All Digital Dual Closed-loop Differential Detection Scheme for Differential FOG Driven by Dual Source

The construction and principle of a differential fiber optic gyroscope driven by dual source (DS-DFOG) were briefly introduced first. And an all digital dual closed-loop differential detection scheme is proposed and demonstrated experimentally. This scheme consists of two parts: dual closed-loop detection circuit and frequency division differential processing algorithm. The former achieves synchronous closed-loop detection for two equivalent FOGs, while the latter obtains the rotation rate that eliminates temperature drift without increasing noise by differentiating the low-frequency signal and reconstructing it with the high-frequency signal. Based on this scheme, a DSDFOG prototype was developed and the comprehensive validation experiment and performance test were conducted. The results proved that the key dispersion compensation coefficient h in the differential algorithm model is a stable characteristic value of the assembled DS-DFOG. The developed DS-DFOG obtains a good linear response with scale factor nonlinearity 1.7 ppm, and provides up to a 12-fold suppression of temperature drift without increasing noise level. This provides a practical solution for constructing FOGs with superior performance and robust temperature adaptability.