Research And Design Of Combined Positioning System In Agricultural Machinery Navigation

The realization of automatic driving of agricultural machinery in the future requires an accurate and reliable navigation and positioning system as a guarantee.Urban vehicles use GNSS(Global Navigation Satellite System)-INS(Inertial Navigation System)positioning system for positioning.When GNSS fails,INS is used to assist positioning,and the results can be corrected through accurate route maps.However,the environment of agricultural machinery cannot Perform matching correction on the route.For the positioning of agricultural machinery,the most common way is to use GNSS-RTK(Carrier Phase Differential Technology)technology.Although it has high accuracy and wide application,a set of GNSS-RTK equipment is expensive,and the cost of early base station construction and later maintenance is greatly limited.Its promotion and application in agricultural machinery.In precision agriculture,a large number of sensors will be laid in the farmland to collect agricultural production data,and then the collected information will be transmitted in real time through WSN(Wireless Sensor Network).The innovation of this paper is to use GNSS-INS traditional positioning combined with WSN positioning in precision agriculture,and finally realize the GNSSS-INS-WSN combined positioning system and conduct system testing.The main content of the article completion includes:First,introduce the research background and significance of this paper,and analyze the research overview of related fields at home and abroad,such as agricultural machinery positioning,combined positioning,etc.by consulting the literature,and the practice and research of positioning based on GNSS-RTK,GNSS-INS,and INS-WSN Make a summary.Second,analyze several commonly used positioning technologies,including GNSS positioning principles,INS positioning principles,and WSN positioning principles;among them,differential positioning is used in GNSS,and INS focuses on the coordinate system used in the calculation process and the relationship between the coordinate system.Conversion formula;the Zigbee protocol and Zigbee networking introduced in WSN positioning provide a theoretical basis for subsequent system design;analyze the positioning technology based on distance measurement in the WSN positioning technology,and the positioning technology that does not require ranging,and the related solution coordinates algorithm.Third,comparing the positioning technologies of WSN,we propose to use the RSSI(Received Signal Strength Indication)based ranging method in this paper to construct a wireless channel propagation model similar to that in the farmland environment that has the influence of obstacles.The Gaussian filter is used to affect the RSSI.Numerical optimization is performed to fit the values ??of variable parameters A and n affected by the environment;research GNSS-INS fusion algorithm,WSN-INS fusion algorithm,GNSS-INS-WSN fusion algorithm,and use collected data for simulation.The simulation experiment shows that the combined positioning technology after fusion has better accuracy and reliability than the single positioning technology.Fourth,analyze and design the hardware of the GNSS-INS-WSN combined positioning system,including the introduction of the selected hardware and the design of each sub-module.The final field measurement results show that GNSS-INS-WSN combined positioning is more accurate and stable than GPS-INS and WSN single positioning technology.Finally,in the summary and outlook,first summarized this article,then thought about the problems in the content of this article,and made an outlook for the future high-tech agricultural machinery technology.