Confocal phased array fed reflector antenna beam stabilization

A method of operating an antenna system, comprising:

• in a star tracker element coupled to a feed structure, determining orientation information relative to star alignment;
• in laser distancing elements coupled to the feed structure, determining distance measurements relative to a plurality of reflective targets disposed about a rim of a main reflector, the reflective targets having corresponding shapes selected to provide reflection of beams emitted by the laser distancing elements over a range of orientations relative to the feed structure producible by a gimbal mechanism for the main reflector;
• and
• in a control system, determining pointing errors of the main reflector based at least on the orientation information and the distance measurements, wherein a sub-reflector coupled to the feed structure is configured to propagate signals between an electronically scanned array (ESA) feed and the main reflector.

A control system for an antenna arrangement having a main reflector positioned in relation to a sub-reflector, the control system comprising:

• a star tracker interface configured to receive orientation information indicating a relative orientation of a feed structure housing the sub-reflector and an antenna feed system to star alignment;
• a laser ranging interface configured to receive indications of at least four distance measurements of the feed structure relative to a rim of the main reflector;
• processing circuitry configured to determine pointing errors of the main reflector relative to the feed structure based at least on the orientation information and the indications of the distance measurements by at least determining normals of at least four planes defined by sets of three distance measurements and averaging the normals to calculate a best fit for a plane defining the rim and corresponding to a relative orientation between the feed structure and the main reflector;
• the processing circuitry configured to apply the pointing errors to instruct the antenna feed system to adjust steering of a signal towards a target.