Fiber optic gyro inertial measurement unit for fly-by-light advanced systems hardware

Smiths Industries (SI) is preparing a Fiber Optic Gyroscope (FOG) Inertial Measurement Unit (IMU) for incorporation into the Advanced Research Projects Agency Technology Reinvestment Project Fly-by-Light Advanced Systems Hardware (FLASH) laboratory demonstration. The IMU provides inertial data to the flight control system through the FLASH optical data bus and consists of three FOGs, three quasi-solid state accelerometers, sensor control electronics, a digital signal processor, and the optical data bus interface. Reliable, low cost solid state sensors are used to satisfy the performance requirements of the system. Specifically, the FOGs use state-of-the-art optical technology to measure aircraft rotations. FOGs have no moving parts and are therefore more reliable and durable than spinning wheel gyroscopes. Many FOG designs are based on a multitude of individual optical components and sensing coils fabricated from expensive polarization preserving fiber. Smiths Industries has developed a FOG design which uses low cost, commercially available single mode fiber in the rate sensing coils and makes maximum use of integrated optics to reduce cost and complexity. This sensor has demonstrated excellent tactical grade performance in a wide range of strenuous test environments. The SI FOG IMU is an important contributor to the performance, reliability, cost, and capability advantages of the FLASH system.