Research On The Positioning And Precision Optimization Method Of Agricultural Machinery BeiDou Based On Wavelet Transform

Applying the Beidou positioning system independently developed by China to replace the global positioning system on agricultural machinery to achieve precision agriculture is an effective measure to ensure the safety of agricultural production informatization in China.At present,a large number of domestic agricultural machines use GPS navigation and the positioning accuracy is low,and high-precision RTK instruments cannot be popularized due to their high cost.Based on this,this paper conducts research on the positioning of agricultural machinery Beidou and its accuracy optimization method based on wavelet transform algorithm at low cost,and innovatively proposes a combined evaluation index to streamline and optimize the process of wavelet transform algorithm and improve the positioning accuracy of wavelet transform algorithm to Beidou The optimized speed solves the problem that agricultural machinery can generally use low-cost Beidou positioning modules for refined operations.The specific work of this article is as follows:(1)An experiment of denoising processing of Beidou positioning data by wavelet transform algorithm under static conditions was carried out.Denoising the collected field data of agricultural machinery field Beidou through wavelet transform algorithm,using Haar,Daubechies,Biorthogonal,Coiflets,Symlet five commonly used wavelet systems as the optimal wavelet base selection samples,respectively,the optimal decomposition layer selection experiment was conducted,and finally It is concluded that the wavelet denoising effect based on sym8 wavelet base is the best under four-layer decomposition.(2)Innovatively constructed a combined evaluation index to optimize the evaluation method of optimal wavelet base and decomposition layers in the process of wavelet parameter selection.The standard deviation coefficient method is used to combine the three different evaluation indicators of root mean square error,smoothness and signal-to-noise ratio.A combined evaluation indicator is designed to select the optimal wavelet base and the number of decomposition layers at the same time.The sym8 wavelet base below has the best denoising effect on static Beidou positioning data.Compared with the single evaluation index selection method,this method optimizes the parameter selection process and improves the denoising rate of the Beidou positioning data by the wavelet transform algorithm.(3)The precision optimization experiment under dynamic conditions was carried out.Two sensitivity factors,which mainly affect the positioning accuracy of the field Beidou and the field shelter index,were selected for experimental analysis.The positioning accuracy obtainedunder the optimal index conditions was compared with the precision RTK positioning instrument..The agricultural machinery with three movement speeds of 5km/h,10km/h and15km/h is used to collect dynamic positioning data in the field at a sampling frequency of 0.5s,and the sym8 wavelet base under the optimal 4-layer decomposition is used to perform wavelet transformation on the dynamic positioning data.Experiments show that the positioning accuracy after de-noising at a driving speed of 5km/h is 52cm-61 cm,which is about 95.41% higher than the original positioning accuracy.At the same time,at a speed of5km/h,the agricultural machinery was tested on three fields with different heights of shelters,such as the field without crops,the broad bean seedling field of about 60 cm,and the rape field of about 120 cm,to obtain Beidou positioning data and carry out Wavelet denoising process,the final positioning accuracy in the field without crops is 52cm-63 cm,which is about 95.54% higher than the original positioning accuracy.Finally,the accuracy comparison experiment between the positioning data under the optimal index conditions and the data collected by the accurate RTK positioning instrument is performed.The experiment shows that the positioning accuracy of the precision RTK is about 76.72% higher than that of the general Beidou positioning module,but it is higher in cost than the general Beidou.The positioning module is nearly a hundred times.Therefore,at low cost,the research on the positioning of agricultural machinery Beidou and its accuracy optimization method based on wavelet transform algorithm is more popular.