Research On INS/GPS Integrated Navigation Algorithm For Crab-cultivating Vessel

Crab meat is a delicious,nutritious,and medicinally valuable food,which is popular in China.Chinese crab cultivation industry has developed on an industrial scale,with yield of 800,000 tons/year.With the development of e-commerce and logistics industries,market demand has grown stronger than ever and the scale of the industry continues to expand.However,the cultivation is still in the traditional breeding method with fixed-point feeding and fixed-point buoy monitoring,which is time-consuming and labor-intensive.Moreover,uneven feeding methods can contribute to poor monitoring of water quality in crab ponds.To improve the level of automation and intelligence in crab farming,deriving scientific crab cultivation and to link up with the “Made in China 2025”,the precise navigation of crab cultivation vessel has been carried out.This work has been completed under the support of the “National Twelfth Five-Year plan” Support Project: Traceability and Supervision System of Aquatic Products Processing Industry Chain(2015BAD17B).Taking the crab cultivation work vessel as the research object and the INS/GPS coupling structure and data fusion algorithms as research contents,the works are as follows:The classical Kalman filter cannot adjust the parameters according to the disturbance,which may cause the deviation or even the dispersion of the filter.To solve the problem,an improved AKF-based data fusion algorithm is proposed based on the INS/GPS loosely coupling model and the INS/GPS tightly coupling model.Firstly,forgetting factors are designed according to statistical information of observed errors.Secondly,the system noise covariance matrix is updated based on the forgetting factors.Lastly,the Kalman filter gain is adjusted to eliminate the filter error.Simulation results indicate that the INS/GPS tightly coupling model based on the proposed improved AKF data fusion algorithm has a stable error curve and high navigation accuracy.Based on the designed mechanical and motion control system structure,a crab vessel has been developed which contains navigation module,motion module,feeding module and water quality monitoring module etc.In the integrated navigation system,the GR87 GPS module,the electronic compass system LSM303 D and the three-axis gyroscope L3GD20 are used to collect navigation information.Furthermore,the STM32F103ZET6 is adopted as the navigation data processing tool,and the double closed-loop PID algorithm is used for navigation direction and speed.According to the control unit,the motion module adopts the rotation of the paddlewheel at different speeds to adjust the navigation direction.The KF-based loosely coupling mode,the EKF-based tightly coupling mode and the proposed AKF-based tightly coupling mode data fusion algorithms are compared in the experiment.The results show that the actual navigation path based on the proposed AKF-based tightly coupled mode data fusion algorithm is the closest to the set navigation path designed by the GIS-based navigation path planning system.Moreover,the horizontal navigation error is less than 1 meter,which satisfies the navigation requirements of crab-cultivating vessel.