A range compensating feed motion concept for spaceborne radar

A feed motion concept has been presented that permits a pair of aberration compensating feed arrays, one transmit and one receive, to cover a circular region of the scan sphere of a spherical reflector radar antenna in such a manner as to compensate via changes in linear velocity for the difference in range from synchronous orbit to the Earth\´s surface across the coverage area. The proposed mechanism requires only a single constant speed drive motor rotating at ω₁. The slower angular velocity is derived from this using a large circular interior ring gear engaging a mating gear on the higher speed axis; i.e., the fast axis "rolls" around the perimeter of the large interior gear ring.