Abstract
The fibre optic gyroscope (FOG) offers the potential of a low cost, high performance strap down inertial navigational instrument. In this article, the principles of the FOG are reviewed and the factors which limit the performance of the system are discussed. The basic Sagnac interferometer is shown to be susceptible to polarisation effects, optically induced nonlinearities and both spatial and temporal coherence within the optical source and within the passive gyroscope optics. However, with due attention to these phenomena, a high performance instrument is feasible. An assessment of the applications role of this instrument is presented together with some speculations on the required technological developments to produce the instrument.