This paper proposes a novel method for calibrating error coefficients of the quartz accelerometer faster on the dynamic centrifuge,which can generate a continuous dynamic acceleration excitation.Firstly,working princi...This paper proposes a novel method for calibrating error coefficients of the quartz accelerometer faster on the dynamic centrifuge,which can generate a continuous dynamic acceleration excitation.Firstly,working principle and structure of the dynamic centrifuge are analyzed,the error sources and the uncertainty of the dynamic centrifuge are expounded,and relevant coordinate systems are established.Then,according to the characteristics of the input specific forces and the propagating methods of the error sources,the accurate input specific forces acted on the input reference axes of accelerometer are obtained.Based on the calibration error model of the accelerometer,the corresponding dynamic calibration method is proposed.Finally,the second-order and high-order coefficients of the acceleration error model are calibrated,and the calibration precision of the coefficients is analyzed.Compared with traditional calibration methods,the method proposed in this paper not only greatly enhances the calibration efficiency by reducing the installing positions of the accelerometer,but also separates the centrifuge errors from the outputs of the accelerometer,which improves the accuracy and efficiency of the calibration method simultaneously.展开更多
Low Earth Orbit satellite on-board accelerometers play an important role in improving our understanding of thermosphere density;however,the accelerometer-derived densities are subject to accelerometer calibration erro...Low Earth Orbit satellite on-board accelerometers play an important role in improving our understanding of thermosphere density;however,the accelerometer-derived densities are subject to accelerometer calibration errors.In this study,two different dynamic calibration schemes,the accelerometer parameter-incorporated orbit fitting and precise orbit determination(POD),are investigated with the Gravity Recovery And Climate Experiment(GRACE)satellite accelerometers for thermosphere density derivation during years 2004–2007(inclusive).We show that the GRACE accelerometer parametrization can be optimized by fixing scale coefficients and estimating biases every 60 min so that the orbit fitting and POD precision can be improved from 10 cm to 2 cm in the absence of empirical acceleration compensations and as a result the integrity of calibration parameters may be reserved.The orbit-fitting scheme demonstrates similar calibration precision with respect to POD.Their bias estimates in the along-track and cross-track components exhibit an offset within 0.1%and a standard deviation(STD)less than 0.3%.Correspondingly,a bias of 2.20%and a STD of 5.75%exists between their thermosphere density estimates.The orbit-fitting and POD-derived thermosphere densities are validated through the comparison against the results published by other institution.The comparison shows that either of them can achieve a precision level at 6%.To derive thermosphere density from the rapid-increasing amount of on-board accelerometer data sets,it is suggested to take full advantage of the orbit-fitting scheme due to its high efficiency as well as high precision.展开更多
文摘This paper proposes a novel method for calibrating error coefficients of the quartz accelerometer faster on the dynamic centrifuge,which can generate a continuous dynamic acceleration excitation.Firstly,working principle and structure of the dynamic centrifuge are analyzed,the error sources and the uncertainty of the dynamic centrifuge are expounded,and relevant coordinate systems are established.Then,according to the characteristics of the input specific forces and the propagating methods of the error sources,the accurate input specific forces acted on the input reference axes of accelerometer are obtained.Based on the calibration error model of the accelerometer,the corresponding dynamic calibration method is proposed.Finally,the second-order and high-order coefficients of the acceleration error model are calibrated,and the calibration precision of the coefficients is analyzed.Compared with traditional calibration methods,the method proposed in this paper not only greatly enhances the calibration efficiency by reducing the installing positions of the accelerometer,but also separates the centrifuge errors from the outputs of the accelerometer,which improves the accuracy and efficiency of the calibration method simultaneously.
基金the National Natural Science Foundation[grant numbers 42004020,42074032,41931075 and 42030109]National Defense Key Laboratory of Aerospace Flight Dynamics technology(grant number 6142210190101)+2 种基金China Postdoctoral Science Foundation[grant number 2021M692460]the Fundamental Research Funds for the Central Universities[grant number 2042021kf0060]Wuhan Science and Technology Bureau[grant number 2019010701011391].
文摘Low Earth Orbit satellite on-board accelerometers play an important role in improving our understanding of thermosphere density;however,the accelerometer-derived densities are subject to accelerometer calibration errors.In this study,two different dynamic calibration schemes,the accelerometer parameter-incorporated orbit fitting and precise orbit determination(POD),are investigated with the Gravity Recovery And Climate Experiment(GRACE)satellite accelerometers for thermosphere density derivation during years 2004–2007(inclusive).We show that the GRACE accelerometer parametrization can be optimized by fixing scale coefficients and estimating biases every 60 min so that the orbit fitting and POD precision can be improved from 10 cm to 2 cm in the absence of empirical acceleration compensations and as a result the integrity of calibration parameters may be reserved.The orbit-fitting scheme demonstrates similar calibration precision with respect to POD.Their bias estimates in the along-track and cross-track components exhibit an offset within 0.1%and a standard deviation(STD)less than 0.3%.Correspondingly,a bias of 2.20%and a STD of 5.75%exists between their thermosphere density estimates.The orbit-fitting and POD-derived thermosphere densities are validated through the comparison against the results published by other institution.The comparison shows that either of them can achieve a precision level at 6%.To derive thermosphere density from the rapid-increasing amount of on-board accelerometer data sets,it is suggested to take full advantage of the orbit-fitting scheme due to its high efficiency as well as high precision.
