Antenna positioner system

A three-axis antenna positioner has an X-Y over azimuth configuration, and includes an azimuth drive assembly, an X-axis drive assembly, and a Y-axis drive assembly. Each drive assembly is independently operable. The azimuth drive assembly imparts 540° azimuthal rotational motion to an antenna about an azimuth axis. The X-axis drive assembly rotates the antenna about a horizontal X-axis at elevation angles between -90° and +90°. The Y-axis drive assembly rotates the antenna about a Y-axis at elevation complement angles between -2° and +105°. The azimuth axis, the X-axis, and the Y-axis all intersect at a common intersection point, and are mutually orthogonal. A controller operates each drive assembly so as to minimize antenna tracking velocity and acceleration. Each drive assembly may include dual drives, and may be operated in a bias drive mode to substantially eliminate backlash.