Low Cost Positioning And Navigation System For Micro And Small Agricultural Machinery

The world’s population has grown dramatically,and the demand for food and agricultural products has more than doubled.Automation and unmanned agricultural machinery is the trend of the development of modern agriculture and the inevitable way to solve the pressure of demand.Location and navigation is one of the key technologies to realize automation and unmanned agricultural machinery.At present,there is an urgent need for high precision,stable and reliable low-cost positioning and navigation system for unmanned small and micro agricultural machinery,and the realization of such a system is still a problem to be solved.In order to solve the above problems,this paper conducts in-depth research on lowcost positioning and navigation system,including the design and construction of low-cost hardware platform,the integrated positioning and navigation algorithm based on multisensor data fusion,and the improved integrated positioning and navigation algorithm based on heading algorithm.The main tasks are as follows:Firstly,the hardware platform of integrated navigation system is designed and built.According to the principle of complementarity,after analyzing the advantages and disadvantages of various sensors,the inertial navigation module and the satellite navigation module are selected;from the original intention of this paper,the inexpensive inertial navigation module,the satellite navigation module and the corresponding calculation module are selected;each module is assembled,and the hardware platform of the system is built.Then the integrated navigation algorithm is analyzed and designed.According to Kalman filter principle,system model,measurement model and covariance matrix are designed,including GNSS and INS error model,dynamic coefficient matrix,process noise matrix and measurement matrix.Then the heading algorithm is proposed and the integrated navigation algorithm is improved.According to the motion characteristics of the carrier,the linear algorithm and the correlation algorithm are proposed;a new heading algorithm is constructed by combining the two algorithms,and the simulation results show that the algorithm works well;the output value of the heading algorithm is integrated into the combined algorithm as a new observation quantity;a new state vector is added,and the corresponding system equation,measurement equation and covariance moment are designed;and the dynamic system is updated and expanded.Number matrix,process noise matrix and measurement matrix are used to design an improved integrated positioning and navigation algorithm based on heading algorithm.Finally,the simulation experiment and on-board experiment are designed and implemented.With the help of open source simulation platform,the simulation experiment is carried out,and the field vehicle experiment is designed and executed.The experimental results show that the positioning accuracy reaches centimeter level,the attitude accuracy is less than 1 degree,and at least 95% of the estimated values are within three standard deviations.Especially for the improved integrated navigation algorithm,at least 95% of the estimated values are within three standard deviations,and the heading accuracy is at least several times higher than that of the original integrated navigation algorithm.It proves that the low-cost integrated navigation system designed in this paper has good effect and good performance.The navigation parameters are abundant,high precision and good stability,which are suitable for unmanned small and micro agricultural machinery.