Antenna Pointing Mechanisms

A common movable element on spacecraft is the communication (or radar/microwave) antenna. Antenna Pointing Mechanisms (APMs) have long been used to perform the vital function of pointing the antenna bore sight to its target and tracking to maintain the RF link to the spacecraft. APMs are typically two-axis gimbals. Antenna motion relative to the spacecraft is produced in either an elevation-over-azimuth or a cross-axis format. While elevation-over-azimuth format can yield full hemispherical coverage, the XY configuration is ideal for tracking satellites in Low-Earth Orbits (LEO) because it eliminates the problem of the overhead keyhole phenomenon, which causes lost data when communicating satellites pass directly overhead. The wide variety of antenna positioner assembles are compact, two-axis gimbals which are ideal for supporting and positioning small- to medium- to large-sized spacecraft communications antennas. Gimbals can be configured with either azimuth-elevation or X/Y (crossed axis) geometry, and several approaches to electrical cable management are available. Electrical cables can be carried across the gimbal axes in flexing loops, in cable wrap drums, or both. If an RF feed to the antenna is required, RF rotary joints can be integrated with the gimbal.


Antenna Pointing Products

Type 22 Antenna Pointing Mechanism

The Type 22 antenna positioner assembly is a compact two-axis gimbal which is ideally suited for supporting and positioning small to medium sized spacecraft communications antennas. It is based on the Moog Type 2 rotary incremental actuator

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Type 33 Biaxial Gimbal

The Type 33 Biaxial Gimbal is of a size appropriate for many antennas, and it has become by far our most popular Antenna Pointing Mechanism configuration. Available in either Elevation/ Azimuth or X/Y, these units have proven their reliability and versatility many times over. 

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Type 55 Biaxial Gimbal Assembly

The Type 55 biaxial gimbal assembly is a robust two-axis gimbal which is right-sized for supporting and positioning the majority of larger payloads. It is based on the Moog Type 5 rotary incremental actuator. The gimbal can be configured for limited rotation, with the inclusion of range-defining hard stops on the actuator outputs, or, for continuous rotation on one or both axes with the integration of a slip ring assembly.

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Type 11 Biaxial Gimbal

The Type 11 biaxial gimbal as shown consists of two Type 1 actuators in an orthogonal combination. The Type 1 actuators can be provided with a variety of options. These gimbals can be used for two-axis antennae or solar array drives.

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