信号采样理论在交通流检测点布设中的应用

在对交通流检测点布设领域研究应用现状进行分析与抽象的基础上,提出交通流检测点布设本质上属于空间交通流信号采样问题。依据信号采样理论,建立了确定检测点间距或密度的方法与流程,该流程包括空间交通流信号产生、离散傅里叶变换、频谱分析、间距确定、误差分析5个步骤。对高速公路拥挤状态下的仿真分析表明:100 m的检测点间距可以满足对拥挤交通流状态的真实检测,该数值接近于实际应用中的最小值(125 m),说明该理论方法具有较好的实用性。

Application of Signal Sampling Theory on Traffic Flow Detector Layout

Based on analysis and abstract of application status in the field of traffic flow detector layout,the problem that essence of traffic flow detector layout belonged to space traffic flow signal sampling was presented.The method and procedure determing interval and density of detector were developed according to the signal sampling theory,which included spatial traffic flow signal production,discrete Fourier transition(DFT),spectrum analysis,interval decision and error analysis.Taking a typical congested freeway as the case study,the simulated result shows that the detector interval of 100 m is enough to detect the true congested traffic flow condition.The value is close to the minimum detector interval(125 m) which demonstrates the practicability of signal sampling theory.