一种基线长度改变的能见度测量和评价方法

Changing Baseline Lengths Method of Visibility Measurement and Evaluation

针对能见度真值难以确定和能见度仪测量结果难以评价的问题，提出了一种基线长度改变的能见度测量和评价的方法，并采用整体最小二乘拟合方法来降低基线长度的定位误差和透射率测量误差对消光系数的影响，提高了消光系数的测量精度。为验证方法的有效性和评价该方法在不同能见度条件下的测量性能，设计了移动测试平台，在大气模拟舱模拟了一次能见度由高到低持续变化的过程，采用多点多次测量的方式测量了环境的消光系数及能见度。实验结果表明该方法在不同能见度条件下，均有较高的测量稳定性和一致性。确定系数随能见度的降低而增大，能见度大于3000m时，确定系数也达到0．9以上，低能见度时可以达到0．99。各种能见度条件下，单位权方差在10-4～10-2之间，表明该方法测量的离散性很小，测量精度高，可作为能见度仪校正和标定的参考。

To improve the accuracy of the visibility measurement and the evaluation of the measurement results, one method of changing baseline lengths visibility measurement is proposed. The least squares method is used to reduce the impact of errors of the position of the receiver and transmittance measurement on extinction coefficient. This can improve the measurement accuracy of the extinction coefficient. To verify the effectiveness of the method and evaluate the performance of the method under different visibility conditions, one mobile measuring platform is designed. Meanwhile a continuous atmospheric environment changing from high to low visibility is simulated in the atmospheric simulation chamber. In the simulation chamber, using the mobile platform, multi-point and multiple times measurements method is used to measure the extinction coefficient under different visibility conditions. The results show that this method has a high measurement stability and consistency under different visibility conditions. In the fitting process, coefficient of determination R2 increases with the visibility decreasing. When visibility is more than 3000 m, coefficient of determination can reach 0.9. Coefficient of determination can reach 0.99 in lower visibility. The unit weight variance is between 10-4 and 10-2 regardless of high or low visibility, this indicates the method has very smaller discrete and higher accuracy, which makes it potential to be used as the calibration of instrument and calibration of reference.