    Another approach to manual telecommunication antenna orientation and adjustment uses the global navigation satellite system (GNSS, including GPS) receiver dishes mounted on frames, which in turn are temporarily mounted on the antennas for conducting azimuth, elevation tilt and slant orientation and adjustment of the antenna. The Boucher U.S. Pat. No. 6,897,828 and No. 7,180,471 are examples of such an approach. Multiple GPS receiver dishes in a predetermined spaced relation can be used for computing orientation of an antenna by triangulating the GPS signals, or a single GPS receiver dish can be moved from one location to another. However, the GPS receiver dishes and the frames on which they are mounted must be relocated for each separate antenna orientation and adjustment. Subsequent antenna adjustments require technicians to ascend the transmission structure to reattach the GPS equipment to the individual antenna enclosures in order to obtain orientation readings in real-time, followed by manual reorientation of the antenna by adjusting the mountings accordingly. 
         [0008]    A significant disadvantage associated with the aforementioned and other previous antenna orientation and adjustment devices and methods involve their inability to continuously monitor antenna orientation and detect disorientation from a baseline orientation. Cellular telecommunications antennas are susceptible to physical disorientation from various causes, such as meteorological, geological, and other impact forces. For example, forces generated during a major storm may change the orientation of antenna housings on telecommunications towers and in other installations within an entire region resulting in communications performance degradation. Consequently, identification of antennas in need of reorientation, and reorientation of each affected antenna would require individualized physical attention from a technician. Therefore, an antenna orientation and adjustment system and method should not only facilitate initial orientation, but also facilitate ongoing orientation monitoring with an ability to detect conditions of disorientation, thereby requiring limited physical visits by technicians to antenna installations, and limited need for specialized equipment in order to effectuate installation and orientation of telecommunications antenna. Moreover, an antenna orientation system and method should be adaptable to existing antenna equipment permitting ease of installation and compliance with stringent regulatory requirements and approval procedures. 
         [0009]    Heretofore there has not been available an antenna orientation system and method with the advantages and features of the present invention. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    In the practice of an aspect of the present invention, a system and method is provided for orientating, and monitoring orientation of telecommunications antennas. The system includes an AISG compliant tilt sensor system mounted in-line between a telecommunications antenna enclosure and a communications cable, and positioned to measure the elevation tilt and slant of a telecommunications antenna enclosure relative to a reference axis. The tilt sensor system consists of a tilt sensor, which can be mounted in-line between a telecommunications antenna and a communications cable, or mounted directly to an antenna enclosure, that measures the angle of tilt and angle of slant of the enclosure with respect to a reference axis, and communicates the values through the communications cable using the AISG protocol for analysis by a telecommunications system operator. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The drawings constitute a part of this specification and include exemplary embodiments of the present invention illustrating various objects and features thereof. 
           [0012]      FIG. 1  is a side elevational view of an in-line tilt sensor system connected to a telecommunications antenna in accordance with an embodiment of the present invention. 
           [0013]      FIG. 2  is a top plan view showing in part the female connector of an in-line tilt sensor system in accordance with an embodiment of the present invention. 
           [0014]      FIG. 3  is a sectional view of the in-line tilt sensor system taken generally along line  3  in  FIG. 2 . 
           [0015]      FIG. 4  is a bottom plan view showing in part the male connector of an in-line tilt sensor system in accordance with an embodiment of the present invention. 
           [0016]      FIG. 5  is a side elevational view of an in-line tilt sensor system connected to a telecommunications antenna having a misalignment about the transverse axis. 
           [0017]      FIG. 6  is a front elevational view of an in-line tilt sensor system connected to a telecommunications antenna having a misalignment about the longitudinal axis. 
           [0018]      FIG. 7  is a side elevational view of an in-line tilt sensor system connected to a conduit in accordance with an embodiment of the present invention. 
           [0019]      FIG. 8  is a side elevational view of an alternative embodiment in-line tilt sensor system connected to a telecommunications antenna in accordance with an embodiment of the present invention. 
           [0020]      FIG. 9  is a side elevational view of an alternative embodiment in-line tilt sensor system in accordance with an embodiment of the present invention. 
           [0021]      FIG. 10  is a schematic view of an alternative embodiment in-line tilt sensor system in accordance with an embodiment of the present invention wherein multiple antenna protocols are orientated and monitored by a single tilt sensor. 
