The Universal Time Solution Method And Implementation Based On Large Ring Laser Gyroscope

With the rapid development of China’s aerospace and deep space exploration,there is an increasingly urgent demand for higher accuracy and resolution time parameters.Universal Time(UT1),as a time scale based on the measurement of the Earth’s rotation,has the characteristics of long cycle and low resolution.Currently,China’s UT1 parameters are mainly obtained through the International Earth Rotation and Reference Systems Service(IERS),which relies heavily on the organization.Therefore,it is necessary to establish an independent and autonomous UT1 measurement and calculation system.Considering the advantages of large-scale laser gyroscopes in measuring real-time changes in Earth’s rotation,they can be used as a real-time supplement to current UT1 parameters.This paper focuses on the compensation methods for two types of errors,tilt and temperature,that large-scale laser gyroscopes are susceptible to,and designs an implementation plan through hardware circuit error compensation and UT1 parameter calculation.The main contents of this paper research include:Firstly,this paper starts from the principle of measuring the earth’s rotation,and derives the equation relating the Sagnac effect to the angular velocity of the earth’s rotation.From the perspective of this equation,the two sources of error in measuring the earth’s rotation,namely tilt error and temperature error,are analyzed.For the tilt error,the observation equation relating the tilt error to the frequency difference of the Sagnac effect is derived,and the self-error of the tilt data is analyzed using the Allan variance method.For the temperature error,three compensation methods are proposed based on the mechanism analysis and derivation of the temperature effect on the gyroscope scale factor,namely the direct adjustment method,the polynomial-based method,and the error backpropagation algorithm.The principles of the three methods are briefly introduced.Secondly,based on the analysis of errors,the design of error compensation algorithms is implemented,and the compensated data is solved.In terms of error compensation,a moving average difference autoregressive model is established using the time series method to compensate for the tilt error,which reduces the impact of the tilt error on the gyroscope Sagnac frequency difference and the angular velocity of the earth’s rotation by one to two orders of magnitude.Experimental verification of the direct adjustment method reveals that its idealized nature cannot compensate for temperature errors effectively.Polynomial-based and backpropagation neural network algorithms are designed and implemented to predict the gyroscope scale factor changes in real-time,thereby indirectly compensating for temperature errors and calculating the angular velocity of the earth’s rotation.A brief description of the relationship and calculation method between UT1 parameters and the angular velocity of the earth’s rotation is presented,and the main structure of the UT1 parameter solving system is established.The correction form of UT1 parameters is experimentally and computationally analyzed.Finally,based on the software algorithm implementation,the algorithm is mapped to a Field Programmable Gate Array(FPGA)circuit to establish a large-scale laser gyroscope hardware signal processing system.The overall hardware framework of the signal processing system and the evaluation criteria for assessing the quality of FPGA processing are introduced.Then,the design methods of each module of the system are described in detail,and simulation,experimental,and hardware calculation accuracy experiments and analysis are conducted.The system is capable of signal acquisition,tilt and temperature error compensation,Earth’s rotation angular velocity calculation,and UT1 parameter correction value calculation.