The sediment concentration measurement is one important part in monitoring soil and water loss. The research on development of sediment measurement sensor is of a great significance for real-time measurement, especially for high sediment concentration. In order to achieve the measurement of high sediment concentration, the paper analyzed the optical reflection and absorption features of sediment-laden water to lights of different wave lengths, and developed the related measurement device based on a near-infrared sensor with 1 800 nm (strong water reflection wave length) and 1 940 nm (strong water absorption wave length). Laboratory experiments were conducted to calibrate the sensor with three different sediment types collected from Yellow River, Weihe River and Tianshui, and the relationship of sediment concentration with sensor’s output was worked out. The results show that all the reflection intensity of two wave lengths near-infrared light increases with the sediment concentration. The sensor outputs are strongly and linearly correlated with sediment concentration when the sediment concentration is less than 300 kg/m3, and the coefficients of determination of the built linear model are greater than 0.9. In order to verify the accuracy of the model, the paper compares the measured sediment concentration with the model computed sediment concentration. The results show that both the regression coefficient close to 1, the relative error is less than 10%. It indicates that the sediment concentration which is computed by the linear model can be used as the measured values. The sensor is capable of measuring sediment concentrations from 1 to 300 kg/m3. When sediment concentration is greater than 10 kg/m3, the measurement accuracy is greater than 90%. The measurement accuracy of near-infrared sensor is also affected by other factors in stream flow,such as sediment types,dissolved NIR-absorbing matter and bubbles. The design of the sensor can meet the measured requirements of high sediment concentration in severe soil erosion area and has good adaptability. The near-infrared reflection sensor can be applied in real-time monitoring system and will be beneficial for the assessment of soil and water loss.% 水流含沙量测量是水土流失监测体系的重要内容,开展含沙量测量传感器的研究对于实时监测具有重要意义.为了实现对水流高含沙量的测量,该文根据含沙水对不同光谱的吸收和反射特性,采用1800 nm(强水分反射波长)和1940 nm(强水分吸收波长)近红外光源开发了泥沙测量传感器和测量装置,并对新型传感器进行了标定试验,分别建立了取自黄河、渭河和天水的泥沙与传感器输出信号之间响应关系.结果表明,当含沙量小于300 kg/m3时,测量得到的反射光强度随含沙量的增加而增加,传感器输出信号与含沙量之间具有很好的线性相关性,并建立了线性模型,决定系数均大于0.9.为了验证模型的精度,将实际含沙量与模型计算含沙量进行比较,结果表明,二者回归系数接近于1,相对误差小于10%,可以使用模型计算值代替实际含沙量.2种波长的传感器对含沙量的测量范围均为1~300 kg/m3,当含沙量大于10 kg/m3时测量精度大于90%,同时传感器精度受到泥沙种类、吸光物质和气泡等其他因素的影响.设计的传感器可以满足对高含沙量水流的测量要求,适用于土壤侵蚀严重的地区.研究结果在水土流失自动监测中具有良好的应用前景.
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