Micro-precision interferometer pointing control system

The paper describes the development of the wavefront tilt (pointing) control system for the JPL micro-precision interferometer (MPI). This control system employs piezoelectric actuators and a digital imaging sensor with feedback compensation to reject errors in instrument pointing. Stringent performance goals require large feedback, however, several characteristics of the plant tend to restrict the available bandwidth. A robust 7th-order wavefront tilt control system was successfully implemented on the MPI instrument, providing sufficient disturbance rejection performance to satisfy the established interference fringe visibility requirement.