Sagem Navigation GmbH is active in design, development, and production of Fiber-Optic Gyroscopes (FOG). Its actual products cover the range from single axis Fiber-Optic Rate Gyros, two-axes FOG modules, three-axes FOG and FOG type Inertial Measurement Units (FMU), up to the FOG triad in the sensing and measurement unit of the Attitude/Heading Reference Systems produced by Sagem, France. A well recognized feature and advantage of the FOG technology is that it provides largely scalable products based on a strictly modular design approach. In addition the form factor of a FOG is adjustable and it offers as one of its main advantages a very large and practically unlimited bandwidth. A demanding application is the use of a two-axes FOG for the stabilization of a periscope mirror. So far this has been a typical domain for mechanical gyros which offered in case of a DTG a two-axes sensor within a very small volume. The paper addresses the specific requirements for this type of application. It describes the theoretical background of the stabilization control loops, especially the need for a large bandwidth of the sensors, the transfer and noise characteristic, and its advantage with respect to stabilization performance. The design approach is presented with an explanation of the mechanical design. Moreover, the FOG sensing part is operated with remotely placed sensor electronics. Consequently, the solution for mounting the two parts has been a demanding task in the design of the product. The main parameters for scaling and adjusting performance are identified and discussed. Experimental results will show bias and noise characteristics of a FOG with a very small sensing coil, reduced noise, and large bandwidth.
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