SBIR-STTR Award

Imaging ladar systems for applications such as seekers on autonomously guided munitions must be compact, inexpensive and reliable. These systems often have a pointing system that consists of a fine-steering mirror (FSM), typically a small high-bandwidth two-axis optic and a course-steering mirror (CSM), typically a full-aperture large-travel optic or a gimballed telescope. This proposal seeks to reduce the mass, volume, power and complexity of the system by combining the FSM and CSM functions in one full-aperture high-bandwidth large-travel FSM. Full-aperture optics with ±175mrad mechanical travel exist, but their servo control bandwidth is limited by large-travel-specific factors. Increased bandwidth must be achieved without sacrificing pointing precision, surface figure, low mass, size or power performance. LHDC’s large-travel FSM currently achieve a -3dB closed-loop servo control bandwidth of >200 Hz. The bandwidth of these FSM is limited by bending modes that are coupled to the servo at full travel. This proposal is to increase servo bandwidth with an innovative suspension with an innovative, stiffer and lighter suspension.

Keywords:
Fine-Steering Mirror, Fast-Steering Mirror, Ladar Scanner, High-Bandwidth, Large Travel, Interceptor Seeker, Low Mass, Remote Sensing

The proposed Fine-steering Mirror (FSM) technology supports high-acceleration flyback and line-of-site (LoS) jitter compensation scanning for enhanced LADAR discrimination onboard interceptor seekers. This FSM combines large-travel, high-acceleration scanning with high-bandwidth LoS stabilization. A number of creative mechanical and servo control electronic innovations have been used to increase the servo control bandwidth of LHDC’s large-travel, high-accuracy FSM designed for a 100mm optical beam. Today’s pointing, tracking and imaging optical systems are in general limited in terms of angular resolution and residual jitter by the servo control bandwidth and surface figure error of the pointing mechanism. Excellent performance in both of these areas is required to support high-quality LADAR imaging. Additionally the ability to survive launch vibration and shock environments is necessary for mission success. The proposed effort extends the ability of FSM to provide improved servo control bandwidth along with high-acceleration, large-travel scanning and surface figure error performance in the harsh vibration environments of interceptor vehicles.

Keywords:
High Bandwidth, High Acceleration, Large-Angle Scanning, Fine-Steering Mirror, Fast-Steering Mirror, Ladar Optics, Ladar Scanning