Research On Autonomous Navigation Of Unmanned Ship For Water Quality Monitoring And Its System Development

The protection of water resources is related to the long-term development of the country and the health of the people.Because of the complicated causes of water pollution,the dynamic monitoring of water quality information in the scattered waters of our country is a hot field at present.At present,the main way of water quality monitoring is general manual monitoring or setting fixed monitoring points,and the monitoring is mainly concentrated in a large area of water area,while the frequency of small water area monitoring is not enough,the cost is high,at the same time,the flexibility,accuracy and timeliness of monitoring are not effectively guaranteed.In order to solve this problem,it is of great significance to study a low-cost unmanned navigation system which can be used in small water quality monitoring.In order to be convenient,practical,low-cost and easy to realize,this dissertation constructs a low-cost unmanned ship integrated navigation system for water quality monitoring in small waters.This paper reasonably optimizes the construction mode of GPS/INS integrated navigation system based on Kalman filter,reduces the complexity of GPS/INS integrated navigation in small water areas and improves the real-time performance of the navigation system on the premise of ensuring navigation accuracy.In the software design process,the feasibility of the optimized GPS/INS Kalman integrated mode is verified through system simulation,which provides a theoretical basis for software implementation.The text proposes a coordinate conversion algorithm based on quadratic Gaussian-Crueger algorithm,which is closer to the actual application,reduces the complexity of the implementation,and also improves the response speed of the navigation system.On the basis of satisfying the performance,this paper selects the appropriate core processing chip to reduce the hardware cost of unmanned ship navigation system and better meet the actual needs.The overall scheme design is that GPS/INS is used to realize integrated navigation,quaternion method is used to carry out complementary filtering to improve the solution accuracy,greedy algorithm-based optimal proximity strategy is used for path planning,and PID is used for control method..In this dissertation,based on theoretical research,the design and implementation of the system are completed.In terms of hardware system,STM32 series embedded chip is selected as the main controller,common single-point GPS,magnetometer module and IMU module are selected to obtain attitude information,and double motors and double propellers are selected for the hull.Hardware design is simple,components are easy to obtain,and the overall price is low.In terms of software system,according to the needs of unmanned ship design,the unmanned ship navigation control system software is written in C language,mainly including attitude solution operator program,inertial navigation position and velocity solution operator program,integrated navigation subprogram,path planning subprogram and navigation control program.Software design is easy to implement because of the optimization of theory.In this dissertation,a systematic experiment has been completed in an artificial lake.Through the coordinate conversion precision test,the positioning precision of the monitoring points in the plane coordinate system is verified.Through the optimal path planning test of water quality monitoring points,unmanned ships can obtain the shortest navigation path between monitoring points,which verifies the effectiveness of the path planning algorithm.Through the course and speed experiments,the effectiveness of the unmanned ship’s motion control strategy is verified.Through the traversal test of the water quality monitoring points of the system,the operation track of the unmanned ship is obtained,which verifies the feasibility of the overall scheme of the system and the effectiveness of the software and hardware realization of the system,and realizes the expected design goal of the development of the autonomous navigation system suitable for small water areas and low-cost water quality monitoring unmanned ships.