Research on noise suppression technology of high precision fiber optic gyroscope

With the rapid development of FOG inertial navigation technology in China, it is possible for FOG inertial navigation system to achieve nautical mile in a navigation accuracy under temperature control environment. As the core component of FOG inertial navigation system, the performance of high precision FOG directly affects the accuracy of navigation system. Even in a good temperature control environment, the current performance index of high precision FOG is not enough to support the navigation accuracy of one mile in January. Broadband ASE light source is widely used in high precision fiber optic gyroscopes. The low temporal coherence of the light source is conducive to improving the noise level and bias stability of the gyroscope. With further research, If the output power of ASE light source exceeds a certain level (The power detected by photoelectric detector greater than 10uw), it is found that the relative intensity noise(RIN) of the light source will be the main noise of the FOG. On the basis of studying the sources of fundamental noises (especially intensity noise) in high precision FOG, this paper puts forward the technology of suppressing the noise of high precision FOG, and further designs (large ring size and fiber length) and develops a prototype of high precision FOG with noise suppression technology. The test results of the prototype demonstrate the effectiveness of the suppression technique (for example, ALLAN variance comparison results before and after using suppression technique). The prototype of the accuracy is expected to approach the navigation accuracy of nautical mile in a month through further testing in the FOG inertial navigation system.