Abstract:

Micro-environment of a tree canopy is a key factor influencing fruit quality and yield. WSN system can be used to achieve real-time and automatic monitoring. All nodes have the same equal status in traditional WSN system, while in a fruit tree canopy, it is redundancy that all nodes have sensing, managing and data transmission capability. The high-density nodes with the same equal status makes the WSN lack of reasonable architecture and levels, thus have low performance. To develop a WSN system for fruit tree canopy micro-environments monitoring, the traditional WSN was split, recombined, and a master-slave WSN system with segmentation of sensing ability was proposed. Each canopy was monitored by one sub-system which was composed of one master node and some slave nodes. The slave nodes were in charge of sensing information, and the master node took charge of managing the slave nodes and communicating with the other master nodes to transmit data. To evaluate the performance of the new system, the hardware and software were designed, and contrast experiments were performed. The results showed that the new system doubled the life cycle, and was more effective and energy saving. At present, it is suitable for micro-environment monitoring of fruit canopies.

Key words: fruit tree canopy, WSN, micro-environment, system framework

摘要：

果树冠层微环境是影响果树结果质量与产量的重要因素，无线传感器网络（WSN）能实现对果树冠层微气候的自动实时监测。传统WSN中所有的节点具有同样平等的地位，而在体积较小的果树冠层内，所有节点都具有信息感知、处理及传输功能是冗余的。高密度的具有平等地位的节点使得WSN系统缺乏合理的架构和层次，性能较低。针对此问题，将传统WSN系统架构进行拆分和重组，提出了一种传感功能分割的主从式WSN系统。每个果树冠层由1个子系统监测，每个子系统由1个主节点和多个从节点组成。从节点主要负责信息感知，主节点负责控制管理从节点并和其他主节点组网进行信息传输。提出了主从式WSN系统的软硬件设计方案，并进行了评估新系统性能的对比实验。实验结果表明，主从式WSN系统较传统WSN系统生命周期延长了约一倍，更加高效节能，适合目前果园冠层微环境监测的应用现状。

关键词: 果树冠层, 无线传感器网络, 微环境, 系统框架