Target Parameter Estimation Based On LFMCW Millimeter-Wave Radar

With the rapid development of China's socialist economy and the improvement of people's consumption ability,cars have become the main means of daily travel,and the safe and intelligent driving experience has attracted the attention of consumers.Compared with ultrasonic radar,lidar and other traditional radars,millimeter wave radar is small and has high azimuth resolution and strong anti-jamming ability,it's widely used in advanced driver assistance system(ADAS),unmanned driving and other fields.Due to the limitation of radar size,automotive radar often adopts time division multiplexing multiple input multiple output(TDM-MIMO)linear frequency modulated continuous wave(LFMCW)radar system,which has the advantages of simple structure,strong clutter suppression ability and no blind area.In this paper,target parameter estimation for LFMCW millimeter wave radar is studied based on the daily vehicle driving environment.Firstly,the influence of radar hardware parameters on detection performance is studied,and the target parameter estimation methods of triangular LFMCW radar and sawtooth LFMCW radar are derived in detail.There is a problem of multi-target pairing when estimating target parameters for triangular wave LFMCW radar.In this paper,sawtooth wave is selected as radar transmitting waveform,and the resolution performance of sawtooth wave transmitting signal is studied using ambiguity function.Secondly,the problem of velocity ambiguity is studied,and two kinds of algorithms are given.By transmitting multiple sawtooth signals with different periods,the velocity ambiguity resolution algorithm based on the remainder theorem calculates the actual velocity of the target by using multiple ambiguous velocity.The velocity ambiguity resolution algorithm based on phase offset compensation takes advantage of the fact that Doppler phase offset need to be compensated for part of virtual channels before azimuth estimation in TDM-MIMO radar,which can double the unambiguous velocity range.The simulation results show that the two algorithms can effectively resolve the ambiguity and accurately estimate the target speed.Finally,by analyzing the principle of Extended Kalman Filter(EKF)and establishing the target motion model and radar observation model.The lateral velocity estimation algorithm based on EKF is proposed.Simulation results show that the algorithm can converge quickly and estimate the lateral velocity accurately.