Development Of The Foreword Scattering Visibility Meter Based On Aerosol

Visibility as the main indicator of meteorological observation,the accuracy of its measurement of shipping,aerospace,aviation,road traffic and other production and life has a crucial role.With the rapid development of China's economy in recent years,haze phenomenon becomes more serious,which also made a higher demand for visibility testing equipment.Traditional transmission visibility detection method due to strict site requirements,high cost and other reasons,can not meet the needs of large quantities of multi-point deployment.This paper analyzes several methods of current visibility detection and based on the principle of aerosol forward scattering,developed a small size,wide application,easy to control,stable performance visibility meter.Firstly,this paper introduces the research status of the visibility meter and the measurement theory of the forward scattering visibility meter,and designs a visibility meter for the forward scattering principle according to the measurement theory of visibility.The hardware part of the visibility device is mainly composed of the transmitter,the receiver,the signal processing circuit and the display output part.The basic principle is:the transmitter sends the modulated infrared light pulse,due to the scattering effect of the atmosphere,the light pulse through the scattering,with the launch angle of 35° infrared receiver device received,and through the signal amplifier circuit to convert the optical signal for the electrical signal,and amplified to the appropriate multiple.Then use low-light detection commonly used lock-in amplifier circuit will receive the signal extracted from the noise,the use of PIC microcontroller A/D module to convert the two voltage signals into digital signals.Secondly,the design of the visibility of the software system.In the next bit machine program mainly AD sampling,visibility calculation and UART data transmission,in the host computer program,the main use of VC own MFC application programming,the use of MSCcomm control to achieve serial transmission and reception,and with the hardware system to work together to achieve the visibility of the measuring instrument,calculation,display and other basic functions.Finally,after the completion of optical path and circuit debugging,the visibility of the experiment,and the measurement process of the error and interference proposed a solution.The experimental results show that the technical specifications of the instrument can meet the design requirements,the measurement range is(10~10000)m,the measurement error is less than ±20%,and the basic visibility measurement function can be achieved.