           [0022]      FIG. 11  is a schematic view of the embodiment of  FIGS. 1-7  of an in-line tilt sensor system using multiple tilt sensors to orient and monitor multiple antenna protocols. 
           [0023]      FIG. 12  is a schematic view of the alternative embodiment of  FIG. 10  of an in-line tilt sensor system using a single tilt sensor to orient and monitor multiple antenna protocols. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     I. Introduction and Environment 
       [0024]    As required, detailed aspects of the present invention are disclosed herein; however, it is to be understood that the disclosed aspects are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art how to variously employ the present invention in virtually any appropriately detailed structure. 
         [0025]    Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, top, bottom, front, back, right and left refer to the invention in relation as orientated in the view being referred to. Moreover, a straight line drawn from right to left through the geometric center of the front plate  40  defines a transverse axis, a straight line drawn from front to back through the geometric center of the front plate  40  defines a longitudinal axis, and a straight line drawn from top to bottom through the geometric center of the front plate  40  defines a vertical axis. Terminology referring to the orientation of the antenna  4  includes: azimuth, the angle from a reference line in a plane (typically level with the horizon) to a second reference line in the same plane resulting from rotation about a vertical axis; elevation tilt, the angle from a reference line in a plane (typically perpendicular to the plane level with the horizon, and at a 90 degree angle to the transverse axis) to a second reference line in the same plane resulting from rotation about a transverse axis; and slant, the angle from a reference line in a plane (typically perpendicular to the plane level with the horizon, and at a 90 degree angle to the longitudinal axis) to a second reference line in the same plane resulting from rotation about a longitudinal axis. The words, “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the front plate  40  and designated parts of the antenna  4 . Said terminology will include the words specifically mentioned, derivatives thereof and words of similar meaning 
       II. Preferred Embodiment Sensor System  2   
       [0026]    Referring to the drawings in more detail, in  FIG. 1 , the reference numeral  2  generally designates an in-line tilt sensor system embodying aspects of the present invention. The sensor system  2  is shown connected to a typical telecommunications antenna  4  installed on a support structure, such as a mast  6  at a height above the surface of the earth. By way of example, a directional panel antenna  4  is shown and described, however, the type of antenna which may be use with the sensor system  2  may include, but is not limited to, a panel or dipole, single or multi band antenna, of a directional, omni directional, or point-to-point type. The antenna  4  generally consists of a front plate  40  facing in the direction of the main beamwidth, an opposite parallel back plate  44 , and a bottom plate  16  at a 90 degree angle to the front plate  40 . In  FIG. 1 , the front plate  40  is parallel to a reference axis  3  which is a line perpendicular to a plane level with the horizon. An eight-pin standardized Antenna Interface Standards Group (AISG) compliant bulkhead connector  14  is mounted perpendicular to the bottom plate  16 . While eight-pin standardized AISG compliant connectors are discussed herein, it should be understood that the connectors may consist of any orientation-dependent pin connectors suitable for use with telecommunications antennas. The back plate  44  of the antenna  4  is releasably connected to the mast  6  by mounts  8  providing up, down, front, back, right and left adjustment of the antenna  4  in relationship to the mast  6 . When desired orientation of the antenna  4  is achieved, it can be secured to maintain the desired position. When reorientation of the antenna  4  is necessary, the mounts  8  can be unsecured, reorientation of the antenna  4  conducted, and the mounts  8  re-secured. While a specific installation of the antenna  4  is shown and described, it should be understood that the antenna  4  can be installed on different types of elevated structures such as buildings, towers, and upon elevated landforms irrespective of the orientation of the support structure. Moreover, it should be appreciated alternative adjustable mounts may be employed for connecting the antenna to a support structure. 
         [0027]    Referring to  FIGS. 2-4 , the sensor system  2  is shown mounted beneath the antenna  4  perpendicular to the bottom plate  16 , and in-line between the bulkhead connector  14  and an eight-pin AISG compliant cable connector  12  of the communications cable  10 . The sensor system  2  consists of a weatherproof housing  17  encasing a printed circuit board (PCB)  18 , and first  20  and second  22  eight-pin AISG compliant connectors positioned at 90 degree angles relative to the PCB  18 . In this preferred embodiment, the first connector  20  is represented by a “female” type connector, and the second connector  22  is represented by a “male” type connector, however, it is appreciated by those skilled in the art that different combinations of connector types can be used to connect the sensor system  2  to respective devices. 
