Research On The High Accuracy Null-indicator Using Two-beam Interference

Dynamic angular-measuring system with a ring laser gyro (RLG) shows many advantages such as high precision, high speed, wide dynamic response. In the dynamic angular measurement, how to establish a reliable null spot is a key issue. The null-indicator (NI) using two-beam interference has the narrow pulse width and the high precision. The research starts with the principle and the optical design of the NI, aiming to seek a zero triggering system with a high precision and a fast dynamic response, which can satisfy the requirement of the dynamic RLG goniometer.Firstly, based on the theory of two-beam interference, the optical system of the NI is built, and the good interference fringes are obtained in the experiment. The interference signals are pre-amplified. The triggering circuit of the NI pulse is designed in view of the high-speed response requirement, and ultimately the ideal NI pulse is obtained.Secondly, the errors of the NI are analyzed. The errors including the manufacturing error of the Dove prism, the installation error and the NI pulse error are preliminarily analyzed, and the notes in the system designing are presented.Thirdly, the stability and dynamic response are tested by experiments. The results indicate that the repeatability is better than±0.20″at the rotation speed of 36o/s-360o/s, and the excellent dynamic response is obtained.Finally, the NI is applied in the RLG goniometer. The scale factor and the random errors are tested, and the measurement of the integer cycle angular is carried on. The results show that the NI using two-beam interference satisfies the application requirement of the RLG goniometer.