Architecture and Encoder Solutions for Common Passive/Active Systems

Period of Performance: 04/17/2000 - 01/17/2001


Phase 1 SBIR

Recipient Firm

Ssg, Inc.
65 Jonspin Road
Wilmington, MA 01887
Principal Investigator


For combined electro-optical (EO) sensors in which infrared and active laser systems operate through a single aperture, beam pointing and hand-over become significant challenges. SSG proposes to address this problem with an innovative optical-proximity sensor (OPS) to replace current temperature-sensitive eddy current devices used in fast steering mirrors. Further, SSG proposes to develop a telescope and pointing architecture that meets the disparate requirements of the passive and active systems, and to compare the results of the OPS against the system design requirements. The OPS will permit agile steering to the micro-radian level without temperature calibration. Combined aperture systems need this accuracy because the active laser beam and field-of-view (FOV) often subtend only 1-2 passive pixels, and thus a thermally sensitive steering mirror can result in misalignment greater than the laser FOV, resulting in a failed hand-over from passive to active. In Phase I, SSG will perform two main tasks: develop a passive/active combined-aperture opto-mechanical design including beam steering provisions; and build and test a brassboard OPS as the baseline for the active channel beam steering encoder. The proposed design and technology will directly apply to passive FLIR targeting with active interrogation, airborne missile warning and countermeasures, and future interceptors. In addition to defense applications, combined sensors can be applied to air-, ground-, and space-borne environmental monitoring where lidar systems can be combined with IR sounders. In the private sector, combined sensors can be applied to commercial metrology, 3-D machine vision, and other forms of non-contact inspection and monitoring. The optical proximity sensor can be applied to a wide variety of closed-loop precision motion systems.