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Measurement Error Analysis and Software Correction of Guided Wave Radar Level Gauge |
LIU Zheng,WEI Meng,XU Ke-Jun |
School of Electrical and Automation Engineering, Hefei University of Technology, Hefei, Anhui 230009, China |
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Abstract The causes of the error of the guided wave radar level gauge (GWRLG) are analyzed, and a software correction method is proposed. The impacts of transmit pulse width and equivalent time sampling interval are studied in hardware. The gross error, the random error and the systematic error generated in the signal processing are researched in software. Based on the existing hardware platform, a set of signal processing method is put forward to reduce the measurement error, i.e., combining feature parameters to recognize the actual level echo, performing 9 point moving average to preprocess the signal, selecting the minimum slope point as the echo positing point, and conducting median average filtering for the calculated values. The experimental results of water level measurement show that the actual measurement error is reduced to within 1 cm when the theoretical error is 2~4 cm, which validates the effectiveness of the proposed software correction method.
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