Influence Analysis And Simulation Research Of Timescale Error In Combined Measurement System

Accurate time measurement and mark the measured value with accurate timescale are very important to improve the measurement accuracy of signal in measurement system.However,in practical applications,due to various possible reasons,there is a deviation between the measurement time of the signal mark and the actual measurement time,which is called timescale deviation.The existence of the timescale deviation will introduce a measurement error into the measured signal,which is called a timescale error.In satellite-to-satellite tracking technology,satellite radar altimetry technology,Two-way time comparison technology between stations and other measurement systems,the timescale error is an important error item that affects the measurement accuracy of signals.When the signals in multi-observation measurement systems are combined,if there is an independent clock source in each measurement system,and the noise of the clock source is unavoidable,after the combined operation of the signals in multi-observation measurement systems,the signal accuracy after operation is also affected by the timescale error.Therefore,it is of great scientific significance to analyze the influence of timescale error on measurement accuracy in combined measurement system.This paper introduces the formation principle,definition and classification of timescale error in combined measurement system.The timescale error of any form of signal in single observation measurement system is theoretically modeled in time domain and frequency domain.It is found that the timescale error will be affected by the change rate of signal with time and the magnitude of time scale deviation.The expression of the total timescale error is given for the linear operation of signals from multi-observation measurement systems.Since the signal of any form can be expressed as the superposition of multiple sinusoidal signals,the relationship between various parameters of the sinusoidal signal and the timescale error in the combined measurement system is analyzed.It is found that the absolute magnitude of the timescale error is mainly affected by the amplitude,frequency and timescale deviation of the signal,and the relative magnitude of the timescale error is mainly affected by the frequency and timescale deviation of the signal.The absolute and relative magnitude of the timescale error is little affected by the initial phase of the signal.Finally,the modeling formulas of the timescale error in the combined measurement system,and the relationship between the parameters of the sinusoidal signal and the timescale error are simulated respectively.The magnitude of the timescale error is evaluated from the relative value of the timescale error and its power spectral density,and the relative value of the variance of the timescale error and its average value in time.The simulation results show that it is consistent with the theoretical analysis.