Research On Coherent Microwave Vehicle Detector

With the increase of urban population and Car Parc, traffic jam has become a major issue in urban. It is an important means to solve the traffic jam that using intelligent transportation system to analyze, predict the traffic conditions and employ the optimal traffic controlling strategy. Microwave Vehicle Detector is an important infrastructure in intelligent transportation because of its characteristics.Numbers of traffic predict model need velocity information. Most of the existing vehicle detectors on the market are not able to measure velocity. This dissertation starts from the waveform of vehicle detector. Four signal processing algorithms are studied and compared. Algorithm verification system is developed and the experiment is carried out after signal processing algorithms are selected. The major works include:1. Study the waveform of the Microwave Vehicle Detector.Waveforms, the installation strategy and the signal processing algorithms of the vehicle detectors which are able to measure velocity, are compared. And then the waveform and installation method are selected in my project. The distance-Doppler coupling phenomenon and the multi-objective matching problem of LFMCW signal are analyzed. Finally, coherent LFMCW signal is selected as the transmit signal.2. Study the signal processing algorithm of coherent Microwave Vehicle Detector.The fixed waveform transform algorithm, the dynamic waveform transform algorithm and 2D-FFT algorithm , Keystone transform algorithm are studied according to the difference of frequency and difference of phase among beat signals in different periods respectively. The computer simulation of the corresponding algorithm is carried out to verify the effect of the algorithm. Those algorithms are compared in computational complexity, robustness, hardware requirement and the resolution.2D-FFT is selected as the signal processing method of coherent Microwave Vehicle Detector.3. Develop the experimental prototype.Appropriate parameters are selected to the development of experimental prototype.This dissertation analyzes the reason of leakage of triangular wave and gives the design of key modules.4. Carry out experiments to verify the effectiveness of the signal processing method.Carry out experiments, sample data. The effectiveness of the 2D-FFT algorithm velocity and distance measurement is verified. According to the experimental results, a method of vehicle detection is proposed to avoid the possibility of repeated detection in practical application.