Free Gyro Imaging IR Sensor In Rolling Airframe Missile Application

The Rolling Airframe Missile (RAM) provides the US and German Navies with a quick reaction, high firepower defense against Anti-Ship Missiles (ASM) such as the Exocet and SSN-22. RAM incorporates passive RF and IR sensors allowing track and guidance against both radiating and nonradiating threats. The "fire and forget" feature coupled with RAMs quick reaction protects ships against dense raids of ASMs. RAM has achieved exceptional accuracy and reliability during firings against simulated and real ASMs in both single and multiple threat scenarios. RAM incorporates several unique design features. RAM incorporates a statically controlled rolling airframe during flight with full maneuverability obtained by a single plane of control surfaces and a closed loop autopilot. A body fixed RF interferometer incorporates only two forward facing antennas, obtaining two planes of target information over the roll cycle. The IR sensor is mounted to a free gyro seeker, which also serves as the inertial reference for body decoupling. The IR sensor incorporates 80-element linear array which uses the free gyro spin and missile roll to provide an accurate inertially referenced IR image. This allows real time acquisition and discrimination of targets in a variety of maritime backgrounds. The IR sensor and signal processing will be the focus of this paper.