ZHU Tianliang， WANG Xiaopeng， WANG Qi
（School of Electronics and Information Engineering, Lanzhou Jiaotong University, Lanzhou 730070， China）
Abstract： The echo of the material level is non-stationary and contains many singularities. The echo contains false echoes and noise, which affects the detection of the material level signals, resulting in low accuracy of material level measurement. A new method for detecting and correcting the material level signal is proposed, which is based on the generalized S-transform and singular value decomposition (GST-SVD). In this project, the change of material level is regarded as the low speed moving target. First, the generalized S-transform is performed on the echo signals. During the transformation process, the variation trend of window of the generalized S-transform is adjusted according to the frequency distribution characteristics of the material level echo signal, achieving the purpose of detecting the signal. Secondly, the SVD is used to reconstruct the time-frequency coefficient matrix. At last, the reconstructed time-frequency matrix performs an inverse transform. The experimental results show that the method can accurately detect the material level echo signal, and it can reserve the detailed characteristics of the signal while suppressing the noise, and reduce the false echo interference. Compared with other methods, the material level measurement error does not exceed 4.01%, and the material level measurement accuracy can reach 0.40% F.S.
Key words： echo signal； false echo； generalized S-transform； singular value decomposition (SVD)； level measurement
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基于广义S变换奇异值分解的料位回波检测与校正
朱天亮， 王小鹏， 王祺
（兰州交通大学 电子与信息工程学院， 甘肃 兰州 730070）
摘要:非平稳及多奇异点的调频料位测量雷达回波中包含虚假回波及噪声， 影响料位回波信号检测， 导致料位测量精度不高。 本文提出了一种基于广义S变换和奇异值分解的料位回波检测与校正方法。 首先， 将料位变化视作低速运动目标， 将料位回波信号与雷达发射信号进行混频解调， 并根据回波信号的频率分布特点对广义S变换窗口的变化趋势进行调节。 之后对其变换所得到的二维时频系数矩阵利用奇异值分解方法重构系数矩阵， 并对其进行广义S逆变换， 得到校正后的回波信号。 实验结果表明： 该方法能够准确检测料位回波信号， 在抑制噪声的同时能最大限度保留信号的细节特征， 减少虚假回波干扰。 料位测量误差不超过4.01%， 测量精度可达到0.40% F.S。
关键词:回波信号； 虚假回波； 广义S变换； 奇异值分解； 料位测量
引用格式：ZHU Tianliang， WANG Xiaopeng， WANG Qi. Detection and correction of level echo based on generalized S-transform and singular value decomposition. Journal of Measurement Science and Instrumentation, 2021, 12（4）： 442-448. DOI： 10.3969／j.issn.1674-8042.2021.04.008
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