         [0028]    A tilt sensor  26  capable of measuring tilt and slant is mounted parallel with the surface of a PCB  18  containing a microprocessor  24 , and related circuitry. The tilt sensor  26  is an electrical or electrical-mechanical device, such device may include, without limitation, an inclinometer, a dual axis accelerometer of the type manufactured by Memsic, Inc. of Andover Mass., or preferably, a dual axis digital inclinometer/accelerometer such as the type manufactured by Analog Devices, Inc. of Norwood Mass. The related circuitry consists of an RS485 driver, and a power supply. 
         [0029]    Because the PCB  18  is perpendicular to the connectors  20 ,  22 , the tilt sensor  26  is parallel with the bottom plate  16  and thereby capable of measuring the tilt and slant of the front plate  40  in relation to the reference axis  3 . The microprocessor  24  and the related circuitry enable the tilt sensor  26  to communicate alignment of the antenna  4  to the network operator through the communications cable  10  using the AISG protocol in addition to information and parameters already available to the operator controlling antennas using the AISG protocol. 
         [0030]    The sensor system  2  is positioned in-line between the antenna  4  and communications cable  10  by inserting the first connector  20  into the bulkhead connector  14  and mechanically securing thereto, and inserting the cable connector  12  into the second connector  22  and mechanically securing thereto. 
         [0031]    Referring to  FIG. 5 , an antenna  4  is shown mounted on a mast  6  having a tilt represented by an angle of tilt α 1 . The angle of tilt α 1  is defined by elevation tilt of the front plate  40  of the antenna  4  between a line representing the reference axis  3 , and a line representing the axis of tilt  30 . The angle of tilt α 1  reflected in  FIG. 5  represents a rotation of the antenna  4  to the right of the reference axis  3 , however, the angle of tilt may also exists when the antenna  4  rotates to the left of the reference axis  3 . Referring to  FIG. 6 , an antenna  4  is shown having a slant represented by an angle of slant α 2 . The angle α 2  is defined by slant of the front plate  40  between a line representing the reference axis  3  and a line representing the axis of slant  32 . The tilt sensor  26 , being in-line with the antenna  4 , and in a plane parallel with the bottom plate  16  measures both the angle of tilt α 1  and angle of slant α 2 , and transmits the values to the network operator through the communications cable  10  for analysis thereby providing the orientation of the antenna  4  with respect to the reference axis  3 . Orientation of the antenna  4  can therefore be verified, and a determination can be made whether the antenna  4  is disorientated requiring adjustment by a technician. Installation of the sensor system  2  can occur on an antenna  4  with or without a pre-existing angle of tilt or angle of slant. 
         [0032]    In  FIG. 7 , the sensor system  2  is shown connected to an AISG compliant control unit  34  connected to an antenna  4 . The control unit  34  permits network engineers to make electrical tilt and slant adjustments to the signal emanating from the antenna  4 . The control unit  34  is mounted perpendicular to the bottom plate  16  using an eight-pin AISG compliant bulkhead connector  14 . At the opposite end of the control unit  34  is a control unit connector  36  which is disposed at a 90 degree angle relative to the bottom plate  16 . 
         [0033]    In this installation, the sensor system  2  is positioned in-line between the control unit  34  and the connector cable  10  by inserting the first connector  20  into the control unit connector  36  and mechanically securing thereto, and inserting the cable connector  12  into the second connector  22  and mechanically securing thereto. Because the control unit  34  and control unit connector  36  are perpendicular to the bottom plate  16 , the tilt sensor  26  is capable of measuring the angle of tilt, and angle of slant of the front plate  40  in relation to the reference axis  3  as described above. Therefore, as described above, the tilt sensor  26  measures the tilt and slant of the antenna  4  and transmits the values to a network operator for analysis. 
       III. Alternative Embodiment Sensor System  52   
       [0034]    A sensor system  52  comprising another embodiment or aspect of the present invention is shown in  FIGS. 8 and 9 , and includes an in-line connector assembly  53  connected to a remote sensor system  54  at opposite ends of a cable  56  using cable connectors  58 . The remote sensor system  54  consists of a tilt sensor  26  attached to a PCB  18  within a housing  62 . Separating the tilt sensor  26  from the in-line connector assembly  53  permits alternative placement of the tilt sensor  26 , such as on the back plate  44  of the antenna  4 , in situations where, for example, the location of the bulkhead connector  14  impedes optimal performance of the tilt sensor  26 . The, first and second connectors  20 ,  22 , microprocessor  24 , and related circuitry are attached to a PCB  18  within the in-line connector assembly  53  housing  60  similar to the sensor system  2  described above. 
