Automatic compensation of optical path for gimbaled phased array telescope

摘要

An optical phased array system is disclosed that uses three methods of phased array retargeting: optical retargeting, element slew, and rigid body array slew. These work together in hierarchical fashion to reduce the retargeting disturbances and enhance system performance by shortening retargeting timelines. The optical train configuration given here is an embodiment for the approach to use the rotation of each array element (e.g. telescopes) in the phased array to provide most of the large optical path length shift required for phasing during a phased array look angle shift by individual telescope slew (i.e. venetian blind steering). The optical train configuration discussed here provides about 97% of the optical path length compensation required for a slew to +/-20 degrees from the array normal. This greatly reduces the amplitude required of the piston control mirror if an equal optical path length is to be maintained from object to sensor. The design geometry is specific to a seven element, one ring array although the concept is applicable to other array configurations.