Method to suppress the temperature dependency of scale factor in measurement-while-drilling surveying utilizing fiber optic gyroscope

We analyze the north finding error caused by temperature dependency of scale factor theoretically in measurement-while-drilling surveying utilizing single-axis fiber optic gyroscope (FOG). Theoretical analysis indicates that the error will increase as the inclination angle increases, and it reaches the maximum when the sensitive axis of FOG points to the east or the west. To suppress the temperature dependency, we first employ a polynomial model to compensate the system error of scale factor. And then we give a formula to estimate the optimal calibration value of scale factor, which can reduce the north finding error caused by the random error of scale factor. Experiments with a specific single-axis FOG demonstrate that, with our method, the north finding error can be reduced from 3.966deg to 1.050deg.