         [0035]    The in-line connector assembly  53  is attached to the antenna  4  and communications cable  10  substantially as described above for the sensor system  2 . Moreover, when the sensor system  52  is connected to the back plate  44 , it  52  functions in the same manner, and is used in the same way by a network operator as the sensor system  2  above, and is capable of measuring angle of tilt and angle of slant of the front plate  40  of the antenna  4  in relation to a reference axis  3  because of the parallel relationship between the front plate  40  and back plate  44 . 
       IV. Alternative Embodiment Sensor System  102   
       [0036]    A sensor system  102  comprising yet another embodiment or aspect of the present invention is shown in  FIG. 10-12 . The previously disclosed embodiments are capable of providing orientation and monitoring service for a single antenna of a single frequency band. In this alternative embodiment, a single inline mechanical tilt sensor module  104  is capable of orientating and monitoring an unlimited number of communication ports on an unlimited number of antenna protocols. 
         [0037]    The alternative embodiment sensor system  102  is a solution for cellular network carriers which utilize multi-band antennas with remote electrical tilt (RET) controllers for one or more frequency bands. It is important for the network provider or carrier to know the mechanical tilt and roll of all directional antennas in the network. This is made complicated by multi-band antennas with multiple remote RET control units (RCUs). The multi-band antenna may have one more RCUs for every frequency band in use. 
         [0038]    Each RCU can be controlled by one or more primary RET controllers (CCU). Such CCU controllers may be installed as a module inside a BTS station, but must also be part of the BTS or antenna transceiver. RET control can then be performed by either running control cables up the mast  6  or other structure a multi-band antenna is mounted to, or by combining the control signals with the transmitted radio signals over an antenna feeder cable. In this way, the RET controls stem from the individual CCU, thus forming separate systems. 
         [0039]    The tilt sensor module  104  provides multiple individual communication ports  105  for multiple communication protocols. The tilt sensor module  104  shares its detected information over the multiple communication ports  105 . The tilt sensor module  104  feeds into a master micro controller  106 , which in turn communications with an unlimited number of slave micro controllers  108 , at least one for each communication protocol. These slave controllers  108 . 1 ,  108 . 2 ,  108 . n  in turn control the slave communications modules  110 . 1 ,  110 . 2 ,  110 . n,  power supplies  112 . 1 ,  112 . 2 ,  112 . n,  and other components located in each protocol. Because each protocol contains a separate power supply  112 , each protocol will respond as an individual device. 
         [0040]    The tilt sensor module  104 , as described in the previous embodiments, may be a one, two, or three axis accelerometer. The module  104  can communicate its readings across the communication ports  105  to the master controller  106 , which then handles each of the unlimited number of slave protocol systems. This allows a single tilt sensor module  104  to capably orient and monitor a multi-band antenna no matter the number of protocols used by that antenna or the number of independent antenna motors or busses are included in the multi-band antenna. 
         [0041]      FIGS. 11 and 12  together show the difference between the present alternative embodiment and employing the previous embodiment within a multi-frequency antenna system. Two separate transceivers, a high-frequency transceiver  122  and a low frequency transceiver  120 , displaying a high frequency signal  124  and a low frequency signal  126 , are connected to two antenna bodies  130 ,  132 .  FIG. 11  displays a separate low frequency tilt sensor system  136  and a high frequency tilt sensor system  138 . Each are connected to the separate low-band RCU  140 . 1 ,  140 . 2  and the high-band RCU  142 . 1 ,  142 . 2 , respectively. 
         [0042]      FIG. 12  displays the present alternative embodiment employed on a multi-frequency antenna system. The single tilt sensor system  102  is communicatively connected to both the low-band RCU  140 . 1 ,  140 . 2  and the high-band RCU  142 . 1 ,  142 . 2 . This allows the single tilt sensor system to send communication signals to each individual RCU, and each RCU controls its separate frequency as an isolated system. 
         [0043]    It will be appreciated that the components of the sensor assemblies  2 ,  52 , and  102  are AISG and 3 rd  Generation Partnership Project (3GPP) compliant, and can be used for various other applications. Moreover, the sensor assemblies  2 , and  52  can be fabricated in various sizes and from a wide range of suitable materials, using various manufacturing and fabrication techniques. 
         [0044]    It is to be understood that while certain aspects of the invention have been shown and described, the invention is not limited thereto and encompasses various other embodiments and aspects.