On Measurement-While-Drilling based on rotational inertial navigation system

In order to solve the problem of the fiber optical gyro's (FOG) long-time measurement error in terms of measuring well trajectory, a method based on rotation modulation along with the Y axis is proposed in this paper. The axial velocity integrated method which uses the closed-loop Kalman filter is proposed to be applied to the Measurement While Drilling (MWD) as well. In this paper, simulation results show that inertial navigation system based on rotation modulation can reduce the impact of constant drift of inertial components, and improve the long-time navigation accuracy which is 2 to 5 times better than the one without it. Simulation also shows that the accuracy of position and attitude is improved largely with the integration of axial velocity.