Research On Acoustic Positioning System For UAV In Specific Space

With the layout and promotion of the national military-civilian integration strategy,our national civilian UAV technology has developed rapidly and the market scale has been expanding.Especially in the industrial market,UAV has great commercial value and broad development prospects.At this stage,the flight operations of civilian UAV are realized by the professional operator's ground remote control,and professional UAV operators are costly to train and use.In some application scenarios where the position control requirements are high,it is difficult to meet the operation requirements by relying solely on human eye observation.Therefore,it is of great significance to realize the autonomous flight of civilian UAV.Positioning is the basis for the autonomous flight of the UAV.Due to the influence of battery life,volume and weight,the positioning and navigation system of the military UAV cannot be applied to the civilian UAV.In order to solve this problem,this paper designs an acousticbased UAV positioning system based on factors such as cost,power consumption,accuracy and robustness.The main research contents include:1.On the basis of sufficient comparison and analysis of several common ranging positioning algorithms,a synchronous TOA-based active ranging positioning scheme is adopted,and the function and performance indicators of the positioning scheme are analyzed.According to the requirements of the functional indicators,based on the ANT protocol,a wireless communication network with a UAV terminal as the main node and acoustic positioning base stations as slave nodes is established,which realizes the unicast of the UAV terminal to the acoustic positioning base station and the communication between the UAV terminal and the acoustic positioning base station;According to the requirements of performance indicators,applying the principle of phaselocked loop to multi-node clock synchronization,combined with the periodic single-point broadcasting feature of ANT protocol,a scheme based on microprocessor clock synchronous phase-locked loop is proposed.The experimental results show that the scheme can achieve microsecond synchronization accuracy,and the clock drift between multiple nodes is effectively compensated.2.Aiming at the propagation characteristics of acoustic signals and noise interference,the pulse compression technology is used to identify and detect sound waves.A large time-width bandwidth product HFM signal that satisfies the pulse compression requirement and is insensitive to the Doppler effect is selected as the positioning signal,and the HFM signal is subjected to pulse compression simulation analysis in MATLAB.The multi-node synchronous ranging scheme is designed by using the constructed synchronous clock and the unicast function of the UAV terminal.3.The hardware structure of the UAV terminal and the acoustic positioning base station positioning component is designed,and the system clock synchronization and ranging positioning process are formulated.Ranging and positioning experiments in quiet and noisy environments.The results show that the positioning system can provide stable high-precision ranging positioning in a specific space,and the average positioning RMSE in noisy environment is about 10 cm.The acoustic-based UAV positioning system studied in this subject achieves stable and high-precision ranging positioning without excessive hardware support.It has certain reference value for the research on navigation of civilian UAVs.In addition,the system has low cost and strong portability,and can be used for reference in indoor positioning.