Design Of Reflective Laser Pavement Meteorological Detection System

The slippery state of roads is closely related to traffic safety.Installing road weather sensors on high-risk sections and issuing real-time warnings to passing vehicles can effectively reduce the incidence of accidents and improve the transportation efficiency of highways.Road surface meteorological sensors are divided into contact and non-contact types based on their detection methods.Contact sensors need to be installed with holes drilled on the roadbed,which has poor flexibility and is also prone to damage due to vehicle rolling.The non-contact sensor adopts remote sensing technology,which does not require damage to the road surface and can measure road meteorological data in real-time from a long distance.It has broad application prospects.In order to solve the problems of traditional contact type road surface weather sensors such as low service life,inconvenience in installation,and easy to damage the roadbed,a non-contact road surface weather sensor method was studied using lasers with two wavelengths of 1310 nm and 1430 nm as detection light sources,combined with infrared temperature measurement assistance.This method measures the backscattered light intensity formed by the illumination of a light source under different road conditions to obtain the reflectivity of water and ice dielectric films at two characteristic wavelengths.By calculating and analyzing the reflectivity,pavement meteorological information can be obtained.Firstly,based on Lambert Beer’s law and the analysis of the propagation path of laser beams,a theoretical model for measuring the thickness of water accumulation and ice formation was derived.An automatic calibration method based on the zero point of relative reflectance was proposed.A simulation platform was built to verify the feasibility of the measurement theory and method through laser wavelength,detection mathematical model,and small signal acquisition method;Then,based on demand analysis,a practical road weather sensor was designed and a related detection system was built;Finally,sensors were used to measure the meteorological status of the road surface,as well as the thickness of accumulated water and ice on asphalt and stone surfaces.In road surface conditions,a mixed discrimination logic of relative reflectance and infrared temperature signals can be used to achieve reliable recognition of various road surface conditions,including dryness,humidity,water accumulation,icing,and frost.For thickness parameter measurement,the reflectance zero point is used to automatically distinguish and calibrate the measurement model parameters.Accurate measurement can be achieved under different road conditions without on-site calibration,effectively solving the problem of baseline drift when measuring at different angles on different road surfaces.The road meteorological sensor designed in this article has the characteristics of simple structure,long detection distance,and low cost.In terms of measurement methods,five road meteorological states are accurately determined through mixed logic judgment;The automatic calibration method of reflectance zero point has been used to measure the thickness of accumulated water and ice.Experiments have shown that the measurement accuracy of this method reaches 0.2mm,the range reaches 3mm,and it can adapt to road surfaces with different water absorption properties,achieving similar measurement capabilities as advanced foreign equipment.It solves the problem of manual on-site calibration in existing methods and has good practical value.