Development Of Field Environmental Monitoring And Irrigation Control System Based On Internet Of Things

China is a big agricultural country,Since the agricultural Internet of Things has made great progress as a national strategic emerging industry,it is necessary to realize the refined,intelligent and scientific management of agricultural production through scientific and technological means,which is a necessary approach to promote China’s transition from traditional agriculture to modern agriculture,and is also an important means to achieve sustainable agricultural development.However,field environmental monitoring has the characteristics of wide monitoring area,long monitoring period and variable environmental factors.Most of the field environmental monitoring equipment put into use at this stage adopts multi-sensor node self-organizing network design,which has problems such as low real-time performance,poor stability,and single monitoring parameter,which cannot meet the needs of modern agriculture for accurate field environmental monitoring.Furthermore,the development of field irrigation control equipment for the complex environment in the wild is not much.Most of the equipments are designed for small-scale experimental fields,and these equipments have high equipment failure rates,poor stability,high maintenance costs,and poor reusability in the actual application scenarios of farmland,which seriously affect the user’s enthusiasm and result in key technology products cannot realize large-scale applications.In response to above problems,this paper deeply analyzes the domestic and international research progress in the field,and combines the Xi’an science and technology plan project “Smart Agricultural Technology Research-Orchard Information Dynamic Perception and Wireless Intelligent Control System Development,Project Number: 20180617YF05NC13(2)” and Shaanxi provincial department of education technology service local special project “Development and application of wireless intelligent water-saving irrigation system,Project Number: 18JC029”,to carry out research work on the key technologies of field environmental monitoring and irrigation control system based on agricultural internet of things.The main research work was as follows:1.Research on key technologies of agricultural internet of things.Analyze the development status of agricultural Internet of Things at home and abroad,and in-depth analysis of related technologies involved in the project requirements.Clarify the overall design and plan the software and hardware functions of the system.A multi-sensor two-level information calibration and fusion algorithm is proposed.The first level uses a software calibration algorithm to calibrate the sensor monitoring data,thereby improving the accuracy of the monitoring data.The second level considers the multi-sensor fusion complementarity from the regional scale.The multi-sensor adaptive weighted data fusion algorithm is used to achieve data fusion between sites,which reduces network redundant data transmission,decreases site energy consumption,and improves the robustness of the monitoring network.2.Hardware design of field environmental monitoring station and irrigation control system.The LoRa wireless communication module is designed with the SX1278 chip solution,which reduces the difficulty of subsequent system development through modular packaging.A field environmental monitoring station based on Modbus protocol was developed.The data acquisition multi-channel design can realize Multi-parameter monitoring such as air temperature,humidity,light intensity,soil temperature,moisture,conductivity,field wind speed,field wind direction and light radiation through a single station.The monitoring of parameters can also realize the independent configuration according to the application requirements.Furthermore,the LoRa communication technology is used to complete the hardware design of the irrigation controller node,the wireless repeater node and the handheld terminal of the field wireless irrigation control system.3.Software design of field environmental monitoring station and irrigation control system.Firstly,complete the transplantation of the Huawei LiteOS embedded operating system to realize multi-task scheduling and management of the field environmental monitoring station;Complete the embedded software design of the corresponding main control board,4G gateway node,LCD terminal display node,AES encrypted storage of the monitoring station.Secondly,detailed description of the workflow of each functional module of the irrigation control system.Thirdly,research on the Internet of Things cloud platform access protocol to realize the online release of monitoring data.4.The equipment function test was carried out in the Luo-Jialing double dwarf apple orchard in Qianxian County,Shaanxi Province.The test results show that the packet loss rate is 0.8% when the LoRa fixed point transmission is 5km,and the packet loss rate corresponding to the multi-hop transmission 10 km through the relay node is 1.4%.Furthermore,the application of field environmental monitoring station and wireless irrigation control system has achieved the technical requirements of the project in terms of stability,real-time and reliability.Finally,the multi-sensor two-level information calibration and fusion algorithm is tested.Taking the soil moisture and illumination intensity sensor as an example,by comparing with the sample data,the average relative error of the monitoring data after calibration using the least squares principle is 1.61% and 4.45%,respectively and the average relative error of the monitoring data after BP neural network calibration was 1.27% and 3.51%,respectively.The multi-sensor data fusion algorithm demonstrates good data fusion effects through the weight self-adaptation principle,improves the reliability and accuracy of the monitoring system,and meets the needs of field environmental monitoring.