Radar Research On Power Line Recognition Of Millimeter Wave Radar

With the continuous development of aviation industry,helicopters and other low-altitude aircraft are more and more widely used.However,due to the existence of obstacles such as power lines,the safety of pilots in low altitude flight is threatened.Therefore,the research of helicopter low altitude anti-collision radar has become the focus of attention,especially for the detection of high-risk targets such as power lines.Millimeter wave radar has many advantages,such as high range resolution,strong anti-jamming ability,small size,good weather and environment adaptability,and can work all-weather.It has great market potential in helicopter anti-collision field.In this thesis,the backscattering of power line and power line frame in the frequency band of 34 GHz is deeply studied,and the micro-Doppler characteristics of power line are modeled and analyzed.The application of Hough transform,phase correlation,Merlin transform and pattern recognition methods in power line and power line frame detection and recognition is studied.The main contents of the thesis can be summarized as follows:1.The data pre-processing algorithms of millimeter wave radar used in helicopter collision avoidance are analyzed and compared.The sidelobe of echo is suppressed by pulse compression and windowing,and the signal-to-clutter ratio of echo is improved by coherent accumulation.E-CFAR processing method is adopted to detect the target,which ensures the detection effect of power line.2.The detected power line frame is used to reconstruct the pre-processed radar echo image,and the Hough transform method is used to detect the power line.The results show that the Hough transform method based on image reconstruction has better false alarm control ability than the Kalman tracking method.3.The Bragg scattering characteristics of power line in single or multiple cases are simulated and analyzed to verify the reliability of the Bragg scattering characteristics of power line;the physical structure of power line frame is analyzed and the RCS simulation model of power line frame is established;the micro-Doppler characteristics of power lines are modeled,and the estimation method of micro-Doppler parameters of power lines based on the model is studied in depth,which provides a new reference for the detection and identification of power lines.4.The application of Hough transform and random Hough transform in power line micro-Doppler feature recognition and detection is simulated and validated.Both methods can estimate the micro-Doppler parameters of power line very well.In this thesis,the scattering feature extraction method of power line is studied in depth,and a classification algorithm based on the Bragg scattering feature and phase ratio feature of power line is proposed,which improves the recognition effect of power line.The phase correlation algorithm,Fourier Mellin transform and other methods for power line frame recognition are studied,and some results are achieved.