Development Of Mobile Pollution Source Telemetry Terminal

With the development of China economy and society,the number of motor vehicles has increased significantly.While these vehicles have improved our quality of life,they have also caused significant damage to the urban air environment and affected the health of people.Therefore,it is crucial to monitor exhaust gas from mobile pollution sources.Roadside mobile pollution source monitoring is a scheme arranged on the side of the road and can implement remote sensing monitoring of motor vehicles.This paper conducts related research on the on-road real-time monitoring of mobile pollution sources and studies how to detect the concentration of a variety of pollutant in motor vehicle exhaust,how to build a terminal system for mobile pollution source monitoring,and how to deploy the mobile source telemetry terminal station reasonably in the urban traffic network.For the detection method of mobile pollution source pollutant gas,this paper studies the method of using differential absorption spectroscopy to measure the gas concentration of NO and HC simultaneously and the detection method of CO and CO2 gas concentration based on tunable laser diode laser technology.NO and HC gas has strong absorption peak in the ultraviolet band,by collecting the light intensity of the deuterium lamp and the light intensity after passing through the gas,and fitting the whole gas absorption spectrum of NO and HC by non-negative multiple linear fitting,accurate gas concentration measurement results can be obtained.For the concentration detection of CO and CO2,this article adopts a tunable laser diode and uses a wavelength modulation method to modulate the output wavelength of the laser to cover their absorption peaks,which improves the sensitivity of the system’s detection.Finally,an analog lock-in amplifier is used to extract the second harmonic information of the echo signal and deduce the gas concentration.The experimental results show that the method can achieve good results in detecting the concentration of each gas.For the research and development of the mobile pollution source monitoring terminal system,this paper has completed the terminal system that monitors the concentration of the mobile pollution source exhaust pollutants,related environment and vehicle body data,and completed the software and hardware design of each component of the monitoring terminal.The system mainly includes: a mobile pollution source data acquisition device to obtain vehicle exhaust gas concentration and opacity data.Real-time environmental data acquisition device used to monitor atmospheric temperature,humidity,wind speed,wind direction,and pressure and other meteorological data,road slope,and equipment location information.The mobile pollution source body data acquisition device mainly detects the vehicle license plate number,license plate color,vehicle speed,and acceleration information.Finally,this paper has completed the integration test and experiment of the complete mobile pollution source remote sensing terminal system.The analysis shows that the exhaust emissions of most vehicles on the road can meet the national standards.For the deployment problem of the mobile pollution source remote sensing station in urban traffic road networks,to balance the monitoring effect of the road network and the cost of site deployment,this paper proposes a new deployment method for sensor nodes in the traffic road network.First of all,to enable the monitoring network to cover all possible routes in the road network,this paper does not consider a fixed start-end pair but proposes a routes search method and searches all possible routes with each node as the starting point.Secondly,to overcome the massive amount of calculation caused by the search path,this paper adopts the mini-cut method to divide the searched path completely and proposes a method to calculating and deploying to reduce the amount of calculation significantly.Finally,this paper proposes a redundant node search method to eliminate redundant sites and reduce costs to the greatest extent.The experimental results show that the telemetry network deployment algorithm proposed in this paper can monitor all the roads in the road network while obtaining the deployment plan with the least number of stations,and the calculation time is also within a reasonable range.