Research On The Measurement Error Of Visibility Sensor

Visibility is not only a basic weather element, but also it reflects the level of atmospheric pollution. Visibility measurement is very important for monitoring the cleanliness of the air and ensuring the safety of highways, aviation and maritime transport. How to improve the accuracy of visibility measurement is an important research topic in the development of visibility measurement. There are many kinds of visibility sensors, and the factors of visibility measurement error are complex, with the improvement of the requirement of the accuracy, it is necessary to further research on the factors affecting visibility measurement error.This thesis studied the impact of the beam drift and the instability of bias voltage on visibility measurement error through experiments. The completed tasks are following:(1) The measurement error of transmission and scattering type visibility meter was analyzed, and the calculation formula of the measurement error of visibility sensor was derived. This paper analyzed the main factors of the visibility measurement error and solutions., deeply studied the beam drift and the instability of bias voltage.(2) This thesis studied the impact of laser spot drift on visibility measurement error, the relationship between the laser spot drift and the relative error of visibility was established. Through the comparison of the visibility relative error caused by two types photoelectric detectors’ sensitivity, a method to reduce the influence the measurement error on the visibility of the laser spot drift was presented.(3) This thesis studied the impact of the reverse bias voltage on the response time of photoelectric detector, and found that the instability of bias voltage would cause changes in the effective value of the output voltage. The relationship between the relative errors of visibility and the instability of bias voltage was established. Then, the pertinent suggestion of the selection of bias voltage value was proposed.