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High-precision gravity correction methods for loess plateau areas, a case study 被引量:1
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作者 Ji Liansheng Zheng Li 《Applied Geophysics》 SCIE CSCD 2007年第2期89-93,共5页
The loess plateau is featured by a sharply undulated and remarkably incised surface. The sharp surface undulation means great variation of loess thickness. Since the loess layer exhibits significant density contrast w... The loess plateau is featured by a sharply undulated and remarkably incised surface. The sharp surface undulation means great variation of loess thickness. Since the loess layer exhibits significant density contrast with the underlying formation, a high frequency gravity anomaly with a certain magnitude will appear. The high frequency gravity anomaly can result in some difficulties for processing and interpreting the gravity data, thereby reducing the usefulness of gravity surveys in loess plateau areas. We carried out a high precision gravity survey in the SHJZ structural zone. During data processing, we applied terrain and loess corrections to effectively remove or suppress the gravity effect resulting from surface undulation and variation of loess thickness. We obtained high precision gravity data which matches well with other geophysical data. The comprehensive interpretation based on the final gravity data help to study local structure integrated with other published geophysical data. 展开更多
关键词 high precision gravity survey gravity anomaly DENSITY loess correction terrain correction
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Semi-analytical assessment of the relative accuracy of the GNSS/INS in railway track irregularity measurements 被引量:2
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作者 Qijin Chen Quan Zhang +1 位作者 Xiaoji Niu Jingnan Liu 《Satellite Navigation》 2021年第1期352-367,共16页
An aided Inertial Navigation System(INS)is increasingly exploited in precise engineering surveying,such as railway track irregularity measurement,where a high relative measurement accuracy rather than absolute accurac... An aided Inertial Navigation System(INS)is increasingly exploited in precise engineering surveying,such as railway track irregularity measurement,where a high relative measurement accuracy rather than absolute accuracy is emphasized.However,how to evaluate the relative measurement accuracy of the aided INS has rarely been studied.We address this problem with a semi-analytical method to analyze the relative measurement error propagation of the Global Navigation Satellite System(GNSS)and INS integrated system,specifically for the railway track irregularity measurement application.The GNSS/INS integration in this application is simplified as a linear time-invariant stochastic system driven only by white Gaussian noise,and an analytical solution for the navigation errors in the Laplace domain is obtained by analyzing the resulting steady-state Kalman filter.Then,a time series of the error is obtained through a subsequent Monte Carlo simulation based on the derived error propagation model.The proposed analysis method is then validated through data simulation and field tests.The results indicate that a 1 mm accuracy in measuring the track irregularity is achievable for the GNSS/INS integrated system.Meanwhile,the influences of the dominant inertial sensor errors on the final measurement accuracy are analyzed quantitatively and discussed comprehensively. 展开更多
关键词 Inertial surveying Relative measurement accuracy Error propagation modeling Steady-state Kalman filter Precise engineering surveying
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