Temperature Compensation Research For Laser Gyro In Strapdown Inertial Measurement System

Ring laser gyro(RLG) is optical sensor based on Sagnac Effect, because of its many advantages, RLG has been the central component in new generation strapdown inertial navigation, which is widely used in aviation, navigation, land navigation, positioning and heading, launch vehicle, missile and other fields. Laser strapdown inertial navigation system(LSINS) works in a complex environment, how to provide accurate, stable position and orientation information is a big challenge in LSINS. When the LSINS works steadily, bias is one of the three errors of RLG. The effect of temperature on the laser gyroscope becomes the main factor of occurring bias. The main features are randomness and instability. When the RLG works in high accuracy conditions,the bias temperature error must be compensated to reduce the effect of temperature on navigation accuracy.The influence of temperature change on RLG's accuracy is a combined process, when LSINS works, the internal temperature field is complex. The influence of temperature to each component is different, which adds more difficulty on temperature error modeling and compensation. At first, the temperature filed of RLG and LSINS is analyzed by the Ansys software,The analysis shows the distribution of temperature field under steady temperature and transient temperature conditions. Thermal stress analysis is also used and shows the curve of thermal stress and temperature. The temperature simulation analysis can offer reference for thermal design and temperature compensation. Subsequently, According to a large amount of experiments, the laser gyroscope drift under different temperature environments was analyzed. By means of correlation analysis and regression analysis, the temperature points location, multi-temperature compensation effect and the stability and environmental adaptability of temperature compensation model were mainly studied. The temperature compensation model of RLG is to be used in navigation system, at last, it is shown that the model can be used for engineering application by actual navigation experiments.The temperature compensation model can improve the precision of RLG and can be used in engineering application. The model parameter can be easily obtained by temperature experiment. The model compensation method nearly needs no extra hardware investment, it only needs to write the model in software and subtract the RLG output by the model value, which has the practicability in engineering.