Low-cost and compact fiber-optic gyroscope with long-term stability

There is a need for rate sensors that can provide long-term stability for augmenting antenna pedestal gyro units and replacing overly expensive devices used to overcome attitude limitations in existing inertial navigators. In this paper, we present an innovative fiber-optic gyroscope (FOG) with excellent long-term stability in a light-weight, compact and low-cost device package. The proposed device is designed to function in high vibration environments typically encountered within inertial navigation platforms. We have demonstrated a FOG prototype comprising a polarization-maintaining coiled fiber, a specially designed phase modulator, an ultra-efficient optical source and packaging designed to minimize size and weight. Preliminary experiments have established the requisite stability and attitude accuracy over a period of several hours. The work reported here describes an innovative approach for the design, fabrication and testing of the FOG toward the production of a small (<; 5 cubic inches), robust and low cost gyro with excellent long-term stability and bandwidth characteristics. The Intelligent Fiber Optic Systems (IFOS) gyros are implemented using a distributed architecture. The sensor package design is environmentally ruggedized. This paper presents the current state-of-the-art performance of FOGs and the potential for further reduction of size with improved long-term stability performance. The noise at high frequencies does not flatten out and extremely high bandwidth (up to 100 kHz) operation is possible without any degradation of the operational stability. The IFOS design has opened the way for a future, smaller and extremely robust FOG. Both theoretical modeling and experimental results will be presented.