Research On Key Technologies Of UAV-borne Millimeter-wave Obstacle Avoidance Radar Based On Broadband Chirp

UAVs have been widely used in military and civilian fields due to their low cost and strong maneuverability.In the military aspect,uavs play a huge role in battlefield reconnaissance and surveillance,positioning and shooting,damage and other aspects;in the civilian field,they have been applied in the inspection of high-voltage power grids.Inspection efficiency improves the safe operation capability of the line grid.It is also widely used in agricultural plant protection.However,in the above-mentioned application environment,drones are all flying at ultra-low altitude.Because the low-altitude flight environment is very complicated,solving the lowaltitude flight safety of drones has become a top priority.To this end,the dissertation conducts research on unmanned airborne obstacle avoidance radar technology based on linear frequency modulated continuous wave radar technology.The main research contents include:1.According to the requirements of the design task,based on the wideband LFM technology,a phase-locked LFM millimeter wave obstacle avoidance radar scheme is proposed.2.According to the technical requirements of the project,optimized the chirp source and completed the development of the chirp source.The technical requirements of the project were achieved through testing.3.Aiming at the shortcomings of the performance degradation of the OSVI-CFAR algorithm in a uniform environment,an improved method of the OSVI-CFAR algorithm is researched,so that it still exerts a good detection effect in a uniform environment.4.In order to improve the accuracy of radar ranging,a frequency estimation algorithm is researched,and simulation experiments are analyzed by computer.5.Based on the FPGA chip,the system design and implementation of the linear frequencymodulated millimeter-wave obstacle avoidance radar signal processing system are completed,which mainly include hardware circuits such as IF filter amplifier circuits,ADC circuits,and FPGA minimum systems;and FIR filters,improved OSVI-CFAR algorithms,and spectrum estimation And other FPGA implementations.6.Finally,the radar system is subjected to static experiments and external field drone mounting experiments.The experimental results show that the radar system can better meet the requirements of the UAV obstacle avoidance power line.