Research on Expressway Vehicle Ranging and Speed Measurement Based on High Resolution Synthetic Aperture Radar Images
At present,the distance and speed measurement methods for vehicles on expressways are affected by various factors.Under different weather,lighting,and road conditions,the measurement results may be unstable,the environmental adaptability may be poor,and the measurement accuracy may not be high enough.Therefore,this article introduces synthetic aperture radar to obtain high-resolution images,which can avoid the limitations of weather and lighting conditions,extract vehicle features and motion information from radar images,and accurately measure the distance and speed of vehicles.Firstly,InSAR(Interferometric Synthetic Aperture Radar)is used to transmit radar signals to target vehicles multiple times at high altitudes,collect vehicle images,avoid weather,lighting,and road influences,and improve environmental adaptability;secondly,the joint pixel method is used to remove noise from the radar image and obtain high-resolution radar images.Then,the least squares method is used to construct the distance measurement objective function for expressway vehicles,and the distance between the vehicle and the satellite is obtained by solving this function.Based on the slant range error of the satellite antenna vehicle imaging,the distance between different vehicles and the satellite is determined,thereby obtaining the distance between vehicles;finally,the covariance matrix of vehicles in radar images is used to replace the interference phase in the interferometric speed measurement along the trajectory,achieving more accurate speed measurement of vehicles on expressways.The experimental results show that the radar speed measurement results of vehicle number 1 are consistent with those of the expressway speed measurement results,with a speed error of 0.The speed error of vehicle number 4 is 1 km/h;the measurement results of this method are highly consistent with the actual speed measurement results on expressways.This indicates that the method proposed in this article can accurately measure speed;under clear weather conditions,the distance measurement accuracy of our method reaches 100％.However,for rainy,foggy,and nighttime conditions,the distance measurement accuracy of our method still exceeds 99.6％,indicating that our method has high distance measurement accuracy and strong adaptability to the environment.This demonstrates the effectiveness of our method.
synthetic aperture radarexpresswayvehicle speed measurementdata reconstructioncovariance matrixsatellite slant range
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