Antenna with low-cost steerable subreflector
Methods of antenna pointing and antenna assemblies implementing those methods are disclosed. An example method includes providing a user terminal antenna assembly including an antenna and an auto-peak device. The antenna includes a reflector, a subreflector, and a feed, the feed oriented relative to the reflector and the subreflector to produce a beam. The antenna further includes a tilt assembly to tilt the subreflector relative to the reflector and the feed. The method further includes providing a control signal to tilt the subreflector in a plurality of tilt positions to move the beam while measuring corresponding signal strength of a signal communicated via the antenna at each of the plurality of tilt positions. Additionally, the method includes selecting a tilt position from the plurality of tilt positions based on a measured signal strength, and providing the control signal to tilt the subreflector to the selected tilt position.
1 . A method of antenna pointing of an antenna that produces a beam, is disposed on a stationary support pier, and comprises a reflector, a subreflector, and a tilt assembly, the method comprising:
receiving, from an auto-peak device, a control signal to control the tilt assembly to tilt the subreflector in a plurality of tilt positions, relative to the reflector, to move the beam while a corresponding signal strength of a signal communicated via the antenna at each of the plurality of tilt positions is measured; and
tilting the subreflector to at least one tilt position of the plurality of tilt positions in response to the control signal,
wherein the tilt assembly comprises:
the subreflector;
the reflector;
a base structure connected to a support beam that further connects to the reflector;
a pivot assembly configured to couple the subreflector to the base structure such that the subreflector is configured to pivot in one or more directions about a pivot point at the pivot assembly relative to the base structure;
one or more actuators configured to tilt the subreflector in one or more tilt positions relative to the reflector and to cause the subreflector to pivot about the pivot point; and
a counter-force device configured to maintain a force on the subreflector and dampen movement of the subreflector in response to the one or more actuators,
wherein the one or more actuators are configured to tilt the subreflector to the one or more tilt positions in response to the control signal.
2 . The method of claim 1 , wherein the tilt assembly further comprises a spring connected between the base structure and a backside of the subreflector.
3 . The method of claim 1 , wherein the one or more actuators comprises a first actuator and a second actuator each comprising a motor configured to tilt the subreflector about the pivot point, and wherein tilting the subreflector in response to the control signal causes movement of the motors in the respective first and second actuators.
4 . The method of claim 1 , further comprising providing a fixed user terminal antenna assembly comprising the antenna and the auto-peak device, wherein the subreflector is coupled to the reflector via a support boom and the reflector is coupled to a support pier by a mounting bracket assembly, wherein the antenna further comprises a feed and a transceiver assembly on the support boom, and wherein the feed is oriented relative to the reflector and the subreflector to produce a beam.
5 . The method of claim 1 , further comprising:
providing, by the auto-peak device, the control signal to the tilt assembly to tilt the subreflector in the plurality of tilt positions, relative to the reflector, to move the beam while measuring the corresponding signal strength of the signal communicated via the antenna at each of the plurality of tilt positions; and
selecting, by the auto-peak device, the control signal to tilt the subreflector to a selected tilt position.
6 . The method of claim 5 , further comprising transmitting an alert when the selected tilt position is at a predetermined maximum tilt angle from a neutral tilt position of the subreflector.
7 . The method of claim 6 , wherein the alert provides notification that the subreflector is near a tilt limit of the subreflector and that gross aiming of a terminal antenna assembly may be required.
8 . The method of claim 1 , further comprising periodically providing the control signal to tilt the subreflector in the plurality of tilt positions and periodically selecting a selected tilt position.
9 . The method of claim 8 , wherein providing the control signal to tilt the subreflector in the plurality of tilt positions and selecting a selected tilt position is performed to verify an installation of a user terminal antenna assembly.
10 . The method of claim 1 , further comprising providing the control signal and selecting a selected tilt position when a determination is made that the antenna is mis-pointed.
11 . The method of claim 1 , wherein moving the beam comprises moving the beam in both elevation and azimuth directions.
12 . A steerable subreflector assembly for adjusting an orientation of a subreflector relative to a reflector of an antenna assembly on a stationary support pier to move a user terminal beam of the antenna assembly in response to a control signal, the subreflector assembly comprising:
the subreflector;
a base structure connected to a support beam that further connects to the reflector;
a pivot assembly configured to couple the subreflector to the base structure such that the subreflector is configured to pivot in one or more directions about a pivot point at the pivot assembly relative to the base structure;
one or more actuators configured to tilt the subreflector in a plurality of tilt positions relative to the reflector and to cause the subreflector to pivot about the pivot point; and
a counter-force device configured to maintain a force on the subreflector and dampen movement of the subreflector in response to the one or more actuators,
wherein the control signal is received from an auto-peak device, and
wherein the one or more actuators are configured to tilt the subreflector to one or more of the plurality of tilt positions in response to the control signal.
13 . The steerable subreflector assembly of claim 12 , wherein the control signal is generated based on measuring corresponding signal strengths of a signal communicated via the antenna assembly at each of the plurality of tilt positions.
14 . The steerable subreflector assembly of claim 12 , wherein the one or more actuators comprises:
a first actuator connected to the base structure and in contact with a backside of the subreflector at a first point; and
a second actuator connected to the base structure and in contact with the backside of the subreflector at a second point, wherein movement of at least one of the first and second actuators tilts the subreflector relative to the base structure and configured to provide both azimuth and elevation movement of the user terminal beam.
15 . The steerable subreflector assembly of claim 14 , wherein the counter-force device contacts the backside of the subreflector at a third point, wherein the third point is located on a first portion of the backside of the subreflector, and wherein the first and second points are located on a second portion of the backside of the subreflector opposite the first portion.
16 . The steerable subreflector assembly of claim 14 , wherein the first actuator is in contact with the backside of the subreflector through a point contact, and wherein the second actuator is coupled to the subreflector through a sliding joint.
17 . The steerable subreflector assembly of claim 14 , wherein the first actuator is connected to the backside of the subreflector through a spherical adapter connection and the second actuator is connected to the backside of the subreflector through a sliding joint connection.
18 . The steerable subreflector assembly of claim 12 , wherein the counter-force device comprises a spring, a hydraulic piston, a rubber band, or a bungy cord.
19 . The steerable subreflector assembly of claim 12 , wherein the one or more actuators are connected to a backside of the subreflector through respective kinematic joint connections.
20 . The steerable subreflector assembly of claim 12 , wherein the one or more actuators each comprise a motor and are configured to tilt the subreflector about the pivot point.
21 . The steerable subreflector assembly of claim 12 , wherein the one or more actuators are each respectively connected to a backside of the subreflector through a snap-fit connection.
22 . The steerable subreflector assembly of claim 12 , wherein moving between the plurality of tilt positions is configured to facilitate moving the user terminal beam in both elevation and azimuth directions.
23 . The steerable subreflector assembly of claim 12 , wherein the auto-peak device is configured to periodically provide the control signal to the steerable subreflector assembly to tilt the subreflector in the plurality of tilt positions and periodically select the tilt position.
24 . The steerable subreflector assembly of claim 23 , further comprising an alert device configured to transmit an alert, when the selected tilt position is at a predetermined maximum tilt angle from a neutral tilt position of the subreflector.
25 . The steerable subreflector assembly of claim 12 , wherein a backside of the subreflector comprises three connection points including a first actuator of the one or more actuators, a second actuator of the one or more actuators, and the counter-force device.
26 . The steerable subreflector assembly of claim 25 , wherein the counter-force device is on an opposite side of a midline of the backside of the reflector from the first and second actuators.