Signal Processing in FMCW Radar Range and Speed Measurements

• Main Authors: Lu, Hsiang-Pin, 呂向斌
• Other Authors: Chieng, Wei-Hua
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/62693517793269224555

博士 === 國立交通大學 === 機械工程系所 === 102 === The frequency modulated continuous wave (FMCW) radar is widely used in the industrial applications. However, in a specific application it requires a specific signal processing algorithm. In this research, two applications are focused, one is the high accuracy range measurement in a FMCW level gauge, and the other one is estimating vehicle speed and length using a side-looking single-radar Vehicle Detector (VD). Estimating the frequency of a single-tone signal is an essential problem in a FMCW level gauge. This research presents a frequency estimation algorithm called the gradient search method (GSM) using the derivative of discrete Fourier transform (DFT). The analytical boundaries of the proposed method for different signal-to-noise ratios in the conditions of with the rectangular window and with the Hann window are derived. This research compares the most appropriate algorithms available in the literature. Simulation and experimental results show that the proposed algorithm provides superior performance than previous methods. This research also presents a side-looking single-beam microwave vehicle detector system for estimating speed and length of multiple vehicles. The proposed vehicle detector system is equipped with a FMCW radar using a squint angle. The associated 2D range-Doppler Fourier processing can extract the range and speed information of each vehicle using a single-beam FMCW radar. The simulation and experimental results show accurate estimations of vehicle speed and length. The measurement errors of speed and length were approximately ±4 km/h and ±1 m respectively. The proposed method has excellent detection capability for small and slow moving targets, such as bikes and pedestrians, at speeds down to 5 km/h.