| Nowadays,China is experiencing the transformation from traditional agriculture to intelligent agriculture.In order to realize intelligent,precise and scientific management of agriculture production,it is necessary to monitor various agriculture-related factors in a real-time,precise and effective way.Thus,the study and application of agricultural Internet of Things(IoT)monitoring system is of great significance.As an important supporting technology of agricultural Io T,the wireless sensor network(WSN)is the key to sensing and transmitting agricultural-related data.However,due to the huge volume of data collection,the complexity of the transmission paths,the ubiquity of environmental noises,and the rigorous constraint on nodes' energy and computation capacities,it is an important issue to ensure the effective,stable and durable functioning of WSN.Therefore,two algorithms are applied in this thesis to fuse the data in WSN,i.e.,LEACH based network data aggregation algorithm,and Kalman filter based node data fusion algorithm.The former algorithm is able to reduce the energy dissipation of nodes and prolong the system lifetime,while the latter helps to reduce the interference of environmental noises with the sensed data and thus improve the data accuracy.Furthermore,based on above data fusion algorithms,hardware and software designs of the agricultural IoT monitoring system are provided,and the effectiveness of the data fusion algorithms is simulated and analyzed.The main contents are as follows.(1)The research and application status of domestic and foreign agricultural IoT are investigated,and the basic model architecture and key technologies of agricultural IoT are systematically combed.(2)The ZigBee based WSN of agricultural IoT is introduced,the significance of data fusion in WSN is described,and the relevant data fusion algorithms are compared and selected.(3)Hardware designs of the agricultural IoT monitoring system are provided,including the designs of the overall hardware architecture,the master circuit,the wireless communication module circuit,four types of sensors'(i.e.,temperature and humidity sensor,light intensity sensor,carbon dioxide sensor,and soil moisture sensor)circuits,and power circuit.(4)Software designs of the agricultural Io T monitoring system are provided,including the designs of the ZigBee based WSN,the work flows of all nodes,and the work flows of two data fusion algorithms(i.e.,LEACH based network data aggregation algorithm,and Kalman filter based node data fusion algorithm).(5)The effectiveness of the above two data fusion algorithms is simulated and analyzed in terms of reducing energy consumption of WSN nodes and improving data accuracy. |
